JP6988168B2 - Printing equipment - Google Patents

Description

The present invention relates to a printing apparatus.

In the printer of Patent Document 1, immediately before printing on the recording paper, the inkjet head is moved to a flushing position facing the flushing receiver to perform flushing (pre-print flushing). In the printer of Patent Document 2, during printing, the inkjet head is moved to a flushing position facing the cap to perform flushing (flushing during printing).

Japanese Unexamined Patent Publication No. 2016-175361 JP-A-2015-157376

In recent years, printers such as Patent Documents 1 and 2 are required to reduce the time required for flushing. If the pre-print flushing in Patent Document 1 takes a long time, the FPOT (First Print Out Time), which is the time from the input of the print command to the completion of printing on the first printing sheet, becomes long. .. Further, in Patent Document 2, if flushing during printing takes a long time, the throughput of the entire printing is lowered. However, if the number of times the ink is ejected during flushing is reduced in order to shorten the time required for pre-printing flushing and flushing during printing, the thickening of the ink in the nozzle is not sufficiently eliminated, and the ink ejection abnormality during printing occurs. It may be a factor.

An object of the present invention is to provide a liquid discharge device capable of sufficiently eliminating the thickening of the liquid in the nozzle and shortening the time required for flushing as much as possible.

The printing device according to the present invention includes a transport device that transports a recording medium in a transport direction, and a liquid discharge head in which a plurality of nozzles are arranged in the transport direction to form a nozzle row and discharge liquid from the plurality of nozzles. A head moving device that moves the liquid discharge head in a scanning direction that intersects the transport direction, a liquid receiver that is located outside the scanning direction of the transport path to which the recorded medium is transported, and a transport path. A control device that decelerates and moves the liquid discharge head in one direction away from the transport path and accelerates and moves in the other direction approaching the transport path by the head moving device outside the scanning direction. The liquid discharge head has a first nozzle row for discharging the first liquid and a second nozzle row for discharging the second liquid, and the control device uses the liquid discharge head as the liquid. Of the flushing that ejects liquid from the nozzle to the liquid receiver facing the receiver, when performing pre-print flushing that is performed before printing, the liquid receiver waits for the liquid discharge head across the transport path. When it is arranged on the opposite side of the standby position, it is the time from the start to the completion of discharge to the liquid receiver at least during deceleration and acceleration of the liquid discharge head. The nozzle is decelerated and moved in one direction at an acceleration set by a flushing time determined by the product of the drive cycle of the liquid discharge head and the number of shots according to the discharged liquid. When the liquid is discharged from the liquid receiver toward the liquid receiver, and the liquid receiver and the standby position are arranged on the same side with respect to the transport path, the liquid discharge head is decelerated or accelerated. in at least during acceleration, an acceleration set by the flushing time, while moving in the other direction by accelerating the liquid discharge head, the liquid ejected toward from the nozzle receiving the liquid, when performing the flushing When the liquid discharge head is moved at the acceleration set based on the longest flushing time among the plurality of flushing times according to the type of each liquid and the pre-printing flushing is performed, the first nozzle is used. The liquid discharge head is moved until the row and the second nozzle row are on the opposite side of the standby position with respect to the liquid receiver, and the liquid receiver is on the opposite side of the standby position across the transport path. When arranged, the first nozzle is located outside the transport path on the liquid receiving side. When the row is located closer to the transport path than the second nozzle row and the liquid receiver and the standby position are located on the same side of the transport path, the liquid receiver side said. Outside the transport path, the first nozzle row is located closer to the transport path than the second nozzle row.
Further, the printing device according to the present invention includes a transport device that transports the recording medium in the transport direction, and a liquid discharge device in which a plurality of nozzles are arranged in the transport direction to form a nozzle row and discharge liquid from the plurality of nozzles. A head, a head moving device that moves the liquid discharge head in a scanning direction intersecting the transport direction, a liquid receiver located outside the scanning direction of the transport path to which the recorded medium is transported, and the transport path. Control that the head moving device decelerates and moves the liquid discharge head in one direction away from the transport path, and accelerates and moves in the other direction approaching the transport path. The control device comprises a device, and the control device performs pre-print flushing performed before printing among flushing in which the liquid discharge head faces the liquid receiver and discharges liquid from the nozzle to the liquid receiver. When the liquid receiver is arranged on the opposite side of the standby position of the liquid discharge head across the transport path, at least during deceleration and acceleration of the liquid discharge head, the liquid discharge head is decelerated. The time from the start to the completion of discharge to the liquid receiver, which is the acceleration set by the flushing time determined by the product of the drive cycle of the liquid discharge head and the number of shots according to the discharged liquid. While decelerating the liquid discharge head and moving in the one direction, the liquid is discharged from the nozzle toward the liquid receiver, and the liquid receiver and the standby position are arranged on the same side with respect to the transport path. If so, at least during deceleration and acceleration of the liquid discharge head, the liquid discharge head is accelerated at the acceleration set by the flushing time and moved in the other direction. When the liquid is discharged from the nozzle toward the liquid receiver and the flushing is performed, the liquid discharge head is ejected at an acceleration set based on the flushing time both during deceleration and acceleration of the liquid discharge head. When the liquid is discharged from the nozzle while decelerating or accelerating and the liquid receiver is arranged on the opposite side of the standby position across the transport path, the liquid discharge head is driven during the deceleration. When the cycle is made longer than that at the time of acceleration and the liquid receiving and the standby positions are arranged on the same side with respect to the transport path, the driving cycle of the liquid discharge head at the time of accelerating is decelerated. Make it longer than sometimes.
Further, the printing device according to the present invention includes a transport device that transports the recording medium in the transport direction, and a liquid discharge device in which a plurality of nozzles are arranged in the transport direction to form a nozzle row and discharge liquid from the plurality of nozzles. A head, a head moving device that moves the liquid discharge head in a scanning direction intersecting the transport direction, a liquid receiver located outside the scanning direction of the transport path to which the recorded medium is transported, and the transport path. Control that the head moving device decelerates and moves the liquid discharge head in one direction away from the transport path, and accelerates and moves in the other direction approaching the transport path. The control device comprises a device, and the control device faces the liquid receiving head to perform pre-printing flushing, which is performed before printing, among flushing in which the liquid is discharged from the nozzle to the liquid receiving. When the liquid receiver is arranged on the opposite side of the standby position of the liquid discharge head across the transport path, at least during deceleration and acceleration of the liquid discharge head, The time from the start to the completion of discharge to the liquid receiver, which is the acceleration set by the flushing time determined by the product of the drive cycle of the liquid discharge head and the number of shots according to the discharged liquid. While decelerating the liquid discharge head and moving in the one direction, the liquid is discharged from the nozzle toward the liquid receiver, and the liquid receiver and the standby position are arranged on the same side with respect to the transport path. If so, the liquid discharge head is accelerated and moved in the other direction at the acceleration set by the flushing time at least during deceleration and acceleration of the liquid discharge head. Liquid is discharged from the nozzle toward the liquid receiver, and in the flushing, the nozzle row is moved to the side opposite to the transport path with respect to the liquid receiver, and the nozzle row is opposite to the transport path with respect to the liquid receiver. When located at, the liquid discharge head is driven so that the liquid in the nozzle belonging to the nozzle row vibrates without being discharged.

Further, the printing device of the present invention includes a transport device that transports the recording medium in the transport direction, and a liquid discharge head in which a plurality of nozzles are arranged in the transport direction to form a nozzle row and discharge liquid from the plurality of nozzles. The head moving device that moves the liquid discharge head in the scanning direction orthogonal to the transport direction, and the liquid discharge head that is outside the scan direction of the transport path to which the recorded medium is transported and stands by. The liquid receiver located on the opposite side of the standby position and the transport path, and the head moving device on the opposite side of the standby position and the transport path decelerate the liquid discharge head in one direction away from the transport path. The control device comprises a control device that moves and accelerates and moves in another direction approaching the transport path, and the control device faces the liquid discharge head to the liquid receiver and moves from the nozzle to the liquid receiver. Of the flushing for discharging liquid, when performing pre-print flushing performed before printing, the liquid discharge head starts decelerating from a position facing the transport path toward the liquid receiver and discharges the liquid. When the head faces the liquid receiver, the liquid discharge head is decelerated in the one direction at an acceleration set by the flushing time required from the start to the completion of the discharge of the liquid to the liquid receiver. While moving, the liquid is discharged from the nozzle toward the liquid receiver.

According to the present invention, in order to discharge the liquid from the nozzle to the liquid receiver at least one of the deceleration and acceleration of the liquid discharge head in flushing, the liquid discharge head is stopped at a position facing the liquid receiver and then to the liquid receiver. It is possible to shorten the time required for flushing as compared with the case of starting the discharge of the liquid. Further, in the present invention, at this time, the liquid discharge head is decelerated or accelerated by the acceleration set by the flushing time required from the start to the completion of the discharge of the liquid to the liquid receiver. Therefore, flushing can sufficiently eliminate the thickening of the liquid in the nozzle.

It is a schematic block diagram of the printer which concerns on 1st Embodiment. It is a block diagram which shows the electric structure of a printer. It is a flowchart which shows the flow of processing by a control device at the time of printing. (A) is a diagram for explaining the speed of the carriage at the time of flushing before printing, (b) is a diagram for explaining the position P1 of (a), and (c) is a diagram for explaining the position P1 of (a). It is a figure for explaining the position P2, (d) is a figure for explaining the position P3 of (a), (e) is a figure for explaining the position P4 of (a), and ( f) is a diagram for explaining the position P5 of (a), (g) is a diagram for explaining the position P6 of (a), and (h) is a diagram for explaining the position P7 of (a). It is a figure for. (A) is a diagram for explaining the drive cycle, the number of shots and the flushing time when the carriage is decelerated in the pre-print flushing, and (b) is the drive cycle, the number of shots and the number of shots when the carriage is accelerated in the pre-print flushing. It is a figure for demonstrating the flushing time. (A) is a diagram for explaining the speed of the carriage during flushing during printing, and (b) is a diagram for explaining the position P8 of (a). (A) is a diagram for explaining the drive cycle, the number of shots, and the flushing time during deceleration of the carriage in flushing during printing, and (b) is the drive cycle, the number of shots, and the number of shots during acceleration of the carriage in flushing during printing. It is a figure for demonstrating the flushing time. It is a schematic block diagram of the printer which concerns on 2nd Embodiment. (A) is a diagram for explaining the speed of the carriage at the time of flushing before printing according to the second embodiment, and (b) is a diagram for explaining the position P11 of (a), (c). ) Is a diagram for explaining the position P12 of (a), and (d) is a diagram for explaining the position P13 of (a). (A) is a diagram for explaining the drive cycle, the number of shots, and the flushing time at the time of deceleration of the carriage in flushing during printing of the second embodiment, and (b) is a diagram for explaining the printing of the second embodiment. It is a figure for demonstrating the drive cycle, the number of shots, and flushing time at the time of acceleration of a carriage in medium flushing. (A) is a diagram showing the relationship between the waiting time in the modified example 1 and the number of shots during acceleration in the pre-printing flushing, and (b) is the standby time in the modified example 2 and the acceleration time in the flushing during printing. It is a figure which shows the relationship with the number of occurrences of. It is a schematic block diagram of the printer of the modification 3. It is a figure which shows the amount of ink ejected from one nozzle at the time of deceleration and acceleration of a carriage in the pre-print flushing of the modification 4. It is a schematic block diagram of the printer of the modification 5.

[First Embodiment]
Hereinafter, a preferred first embodiment of the present invention will be described.

<Overall configuration of printer>
As shown in FIG. 1, the printer 1 (“printing apparatus” of the present invention) according to the first embodiment includes a carriage 2, an inkjet head 3 (“liquid ejection head” of the present invention), a platen 4, a transfer roller 5, and the like. 6. It is equipped with a maintenance unit 7.

The carriage 2 is supported by two guide rails 11 and 12 and can move along the scanning direction. The carriage 2 is connected to the carriage motor 56 (see FIG. 2) via a belt or the like (not shown). When the carriage motor 56 is driven, the carriage 2 moves along the guide rails 11 and 12. In the first embodiment, the carriage 2, the guide rails 11, 12, the carriage motor 56, and the like are combined to correspond to the "head moving device" of the present invention. The right side and the left side in the scanning direction are as shown in FIG.

The inkjet head 3 is mounted on the carriage 2. The inkjet head 3 has a plurality of nozzles 10 on the lower surface thereof, and the lower surface on which ink is ejected from the plurality of nozzles 10 is an ejection surface. The plurality of nozzles 10 are arranged in a transport direction orthogonal to the scanning direction to form a plurality of nozzle rows 9. Here, four nozzle rows are arranged in the scanning direction. Then, black (K) pigment ink is ejected from the nozzle 10 belonging to the leftmost nozzle row 9 (“second nozzle row” of the present invention). Dye inks of yellow (Y), cyan (C), and magenta (M) colors are ejected from the nozzles 13 belonging to the three nozzle rows 9 on the right side (“first nozzle row” of the present invention) in order from the left side. To.

The platen 4 faces the lower surface of the inkjet head 3 and constitutes a transport path for the recording paper 100. The platen 4 supports the recording paper 100 from below over its entire length in the scanning direction. When the recording paper 100 has the maximum size that can be conveyed, both ends of the recording paper 100 coincide with both ends of the platen 4. The transport rollers 5 and 6 are arranged so as to sandwich the platen 4 in the transport direction. The transfer roller 5 is on the upstream side of the platen, and the transfer roller 6 is on the downstream side thereof. The transfer rollers 5 and 6 are connected to the transfer motor 57 (see FIG. 2) via a gear (not shown) or the like. When the transfer motor 57 is driven, the transfer rollers 5 and 6 rotate, and the recording paper 100 on the platen 4 is transferred in the transfer direction. In the first embodiment, the platen 4, the transfer rollers 5, 6, the transfer motor 57, and the like correspond to the "transfer device" of the present invention.

The maintenance unit 7 includes a nozzle cap 21, a switching device 22, a suction pump 23, a waste liquid tank 24, a flushing foam 8 (the "liquid receiver" of the present invention), and the like. The nozzle cap 21 is arranged on the right side of the platen 4. The nozzle cap 21 has two cap portions 21a and 21b. The cap portion 21a is located to the left of the cap portion 21b, and both are integrally molded. The arrangement position of the nozzle cap 21 is also the standby position of the inkjet head 3 (carriage 2). In the standby position, the nozzle row 9 for black ink faces the cap portion 21a, and the three nozzle rows 9 for color ink face the cap portion 21b. Further, the nozzle cap 21 is raised and lowered by the cap raising and lowering device 58 (see FIG. 2). When the nozzle cap 21 is raised when the carriage 2 is in the standby position, the plurality of nozzles 10 are covered with the nozzle caps 21. Specifically, the leftmost nozzle row 9 is covered with the cap portion 21a, and the three rightmost nozzle rows 9 are covered with the cap portion 21b.

The switching device 22 is connected to the cap portions 21a and 21b via the tubes 29a and 29b. Further, a suction pump 23 is connected to the switching device 22 via a tube 29c. The switching device 22 switches the communication destination of the suction pump 23 (tube 29c) to any one of the cap portions 21a and 21b (tubes 29a and 29b). The suction pump 23 is a tube pump or the like. Further, the suction pump 23 is connected to the waste liquid tank 24 via the tube 29d.

The plurality of nozzles 10 are covered with the nozzle caps 21 at the time of suction purging in which the thickening ink in the nozzles 10 is sucked and discharged. If the suction pump 23 is connected to the cap portion 21a, the black ink is discharged from the leftmost nozzle row 9 by driving the suction pump 23. On the other hand, if the connection destination is the cap portion 21b, the color ink is similarly discharged from the three nozzle rows 9 on the right side. The ink discharged by the suction purge is stored in the waste liquid tank 24.

The flushing foam 8 is on the left side of the platen 4 and is located on the side opposite to the standby position with respect to the transport path of the recording paper 100. The length L1 of the flushing foam 8 in the scanning direction is shorter than the distance I between the nozzle rows 9. When the carriage 2 is located on the far left, the rightmost nozzle row 9 is located near the left side of the flushing foam 8.

<Control device>
As shown in FIG. 2, the control device 50 includes a CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53, an EEPROM (Electrically Erasable Programmable Read Only Memory) 54, and an ASIC (Application). Specific Integrated Circuit) 55 and the like, which control the operation of the carriage motor 56, the inkjet head 3, the transfer motor 57, the cap elevating device 58, the switching device 22, the suction pump 23 and the like. Further, the printer 1 has a linear encoder 59 provided for the carriage 2, and the control device 50 acquires the position of the carriage 2 in the scanning direction based on the signal from the linear encoder 59.

Here, in FIG. 2, one CPU 51 is shown. At this time, one CPU 51 is composed of one unit CPU (single processor), which may be configured to collectively process various programs, or is composed of a plurality of unit CPUs (multiprocessors), and these are configured to share the processing. There may be. Further, in the figure, one ASIC 55 is shown. At this time, one ASIC 55 has the same configuration and operation as the above-mentioned CPU 51.

<Control during printing>
Next, the control at the time of printing in the printer 1 will be described with reference to FIG. At the time of printing, the printer 1 performs a ejection operation by reciprocating the carriage 2. Image formation for one recording sheet 100 is completed by a plurality of ejection processes. During this time, the flushing process maintains and restores the discharge capacity. The processing for one print job (including the print command) follows the flow in the figure.

When a print command is input to the printer 1, the control device 50 resets the number of executions N of the ejection process to 0 (S101). Subsequently, the control device 50 causes flushing before printing (S102). In pre-print flushing, the carriage 2 at the standby position moves to the flushing form 8 without forming an image. When the nozzle row 9 faces the nozzle row 9, the inkjet head 3 is driven, and a predetermined amount of ink is ejected from the corresponding nozzle 10. At this time, the thickened ink is discharged from the nozzle 10.

Subsequently, the control device 50 executes one discharge process (S103). The control device 50 controls the carriage motor 56 to move the carriage 2 in the scanning direction, and controls the inkjet head 3 to eject ink from a plurality of nozzles 10 toward the recording paper 100. At this time, the ink ejection follows the image data, and the ejection timing is synchronized with the signal from the linear encoder 59. Ink is ejected in the drive cycle R0. In the first ejection process, one strip-shaped print area is formed while the carriage 2 moves to the right.

After this ejection process, if printing on the recording paper 100 is not completed (S104: NO), the control device 50 executes the transfer process (S105). The control device 50 controls the transfer motor 57 to transfer the recording paper 100 to the transfer rollers 5 and 6 in the transfer direction. The transport distance is approximately equal to the width of the strip print area in the transport direction.

Subsequently, the control device 50 increments the value of the number of times N by 1 (S106). Further, the control device 50 determines whether or not the number of times N is a predetermined number of times Na (Na is an even number) (S107). If the number of times N is less than the predetermined number of times Na (S107: NO), the process returns to S103. On the other hand, when the number of times N is a predetermined number of times Na (S107: YES), the control device 50 causes flushing during printing (S108).

In flushing during printing, ink is ejected from a plurality of nozzles 10 to the flushing foam 8 as in the case of flushing before printing. The flushing before printing and the flushing during printing will be described in detail later. Then, after flushing during printing, the control device 50 resets the number of times N to 0 (S109), and then returns to S103.

As described above, in the first embodiment, the ejection process and the transfer process are repeated until printing is completed (S103: NO). Flushing is performed during printing for each Na-time ejection process. At this time, in the odd-numbered ejection process, the carriage 2 is moved to the right. In the even-numbered discharge process, the carriage 2 is moved to the left. In the first embodiment, Na is an even number. After the ejection process, flushing is performed during printing without changing the moving direction of the carriage 2. In addition, Na may be an odd number. In this case, after the Nath discharge process is completed, the carriage 2 changes direction and returns to the flushing foam 8.

Then, when the printing is completed, the control device 50 executes the paper ejection process (S110). At this time, the control device 50 controls the transfer motor 57 to cause the transfer roller 6 to eject the recording paper 100. Subsequently, the control device 50 executes the standby process (S111). In the standby process, the carriage motor 56 is driven and the carriage 2 is returned to the standby position. Further, the nozzle cap 21 is raised by the cap elevating device 58, and the plurality of nozzles 10 are covered with the nozzle caps 21. This completes one print job.

<Flushing before printing>
Next, pre-print flushing will be described. FIG. 4A shows a profile of the speed of the carriage 2 in pre-print flushing. In FIG. 4A, the speed is shown as a positive value as the carriage 2 moves from the right side to the left side. 4 (b) to 4 (h) show the positional relationship between the carriage 2 and the portion facing the carriage 2 in order along the movement path of the carriage 2. The starting point of movement is the standby position of the carriage 2. The end point is the position where the carriage 2 faces the flushing foam 8.

FIG. 4 (b) shows the positional relationship at the position P1 (standby position of the carriage 2) of FIG. 4 (a). The inkjet head 3 and the nozzle cap 21 face each other. FIG. 4 (c) corresponds to position P2 in FIG. 4 (a). The leftmost nozzle row 9 and the right end of the platen 4 face each other. FIG. 4 (d) corresponds to the position P3 in FIG. 4 (a). The rightmost nozzle row 9 and the left end of the platen 4 face each other. The leftmost nozzle row 9 is on the right side of the flushing foam 8. FIG. 4 (e) corresponds to the position P4 in FIG. 4 (a). The leftmost nozzle row 9 and the right end of the flushing foam 8 face each other. The rightmost nozzle row 9 is on the left side of the platen 4. FIG. 4 (f) corresponds to the position P5 in FIG. 4 (a). The rightmost nozzle row 9 and the left end of the flushing foam 8 face each other. FIG. 4 (g) corresponds to the position P6 (end point) of FIG. 4 (a). The carriage 2 is in a position facing the flushing foam 8, but all nozzle rows 9 are on the left side of the flushing foam 8. Note that FIG. 4 (h) corresponds to the position P7 in FIG. 4 (a). The position P7 is between the position P2 and the position P3, and the carriage 2 (the entire nozzle row 9) faces the platen 4. Here, the carriage 2 starts decelerating toward the end point (position P6).

During pre-print flushing, the carriage 2 reciprocates between position P1 (standby position) and position P6 (end point). During this time, the position of the carriage 2 is detected by the linear encoder 59. On the way, the carriage 2 is decelerated at a constant acceleration from the position P7.

First, when the control device 50 receives a print command, it controls the cap elevating device 58 to lower the nozzle cap 21. The carriage 2 is movably released. Subsequently, when the control device 50 controls the carriage motor 56, the carriage 2 starts moving toward the position P2. The carriage 2 is accelerated and its moving speed becomes V1 before reaching the position P2. At least from the position P2 to the position P7, the carriage 2 moves at a constant speed of V1.

At position P7, carriage 2 begins decelerating. At this time, the carriage 2 is decelerated at a constant acceleration toward the position P6 (the position where the moving speed is zero). During this time, the nozzle row 9 passes above the flushing foam 8. The control device 50 controls the inkjet head 3 to perform the flushing process of the nozzle row 9. Ink is ejected from the plurality of nozzles 10 to the flushing foam 8. This process is performed in order from the nozzle row 9 on the left side. The switching timing of the control target (nozzle row 9) follows the output (encoder output) from the linear encoder 59. However, the ejection operation is asynchronous with the encoder output.

Here, the ink ejection conditions (flushing conditions) are determined by the viscosity and type of ink. The flushing conditions (drive cycle R and number of shots A) are determined by the viscosity, and the change in viscosity differs depending on the type of ink. Black ink is a pigment ink and is easier to thicken than color ink (dye ink). As the thickening of the ink progresses, the shorter the drive cycle R, the more conspicuous the ink stains on the ejection surface during flushing. This dirt later induces ejection failure (non-ejection or twisting). Further, in order to restore the discharge, it is necessary to increase the number of discharge operations (number of shots A).

Therefore, in the first embodiment, the black ink has a longer drive cycle R and a larger number of shots A than the color ink. This relationship is summarized in FIG. 5 (a). However, the drive cycle R is Rk1> Ry1 = Rc1 = Rm1> R0, and the number of shots A has a magnitude relationship of Ak1> Ay1 = Ac1 = Am1. There is no difference in the drive cycle R and the number of shots A between the color inks. All drive cycles R are longer than the drive cycle R0 at the time of ejection processing (image formation). Note that Rk1, Ry1, Rc1, and Rm1 are drive cycles R set for black, yellow, cyan, and magenta inks in this order. Ak1, Ay1, Ac1, and Am1 are the number of shots A set for the black, yellow, cyan, and magenta inks in this order. Each information related to the drive cycle R and the number of shots A is stored in advance in the ROM 52 or the like.

In this case, the required flushing time T is obtained by driving cycle R × number of shots A. Black ink has the longest flushing time T. Specifically, there is a magnitude relationship of Tk1> Ty1 = Tc1 = Tm1. Note that Tk1, Ty1, Tc1, and Tm1 are flushing times T set for black, yellow, cyan, and magenta inks in this order.

For each ink, the corresponding nozzle row 9 may have a flight time above the flushing foam 8 that is equal to or longer than the flushing time T. In the case of the nozzle row 9 for black ink, the flight time is equal to or longer than the flushing time Tk1. Here, the acceleration of the deceleration from the position P7 is determined so as to satisfy this condition for the black ink nozzle row 9. The color ink nozzle row 9 is on the right side of the black ink nozzle row 9. From this positional relationship, the color ink nozzle row 9 is secured with an airborne time of the flushing time T (Ty1, Tc1, Tm1) or more.

For the black ink nozzle row 9, flushing begins at position P4 and crosses over flushing foam 8 at flushing time Tk1. Flushing ends at position P5. During this time, the ejection operation of Ak1 is repeated. Immediately before reaching the position P5, the magenta ink nozzle row 9 crosses over the flushing foam 8 over a flushing time of Tk1 or more (> Tm1). During this time, the ejection operation once Am is repeated. After this, the carriage 2 moves further to the left and stops at the end point: position P6. This completes the first half of the pre-print flushing (discharging restoration process).

The second half of the pre-print flushing (replacement process with fresh ink) is performed during the folding immediately after the first half. At position P6, the control device 50 controls the carriage motor 56 to move the carriage 2 to the right. Carriage 2 begins accelerating towards position P1. Carriage 2 is accelerated to speed -V1 before reaching position P3. Negative numbers correspond to the movement of the carriage 2 to the right.

As the ink thickens, the effect extends deeper from the meniscus. Therefore, it takes a large amount of ink to recover the ejection characteristics. Here, for the black ink, a larger number A is set as compared with the color ink. This relationship is summarized in FIG. 5 (b). However, the drive cycle R is R0. The number of shots A has a magnitude relationship of Ak2> Ay2 = Ac2 = Am2. There is no difference in the number of shots A between the color inks. Ak2, Ay2, Ac2, and Am2 are the number of shots A set for the black, yellow, cyan, and magenta inks in this order. The required flushing time T has a magnitude relationship of Tk2> Ty2 = Tc2 = Tm2. Tk2, Ty2, Tc2, and Tm2 are flushing times T set for black, yellow, cyan, and magenta inks in this order.

The black ink nozzle row 9 may have a flushing time of Tk2 or more in the air above the flushing foam 8. The acceleration of the carriage 2 from the position P6 is determined so that the flight time of the black ink becomes the flushing time Tk2. Due to the positional relationship with the black ink nozzle row 9, the color ink nozzle row 9 crosses the sky over the flushing time Tk2 or more (> Ty2, Tc2, Tm2). In the color ink nozzle row 9, a flight time of the required flushing time T or more is secured. During each flight time, the thickening ink is discharged from the nozzle 10, and fresh ink is replenished to the nozzle 10. This completes the latter half of the pre-print flushing (replacement process with fresh ink).

After this, the carriage 2 is accelerated to a velocity −V1 at a constant acceleration before reaching the position P3. At the end of the latter half of the pre-print flushing (at the time at position P4), the arrival speed Vp4 of the carriage 2 assumes that the carriage 2 is accelerated to a position near the position P3 at a constant acceleration to the speed −V1. If it is smaller than the velocity V0 at, it will accelerate from the position P4 to the position P3 with a larger acceleration. On the contrary, if the arrival speed Vp4 is larger than the arrival speed V0, it will be accelerated with a smaller acceleration thereafter. Of course, the vehicle may be accelerated at the same acceleration, and when the speed reaches −V1, the vehicle may be switched to constant speed running at a speed of −V1. The movement time of the carriage 2 is shortened.

In the latter half of the pre-print flushing, when the arrival speed Vp4 is larger than the arrival speed V0 from the viewpoint of allowing a margin for the flushing time, the "constant acceleration" that dares to reach the arrival speed V0 at the position P4 is near the position P3. You may accelerate to. As a result, the flushing time T can be adjusted according to the viscosity increase regardless of the ink color.

Also in the latter half of the pre-print flushing, each information related to the drive cycle R and the number of shots A is stored in advance in the ROM 52 or the like. Further, the drive cycle R is a drive cycle R0 at the time of discharge processing. However, the drive itself is not encoder synchronization. The drive synchronizes with the encoder output between position P3-position P2. This section includes an image forming region. In the image forming region, image dots are formed on the recording paper 100 in synchronization with the encoder.

In the first embodiment, the acceleration of the carriage 2 is set so that the time facing the flushing foam 8 is Tk2 or more for the leftmost nozzle row 9 (nozzle 10 for ejecting black ink). As a result, the time for each nozzle row 9 to face the flushing foam 8 is longer than the set flushing time.

Further, in the pre-print flushing, the control device 50 controls the inkjet head 3 for the nozzle row 9 located on the left side of the flushing foam 8 to vibrate the meniscus. Ink is not ejected due to this vibration. Thickening near the meniscus is suppressed.

<Flushing during printing>
Next, flushing during printing will be described in detail. Flushing during printing, like flushing before printing, consists of a first half and a second half. Regarding the first half, the position where the carriage 2 starts decelerating (position P8 in FIG. 6A) is different from the pre-print flushing. The deceleration start position is near the position P3 on the position P4 side. This position is closer to the position P3 than the position where the velocity −V1 in the latter half is reached. FIG. 6B shows the positional relationship at the position P8 in FIG. 6A. Each nozzle row 9 is sandwiched between the platen 4 and the flushing foam 8 and does not face each other.

FIG. 6 (a) shows the speed profile of flushing during printing. According to this speed profile, the control device 50 advances control. When the number of discharge processes N = Na, the control device 50 controls the carriage motor 56 and starts decelerating the carriage 2 at the position P8. Since the number of times Na is an even number, the carriage 2 is in the process of moving to the left (position P6). Between the position P4 and the position P5, the nozzle row 9 faces the flushing foam 8. The control device 50 controls the inkjet head 3 to eject ink from the opposing nozzle rows 9. This is done in order from the nozzle row 9 on the left side. The carriage 2 reaches position P6 and the first half of flushing during printing ends.

Even during printing, if the ejection is stopped for a predetermined time or longer, the effect of thickening becomes apparent. Black ink is the shortest in this predetermined time. Therefore, the black ink has a longer drive cycle R and a larger number of shots A than the color ink. FIG. 7A summarizes this relationship. However, the drive cycle R is Rk3> Ry3 = Rc3 = Rm3> R0, and the number of shots A has a magnitude relationship of Ak3> Ay3 = Ac3 = Am3. Regarding the required flushing time T, there is a magnitude relationship of Tk3> Ty3 = Tc3 = Tm3 from the flushing time T = drive cycle R × number of shots A. The information of each index is stored in ROM 52 or the like in advance.

The second half of the flushing during printing is performed during the wrapping immediately after the first half. At position P6, the control device 50 controls the carriage motor 56 to move the carriage 2 to the right. Carriage 2 begins accelerating towards position P1. Carriage 2 is accelerated to speed -V1 before reaching position P3. This acceleration stop position (constant speed movement start position) is closer to position 4 than the deceleration start position in the first half. Further, the leftmost nozzle row 9 is on the right side of the flushing foam 8.

On the way the carriage 2 reaches position P3, the nozzle row 9 crosses over the flushing foam 8. While the nozzle row 9 faces the flushing foam 8, the control device 50 controls the inkjet head 3 to eject ink from the corresponding nozzle 10. In this case, the number of shots A of the black ink is set to be larger than that of the color ink. This relationship is summarized in FIG. 7 (b). However, the drive cycle R is R0. The number of shots A has a magnitude relationship of Ak4> Ay4 = Ac4 = Am4. The required flushing time T also has a magnitude relationship of Tk4> Ty4 = Tc4 = Tm4. The information of each index is stored in ROM 52 or the like in advance.

The flight time of the nozzle row 9 over the flushing foam 8 is rate-determined by the flushing time T required by the nozzle row 9 for black ink, as in the case of pre-printing flushing. In the first half, the flushing time is defined as Tk3. That is, the acceleration during deceleration is determined so that the flight time is the flushing time Tk3. In the latter half, the flushing time is defined as Tk4. The acceleration at the time of acceleration is determined so that the flight time is the flushing time Tk4. As a result, each flushing time can be secured with a margin for each color ink nozzle row 9. For the black ink nozzle row 9, if the flight time is set longer than the required flushing time T, this effect is enhanced regardless of the ink color.

Regarding flushing during printing, the drive cycle R at the time of ink ejection is not encoder synchronization. At position P3, the drive synchronization relationship is switched. In the image forming region between the position P3 and the position P2, the image dots are formed by the encoder synchronization. Also, the position identification is based on the encoder output, as in the case of pre-print flushing.

Further, even in flushing during printing, the control device 50 controls the inkjet head 3 for the nozzle row 9 located on the left side of the flushing foam 8 to vibrate the meniscus. Ink is not ejected due to this vibration.

In the present embodiment, in the printer 1 in which flushing is performed before and during printing, flushing is a set of a first half portion performed during deceleration of the carriage 2 and a second half portion performed thereafter during acceleration. In ink ejection, the drive cycle of the first half is longer than the drive cycle (= R0) of the second half. Regarding the drive cycle of the first half, the drive cycle in the pre-print flushing is longer than the drive cycle in the flushing during printing. In pre-print flushing, the deceleration start position is located opposite to the platen 4. In addition to this, deceleration in the first half and acceleration in the second half are performed at constant accelerations, and the encoder output is used to identify the position between them. However, the ejection operation has a feature that it is performed in non-encoder synchronization.

In the embodiment described above, the ink is discharged during the deceleration and acceleration of the carriage 2 in the pre-printing flushing and the printing flushing. As a result, the time required for flushing before printing and flushing during printing can be shortened as compared with the case where each nozzle row 9 is stopped at a position facing the flushing foam 8 and the ink is discharged. Since the time required for pre-print flushing can be shortened, the time from the input of the print command to the start of printing on the first recording paper 100 can be shortened. Further, since the time required for flushing during printing can be shortened, the throughput of the entire printing can be increased.

Further, in the first embodiment, the ink is discharged both when the carriage 2 is decelerated and when the carriage 2 is accelerated. The time for flushing before printing and flushing during printing can be further shortened as compared with the case where only one of the carriage 2 is discharged during deceleration and acceleration.

Further, in the first embodiment, in the pre-printing flushing and the in-printing flushing, the ejection cycle and the number of shots are set for each ink color, and the pre-printing flushing and the in-printing flushing are performed based on the flushing time which is the product of these. The acceleration of the carriage 2 is set. This makes it possible to secure the time required to eject an appropriate amount of ink for each color.

Further, as the thickening of the ink progresses, it is necessary to increase the number of ejection drives (number of shots) during flushing. At this time, if the drive cycle is also lengthened, ink stains on the ejection surface can be reduced. Therefore, in the first embodiment, the flushing time (= drive cycle × number of shots) required for each ink color and the corresponding acceleration of the carriage 2 during flushing are set according to the ease of thickening. ing. This acceleration is determined based on the required flushing time (specifically, Tk1, Tk2, Tk3, Tk4) of the ink that is most easily thickened. As a result, for all the nozzle rows 9, the time during which the nozzle rows 9 face the flushing foam 8 can be set to a time equal to or longer than the set flushing time.

Further, in the pre-printing flushing and the in-printing flushing, during the deceleration of the carriage 2, the nozzle row 9 on the left side faces the flushing foam 8 in order. When facing the flushing foam 8, the nozzle row 9 on the right side has a slower moving speed of the carriage 2 than the nozzle row 9 on the left side. Therefore, the time for facing the flushing foam 8 becomes longer in order from the nozzle row 9 on the left side, that is, in the order of the nozzle rows 9 of black, yellow, cyan, and magenta.

On the other hand, in pre-printing flushing and printing-during flushing, while the carriage 2 is accelerating, it faces the flushing foam 8 in order from the nozzle row 9 on the right side. At this time, the acceleration during movement is adapted to the leftmost black ink nozzle row 9. Regarding the speed of the carriage 2 when facing the flushing foam 8, the nozzle row 9 for color ink on the right side is lower than the nozzle row 9 for black ink on the left end. That is, the time for facing the flushing foam 8 becomes longer in the order of the nozzle rows 9 of black, yellow, cyan, and magenta.

Further, in the pre-printing flushing and the in-printing flushing, if the ink is strongly thickened, the ink in the nozzle 10 is scattered around when the carriage 2 is driven with a short drive cycle by the ejection operation during deceleration. There is a risk that it will end up.

On the other hand, when the carriage 2 is accelerated, the ink is discharged at the time of deceleration immediately before, so that the viscosity of the ink in the nozzle 10 is lowered. Therefore, when the carriage 2 is accelerated, the ink does not scatter even if the inkjet head 3 is driven with a short drive cycle.

Therefore, in the first embodiment, in the pre-printing flushing and the printing-during flushing, the drive cycle of the inkjet head 3 when the carriage 2 is decelerated is made longer than the drive cycle of the inkjet head 3 when the carriage 2 is accelerated. This makes it possible to prevent the ink in the nozzle 10 from scattering to the surroundings when the carriage 2 is decelerated. Further, when the carriage 2 is accelerated, the ink in the nozzle 10 can be quickly discharged to shift to the ejection process.

Further, in pre-printing flushing and printing-during flushing, when the carriage 2 is decelerated, the drive cycle is set asynchronously with the signal from the linear encoder 59 to eject ink. As a result, the degree of freedom in setting the drive cycle during deceleration of the carriage 2 can be increased. When the carriage 2 is decelerated, the ink in the nozzle 10 is greatly thickened, so that the drive cycle is lengthened. At this time, the drive cycle can be set appropriately according to the thickening of the ink in the nozzle 10.

Further, when accelerating the carriage 2, ink is ejected in the same drive cycle as in the ejection process. Since the ink is discharged when the carriage 2 is decelerated, the thickening of the ink is eliminated to some extent when the carriage 2 is accelerated. Therefore, the ink can be ejected with a short drive cycle R without scattering the ink. Since a large amount of ink can be ejected per unit time, the ejection performance can be reliably recovered in a short time. Further, by setting the drive cycle R to the drive cycle R0 at the time of the ejection process, there is no noticeable change in the ejection characteristics at the time of switching to the encoder synchronization, and the transition can be made smoothly. Specifically, residual vibration corresponding to the drive cycle exists in the flow path being driven. Normally, at the time of such switching, the drive timing is also harmonized by taking advantage of the fact that the drive cycles are the same. As a result, there is no difference in the state of residual vibration before and after switching. Good image quality will be obtained.

Further, in the case of flushing before printing, there is no big restriction on the deceleration start position. Therefore, the acceleration during deceleration can be set with a high degree of freedom. For the nozzle row 9 for ink types that easily thicken, if the flight time over the flushing foam 8 is set to the flushing time T that is just required, the pre-printing flushing can be completed quickly. On the other hand, if the flight time is made larger than the flushing time T, fine adjustment can be made for all the nozzle rows 9. For example, the flushing time T can be adjusted to the environmental conditions.

Further, in the first embodiment, when the nozzle row 9 is on the left side of the flushing foam 8, the inside of the nozzle 10 vibrates to the extent that ink is not ejected from the nozzle 10. As a result, thickening in the vicinity of the meniscus can be suppressed more effectively. From the same point of view, the same vibration may be applied to the meniscus in the latter half of the flushing even in the section from the completion of the flushing operation to the switching to the encoder synchronization.

[Second Embodiment]
Next, a preferred second embodiment of the present invention will be described.

The second embodiment differs from the first embodiment in two respects. As shown in FIG. 8, the standby position and the arrangement position of the flushing foam 102 are on the same side with respect to the transport path. The flushing foam 102 is closer to the transport path. Next, corresponding to this arrangement form, the arrangement order of the nozzle row 9 and the cap portion is opposite to that of the first embodiment in the scanning direction. The black ink nozzle row 9 is on the far right of the row. To the left of this, the corresponding nozzle rows 9 are arranged in the order of yellow, cyan, and magenta. The cap portion 101a for black ink is also on the right side of the cap portion 101b.

The cap portions 101a and 101b are integrally molded. In the scanning direction, the width of the arrangement of the nozzle rows 9 is smaller than the distance between the right end of the platen 4 and the left end of the flushing foam 102. These two points are the same as those in the first embodiment.

Regarding the flushing operation, in the second embodiment, the pre-print flushing is different from the first embodiment. The operation of flushing before printing will be described with reference to FIG. FIG. 9 (a) shows the speed profile of pre-print flushing. 9 (b) to 9 (d) show the positional relationship between the carriage 2 and the portion facing the carriage 2 in order along the movement path of the carriage 2. The starting point of movement is the standby position of the carriage 2. The end point is the position where the carriage 2 faces the platen 4.

9 (b) shows the positional relationship at the position P11 of FIG. 9 (a). The leftmost nozzle row 9 and the right end of the flushing foam 102 face each other. 9 (c) corresponds to position P12 in FIG. 9 (a). The rightmost nozzle row 9 and the left end of the flushing foam 102 face each other. The leftmost nozzle row 9 is on the right side of the platen 4. 9 (d) corresponds to the position P13 in FIG. 9 (a). Here, the carriage 2 finishes accelerating and starts decelerating toward the end point. Position P13 is to the left of position P2. There is an end point to the left of position P13. At the end point, all nozzle rows 9 face the platen 4. The position P14 in FIG. 9A is a position in the latter half where the carriage 2 finishes accelerating and starts decelerating toward the starting point.

First, the control device 50 controls the carriage motor 56 to accelerate the carriage 2. At position P13, the moving speed of the carriage 2 is V2 (≦ V1). During this time, the nozzle row 9 sequentially crosses over the flushing foam 102. At position 11, ink ejection starts from the first nozzle row 9 (magenta ink nozzle row 9). At position P12, ink ejection (flushing operation) is completed. Immediately before this, ink is discharged from the last nozzle row 9 (black ink nozzle row 9).

For the first half of the pre-print flushing, the flushing conditions (drive cycle R, number of shots A, flushing time T) are summarized in FIG. 10 (a). The information of each index is stored in ROM 52 or the like in advance. At this time, the drive cycle R is Rk5> Ry5 = Rc5 = Rm5> R0, and the number of shots A has a magnitude relationship of Ak5> Ay5 = Ac5 = Am5. The flushing time T is the longest for black ink, and there is a magnitude relationship of Tk5> Ty5 = Tc5 = Tm5. Note that Rk5, Ry5, Rc5, and Rm5 are drive cycles R set for black, yellow, cyan, and magenta inks in this order. Ak5, Ay5, Ac5, and Am5 are the number of shots A set for the black, yellow, cyan, and magenta inks in this order. Tk5, Ty5, Tc5, and Tm5 are flushing times T set for black, yellow, cyan, and magenta inks in this order.

In the sky above the flushing foam 102, the flight time of the nozzle row 9 may be longer than or equal to the flushing time T required by the corresponding ink. Here, in the black ink nozzle row 9, the acceleration of the carriage 2 is set so that the flight time = the required flushing time Tk5. The color ink nozzle row 9 is on the left side of the black ink nozzle row 9. Due to this positional relationship, the flight time of the color ink nozzle row 9 is longer than the required flushing time Tk5 of the black ink nozzle row 9. Each flushing time T (Ty5, Tc5, Tm5) can be easily secured.

After this, the carriage 2 moves further to the left. In this embodiment, the carriage 2 passes through position P2 and continues to accelerate to position P13. The position P13 is also a deceleration start position, and the carriage 2 stops at the left end point. This completes the first half of the pre-print flushing (discharging restoration process). The second half of the pre-print flushing (replacement process with fresh ink) is performed during folding from the end point. Carriage 2 accelerates from the end point toward position P14. Position P14 is to the right of position P2. At position P14, the speed V = −V2 of the carriage 2. Further, the carriage 2 is decelerated from here toward the starting point (position P1).

During deceleration towards position P1, the nozzle row 9 sequentially crosses over the flushing dome 102. At the position 12, ink ejection is started, and ink is ejected from the rightmost nozzle row 9 (black ink nozzle row 9). At position 11, ink ejection ends. Immediately before this, ink is discharged from the leftmost nozzle row 9 (magenta ink nozzle row 9).

For the latter half of the pre-print flushing, the flushing conditions (drive cycle R, number of shots A, flushing time T) are summarized in FIG. 10 (b). The information of each index is stored in ROM 52 or the like in advance. At this time, the drive cycle R is Rk6> Ry6 = Rc6 = Rm6> R0, and the number of shots A has a magnitude relationship of Ak6> Ay6 = Ac6 = Am6. The flushing time T is the longest for black ink, and there is a magnitude relationship of Tk6> Ty6 = Tc6 = Tm6. Note that Rk6, Ry6, Rc6, and Rm6 are drive cycles R set for black, yellow, cyan, and magenta inks in this order. Ak6, Ay6, Ac6, and Am6 are the number of shots A set for the black, yellow, cyan, and magenta inks in this order. Tk6, Ty6, Tc6, and Tm6 are flushing times T set for black, yellow, cyan, and magenta inks in this order.

Also in this case, the acceleration of the carriage 2 is set in the black ink nozzle row 9 so that the flight time = the required flushing time Tk6. The color ink nozzle row 9 is on the left side of the black ink nozzle row 9. From this positional relationship, the color ink nozzle row 9 can secure the required flushing time T (Ty6, Tc6, Tm6) with a time margin. As shown in FIG. 9, the acceleration in the first half and the deceleration in the second half are performed at constant accelerations, respectively. The encoder output is used to identify the position in between. However, the ejection operation is performed in non-encoder synchronization.

In this embodiment, the flushing is a set of a first half portion in which the carriage 2 is performed while moving away from the standby position and a second half portion in which the carriage 2 is performed while facing the standby position. Regarding the drive cycle, the magnitude relationship between the first half and the second half, and the magnitude relationship between the pre-printing flushing and the in-print flushing regarding the drive cycle of the first half are the same as in the first embodiment. In pre-print flushing, the end point is at a position facing the platen 4.

As for the flushing during printing in the second embodiment, the moving direction of the carriage 2 is only opposite to that in the flushing during printing in the first embodiment, and thus the description thereof will be omitted here. Further, also in the second embodiment, as in the first embodiment, in the pre-printing flushing and the in-printing flushing, the meniscus is vibrated when the nozzle row 9 does not face the flushing foam 102.

Further, in the case of the second embodiment, in the pre-printing flushing and the in-printing flushing, during the acceleration of the carriage 2 (first half portion), the flight time over the flushing foam 102 is the rightmost nozzle row 9 (for black ink). It is defined by the flushing time T required by the nozzle row 9). Here, the flight time = the required flushing time T. At this time, the nozzle row 9 for color ink has a lower moving speed with respect to the flushing foam 102 than the nozzle row 9 for black ink, and the flight time is longer by that amount. That is, the time for facing the flushing foam 102 becomes longer in the order of the nozzle rows 9 of black, yellow, cyan, and magenta.

On the other hand, in the flushing before printing and the flushing during printing, the carriage 2 faces the flushing foam 102 in order from the nozzle row 9 on the right side during deceleration (second half). The moving speed is as low as the nozzle row 9 on the left side with respect to the flushing foam 102. That is, the time for facing the flushing foam 102 becomes longer in order from the nozzle row 9 on the right side, that is, in the order of the nozzle rows 9 of black, yellow, cyan, and magenta.

Next, a modified example in which various changes are made to the first and second embodiments will be described.

In the first embodiment, in the pre-printing flushing and the printing-during flushing, the drive cycle during deceleration of the carriage 2 is set independently of the signal from the linear encoder 59, and the drive cycle during acceleration of the carriage 2 is set. The drive cycle R0 at the time of image formation was the same as at the time of printing, but the present invention is not limited to this.

For example, in the pre-printing flushing and the printing-during flushing of the first embodiment, the drive cycle during deceleration of the carriage 2 is an integral multiple of the drive cycle corresponding to the signal from the linear encoder 59 (for example, the drive cycle during printing). It may be set to (cycle). Further, the drive cycle during acceleration of the carriage 2 may be a drive cycle associated with the encoder output or a drive cycle unrelated to the drive cycle.

Similarly, in the pre-print flushing of the second embodiment, the drive cycle at the time of acceleration of the carriage 2 may be set to the drive cycle corresponding to the signal from the linear encoder 59. Further, the drive cycle at the time of deceleration of the carriage 2 may be another drive cycle corresponding to the signal from the linear encoder 59, or may be irrelevant to it.

Further, in the pre-printing flushing and the in-printing flushing of the first and second embodiments, ink is ejected from the nozzle 10 toward the flushing foam during both deceleration and acceleration of the carriage 2, but this is limited to this. I can't. In the case of the first embodiment, the ink may be ejected only when the carriage 2 is decelerated. Further, in the case of the second embodiment, the ink may be ejected only when the carriage 2 is accelerated.

Further, in the pre-printing flushing and the in-printing flushing of the first and second embodiments, when the nozzle row 9 does not face the flushing foams 8 and 102, the ink in the nozzle 10 is vibrated to the extent that the ink is not ejected. However, it does not have to be vibrated.

Further, in the first embodiment, the number of inks emitted from the nozzle 10 during deceleration and acceleration of the carriage 2 in pre-printing flushing and printing-during flushing is set to a constant value in advance, but this is limited to this. I can't. The number of shots may be different depending on the viscosity of the ink in the nozzle 10 at the timing immediately before flushing before printing and flushing during printing.

For example, in the first modification, as shown in FIG. 11A, the number of shots A during deceleration may be associated with the waiting time Tw at the waiting position of the carriage 2 for flushing before printing. The number of shots A is set for each color, and the longer the waiting time Tw, the larger the number of shots A. For example, Ak73> Ak72> Ak71. As shown in FIG. 11A, the waiting time Tw has two threshold values. The number of shots A is set for each time range defined by the threshold value. The relationship between the waiting time and the number of shots A, including the threshold value, is stored in the ROM 52 or the like. This is because the thickening progresses slightly even in the standby state, and the degree of thickening depends on the ease of thickening of the ink. Further, also when the carriage 2 is accelerated in the pre-print flushing, the number of shots may be increased as the waiting time Tw is longer.

Alternatively, for example, in the second modification, as shown in FIG. 11B, the number of shots A during deceleration may be associated with the average duty D in the immediately preceding plurality of ejection processes for flushing during printing. .. The number of shots A is set for each color, and the smaller the average duty D, the larger the number. For example, Ak83> Ak82> Ak81. As shown in FIG. 11B, the average duty D has two thresholds. The number of shots A is set for each range defined by the threshold value. The relationship between the average duty D and the number of shots A, including the threshold value, is stored in the ROM 52 or the like. This is because the lower the printing duty, the lower the ejection opportunity at the time of image formation (ink ejection), and the more difficult it is to maintain / recover the ejection characteristics. Further, even when the carriage 2 is accelerated during flushing during printing, the smaller the duty D, the larger the number of shots may be.

Further, in the first embodiment, the flushing foam 8 is located on the side opposite to the standby position with respect to the platen 4 (the transport path of the recording paper 100). Then, the nozzle row 9 for ink (nozzle row 9 for black ink) that is most easily thickened is arranged on the leftmost side. The time when the nozzle row 9 faces the flushing foam 8 is set to be equal to or longer than the flushing time T required by the nozzle row 9. However, it is not limited to this.

For example, in the third modification, as shown in FIG. 12, the flushing foam 201 is on the left side of the platen 4, but the length L2 in the scanning direction is the length J in the range in which the four nozzle rows 9 are arranged. Longer than. At this time, the four nozzle rows 9 eject black, yellow, cyan, and magenta inks in this order from the left side. Here, in pre-printing flushing and printing-during flushing, when the carriage 2 is decelerated, the four nozzle rows 9 are moved to positions facing the flushing foam 201.

In this case, the nozzle row 9 faces the flushing foam 201 in order from the left side. Further, the nozzle row 9 on the left side continues to face the flushing foam 201 after facing the flushing foam 201 until all the nozzle rows 9 face each other. Further, when the carriage 2 is moved to the right side while accelerating, the nozzle row 9 moves to the right side of the flushing foam 201 in order from the right side. From these facts, in the modification 3, the nozzle row 9 for ejecting the black ink that easily thickens is on the leftmost side, and the time facing the flushing foam 201 is the longest.

Furthermore, the relationship between the four nozzle rows 9 and the color of the ejected ink is not limited to the example described above. As long as the leftmost nozzle row 9 ejects the ink most easily thickened, any other color may be ejected for the other nozzle rows.

Further, in the pre-printing flushing and the printing-during flushing of the first and second embodiments, the drive cycle is different between the acceleration and deceleration of the carriage 2, but the drive cycle is different between the acceleration and deceleration of the carriage 2. It may be the same.

Further, in the pre-printing flushing and the in-printing flushing of the first and second embodiments, the drive cycle and the number of shots are the same among the three color inks. However, if there is a difference in the progress of thickening among the three color inks, the drive cycle and the number of shots may be changed accordingly. The easier the thickening progresses, the longer the drive cycle and the larger the number of shots.

Further, in the pre-printing flushing and the in-printing flushing of the first and second embodiments, the drive cycle and the number of shots are set for each ink color, and the longest flushing time among the flushing times calculated from these is set. The acceleration of the carriage 2 was determined, but the acceleration is not limited to this. For example, the drive cycle and the number of shots may be set in common for the four color inks, and the acceleration of the carriage 2 may be set according to the flushing time determined by the product of the drive cycle and the number of shots.

Further, in the first and second embodiments, in the pre-printing flushing and the printing-during flushing, the drive cycle of the inkjet head 3 is different between the acceleration and deceleration of the carriage 2, but the present invention is not limited to this. For example, in the fourth modification, in the pre-print flushing of the first embodiment, the drive cycle of the inkjet head 3 is the same when the carriage 2 is accelerated and when the carriage 2 is decelerated. Then, as shown in FIG. 13, the ink ejection amount (Ek1, Ek2, etc.) at one time is set individually for the acceleration and deceleration of the carriage 2. At this time, when the carriage 2 is decelerated, the discharge amount is made smaller than when the carriage 2 is accelerated (Ek2> Ek1 or the like). The one-time ejection amount is changed, for example, by changing the drive waveform or drive voltage of the inkjet head 3.

In a state where the ink is greatly thickened, if an attempt is made to increase the amount of ink ejected at one time, the ejected ink may be scattered around. On the other hand, during deceleration, it is possible to prevent ink from scattering by reducing the amount of ink ejected at one time. On the other hand, at the time of acceleration after the thickening is eliminated to some extent, the ink ejected at one time can be increased to eject the required amount of ink in the pre-printing flushing and the in-printing flushing. Similarly, in the flushing during printing of the first embodiment, the amount of ink ejected from the nozzle 10 at one time may be smaller when the carriage 2 is decelerated than when it is accelerated.

Further, in the pre-printing flushing and the in-printing flushing of the second embodiment, the drive cycle is the same during acceleration and deceleration. Further, during deceleration, the amount of ink ejected at one time may be smaller than that during acceleration.

Further, in the above example, in the flushing, the ink is ejected to the flushing foam arranged on the right side or the left side of the platen 4, but the ink is not limited to this.

In the modified example 5, as shown in FIG. 14, foam 211 (“liquid receiver” of the present invention) is arranged at both ends of the platen 4 in the scanning direction. In the scanning direction, the foam 211 extends over a region (conveyance path) in which the recording paper 100 on the platen 4 is transported and a portion outside the region (conveyance path). As a result, when printing an image on the recording paper 100 without providing a margin, that is, so-called borderless printing, the ink protruding from the recording paper 100 can be absorbed by the foam 211.

Then, in the modification 4, in the pre-printing flushing and the in-printing flushing, the ink is ejected toward the portion outside the transport path of the recording paper 100. In pre-print flushing, when the ink is ejected toward the left side (farther from the standby position), the carriage 2 is decelerated and accelerated, and the carriage 2 is decelerated and accelerated during the deceleration and acceleration, as in the first embodiment. Ink is ejected. On the other hand, in pre-print flushing, when ink is ejected toward the right side (closer to the standby position), the carriage 2 is decelerated and accelerated, and the carriage 2 is being decelerated, as in the second embodiment. And during acceleration, ink is ejected.

Further, in flushing during printing, when ink is ejected toward the foams on both sides, the carriage 2 is decelerated and accelerated, and the carriage 2 is decelerated and accelerated, as in the first and second embodiments. , Ink is ejected from the nozzle 10 toward the foam 211.

Further, in the above, an example in which the present invention is applied to an inkjet printer that prints by ejecting ink from a nozzle has been described, but the present invention is not limited to this. For example, the present invention can be applied to a printing apparatus that prints by ejecting a liquid other than ink, such as a material for a wiring pattern of a wiring board from a nozzle.

1 Printer 2 Carriage 3 Inkjet Head 8 Flushing Foam 9 Nozzle Row 10 Nozzle 5, 6 Conveying Roller 50 Control Device 56 Carriage Motor 57 Conveying Motor 59 Linear Encoder 102 Flushing Foam 201 Flushing Foam 211 Form

Claims (13)

A transport device that transports the recording medium in the transport direction,
A liquid discharge head in which a plurality of nozzles are lined up in the transport direction to form a nozzle row and discharge liquid from the plurality of nozzles.
A head moving device that moves the liquid discharge head in a scanning direction that intersects the transport direction,
A liquid receiver located outside the scanning direction of the transport path through which the recording medium is transported,
Outside the transport path in the scanning direction, the head moving device decelerates and moves the liquid discharge head in one direction away from the transport path and accelerates it in the other direction approaching the transport path. Equipped with a moving control device,
The liquid discharge head is
The first nozzle row that discharges the first liquid and
It has a second nozzle row for discharging a second liquid, and has.
The control device is
When performing pre-print flushing performed before printing among flushing in which the liquid discharge head faces the liquid receiver and the liquid is discharged from the nozzle to the liquid receiver.
When the liquid receiver is arranged on the opposite side of the standby position of the liquid discharge head across the transport path, the liquid discharge head is decelerated and accelerated at least during deceleration. The time from the start to the completion of discharge to the liquid receiver, which is the acceleration set by the flushing time determined by the product of the drive cycle of the liquid discharge head and the number of shots according to the discharged liquid. While decelerating the liquid discharge head and moving in the one direction, the liquid is discharged from the nozzle toward the liquid receiver.
When the liquid receiving position and the standby position are arranged on the same side with respect to the transport path, the flushing time is set at least during deceleration and acceleration of the liquid discharge head. in acceleration, while moving in the other direction by accelerating the liquid discharge head, the liquid ejected toward from the nozzle receiving the liquid,
When performing the flushing, the liquid discharge head is moved at an acceleration set based on the longest flushing time among the plurality of flushing times according to the type of each liquid.
When performing the pre-print flushing, the liquid discharge head is moved until the first nozzle row and the second nozzle row are at positions opposite to the standby position with respect to the liquid receiver.
When the liquid receiver is arranged on the opposite side of the standby position across the transport path, the first nozzle row is located outside the transport path on the liquid receiver side from the second nozzle row. Is also located near the transport path
When the liquid receiving position and the standby position are arranged on the same side with respect to the transport path, the first nozzle row is located outside the transport path on the liquid receiving side from the second nozzle row. Is also a printing apparatus characterized in that it is located near the transport path. A transport device that transports the recording medium in the transport direction,
A liquid discharge head in which a plurality of nozzles are lined up in the transport direction to form a nozzle row and discharge liquid from the plurality of nozzles.
A head moving device that moves the liquid discharge head in a scanning direction that intersects the transport direction,
A liquid receiver located outside the scanning direction of the transport path through which the recording medium is transported,
Outside the transport path in the scanning direction, the head moving device decelerates and moves the liquid discharge head in one direction away from the transport path and accelerates it in the other direction approaching the transport path. Equipped with a moving control device,
The control device is
When performing pre-print flushing performed before printing among flushing in which the liquid discharge head faces the liquid receiver and the liquid is discharged from the nozzle to the liquid receiver.
When the liquid receiver is arranged on the opposite side of the standby position of the liquid discharge head across the transport path, the liquid discharge head is decelerated and accelerated at least during deceleration. The time from the start to the completion of discharge to the liquid receiver, which is the acceleration set by the flushing time determined by the product of the drive cycle of the liquid discharge head and the number of shots according to the discharged liquid. While decelerating the liquid discharge head and moving in the one direction, the liquid is discharged from the nozzle toward the liquid receiver.
When the liquid receiving position and the standby position are arranged on the same side with respect to the transport path, the flushing time is set at least during deceleration and acceleration of the liquid discharge head. in acceleration, while moving in the other direction by accelerating the liquid discharge head, the liquid ejected toward from the nozzle receiving the liquid,
When performing the flushing, the liquid is discharged from the nozzle while decelerating or accelerating the liquid discharge head at an acceleration set based on the flushing time both during deceleration and acceleration of the liquid discharge head. ,
When the liquid receiver is arranged on the opposite side of the standby position across the transport path, the drive cycle of the liquid discharge head during deceleration is lengthened as compared with that during acceleration.
When the liquid receiver and the standby position are arranged on the same side with respect to the transport path, the drive cycle of the liquid discharge head during acceleration is made longer than that during deceleration. Printing equipment. The control device is
The flushing is characterized in that the shorter drive cycle of the acceleration drive cycle and the deceleration drive cycle of the liquid discharge head is the same as the drive cycle of the liquid discharge head during printing. The printing apparatus according to claim 2. An encoder for detecting the position of the liquid discharge head in the scanning direction is further provided.
The control device is
At the time of printing, the liquid discharge head is driven in a drive cycle synchronized with the signal from the encoder.
2. Or the liquid discharge device according to 3. The control device is
In the flushing, both when decelerating and accelerating the liquid discharge head, the liquid is discharged from the nozzle while decelerating or accelerating the liquid discharge head at an acceleration set based on the flushing time.
When the liquid receiver is arranged on the opposite side of the standby position across the transport path, the volume of the liquid discharged from the nozzle is larger when the liquid discharge head is accelerated than when the liquid is decelerated.
When the liquid receiver and the standby position are arranged on the same side with respect to the transport path, the volume of the liquid discharged from the nozzle is larger when the liquid discharge head is decelerated than when it is accelerated. The printing apparatus according to any one of claims 2 to 4. The control device is
The printing apparatus according to any one of claims 1 to 5 , wherein the number of times the liquid is ejected from the nozzle in the flushing is made different according to the viscosity of the ink in the nozzle immediately before the flushing. The liquid receiver is arranged on the opposite side of the standby position across the transport path.
The control device is
The printing apparatus according to any one of claims 1 to 6 , wherein during the pre-printing flushing, the deceleration of the liquid discharge head is started from a position where the liquid discharge head faces the transport path. The control device is
The seventh aspect of the present invention is characterized in that the liquid is discharged from the nozzle while accelerating the liquid discharge head at an acceleration set based on the flushing time even when the liquid discharge head is accelerated in the pre-printing flushing. The printing device described. A transport device that transports the recording medium in the transport direction,
A liquid discharge head in which a plurality of nozzles are lined up in the transport direction to form a nozzle row and discharge liquid from the plurality of nozzles.
A head moving device that moves the liquid discharge head in a scanning direction that intersects the transport direction,
A liquid receiver located outside the scanning direction of the transport path through which the recording medium is transported,
Outside the transport path in the scanning direction, the head moving device decelerates and moves the liquid discharge head in one direction away from the transport path and accelerates it in the other direction approaching the transport path. Equipped with a moving control device,
The control device is
When performing pre-print flushing performed before printing among flushing in which the liquid discharge head faces the liquid receiver and the liquid is discharged from the nozzle to the liquid receiver.
When the liquid receiver is arranged on the opposite side of the standby position of the liquid discharge head across the transport path, the liquid discharge head is decelerated and accelerated at least during deceleration. The time from the start to the completion of discharge to the liquid receiver, which is the acceleration set by the flushing time determined by the product of the drive cycle of the liquid discharge head and the number of shots according to the discharged liquid. While decelerating the liquid discharge head and moving in the one direction, the liquid is discharged from the nozzle toward the liquid receiver.
When the liquid receiving position and the standby position are arranged on the same side with respect to the transport path, the flushing time is set at least during deceleration and acceleration of the liquid discharge head. With acceleration, the liquid discharge head is accelerated to move in the other direction, and the liquid is discharged from the nozzle toward the liquid receiver.
In the flushing, the nozzle row is moved to the opposite side of the transport path with respect to the liquid receiver.
When the nozzle row is located on the opposite side of the transport path with respect to the liquid receiver, the liquid discharge head is driven so that the liquid in the nozzles belonging to the nozzle row vibrates without being discharged. A printing device characterized by. A transport device that transports the recording medium in the transport direction,
A liquid discharge head in which a plurality of nozzles are lined up in the transport direction to form a nozzle row and discharge liquid from the plurality of nozzles.
A head moving device that moves the liquid discharge head in a scanning direction orthogonal to the transport direction, and
A liquid receiver located outside the scanning direction of the transport path to which the recording medium is transported, and located on the opposite side of the standby position where the liquid discharge head stands by and the transport path.
On the opposite side of the standby position and the transport path, the head moving device decelerates and moves the liquid discharge head in one direction away from the transport path and accelerates it in the other direction approaching the transport path. Equipped with a moving control device,
The control device is
When performing pre-print flushing performed before printing among flushing in which the liquid discharge head faces the liquid receiver and the liquid is discharged from the nozzle to the liquid receiver.
The liquid discharge head starts decelerating from the position facing the transport path toward the liquid receiver, and at the same time, it starts decelerating.
When the liquid discharge head faces the liquid receiver, the liquid discharge head is decelerated by the acceleration set by the flushing time required from the start to the completion of the discharge of the liquid to the liquid receiver. A printing device characterized in that a liquid is discharged from the nozzle toward the liquid receiver while moving in one direction. The control device is
When the nozzle row is located on the opposite side of the transport path with respect to the liquid receiver, the liquid discharge head is driven so that the liquid in the nozzles belonging to the nozzle row vibrates without being discharged. The liquid discharge device according to claim 10. The control device is
When the liquid discharge head faces the liquid receiver during both deceleration and acceleration of the liquid discharge head, the liquid is discharged from the nozzle to the liquid receiver and at the same time.
The liquid discharge device according to claim 10 , wherein the drive cycle of the liquid discharge head during deceleration is made longer than that during acceleration. The control device is
When the liquid discharge head faces the liquid receiver during both deceleration and acceleration of the liquid discharge head, the liquid is discharged from the nozzle to the liquid receiver and at the same time.
The liquid discharge device according to any one of claims 10 to 12 , wherein when accelerating the liquid discharge head, the volume of the liquid discharged from the nozzle is larger than when decelerating.

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