JP2011088374A - Stop control method of carriage during liquid supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep a carriage at a home position A during ink supply even if a drive load of the carriage is varied in an ink supply operation to a sub-tank mounted to the carriage. <P>SOLUTION: The control unit 30 of an ink jet printer 1 assumes a variation of the drive load of the carriage 13 incident to a variation of a remaining amount of ink in the sub-tank during ink supply operation to the sub-tanks 15a-15d at the home position A, computes a time required for ink supply operation in advance and determines a stop control time t. After the carriage 13 returns to the home position A before the stop control time t elapses, a drive current of a carriage motor 14a is adjusted according to the position detection result of the carriage 13. After the elapse of the stop control time t, the control unit is brought into a standby state by setting the drive current of a carriage motor 14a to a constant value (hold current), or performs next print operation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  According to the present invention, a liquid discharge head and a sub tank are mounted on a carriage, and liquid is supplied from the main tank to the sub tank in the liquid discharge apparatus configured to supply liquid from the main tank to the sub tank while the carriage is stopped at the home position. The present invention relates to a carriage stop control method.

  2. Description of the Related Art Conventionally, an ink jet printer that includes a sub tank mounted on a carriage together with an ink jet head and supplies ink from the sub tank to the ink jet head when performing an ink discharge operation has been used. Some ink jet printers of this type perform an ink replenishing operation from a main tank to a sub tank such as an ink cartridge mounted on the printer body at the timing when the carriage returns to the home position.

  In this type of configuration, the ink supply operation to the sub tank is performed by driving a pump. However, if a drive system for driving the pump is provided independently of other drive systems, the manufacturing cost of the apparatus increases. End up. Therefore, a pump unit has been proposed in which the pump is driven by the operation of moving the carriage from the printing area to the home position, and the ink supply operation to the sub tank is performed. Specifically, when the carriage returns to the home position, the pump unit is configured to operate by pressing the pump lever of the sub tank against the inner wall surface of the printer case on the home position side or the frame of the printer mechanism, etc. As the pump lever is actuated by the pressing force, the volume of the sub-tank is increased, and ink is replenished by sucking ink from the main tank into the sub-tank by the negative pressure formed at this time.

  When such a pump unit is used, it is necessary to hold the pump lever in the operating position until the ink supply is completed. For this reason, the carriage is prevented from moving from the home position during the ink supply. It is necessary to perform stop control. That is, in such a pump unit, as ink is sucked into the sub tank, the driving load of the carriage for pressing the pump lever against the frame and holding it in the operating position decreases. On the other hand, the carriage stop position at the home position is set slightly in front of the position where the carriage stops against the home position side frame. Therefore, if the carriage drive system is not controlled at all during replenishment, the carriage starts to move as the driving load decreases during replenishment, and may collide with the frame or the inner wall surface beyond the stop position. And the meniscus in the nozzle of an inkjet head may be broken by the vibration and impact at this time.

  Patent Document 1 describes hold control of a carriage motor for holding the carriage at a stop position. In this hold control, when the carriage enters the target range, the drive current at the time of holding is determined by subtracting or adding the current value corresponding to the friction load to the drive current at that time according to the traveling direction of the carriage. The carriage is held at the target position by passing this value of drive current.

JP 2005-262885 A

  In Patent Document 1, a constant drive current (hold current) is supplied to the carriage motor while the carriage is held within the target range. Therefore, in an inkjet printer having a pump unit as described above, the drive load of the pump unit (the load for pressing the pump lever to hold it in the operating position) changes due to ink supply during stoppage. There is a possibility that the carriage may start to move from the stop position (supply position) during the replenishment and collide with the frame or the inner wall surface. And the meniscus in the nozzle of an inkjet head may be broken by the vibration and impact at this time.

  In addition, if stop control assuming ink replenishment is performed uniformly at the timing when the carriage returns to the home position during printing, stop control is performed until ink replenishment is not necessary, and throughput is reduced. There is a problem. Furthermore, if the control corresponding to the fluctuation of the driving load is always continued during the stop, the extra control is performed until the ink supply is completed and the control is no longer necessary. There is a problem that increases.

  In view of this point, an object of the present invention is to change the driving load for holding the carriage at the replenishment position (home position) during replenishment in a liquid replenishment operation in which a liquid such as ink is replenished to a sub tank mounted on the carriage. Even in this case, the present invention is to propose a carriage stop control method at the time of liquid replenishment that can reliably hold the carriage at the replenishment position.

  Another object of the present invention is to reduce the throughput by performing drive control that can cope with fluctuations in the drive load of the carriage that is being replenished, but not performing unnecessary control until such drive control is not necessary. An object of the present invention is to propose a carriage stop control method capable of improving and suppressing an increase in an excessive control load.

In order to solve the above problems, the present invention provides:
Supplying liquid to the liquid discharge head from a sub-tank mounted on the carriage together with the liquid discharge head;
By moving the carriage to a predetermined supply position, a liquid supply operation for sucking liquid from the main tank to the sub tank is performed at the supply position.
In the liquid supply operation,
Before the carriage reaches the replenishment position, the time required to suck the liquid to the sub tank to the maximum capacity is calculated,
After the carriage reaches the replenishment position until the necessary time elapses,
The carriage driving means is controlled so as not to move the carriage from the replenishment position due to fluctuations in the driving load for holding the carriage at the replenishment position during liquid replenishment. .

  In the present invention, assuming that the driving load of the carriage fluctuates during the liquid replenishing operation, the carriage is not moved from the replenishing position even when the driving load fluctuates during replenishment. The carriage drive means is controlled. Therefore, the necessary time required for the liquid replenishing operation is calculated in advance, and the drive control is performed only until the necessary time elapses. As a result, the carriage can be reliably held at the replenishment position even if the driving load fluctuates during the necessary time, and the liquid can be reliably replenished to the maximum capacity. In addition, there is no possibility that the carriage will start to move from the stop position (supply position) during replenishment and collide with the inner wall surface of the device case or the frame of the liquid discharge mechanism. There is no risk of the inner meniscus breaking. Therefore, the discharge quality can be improved. In addition, since unnecessary control is not continued until after replenishment is completed, an increase in control load during standby can be suppressed. Furthermore, since the printing operation can be promptly returned after the replenishment is completed, the throughput of the liquid ejection operation can be improved.

  In the present invention, after the liquid replenishment operation is completed, when shifting to a standby state in which the carriage is in a standby state at the replenishment position, after the necessary time has elapsed, the driving means applies a certain holding force to the carriage. Is in a state to add. In this way, since it is not necessary to control the driving means unnecessarily until the drive load no longer fluctuates, an increase in the standby control load can be suppressed.

  Here, in the present invention, the required time can be calculated based on the liquid remaining amount in the sub tank before the start of replenishment. At this time, the remaining amount of liquid in the sub tank can be calculated based on the liquid discharge amount from the liquid discharge head. In this way, the remaining amount of liquid is calculated using data indicating the discharge content of the liquid and information on the liquid discharge amount that can be grasped based on the count value of the number of discharged droplets, etc. Time can be calculated. For example, a table in which the remaining amount of liquid and the required time are associated with each other in advance by experiment or calculation, and the corresponding required time can be extracted from the table based on the calculated remaining liquid amount.

  In the present invention, the subtank is provided with a diaphragm that is displaced in a first direction in which the volume of the subtank decreases as the liquid remaining amount decreases, and an operation member connected to the diaphragm via a spring member. When the carriage is moved closer to the replenishment position, the operating member is pressed by the contact member provided at the replenishment position, and the spring member is extended. A configuration can be adopted in which a negative pressure is formed in the sub-tank by applying an elastic force in a direction opposite to the first direction to the diaphragm to suck the liquid. In this case, since the contact member is pressed via the operation member by the elastic return force of the spring member, the carriage is caused to move due to fluctuations in the driving load including a force applied to the carriage as a reaction. The carriage driving means can be controlled so as not to move from the replenishment position.

  In such a configuration, since the liquid can be sucked by forming a negative pressure in the sub-tank by moving the carriage to the replenishment position, it is not necessary to provide a separate drive source for suction, and the apparatus cost can be reduced. it can. Further, the liquid supply operation can be performed at the timing when the carriage is returned to the supply position. In such a configuration, even if the elastic restoring force of the spring member decreases as the remaining amount of liquid increases and the driving load of the carriage for holding the carriage at the supply position fluctuates, the carriage is replenished. Can be held in position. Accordingly, it is possible to suppress the carriage from moving toward the contact member side and colliding with the contact member as the liquid is sucked, and the meniscus in the nozzle of the liquid discharge head may be broken by the vibration or impact at this time. Disappears.

  Here, when the carriage drive means is a DC motor, the stop control method of the present invention can be executed by controlling the drive current of the DC motor in accordance with the fluctuation of the drive load.

  Further, the replenishment position may be a home position of the carriage, and the liquid replenishment operation may be performed at a timing when the carriage returns to the home position. In this way, since the standby position (home position) becomes the replenishment position, drive control is performed only while replenishment is performed at the home position, and waste is made until the replenishment is completed and the drive load no longer fluctuates. Therefore, it is possible to prevent the control load from being increased.

  According to the present invention, the necessary time required for the liquid replenishing operation is calculated in advance, and the carriage drive control is performed until the necessary time elapses. The carriage can be reliably held at the replenishment position. Therefore, the liquid can be reliably replenished to the maximum capacity. Further, there is no possibility that the carriage starts to move from the stop position (supply position) during replenishment and collides with the inner wall surface of the apparatus case or the frame of the liquid discharge mechanism, so that the meniscus in the nozzle of the liquid discharge head is not affected by vibration or impact. There is no risk of breaking. Therefore, the discharge quality can be improved. In addition, since unnecessary control is not continued until after replenishment is completed, an increase in control load during standby can be suppressed. Furthermore, since the liquid discharge operation can be promptly returned after the replenishment is completed, the throughput of the liquid discharge operation can be improved.

1 is an external perspective view of an ink jet printer to which the present invention is applied. It is a schematic perspective view of a printer mechanism part. It is explanatory drawing which shows schematic structure of the ink supply system of an inkjet printer. It is a perspective view of a carriage and an ink supply system. It is a schematic sectional drawing which shows the principal part of a diaphragm pump unit. FIG. 6 is an explanatory diagram illustrating a carriage stop position during an ink supply operation. It is a schematic block diagram which shows the control system of an inkjet printer. It is a timing chart which shows the position of a carriage, its driving load, and the driving current of a carriage motor. 6 is a flowchart of stop control in an ink supply operation.

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

(overall structure)
FIG. 1 is an external perspective view of an ink jet printer. An ink jet printer 1 (liquid ejection device) performs color printing on a long recording paper fed out from roll paper using a plurality of types of color inks, and includes a printer case 2 having a rectangular parallelepiped shape as a whole. An opening 3 for mounting a roll paper is formed at the center of the front surface of the printer case 2. The opening 3 is sealed by an opening / closing lid 5 to which a recording paper discharge guide 4 is attached at the upper end. A recording paper discharge port 6 is formed between the recording paper discharge guide 4 and the upper edge portion of the opening 3 of the printer case 2. When the lock (not shown) is released and a finger is placed on the recording paper discharge guide 4 and pulled forward, the opening / closing lid 5 can be opened from the closed position shown in the drawing to the open position that falls forward about the lower end.

  A power switch 7a, a paper feed switch 7b, a plurality of operation state display lamps 7c, and the like are arranged on the right side of the opening / closing lid 5 on the front surface of the printer case 2. A mounting port 8 a of an ink cartridge mounting portion 8 having a vertically long rectangular cross section extending in the front-rear direction of the printer is opened on the left side portion of the opening / closing lid 5 on the front surface of the printer case 2. Is installed. When a button (not shown) is operated, the lock is released, the ink cartridge 9 is pushed forward by the spring force, and the ink cartridge 9 can be pulled out.

  FIG. 2 is a schematic perspective view showing the printer mechanism unit 10 covered with the printer case 2 in the inkjet printer 1. A roll paper storage unit is formed in the center of the printer mechanism unit 10. When the opening / closing lid 5 is opened, the roll paper storage unit opens forward, and the roll paper can be replaced. A platen 11 is bridged in the printer width direction on the upper side of the roll paper storage unit, and a carriage 13 on which an inkjet head 12 (liquid ejection head) with a nozzle surface facing downward is mounted on the upper side of the platen 11. Has been placed.

  On the rear side of the carriage 13, a carriage guide shaft 13a is spanned in parallel with the platen 11 in the printer width direction, and a carriage motor 14a is disposed on the rear side of the carriage guide shaft 13a. The carriage motor 14a serves as a drive source for the carriage drive mechanism 14 that drives the carriage 13 to reciprocate in the carriage scanning direction along the carriage guide shaft 13a. In this embodiment, a DC motor is used. The carriage 13 is moved by the carriage drive mechanism 14 from a home position A indicated by a solid line in FIG. 2 that is off the right side of the platen 11 to a left end position B indicated by an imaginary line in FIG. 2 that is off the left side of the platen 11. Is possible. The ink jet printer 1 transports the recording paper fed from the roll paper by a recording paper transport mechanism (not shown) along the surface of the platen 11, and performs ink jet toward the recording paper while scanning the carriage 13 in conjunction with the transport operation. Printing on recording paper is performed by ejecting ink from the head 12.

(Ink supply system)
FIG. 3 is an explanatory diagram showing a schematic configuration of an ink supply system of the ink jet printer 1, and FIG. 4 is a perspective view showing portions of a carriage and an ink supply system in the printer mechanism portion of FIG. Along with the inkjet head 12, the carriage 13 is mounted with a diaphragm pump unit 16 including subtanks 15a to 15d for storing inks of four colors of cyan, magenta, yellow, and black. The ink supplied from the diaphragm pump unit 16 to the inkjet head 12 is temporarily stored in each of the sub tanks 15a to 15d, and then the head of the inkjet head 12 through the ink flow path portion provided with the check valve 19a. It is supplied to the inner flow paths 12a to 12d.

  One end of the flexible ink tubes 17a to 17d is connected to each of the sub tanks 15a to 15d of the diaphragm pump unit 16 via a joint flow path. On the other hand, the other ends of the flexible ink tubes 17a to 17d are connected to the upper end portion of the flat flow path 18 disposed at the position on the rear end side of the ink cartridge mounting portion 8, and the flat flow path 18 is The ink packs 9a to 9d (main tanks) in the ink cartridge 9 are connected to each other. As shown in FIG. 3, the planar flow path 18 includes four ink supply paths 18a to 18d extending in the vertical direction, and flexible ink tubes 17a to 17d are provided at the upper ends of the ink supply paths 18a to 18d, respectively. Is connected. Each ink supply path 18a-18d is provided with a choke valve mechanism 19b so that the ink supply paths 18a-18d can be closed during head cleaning. Further, a check valve 19c is provided on the upstream side of the choke valve mechanism 19b so that ink flows only in one direction from the ink packs 9a to 9d toward the inkjet head 12.

  The ink cartridge 9 as a whole has a flat rectangular parallelepiped shape that is long in the front-rear direction and the up-down direction, and four types of ink packs 9a to 9d of cyan, magenta, yellow, and black are accommodated therein. When the ink cartridge 9 is inserted into the mounting position of the ink cartridge mounting portion 8, the ink supply needles provided at the lower ends of the ink supply paths 18a to 18d are inserted into the ink supply ports of the ink packs 9a to 9d. Thereby, an ink supply path for supplying each color ink from the ink packs 9a to 9d of the ink cartridge 9 to the ink jet head 12 side via each ink supply needle is formed. The inside of the ink cartridge 9 is pressurized by the supply of compressed air from a pressure mechanism (not shown), and the ink stored in each of the ink packs 9a to 9d is sent to the ink supply paths 18a to 18d by this pressure. .

  As shown in FIG. 4, an IC chip 9 e is mounted on the ink cartridge 9. When the ink cartridge 9 is mounted on the ink cartridge mounting unit 8, the IC chip 9e and the control unit 30 (see FIG. 7) of the ink jet printer 1 are electrically connected, and information from the control unit 30 to the IC chip 9e is transmitted. Reading and writing are possible. Information read / written between the control unit 30 and the IC chip 9e includes the date when the ink cartridge 9 is used and the number of ink droplets of each color of ink ejected by the ink jet head 12 from the time when the ink cartridge 9 is used. For example, the cumulative number of ink droplets accumulated.

(Configuration of diaphragm pump unit)
FIG. 5 is a schematic cross-sectional view showing the main part of the diaphragm pump unit. The diaphragm pump unit 16 is configured such that a suction mechanism 20 for sucking ink into the sub tanks 15a to 15d is provided above the sub tanks 15a to 15d, respectively. As shown in FIG. 5, the sub tank 15 a (15 b to 15 c) includes a cylindrical cylinder 21 that extends in the vertical direction, and an ink chamber 22 is provided at the bottom of the cylinder 21. A diaphragm 23 is attached to the cylinder 21 so as to close the upper portion of the ink chamber 22, and a thick portion 23 a is formed at the center of the diaphragm 23. A piston member 24 that can reciprocate in the vertical direction in the cylinder 21 is connected to the thick portion 23a.

  The suction mechanism 20 includes the diaphragm 23 and the piston member 24 provided in the cylinder 21, a coil spring 25 (spring member) attached to the top of the piston member 24, and a side of the cylinder 21 from above the coil spring 25. And a suction lever (operation member) 25 that is bent and extends in an L-shape. The suction lever 26 can swing around a support shaft 27 provided above the cylinder 21 on the home position A side (that is, the inner wall surface 29 side of the printer case 2). A first arm portion 26 a extending laterally upward from the cylinder 21, and a second arm portion 26 b extending downward from the support shaft 27. A hook 28 is formed at the tip of the first arm portion 26 a, and the upper end of the coil spring 25 is locked to the hook 28. The lower end of the coil spring 25 is connected to the piston member 200. Further, the distal end portion of the second arm portion 26b protrudes toward the inner wall surface 29 side.

(Ink supply operation)
When the carriage 13 moves away from the home position A and moves onto the platen 11 and ejects ink from the inkjet head 12 in the printing area on the platen 11, ink is supplied from the sub tanks 15 a to 15 d to the inkjet head 12. That is, the inkjet head 12 performs printing while consuming the ink in the sub tanks 15a to 15d. Here, when the ink in the sub tanks 15a (15b to 15d) shown in FIG. 5 is reduced, the diaphragm 23 is lowered downward (first direction) by the negative pressure generated by the reduction of the ink, and the volume of the ink chamber 22 is increased. Decrease. Accordingly, the suction lever 26 swings in the X direction in FIG. 5 about the support shaft 27 as the tip end portion of the first arm portion 26a connected to the diaphragm 23 descends. As a result, the amount of protrusion of the distal end portion of the second arm portion 26b toward the home position A side (inner wall surface 29 side) increases.

  FIG. 6 is an explanatory view showing the stop position of the carriage during the ink supply operation. When the carriage 13 is moved from the printing area on the platen 11 to the home position A (supply position) at the end of printing, the suction lever 26 is moved by the inner wall surface 29 (contact member) of the printer case 2 to the second arm portion 26b. The tip portion is pressed and swings, and moves to the suction position C shown in FIG. At the suction position C, the distal end of the first arm portion 26a moves upward to extend the coil spring 25, so that the diaphragm 23 is pulled upward by the elastic return force of the coil spring 25. As a result, the capacity of the sub tank 15a (15b to 15d) is increased, and a negative pressure is formed in the sub tank 15a (15b to 15d).

  While the carriage 13 is stopped at the home position A, since the suction lever 26 is held at the suction position C, the elastic return force of the coil spring 25 is continuously applied and the capacity of the sub tank 15a (15b to 15d) is increased. Increased state is maintained. Therefore, during this time, ink is sucked into the ink chamber 22 from the flexible ink tube 17a (17b to 17d) side, and ink is supplied to the sub tank 15a (15b to 15d).

(Control system)
FIG. 7 is a schematic block diagram showing a control system of the ink jet printer. The control system of the inkjet printer 1 is mainly configured by a control unit 30 including a CPU, a ROM, a RAM, and the like. The control unit 30 is connected to the host device 31 and the like, and controls each unit of the inkjet printer 1 based on a print command received from the host device 31. When receiving the print command, the control unit 30 conveys the recording paper fed out from the roll paper along the surface of the platen 11 and drives the carriage driving mechanism 14 in conjunction with this conveyance to perform recording while scanning the carriage 13. A printing operation is performed to eject ink droplets from the inkjet head 12 toward the paper, and the carriage 13 is returned to the home position A during printing standby. Further, as described above, the IC chip 9e mounted on the ink cartridge 9 is connected to the control unit 30. The control unit 30 is connected to a linear encoder 13 b provided in the printer mechanism unit 10. The linear encoder 13b detects the position of the carriage 13 that reciprocates along the carriage guide shaft 13a.

  The control unit 30 includes an ink droplet number accumulating unit 32, an ink discharge amount acquiring unit 33, a sub tank remaining amount acquiring unit 34, a main tank remaining amount acquiring unit 35, a required time calculating unit 36, and an ink end determining unit. 37 and stop control time setting means 38.

  The ink droplet number accumulating unit 32 counts the number of ink droplets of each ink ejected from the inkjet head 12 each time printing or flushing is performed, and accumulates them as the cumulative number of ink droplets of each ink. Further, the cumulative number of ink droplets of each ink is written to the IC chip 9e.

  Each time the carriage 13 is returned to the home position A, the ink discharge amount acquisition means 33 reads the cumulative ink droplet number of each ink written on the IC chip 9e by the ink droplet number accumulation means 32, and returns to the previous home position A. The ink discharge amount is calculated based on the difference between the cumulative ink droplet number read when returning and the cumulative ink droplet number newly read this time.

  The sub tank remaining amount acquisition means 34 acquires the ink remaining amount (liquid remaining amount) in the sub tanks 15a to 15d. That is, every time the carriage 13 is returned to the home position A, the ink discharge amount acquired by the ink discharge amount acquisition unit 33 is subtracted from the maximum capacity of each sub tank 15a to 15d, and the remaining ink amount in each sub tank 15a to 15d. Is calculated.

  The main tank remaining amount acquisition means 35 acquires the remaining amount of ink in the ink packs 9a to 9d. That is, every time the carriage 13 is returned to the home position A, the ink droplet number accumulating means 32 reads the accumulated ink droplet number of each ink written on the IC chip 9e, and based on this accumulated ink droplet number, The ink remaining amount of the packs 9a to 9d is calculated.

  The required time calculation means 36 should maintain the state where the carriage 13 is stopped at the home position A in order to complete the replenishment of ink to the sub tanks 15a to 15d based on the ink remaining amount in each of the sub tanks 15a to 15d. The time length, that is, the time length (required time) required to suck ink from the ink packs 9a to 9d to the maximum capacity of the sub tanks 15a to 15d is calculated for each sub tank, that is, for each ink color. More specifically, the required time calculation means 36 calculates the required time defined in advance based on the relationship with the remaining amount of ink in the sub tanks 15a to 15d through experiments and calculations, and the remaining ink in the sub tanks 15a to 15d. A time length table in which the amount and the required time are associated is stored and held in a ROM or the like. When the carriage 13 returns to the home position A, the required time calculating unit 36 uses the ink remaining amount in each of the sub tanks 15a to 15d calculated by the sub tank remaining amount acquiring unit 34, and sets the corresponding required time to the time length table. Extract from

  Here, in the case where the required time varies according to the ink remaining amount of the ink packs 9a to 9d, the ink remaining amount in the ink packs 9a to 9d and the ink remaining amount in the sub tanks 15a to 15d are determined in advance. The time length (required time) required for ink suction defined based on the relationship is calculated by experiment or calculation, and the remaining ink amount in the sub tanks 15a to 15d, the remaining ink amount in the ink packs 9a to 9d, and the required time, Is stored in a ROM or the like. In this case, when the carriage 13 returns to the home position A, the required time calculation unit 36 uses the remaining ink amount in the ink packs 9a to 9d and the remaining ink amount in the sub tanks 15a to 15d to this. The corresponding required time is extracted from the time length table.

  The ink end determination unit 37 determines whether or not the ink end is substantially zero in the ink packs 9a to 9d. More specifically, it is determined that the ink cartridge 9 is in an ink end when the remaining amount of ink in each of the ink packs 9a to 9d is less than a predetermined threshold value.

  The stop control time setting means 38 stops the carriage 13 at the home position A until the ink supply is completed when the carriage 13 returns to the home position A based on the required time calculated by the required time calculation means 36. The time for performing the control (stop control time t) is determined. That is, the stop control time setting means 38 selects the longest required time from the four required times for each color ink calculated for each of the sub tanks 15a to 15d, and sets this time as the stop control time t. .

(Carriage stop control method)
As shown in FIG. 6, the stop position of the carriage 13 during ink supply, that is, the home position A (supply position) is set slightly in front of the inner wall surface 29 of the printer case 2. The carriage 13 is held at the home position A until ink replenishment is completed, and if ink replenishment during printing is performed, printing is continued after completion of replenishment. If printing is on standby, the printer waits at the home position A until the next printing is performed.

  FIG. 8 is a timing chart showing the position of the carriage, its driving load, and the driving current of the carriage motor. In FIG. 8, T1 is the timing when the tip of the second arm portion 26b of the suction lever 26 contacts the inner wall surface 29 of the printer case 2 during the movement to the home position A, and T2 is the carriage 13 reaching the home position A. The timing T3 is the timing at which the ink supply operation is completed. In this example, after the ink supply operation is completed, the print standby state is entered, and the carriage 13 is held at the home position A as it is.

  The solid line P in FIG. 8 is the position of the carriage 13, and the upper side of the vertical axis is the home position A side. In the example of this figure, the carriage 13 is moved at a constant speed until it reaches the home position A (at time T2). A solid line F in FIG. 8 is a driving load of the carriage 13. When the carriage 13 is moved to the home position A, the driving load is constant until the tip of the second arm portion 26b hits the inner wall surface 29 (at time T1). Therefore, the drive current (solid line I in FIG. 8) during this period is a constant value.

  Subsequently, the tip end portion of the second arm portion 26b abuts against the inner wall surface 29, and during the period until the suction lever 26 moves to the suction position C while turning (period from T1 to T2), The driving load increases as the carriage 13 approaches the home position A. That is, during this period, the extension amount of the coil spring 25 that pulls the diaphragm 23 upward increases as the suction lever 26 pivots, and the home position is increased by the elastic return force of the extended coil spring 25. The biasing force of the second arm portion 26b biased toward the A side increases. That is, the driving load for driving the carriage 13 to the home position A side while turning the suction lever 26 against the increase in the urging force increases as the carriage 13 approaches the home position A.

  Subsequently, the driving load of the carriage 13 during the period in which the carriage 13 is stopped at the home position A in order to complete the ink supply operation (period T2 to T3) depends on the remaining amount of ink in the sub tanks 15a to 15d. fluctuate. That is, the extension amount of the coil spring 25 that pulls the diaphragm 23 upward against the negative pressure decreases as the ink remaining amount in the sub tanks 15a to 15d increases, and the elastic restoring force of the coil spring 25 decreases accordingly. And the force which presses the inner wall surface 29 by the 2nd arm part 26b urged | biased by the home position A side reduces. For this reason, as a reaction of pressing the inner wall surface 29 by the second arm portion 26b, the force that urges the carriage 13 from the home position A toward the left end position B is reduced, and this urging force is countered. The driving load for stopping the carriage 13 at the home position A decreases as the ink remaining amount in the sub tanks 15a to 15d increases.

  When the ink replenishment operation is completed, the elastic restoring force of the coil spring 25 does not decrease any more, so that the drive load fluctuation due to ink suction is eliminated. Therefore, in order to hold the carriage 13 at the home position A after the completion of the ink replenishment operation and enter the standby state, it is only necessary to apply a certain holding force to the carriage 13. That is, after the ink supply operation is completed, the drive current of the carriage motor 14a may be set to a constant value (hold current).

  In the period from T1 to T2, the control unit 30 of the ink jet printer increases the driving current of the carriage motor 14a according to the position of the carriage 13 so that the carriage 13 moves to the home in response to the increase in driving load. Move to position A. On the other hand, during the ink supply operation (period T2 to T3), stop control for holding the carriage 13 at the home position A is performed by adjusting the drive current of the carriage motor 14a in accordance with the decrease in the drive load.

  FIG. 9 is a flowchart of stop control in the ink supply operation. The control unit 30 starts the stop control according to this flowchart at the timing when the carriage 13 returns to the home position A. Here, when it is determined by the ink end determination means 37 that the ink end is reached, the ink cannot be sucked, so that stop control is not necessary. Therefore, in such a case, the control unit 30 does not perform the stop control according to the flowchart of FIG. 9 even at the timing when the carriage 13 returns to the home position A.

  First, the control unit 30 sets a stop control time t until the carriage 13 reaches the home position A (step S1). The stop control time t is the length of the period from T2 to T3, and as described above, the stop control time t is determined as the longest time from the necessary time for each color ink. That is, the stop control time t is a necessary time for filling all the sub tanks 15a to 15d to the maximum capacity.

  Next, in step S2, the control unit 30 sets the drive current of the carriage motor 14a to a preset initial current value. The initial current value may be determined based on the drive current when the home position A is reached.

  Subsequently, the control unit 30 determines the current position of the carriage 13 (step S3) every time a predetermined time elapses. In step S3, the control unit 30 detects the current position of the carriage based on the output of the linear encoder 13b. Then, it is determined whether or not the detected position matches the home position A, and if not, whether the detected position is on the left end position B side or the inner wall surface 29 side of the home position A is determined. If the current position matches the home position A (step S3: Yes), the process proceeds to step S4. On the other hand, when the current position does not coincide with the home position A (step S3: No), the process proceeds to step S5.

  In step S4, the control unit 30 determines whether or not the elapsed time measured from the time when the carriage 13 reaches the home position A is equal to or longer than the stop control time t. If this elapsed time is less than the stop control time t (step S4: No), the process returns to step S3. And the process of step S3-S4 or step S3-S5 is continued until elapsed time becomes more than stop control time t. On the other hand, when the elapsed time is equal to or longer than the stop control time t, the process ends.

  In step S <b> 5, the control unit 30 adjusts the drive current of the carriage motor 14 a according to the current position of the carriage 13. When determining that the carriage 13 is closer to the inner wall surface 29 than the home position A, the control unit 30 reduces the drive current of the carriage motor 14a by a predetermined amount. At this time, the adjustment amount of the drive current in step S5 is set to exceed the assumed decrease amount of the drive load. On the other hand, when it is determined that the carriage 13 is on the left end position B side from the home position A, the control unit 30 increases the drive current of the carriage motor 14a by a predetermined amount. In this case, the adjustment amount (increase amount) is set to be small in consideration that the drive load decreases with ink suction. By such adjustment, the carriage 13 can be returned to the home position A side again.

  After the control according to the flowchart of FIG. 9 is completed, either the printing operation is resumed or the apparatus waits at the home position A as it is due to the completion of the ink supply operation. When the carriage 13 is kept on standby at the home position A as it is, the drive current of the carriage motor 14a is set to a constant value (hold current) as described above. The current value of the hold current may be set in advance, or may be calculated according to the drive current when the stop control time t has elapsed.

  As described above, according to the stop control described above, when the ink supply operation is performed, the required time required for the ink supply operation is calculated in advance to determine the stop control time t until the stop control time t elapses. During this period, the carriage 13 is stopped. As a result, the carriage 13 can be prevented from leaving the home position A before ink is supplied to the maximum capacity, and ink can be reliably supplied. In addition, since the carriage 13 can be prevented from colliding with the inner wall surface 29 of the printer case 2 during replenishment, there is no possibility that the meniscus in the nozzles of the inkjet head 12 will be broken by vibration or impact at the time of collision, and the print quality can be improved. Can be improved. Further, since the stop control is terminated simultaneously with the completion of the ink replenishment, an increase in the control load during standby for printing can be suppressed. Further, since the next printing operation can be started immediately after the ink supply is completed, the throughput of the print job is improved.

(Modification example)
(1) In the above embodiment, the remaining amount of ink in the subtanks 15a to 15d is calculated by the subtank remaining amount acquisition unit 34, and the necessary time calculating unit 36 calculates the necessary time based on this, but the subtank remaining amount is calculated. The acquisition unit 34 may be omitted, and the necessary time may be calculated based on the ink discharge amount of each color ink calculated by the ink discharge amount acquisition unit 33. In this case, a time length table in which the ink discharge amount is associated with the required time, or a time length table in which the ink discharge amount is associated with the ink remaining amount of the ink packs 9a to 9d is created in advance in the ROM or the like. Just keep it in memory.

(2) In the above embodiment, during the ink supply operation (period from T2 to T3), the drive current is increased or decreased step by step at regular intervals, and the drive current is not changed except at the timing of performing this increase / decrease. However, after setting the drive current to the stop current value at the timing of T2, the drive current is decreased according to a predetermined decrease pattern considering the decrease in the drive load, and position determination is performed at regular intervals to determine the drive current. You may make it perform control which adjusts. In this way, an increase in the difference between the driving load and the driving force by the carriage motor 14a can be suppressed, and the driving force can be increased or decreased as necessary. Therefore, the deviation of the carriage 13 from the home position A can be further reduced.

(3) In the above embodiment, except for the case where the current position of the carriage 13 coincides with the home position A, the process proceeds to step S5 to adjust the drive current. However, the target position range including the home position A is set in advance. The drive current may be adjusted when the carriage 13 is outside the target position range, and may not be adjusted when the carriage 13 is within the target position range. In this case, the target position range is such that the carriage 13 does not collide with the inner wall surface 29, and the swiveling position of the suction lever 26 pressed by the inner wall surface 29 has a negative pressure that can suck ink. It is good to set so that it may become the range which can be formed in the chamber 22. FIG.

(4) In the above embodiment, the drive current is adjusted based on the position detection result of the carriage 13, but the turning position of the suction lever 26 is detected, and the drive current is adjusted based on the detection result. You can go. Alternatively, a pressure sensor is provided at the tip of the second arm portion 26b of the suction lever 26, the pressure applied to the contact position of the second arm portion 26b with the inner wall surface 29 is detected to directly detect the driving load, The drive current may be adjusted based on this. Alternatively, the fluctuation pattern of the driving load may be obtained in advance by experiment or calculation, and the fluctuation pattern of the driving load may be acquired simultaneously when calculating the necessary time, and the driving current may be controlled based on this.

(5) In the above-described embodiment, the home position A is the position where the ink replenishment operation is performed (replenishment position). However, a configuration in which another position is the replenishment position is also possible. For example, if the suction lever 26 is provided on the left end position B side, the left end position B can be set as the supply position.

(6) In the above embodiment, the stop control time t is set to the longest value among the necessary times for the suction of the inks of the respective colors calculated by the necessary time calculating unit 36. Depending on other parameters, the required time may be determined differently. For example, when only a part of the color inks is used in the next printing, it may be possible to determine the stop control time t while paying attention only to the necessary time for the color inks to be used. In addition, for a sub-tank whose ink remaining amount is equal to or greater than a specified amount, the required time may be set to zero, assuming that the current replenishment is not necessary.

(Other embodiments)
Each of the above embodiments is an example in which the present invention is applied to a method for controlling the stop of the carriage 13 during an ink replenishment operation in the inkjet printer 1, but the present invention is applicable to other liquid ejecting apparatuses that eject liquid other than ink. Is also applicable. For example, it can also be applied to liquid ejection devices for ejecting reagent solutions and liquid samples from liquid ejection heads, and liquid ejection devices for ejecting liquid paints and liquid materials from liquid ejection heads and applying them by printing It is.

DESCRIPTION OF SYMBOLS 1 ... Inkjet printer, 2 ... Printer case, 3 ... Opening part, 4 ... Recording paper discharge guide, 5 ... Opening / closing lid, 6 ... Recording paper discharge port, 7a ... Power switch, 7b ... Paper feed switch, 7c ... Operation status display Lamp: 8 ... Ink cartridge mounting part, 8a ... Mounting port, 9 ... Ink cartridge, 9a to 9d ... Ink pack (main tank), 9e ... IC chip, 10 ... Printer mechanism part, 11 ... Platen, 12 ... Inkjet head ( (Liquid ejection head), 12a to 12d ... flow path in head, 13 ... carriage, 13a ... carriage guide shaft, 13b ... linear encoder, 14 ... carriage drive mechanism, 14a ... carriage motor (carriage drive means), 15a-15d ... Sub tank, 16 ... diaphragm pump unit, 17a-17d ... flexible 18: plane flow path, 18a-18d: ink supply path, 19a: check valve, 19b ... choke valve mechanism, 19c: check valve, 20 ... suction mechanism, 21 ... cylinder, 22 ... ink chamber, 23 ... Diaphragm, 23a ... thick part, 24 ... piston member, 25 ... coil spring (spring member), 26 ... suction lever (operation member), 26a ... first arm part, 26b ... second arm part, 27 ... support shaft, 28 ... Hook, 29 ... Inner wall surface (contact member), 30 ... Control unit, 31 ... Host device, 32 ... Ink droplet number accumulating means, 33 ... Ink discharge amount obtaining means, 34 ... Sub tank remaining amount obtaining means, 35 ... main tank remaining amount acquisition means, 36 ... required time calculation means, 37 ... ink end determination means, 38 ... stop control time setting means, A ... home position (replenishment position), B ... left end position, C ... suction position, t Stop control time

Claims (7)

Supplying liquid to the liquid discharge head from a sub-tank mounted on the carriage together with the liquid discharge head;
By moving the carriage to a predetermined supply position, a liquid supply operation for sucking liquid from the main tank to the sub tank is performed at the supply position.
In the liquid supply operation,
Before the carriage reaches the replenishment position, the time required to suck the liquid to the sub tank to the maximum capacity is calculated,
After the carriage reaches the replenishment position until the necessary time elapses,
The carriage driving means is controlled so as not to move the carriage from the replenishment position due to fluctuations in the driving load for holding the carriage at the replenishment position during liquid replenishment. Carriage stop control method when refilling liquid. In claim 1,
When shifting to a standby state in which the carriage waits at the replenishment position after the liquid replenishment operation is completed,
A carriage stop control method at the time of liquid replenishment, wherein a predetermined holding force is applied to the carriage by the driving means after the necessary time has elapsed. In claim 1 or 2,
A carriage stop control method at the time of liquid replenishment, wherein the required time is calculated based on a liquid remaining amount in the sub-tank before the start of replenishment. In claim 3,
A carriage stop control method at the time of liquid replenishment, characterized in that a liquid remaining amount in the sub-tank is calculated based on a liquid discharge amount from the liquid discharge head. In any one of claims 1 to 4,
The sub tank is provided with a diaphragm that is displaced in a first direction in which the volume of the sub tank decreases as the liquid remaining amount decreases, and an operation member connected to the diaphragm via a spring member,
By bringing the carriage closer to the replenishment position, the operation member is pressed by a contact member provided at the replenishment position, and the spring member is extended,
In the replenishment position,
A negative pressure is formed in the sub-tank by applying an elastic force in the direction opposite to the first direction from the extended spring member to the diaphragm, and the liquid is sucked;
The abutting member is pressed through the operation member by the elastic return force of the spring member, and the carriage is moved from the replenishment position due to fluctuations in the driving load including a force applied to the carriage as a reaction. A carriage stop control method during liquid replenishment, characterized in that the carriage drive means is controlled so as not to cause a failure. In any one of claims 1 to 5,
The carriage drive means is a DC motor,
A carriage stop control method at the time of liquid replenishment, characterized in that the drive current of the DC motor is controlled in accordance with fluctuations in the drive load. In any one of claims 1 to 6,
The replenishment position is a home position of the carriage;
A carriage stop control method during liquid supply, wherein the liquid supply operation is performed at a timing when the carriage returns to the home position.

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