JP7215167B2 - Controller and program - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling a print execution unit including a head to which ink stored in a container is supplied through a tube, and a carriage on which the head is mounted and which moves. and a program executed by the control device that causes the head to eject ink in both the acceleration/deceleration region and the constant-velocity movement region.

Patent Document 1 discloses an inkjet printer including an ink cartridge, an ink supply tube connected to the ink cartridge, and a carriage unit connected to the ink supply tube. The inkjet printer further includes a guide rail that slidably supports the carriage unit, a carriage motor that slides the carriage unit, and a controller.

The carriage unit includes a buffer tank connected to the ink supply tube, an ejection head having an inlet through which ink flows from the buffer tank, and a pressure sensor that detects the pressure of the ink at the inlet. The ejection head has a channel communicating with the inlet, a nozzle communicating with the channel, and a piezoelectrically driven actuator for ejecting ink from the nozzle. The control device obtains the flow resistance of the ink in the flow path in the ejection head based on the pressure detected by the pressure sensor, and when the obtained flow resistance is smaller than the threshold value, performs printing without limiting the print duty ratio. do. On the other hand, if the obtained flow resistance is greater than the threshold, the control device limits the print duty ratio to prevent insufficient ink from being supplied to the ejection head.

JP 2010-214726 A

The inventors of the present application considered making the ejection head eject ink in the acceleration area and deceleration area (hereinafter also referred to as acceleration/deceleration area) of the carriage unit in addition to the constant-velocity movement area of the carriage unit. This allows, for example, the size of the printer to be reduced. More specifically, the carriage unit is accelerated, then moved at a constant speed, and then decelerated. Conventionally, a printer causes an ejection head to eject ink while a carriage unit is moving at a constant speed. Since the ejection head ejects ink in the acceleration/deceleration region of the carriage unit, the range in which the carriage unit must move can be narrowed, and as a result, the size of the printer can be reduced.

When the carriage unit accelerates or decelerates, the ink in the ejection head flows out into the ink supply tube due to the inertial force generated in the ink inside the ejection head and the ink supply tube, and the pressure that the ink exerts on the ejection head decreases. The inventors of the present application have found that if the ejection head ejects ink in a state in which the pressure exerted by the ink on the ejection head is reduced, the amount of ink supplied to the ejection head may become insufficient. If the amount of ink supplied to the ejection head becomes insufficient, the amount of ink ejected from the protruding head will be less than the appropriate amount, resulting in reduced printing accuracy or destruction of the ink meniscus in the ejection head. Fear arises.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent an insufficient amount of ink from being supplied to the head in a configuration in which ink is ejected to the head even in the acceleration/deceleration region of the carriage. To provide a means capable of changing the type of printing by judging whether or not.

Various disclosures are made herein. A control device, which is one of the disclosed examples, includes a tube having a first end connected to a container in which ink is stored, and a head to which a second end of the tube is connected. a head having nozzles and a plurality of driving elements provided corresponding to the nozzles; a carriage on which the heads are mounted, the carriage being movable between a first position and a second position; and a drive source for moving the print execution unit. The control device includes a control section that controls driving of the drive element and the drive source, and a memory. The control unit performs an acquisition process of acquiring print data, and moves the carriage from one of the first position and the second position to the other by accelerating movement, constant velocity movement, and deceleration movement, while moving the carriage. The ink pressure relation value corresponding to the pressure exerted by the ink on the head when the ink is ejected from the nozzles of the head in the acceleration region, the constant-velocity movement region, and the deceleration region, and the acquired print data and the carriage determination processing for determining based on the acceleration movement and deceleration movement of the ink pressure relationship; determination processing for determining whether the determined ink pressure relation value reaches a threshold value stored in the memory; a first type of printing process executed according to the print data when it is determined that the value does not reach the threshold; and the printing when it is determined that the ink pressure-related value reaches the threshold. a second type of print processing executed according to the data, the second type of print processing being different from the first type of print processing;

When the driving element is driven and ink is ejected from the head, the pressure exerted by the ink on the head (hereinafter also referred to as ink pressure) decreases. The reduced ink pressure causes ink to be supplied from the container through the tube to the head. If more ink is ejected before the ink pressure returns to the original pressure, the ink pressure will gradually decrease. Further, when the carriage is accelerated or decelerated (hereinafter also referred to as acceleration/deceleration movement), inertial force causes the ink in the tube to flow into the head or the ink in the head to flow out to the tube. When the ink in the head flows out to the tube, the ink pressure drops. The controller determines an ink pressure related value corresponding to the ink pressure based on the acquired print data and the acceleration/deceleration movement of the carriage. The ink pressure-related value is, for example, the minimum value of the ink pressure or the maximum value of the amount of change in the negative direction of the ink pressure from the reference value (for example, atmospheric pressure). Then, the controller determines whether the determined ink pressure-related value reaches the threshold value stored in the memory. When the ink pressure-related value reaches the threshold, there is a possibility that the amount of ink supplied to the head will be insufficient. When the controller determines that the determined ink pressure-related value does not reach the threshold value (that is, when the amount of ink supplied to the head is sufficient), it executes the first type of print processing. On the other hand, when the controller determines that the determined ink pressure-related value reaches the threshold value (that is, when there is a risk that the amount of ink supplied to the head may become insufficient), it executes the second type of print processing. . The second type of print processing is print processing different from the first print processing. That is, in a configuration in which ink is ejected from the head even in the acceleration/deceleration region of the carriage, the control device determines whether or not the ink pressure-related value reaches the threshold based on the print data and the acceleration/deceleration movement of the carriage. By doing so, different printing processes can be executed depending on whether the amount of ink supplied to the head is sufficient or when the amount of ink supplied to the head may be insufficient.

The technology disclosed in the present specification can be implemented in various forms, for example, a control method, a control system, a computer program for realizing the functions of these devices and methods, It can be realized in the form of a recording medium or the like.

FIG. 1 is a perspective view of the printer 10. FIG. FIG. 2 is a schematic longitudinal sectional view of the printer 10. As shown in FIG. FIG. 3 is a perspective view of the printing section 31. As shown in FIG. 4 is a bottom view of the carriage 32 and the printing unit 33. FIG. FIG. 5 is a functional block diagram of the printer 10. As shown in FIG. FIG. 6 is a flowchart of main processing. FIG. 7 is a flowchart of the second scanning process in Modification 1. FIG. FIG. 8 is an explanatory diagram for explaining calculation of the ink pressure. FIG. 9 is an explanatory diagram for explaining Modification 3. As shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. It should be noted that the embodiment described below is merely an example of the present invention, and it goes without saying that the embodiment of the present invention can be changed as appropriate without changing the gist of the present invention. For example, the execution order of each process to be described later can be changed as appropriate without changing the gist of the present invention.

A printer 10 shown in FIG. 1 is a printer that prints an image on a sheet 6 by ejecting ink onto the sheet 6 (FIG. 2). That is, the printer 10 is a so-called inkjet printer. Printer 10 is an example of a control device.

Further, the printer 10 is a printer that prints an image on the sheet 6 while moving a head 62 (FIG. 2) that ejects ink. That is, the printer 10 is a so-called serial printer.

Further, the printer 10 is a printer in which the ink cartridge 18 (FIG. 2) that stores ink is not mounted on the carriage 32 (FIG. 2), but is installed in the housing 11 .

The printer 10 prints an image on the sheet 6 while suppressing insufficient ink supply to the head 62 . A detailed description will be given below.

The printer 10 includes a housing 11, an operation panel 12 held by the housing 11, a paper feed tray 15, and a paper discharge tray 16, as shown in FIG. In the illustrated example, the operation panel 12 is arranged on the upper side of the housing 11 . In the following description, the side surface of the housing 11 on which the operation panel 12 is provided is defined as the front surface of the printer 10, and the front-rear direction 8 is defined, and the direction orthogonal to the front-rear direction 8 and the vertical direction 7 is defined as the left-right direction 9. . In the illustrated example, the paper feed tray 15 and the paper discharge tray 16 are positioned below the operation panel 12 .

The operation panel 12 has a display 13 and operation switches 14 . The display 13 has a liquid crystal screen and a transparent film-like touch sensor superimposed on the liquid crystal screen. That is, the display 13 is a so-called touch panel. The user inputs an instruction such as a print instruction to the printer 10 by touching the display 13 or pressing the operation switch 14 .

Further, as shown in FIG. 2, the printer 10 includes a mounting case 17 in which the ink cartridge 18 is attached and detached, a conveying device 21 for conveying the sheet 6, and ink ejected onto the conveyed sheet 6 to print an image. The housing 11 has a printing unit 31 for printing. The conveying device 21 and the printing section 31 are examples of a printing execution section.

The mounting case 17 is arranged deep inside the opening 19 (FIG. 1B) of the housing 11 . The mounting case 17 has a holding portion that holds the ink cartridge 18 detachably. The number of holders corresponding to the type of printer 10 is provided in the mounting case 17 . For example, if the printer 10 is a so-called monochrome printer, the mounting case 17 is provided with only one holder so that only the ink cartridge 18 that stores black ink can be mounted. When the printer 10 is a so-called color printer, the mounting case 17 can be mounted with, for example, four ink cartridges 18 each storing black ink, cyan ink, magenta ink, and yellow ink. A retainer is provided. An example in which the printer 10 is a color printer will be described below. That is, a plurality of ink cartridges 18 are attached to the attachment case 17 . The ink stored in the ink cartridge 18 may be dye ink or pigment ink.

The plurality of ink cartridges 18 have the same configuration. The ink cartridge 18 is box-shaped and has a space for storing ink therein. The ink cartridge 18 has an air communication port 20 in the upper part of the outer wall for communicating the internal space and the outside. That is, the internal space of the ink cartridge 18 is open to the atmosphere. The ink cartridge 18 is an example of a container.

The conveying device 21 includes a conveying path 22 along which the sheet 6 is conveyed, feeding rollers 23 that feed the sheet 6 placed on the paper feed tray 15 to the conveying path 22, and conveying rollers that convey the sheet 6 in the conveying path 22. 24 , a discharge roller 25 , and a platen 26 .

The transport path 22 is, for example, a space partitioned by a plurality of pairs of guide members (not shown). In the illustrated example, the transport path 22 makes a U-turn from the rear portion of the paper feed tray 15 toward the top of the paper feed tray 15 and then extends forward.

The platen 26 is a member that supports the sheet 6 when the printing section 31 (to be described later) prints an image on the sheet 6 . The platen 26 is positioned above the paper feed tray 15 .

The feeding roller 23 is provided so as to come into contact with the sheet 6 placed on the sheet feeding tray 15 . A rotating feed roller 23 feeds the sheet 6 from the paper feed tray 15 to the transport path 22 .

The transport roller 24 is rotatably supported by a frame (not shown) fixed to the housing 11 . Further, the transport roller 24 is positioned behind the platen 26 in the front-rear direction 8 . The conveying roller 24 forms a roller pair together with the pinch roller 27 . A rotating conveying roller 24 conveys the sheet 6 in the conveying path 22 .

The discharge roller 25 is rotatably supported by a frame (not shown) fixed to the housing 11 . Also, the discharge roller 25 is positioned in front of the platen 26 in the front-rear direction 8 . The discharge roller 25 and the spur 28 form a roller pair. A rotating sheet discharge roller 25 conveys the sheet 6 in the conveying path 22 and discharges the sheet 6 to the sheet discharge tray 16 .

The feed roller 23, the transport roller 24, and the paper discharge roller 25 are rotated by a transport motor 42 (FIG. 5). More specifically, the printer 10 includes a transport motor 42 and a driving force switching mechanism 44, as shown in FIG.

The conveying motor 42 is a direct current motor that is rotationally driven by being supplied with a direct current voltage. However, the transport motor 42 may be an AC motor.

The driving force switching mechanism 44 is, for example, a gear switching mechanism configured by a plurality of gears such as a switching gear and a gear train. The driving force switching mechanism 44 selectively transmits the rotational driving force of the conveying motor 42 to the feeding roller 23 , the conveying roller 24 , and the paper discharge roller 25 . Since the configuration of the driving force switching mechanism 44 is well known, detailed description thereof will be omitted. Note that the feeding roller 23, the conveying roller 24, and the paper discharging roller 25 may be rotated by individual motors without using the driving force switching mechanism 44. FIG.

The printing unit 31 is arranged above the platen 26 as shown in FIG. The printing section 31 includes a carriage 32 and a printing unit 33 mounted on the carriage 32 .

As shown in FIG. 3, the carriage 32 is supported by a pair of guide rails 34, 35 so as to be movable in the left-right direction 9. As shown in FIG. The pair of guide rails 34 and 35 respectively extend along the left-right direction 9 and are spaced apart from each other in the front-rear direction 8 .

A moving device for moving the carriage 32 along the left-right direction 9 is provided in the printer 10 . More specifically, the printer 10 includes, as moving devices, a carriage motor 36 (FIG. 5), a driving pulley rotated by the carriage motor 36, a driven pulley paired with the driving pulley, and a driving pulley and driven pulley. and an endless ring belt that is stretched over the belt. The carriage motor 36 is a direct current motor that is rotationally driven by being supplied with a direct current voltage. However, the carriage motor 36 may be an AC motor. The endless ring belt is fixed to the carriage 32 .

When the drive pulley is rotationally driven by the carriage motor 36, the endless ring belt is moved. As a result, the carriage 32 fixed to the endless ring belt is moved along the left-right direction 9 .

The carriage 32 is reciprocated between the first position and the second position shown in FIG. 8 by the moving device described above. The first position is, for example, the position when the carriage 32 is on the left side of the printer 10 . The second position is, for example, the position when the carriage 32 is on the right side of the printer 10 . For example, the carriage 32 is accelerated from one of the first and second positions, then moved at a constant speed, and then decelerated and stopped at the other of the first and second positions. While the carriage 32 is moved between the first position and the second position, a head 62 mounted on the carriage 32 ejects ink onto the sheet 6 (scanning process). Thereafter, the sheet 6 is conveyed by a predetermined conveying amount by the conveying rollers 24 (line feed processing). An image is printed on the entire surface of the sheet 6 by alternately executing the scanning process and the line feed process. Details will be described later.

The printing unit 33 has a buffer tank 61 and a head 62 as shown in FIG. The buffer tank 61 is box-shaped and has an internal space for storing ink. One end of a tube 63 is connected to the buffer tank 61 . The other end of the tube 63 is connected to the mounting case 17 . That is, the internal space of the buffer tank 61 communicates with the internal space of the ink cartridge 18 mounted in the mounting case 17 through the tube 63 . Ink stored in the ink cartridge 18 is supplied to the buffer tank 61 through the tube 63 . One end of the tube 63 is an example of a second end connected to the head. The other end of tube 63 is an example of a first end connected to a container. The tube 63 is flexible and bends as the carriage 32 moves.

The buffer tank 61 is connected to the head 62 by four channel members 64 . The channel member 64 is, for example, a pipe having one end (upper end) connected to the buffer tank 61 and the other end (lower end) connected to the head 62 . Ink of each color is supplied from the buffer tank 61 to the head 62 through the four flow path members 64 .

The upper surface of the buffer tank 61 is open. A membrane sheet 50 is attached to the upper surface of the buffer tank 61 . The membrane sheet 50 closes the upper opening of the buffer tank 61 .

The membrane sheet 50 has flexibility. The membrane sheet 50 flexes to swell upward when ink suddenly flows from the tube 63 into the buffer tank 61 , and dents downward when ink suddenly flows out from the buffer tank 61 to the tube 63 . bend. The deflection of the membrane sheet 50 mitigates sudden changes in ink pressure due to the inflow and outflow of ink from the tube 63 to the buffer tank 61 . The ink pressure means the pressure exerted by the ink on the membrane sheet 50 of the head 62, the manifold 68 and the nozzle flow paths 69, which will be described later.

For example, inertial force acts on the ink in the buffer tank 61 and the tube 63 due to the accelerated movement and decelerated movement of the carriage 32 . Ink flows into and out of the buffer tank 61 from the tube 63 due to the inertial force acting on the ink. That is, the buffer tank 61 mitigates sudden changes in ink pressure caused by the acceleration/deceleration movement of the carriage 32 .

The head 62 is positioned below the buffer tank 61 . The head 62 has four inlets 65 connected to the lower end of the channel member 64 . Each color ink flows from the buffer tank 61 into four inlets 65 through four flow path members 64 .

The head 62 has, as shown in FIG. 4, four nozzle rows 66 for ejecting ink that has flowed in from the inlet 65 . Each nozzle row 66 has a plurality of nozzles 67 respectively. Each nozzle row 66 ejects ink of each color.

One inlet 65 and the plurality of nozzles 67 of one nozzle row 66 are connected by one manifold 68 and a plurality of nozzle flow paths 69, as shown in the enlarged view of FIG. The configurations of the manifold 68 and the nozzle flow paths 69 are the same for each color of black, cyan, magenta, and yellow. Specifically, a manifold 68 and nozzle flow paths 69 through which black ink flows, a manifold 68 and nozzle flow paths 69 through which cyan ink flows, a manifold 68 and nozzle flow paths 69 through which magenta ink flows, The manifold 68 and the nozzle flow path 69 through which the yellow ink flows have the same configuration and are arranged side by side in the left-right direction 9 (the direction perpendicular to the plane of FIG. 2).

The manifold 68 extends forward in the front-rear direction 8 from the inlet 65 . A plurality of nozzle flow paths 69 extend downward from the manifold 68 to the lower surface of the head 62 . Each opening of a plurality of nozzle flow paths 69 on the lower surface of the head 62 is a plurality of nozzles 67 .

The plurality of nozzle flow paths 69 are arranged along the front-rear direction 8 and are separated from each other in the front-rear direction 8 . The separation distance between the nozzle channels 69 is constant. That is, as shown in FIG. 4, in each nozzle row 66, a plurality of nozzles 67 are arranged along the front-rear direction 8 at regular intervals.

As shown in FIG. 2, a piezoelectric element 70 is provided in each nozzle channel 69 respectively. That is, the head 62 has multiple piezoelectric elements 70 . The piezoelectric element 70 is an element that deforms when supplied with a DC voltage. By deforming, the piezoelectric element 70 applies pressure to the ink in the nozzle channel 69 to eject ink (ink droplets) from the nozzle 67 . Lead zirconate titanate (PZT) or the like is used as the piezoelectric element 70 . The piezoelectric element 70 is an example of a driving element. A heater that generates heat when supplied with power may be used as the drive element instead of the piezoelectric element 70 . The heater generates heat to cause the ink in the nozzle flow path 69 to boil and eject ink (ink droplets) from the nozzle 67 .

The height positions of the plurality of nozzles 67 in the vertical direction 7 are positioned above the height position of the liquid surface in the ink cartridge 18 . Therefore, ink is not ejected from the nozzles 67 due to the atmospheric pressure. Backflow of ink from the head 62 to the ink cartridge 18 is prevented by the meniscus of the ink at the nozzle 67 . That is, when the meniscus of ink at the nozzle 67 is destroyed, air enters the head 62 from the nozzle 67 and the supply of ink from the ink cartridge 18 to the head 62 is blocked.

The printer 10, as shown in FIG. It includes a control device 71 that controls driving, and various sensors, switches, and the like.

The power supply circuit 41 and the control device 71 are realized by, for example, a control board, an IC mounted on the control board, a microcomputer, a coil, a capacitor, a resistor, and the like. That is, the printer 10 has one or more control board units that implement the power supply circuit 41 and the control device 71 .

The power supply circuit 41 is a circuit that converts an input commercial AC voltage into a DC voltage of a predetermined voltage value. The power supply circuit 41 is formed by combining, for example, a switching regulator, a series regulator, a constant voltage circuit using a Zener diode, or the like. The DC voltage output by the power supply circuit 41 is supplied to the display 13, the control device 71, a communication I/F 75 (to be described later), the carriage motor 36, the conveying motor 42, and the like.

A selector switch 38 and a switching element 37 are provided between the power supply circuit 41 and the carriage motor 36 . The changeover switch 38 is a switch for switching between positive and negative of the DC voltage supplied to the carriage motor 36 . The change-over switch 38 switches contacts when a control signal is input from the control device 71 to switch between positive and negative of the DC voltage supplied to the carriage motor 36 . By switching the polarity of the DC voltage supplied to the carriage motor 36, the direction of rotation of the carriage motor 36 is switched. By switching the direction of rotation of the carriage motor 36, the direction of movement of the carriage 32 is switched. That is, the control device 71 controls the direction of movement of the carriage 32 by controlling the driving of the switch 38 . The carriage motor 36 is an example of a drive source.

The switching element 37 is, for example, a MOSFET. The switching element 37 is turned on and off by receiving a drive signal having a constant frequency from the control device 71 . The control device 71 controls the amount of electric power supplied to the carriage motor 36 per unit time by changing the duty ratio of the constant-frequency drive signal input to the switching element 37 . That is, the control device 71 controls the rotation speed of the carriage motor 36 by so-called PWM control. Further, the control device 71 controls the driving of the switching element 37 and the switch 38 to rotate the carriage motor 36, or stops the rotation of the carriage motor 36 to drive the carriage motor 36. It controls the amount of rotation of the motor 36 . The control device 71 controls the amount of movement of the carriage 32 by controlling the amount of rotation of the carriage motor 36 .

The control of the rotation direction and rotation speed of the carriage motor 36 using the changeover switch 38 and the switching element 37 is an example, and other methods may be used to control the rotation direction and rotation speed of the carriage motor 36. may be done.

A selector switch 45 and a switching element 43 are provided between the power supply circuit 41 and the transport motor 42 . The changeover switch 45 is a switch that switches between positive and negative of the DC voltage supplied to the carry motor 42 . The change-over switch 45 switches contacts when a control signal is input from the control device 71 to switch between positive and negative of the DC voltage supplied to the conveying motor 42 . By switching the polarity of the DC voltage supplied to the transport motor 42, the direction of rotation of the transport motor 42 is switched.

The switching element 43 is, for example, a MOSFET. The control device 71 controls the rotation speed of the carry motor 42 by PWM control, similarly to the switching element 37 . Further, the control device 71 controls the driving of the switching element 43 and the changeover switch 45 to rotate the transport motor 42, or stops the rotation of the transport motor 42 so that the transport motor 42 is driven when the transport motor 42 is driven. It controls the amount of rotation of the motor 42 . The control device 71 controls the conveying amount of the sheet 6 by controlling the rotation amount of the conveying motor 42 .

It should be noted that the control of the rotation direction and rotation speed of the transport motor 42 using the changeover switch 45 and the switching element 43 is an example, and other methods may be used to control the rotation direction and rotation speed of the transport motor 42. may be done.

The printer 10 includes various sensors such as a linear encoder 51, a rotary encoder 52, and a A registration sensor 57 is provided.

A linear encoder 51 is a sensor that detects the position of the carriage 32 . The linear encoder 51 includes a reading section 53 provided on the guide rail 34 and a photointerrupter 54 provided on the carriage 32, as shown in FIG. The reading unit 53 has a configuration in which light transmitting portions that transmit light and light blocking portions that block light are alternately arranged along the left-right direction 9 . The photointerrupter 54 scans the reading unit 53 as the carriage 32 moves, and outputs a pulse train composed of a plurality of pulses. A pulse train output from the photointerrupter 54 is input to the controller 71 . The control device 71 controls driving of the carriage motor 36 according to the input pulse train.

The rotary encoder 52 is a sensor that detects the rotational speed and amount of rotation of the conveying roller 24 . The rotary encoder 52 includes a disk-shaped encoder disk 55 that rotates together with the transport roller 24 and a photointerrupter 56 . The encoder disk 55 has a configuration in which light-transmitting portions that transmit light and light-shielding portions that shield light are alternately arranged along the circumferential direction. The photointerrupter 56 scans the encoder disk 55 as the encoder disk 55 rotates and outputs a pulse train consisting of a plurality of pulses. A pulse train output from the photointerrupter 56 is input to the controller 71 . The control device 71 controls driving of the transport motor 42 according to the input pulse train.

The registration sensor 57 shown in FIG. 5 is provided at a position behind the conveying roller 24 (FIG. 2) in the front-rear direction 8 . That is, the registration sensor 57 is provided at a position upstream of the conveying roller 24 in the conveying direction of the sheet 6 . The registration sensor 57 has, for example, a rotating member that rotates when pressed by the sheet 6 conveyed on the conveying path 22, and a photointerrupter that detects the rotating position of the rotating member. The voltage value of the signal output by the registration sensor 57 changes as the leading edge of the sheet 6 passes through the registration sensor 57 .

A signal output from the registration sensor 57 is input to the control device 71 . The control device 71 counts the number of pulses output from the rotary encoder 52 starting from a change in the voltage value of the signal input from the registration sensor 57, for example. The control device 71 specifies the leading edge position of the sheet 6 based on the count value (integrated value) of the number of pulses. The control device 71 uses, for example, signals input from the registration sensor 57 and the rotary encoder 52 to perform cueing for conveying the sheet 6 until the position of the leading edge of the sheet 6 reaches a predetermined cueing position facing the head 62 . Execute the process.

As shown in FIG. 5 , the control device 71 includes a CPU 72 as a central processing unit, a storage section 73 and a communication bus 74 . The communication bus 74 is connected with the CPU 72 , the storage unit 73 , the display 13 , the switching elements 37 and 43 , the power supply circuit 41 , and a communication interface (hereinafter referred to as communication I/F) 75 . The communication I/F 75 is an interface that connects with a communication line using, for example, a USB cable, a LAN cable, a wireless LAN, or the like. The communication line is the Internet, a LAN (local area network), or the like. The printer 10 communicates with devices such as servers, mobile terminals, and personal computers through the communication I/F 75 . The printer 10 receives a print instruction through the communication I/F 75 from, for example, a mobile terminal or a personal computer.

The storage unit 73 includes a ROM 76 , a RAM 77 and an EEPROM 78 . The ROM 76 stores an operating system (hereinafter referred to as OS) 81 and a control program 82 . The control program 82 may be a single program or an aggregate of multiple programs. The control program 82 includes, for example, a UI module that accepts a user's input operation, a communication module that communicates with other devices via the communication I/F 75, a power supply module that controls the operation of the power supply circuit 41, a conveying device 21 and a printer. It is composed of a print module that controls the unit 31 . A plurality of programs (modules) are executed by the CPU 72 in pseudo-parallel, for example, by multitasking. The CPU 72 that executes the control program 82 is an example of a control section. The control program 82 is an example of a program. The storage unit 73 is an example of memory.

Also, the ROM 76 stores the velocity function V(t) and the threshold. The velocity function V(t) is used to control the velocity of the carriage 32 when the carriage 32 accelerates, moves at a constant speed, or moves at a deceleration. Specifically, the control program 82 reads the velocity function V(t) from the storage unit 73 . The control program 82 then drives the switching element 37 with a predetermined duty ratio. The control program 82 then calculates the moving speed of the carriage 32 based on the pulse train input from the linear encoder 51 . The control program 82 causes the calculated moving speed of the carriage 32 at time t (hereinafter also referred to as carriage speed) to be higher than the speed at time t (hereinafter also referred to as target speed) indicated by the speed function V(t). , to determine how slow or how fast. When the control program 82 determines that the carriage speed is lower than the target speed, the control program 82 increases the duty ratio according to the difference between the carriage speed and the target speed to drive the carriage motor 36 . When the control program 82 determines that the carriage speed is faster than the target speed, the control program 82 drives the carriage motor 36 with a reduced duty ratio according to the difference between the carriage speed and the target speed. That is, the control program 82 controls the amount of power supplied to the carriage motor 36 so that the carriage speed matches the speed indicated by the speed function V(t).

The threshold is used to determine whether ink supply to the head 62 is insufficient. Details will be described later. Note that the velocity function V(t) and the threshold value may be stored in EEPROM 78 instead of ROM 76 . Also, the velocity function V(t) and the threshold value are pre-stored in the storage unit 73 when the printer 10 is shipped.

The RAM 77 temporarily stores data necessary for executing the OS 81 and the control program 82 . The EEPROM 78 stores, for example, data that should be retained even after the power of the printer 10 is turned off.

Processing executed by the control program 82 will be described below with reference to FIGS. 6 and 8. FIG. Specifically, a process in which the control program 82 causes the head 62 to eject ink to print an image on the sheet 6 while suppressing insufficient ink supply to the head 62 will be described.

The control program 82 executes main processing shown in FIG. First, the control program 82 determines whether or not a print instruction has been input (S11). A print instruction is input to the printer 10 using, for example, the touch sensor of the display 13 and the operation switches 14 on the operation panel 12 . Alternatively, the print instruction is input to the printer 10 from a personal computer or mobile terminal through the communication I/F 75 .

When the control program 82 determines that the print instruction has not been input (S11: No), the main process ends. When the control program 82 determines that a print instruction has been input (S11: Yes), it executes the processing from step S12 onward. Note that the control program 82, for example, periodically executes the main process.

When the control program 82 determines that a print instruction has been input (S11: Yes), it determines whether or not print data has been input (S12). Print data is input to the control device 71 from a personal computer or a mobile terminal through the communication I/F 75, for example. Alternatively, the print data is input to the control device 71 from a portable storage medium such as a USB memory (registered trademark) attached to the printer 10 . Alternatively, if the printer 10 has a scanner, the print data is input from the scanner as the data of the image to be copied. Alternatively, if the printer 10 has a FAX function section, print data is input from the FAX function section. The step S12 of receiving the input of the print data and obtaining the print data: Yes is an example of the obtaining process.

The print data includes print settings, path data, and the like. The print settings include settings such as paper type, paper size, paper printing orientation, and enlargement ratio, for example. The pass data is data indicating an image to be printed on the print area (FIG. 8) of the sheet 6 by one movement of the carriage 32 from one of the first position and the second position to the other (hereinafter referred to as one pass data). Also referred to as data). For example, the control program 82 sequentially acquires path data for one pass from a personal computer, a mobile terminal, or a USB memory (registered trademark). If the storage unit 73 has enough free space, the control program 82 may acquire pass data for multiple passes or pass data for one page. "Path" means movement of the carriage 32 from one of the first and second positions to the other.

The control program 82 waits until print data is input (S12: No). When the control program 82 determines that the print data has been input (S12: Yes), it determines the cue amount or the line feed amount based on the input print data. The cue amount is the conveying amount of the sheet 6 when conveying the sheet 6 to the position where the first print area ( FIG. 8 ) where the image is printed on the sheet 6 faces the head 62 . The line feed amount is the length of the sheet 6 when the sheet 6 is conveyed to the position where the print area (FIG. 8) next to the print area where the image is printed in the scanning process (S19, S20) described below faces the head 62. conveyed amount.

The control program 82 drives the conveying motor 42 to convey the sheet 6, and when the count value of the number of pulses input from the rotary encoder 52 reaches a value corresponding to the determined cue amount or line feed amount, to stop driving the conveying motor 42 . That is, the control program 82 executes so-called cue processing or line feed processing (S13). The cueing process is performed before the first scanning process (S19, S20) is performed in the main process, and the line feed process is performed before the second and subsequent scanning processes are performed. In the example shown in FIG. 8, the control program 82 conveys the sheet 6 in the conveying direction to a position where the "first print area" shown in FIG. 8 to the position where the "next print area" shown in FIG. The sheet 6 is conveyed in the conveying direction by the determined line feed amount.

Next, the control program 82 determines the number of times each piezoelectric element 70 is driven and the voltage value of the DC voltage to be supplied to the piezoelectric element 70 based on the acquired pass data of the print data. Then, the control program 82 calculates and acquires the number of ink dots in each nozzle row 66 in one pass based on the number of times the piezoelectric element 70 is driven in one pass and the voltage value supplied to the piezoelectric element 70 (S14). . The number of ink dots is a numerical value indicating the total amount of ink ejected by one nozzle row 66 in one pass.

Specifically, the control program 82 determines the voltage value of the DC voltage to be supplied to the piezoelectric element 70 based on the acquired path data, for example, by dividing it into "large", "medium", and "small". . When a "large" DC voltage is supplied to the piezoelectric element 70, the nozzle 67 ejects a "large" ink droplet. When the piezoelectric element 70 is supplied with a "medium" DC voltage, the nozzle 67 ejects a "medium" ink droplet. When a "small" DC voltage is supplied to the piezoelectric element 70, the nozzle 67 ejects a "small" ink droplet. For example, "medium" ink droplets are a (<100)% of "large" ink droplets, and "small" ink droplets are b (<a)% of "large" ink droplets. The control program 82 calculates the number of ink dots ejected as the number of ink dots on the assumption that all the "large" inks are ejected in one pass. That is, the control program 82 defines all ink droplets ejected by the nozzles 67 as "large" and calculates the number of ink dots.

It should be noted that the control program 82 may use a number of ink dots other than the number of ink dots indicating the number of ejections of the "large ball" as long as the amount of ink ejected by the head 62 is indicated. For example, the control program 82 may calculate and acquire a numerical value indicating the amount of ink ejected by the head 62 based on the acquired print data.

The control program 82 determines the first pressure based on the calculated number of ink dots (S15). The first pressure indicates the amount of ink pressure that decreases due to ejection of ink from the nozzles 67 . More specifically, when the piezoelectric element 70 returns to its original shape after the piezoelectric element 70 is deformed and the ink is ejected from the nozzle 67, the pressure (first pressure) exerted by the ink on the manifold 68 and the nozzle channel 69 increases. descend. The reduced first pressure draws ink from the ink cartridge 18 into the head 62 through the channel member 64 , buffer tank 61 and tube 63 . As the ink is drawn into the head 62, the reduced first pressure returns to the original pressure. The original pressure is atmospheric pressure. If the piezoelectric element 70 is continuously driven before the reduced first pressure returns to the original pressure, the first pressure gradually decreases as shown in FIG. The degree of decrease in the first pressure increases as the pixel density of the image to be printed increases and the amount of ink ejected by the head 62 per unit time increases. When the moving speed of the carriage 32 is known, the amount of ink ejected by the head 62 per unit time is determined by the number of ink dots. That is, the first pressure is determined by the number of ink dots. The first pressure is an example of a first ink pressure related value.

The control program 82 determines the first pressure based on the number of ink dots obtained in step S14 (FIG. 8). For example, the control program 82 reads out the pressure corresponding to the obtained number of ink dots from the storage unit 73 and determines the first pressure. Alternatively, the control program 82 reads a formula for calculating the first pressure from the obtained number of ink dots from the storage unit 73 and calculates the first pressure. The ROM 76 or EEPROM 78 of the storage unit 73 stores in advance the table showing the correspondence between the number of ink dots and the first pressure and the above-described calculation formula. In the graph shown in FIG. 8, the vertical axis indicates the pressure, and the horizontal axis indicates the position of the carriage 32. As shown in FIG. Further, the first pressure shown in FIG. 8 has the atmospheric pressure as a reference value (zero), and the pressure that decreases due to the ejection of ink is shown as a negative pressure.

After determining the first pressure, the control program 82 determines the second pressure (S16), as shown in FIG. Note that the process of step S16 for determining the second pressure may be performed before the process of step S15 for determining the first pressure.

The second pressure is the pressure exerted by the ink on the head 62 due to the acceleration movement and deceleration movement of the carriage 32 (hereinafter also referred to as the acceleration and deceleration movement of the carriage 32), and the pressure after being relieved by the membrane sheet 50 described above. indicates Whether the ink flows into the head 62 or the ink flows out from the head 62 depends on whether the carriage 32 accelerates or decelerates, the connection position between the tube 63 and the carriage 32, and the like. In the example shown in FIG. 8, when the carriage 32 accelerates from the first position toward the second position, ink flows from the tube 63 into the head 62, and when the carriage 32 decelerates toward the second position, the head 62 , the ink flows out to the tube 63 . That is, in the acceleration region where the carriage 32 accelerates and moves, ink flows from the tube 63 into the head 62, thereby increasing the second pressure. In the deceleration region where the carriage 32 decelerates, ink flows out from the head 62 to the tube 63, thereby reducing the second pressure. Note that the second pressure in FIG. 8 has the atmospheric pressure as a reference value (zero), and the amount of pressure that decreases due to the outflow of ink from the head is indicated as negative pressure.

Control program 82 determines the second pressure at each position of carriage 32 based on the acceleration and deceleration movements of carriage 32 as indicated by velocity function V(t). For example, the control program 82 reads the second pressure from the storage unit 73 and determines it. The ROM 76 of the storage unit 73 includes a first table showing the correspondence between each position of the carriage 32 in the acceleration region and the second pressure, and a second table showing the correspondence between each position of the carriage 32 and the second pressure in the deceleration region. are stored in advance. Alternatively, the control program 82 differentiates the velocity function V(t) to calculate the acceleration function A(t), and calculates the position x(t1) of the carriage 32 at time t1 based on the calculated acceleration function A(t). A second pressure is calculated by multiplying the acceleration A(t1) at . The predetermined coefficients are pre-stored in the ROM 76 or EEPROM 78 of the storage unit 73 at the time of shipment. The second pressure is an example of a second ink pressure related value.

When the carriage 32 moves from the first position toward the second position, the acceleration region is the left portion of the movement range of the carriage 32 (the carriage movement range in FIG. 8), and the deceleration region is the movement range of the carriage 32. Right part of the range. On the other hand, when the carriage 32 moves from the second position toward the first position, the acceleration region is the right portion of the movement range of the carriage 32 and the deceleration region is the left portion of the movement range of the carriage 32 .

As shown in FIG. 6, after determining the second pressure in step S16, the control program 82 determines the minimum ink pressure value, which is the minimum value of the ink pressure in one pass (S17). Specifically, first, the control program 82 determines the ink pressure. Specifically, the first pressure (partial pressure) that changes due to the ejection of ink and the second pressure (partial pressure) that changes due to the acceleration/deceleration movement of the carriage 32 are added together, and the pressure of the ink exerted on the head 62 is Calculate a certain ink pressure. The control program 82 determines the lowest ink pressure value as the minimum ink pressure value (FIG. 8). The "boundary position" and the "ejection stop position" in FIG. 8 will be described in Modification 1 below. The ink pressure and the ink pressure minimum value are examples of ink pressure related values. The processing of step S17 for determining the ink pressure and the ink pressure minimum value is an example of determination processing.

As shown in FIG. 6, the control program 82 determines whether or not the determined minimum ink pressure value is greater than or equal to the threshold value (FIG. 5) read out from the storage unit 73 (S18). The processing of step S18 is an example of determination processing.

When the control program 82 determines that the determined minimum ink pressure value is greater than or equal to the threshold value, it executes the first scanning process (S19). On the other hand, when the control program 82 determines that the determined minimum ink pressure value is not equal to or greater than the threshold value, it executes the second scanning process (S20). The first scanning process is an example of a first type printing process. The second scanning process is an example of a second type printing process. The fact that the minimum ink pressure value is greater than or equal to the threshold is an example of the fact that the ink pressure related value has not reached the threshold. The fact that the minimum ink pressure value is not equal to or greater than the threshold value is an example of the ink pressure related value reaching the threshold value.

The processes from step S14 to step S18 are executed for each color ink of black, cyan, magenta, and yellow. When the control program 82 determines in step S18 that the minimum ink pressure value for all colors is greater than or equal to the threshold value, it executes the first scanning process (S19). If it is determined that it is not, the second scanning process (S20) is executed.

For example, when the minimum value of ink pressure reaches the threshold, the amount of ink supplied to the head 62 becomes insufficient, and an appropriate amount of ink is not ejected from the head 62, resulting in a decrease in printing accuracy. or the ink meniscus at the nozzle 67 is destroyed and air enters the head 62 . Specifically, the threshold is set to a value according to the diameter of the nozzle 67 . For example, the larger the diameter of the nozzle 67, the smaller the threshold value (negative value).

The control program 82 determines whether the ink supply amount to the head 62 is insufficient by determining whether the determined minimum ink pressure value is equal to or greater than the threshold value. Then, the control program 82 determines whether the amount of ink supplied to the head 62 is sufficient (S18: Yes) or when the amount of ink supplied to the head 62 is insufficient (S18: No). Change the type of processing (first scanning processing, second scanning processing). The second scanning process is a process in which a decrease in the amount of ink supplied to the head 62 is suppressed more than the first scanning process. A detailed description will be given below.

The first scanning process is a process of printing an image by moving the carriage 32 from one of the first position and the second position to the other once. and a second position to print an image. For example, in the second scanning process, the control program 82 selects the nozzles 67 to be used in the first movement of the carriage 32 from the first position to the second position and the nozzles 67 to be used in the first movement of the carriage 32 from the second position to the first position. The nozzle 67 to be used in the first movement is determined. Then, the control program 82 moves the carriage 32 from one of the first position and the second position to the other, ejects ink from the nozzles 67 , and then moves the carriage 32 to the first position without conveying the sheet 6 . Ink is ejected from the nozzle 67 while moving from the other to the second position.

The number of nozzles 67 used in the first movement of the carriage 32 and the number of nozzles 67 used in the second movement of the carriage 32 are approximately the same. That is, the amount of ink ejected from the head 62 during one movement of the carriage 32 in the second scanning process is the amount of ink ejected from the head 62 during the movement of the carriage 32 in the first scanning process. about half. Therefore, in the second scanning process, the amount of ink ejected by the head 62 per unit time is smaller than that in the first scanning process. That is, the ink ejection frequency (so-called print duty) decreases. As described above, the drop in the first pressure due to the ejection of ink is caused by continuous ejection of ink before the first pressure, which has been lowered due to the ejection of ink, recovers to the original pressure. Therefore, when the ink ejection frequency decreases, the decrease in the first pressure is suppressed. As a result, in the second scanning process, the time required for printing is longer than in the first scanning process, but the decrease in the amount of ink supplied to the head 62 is suppressed.

As shown in FIG. 6, the control program 82 determines whether or not there is a next pass after executing the first scanning process or the second scanning process (S21). Whether or not there is a next pass means whether or not there is a print area (FIG. 8) next to the print area in which the image is printed. The control program 82 determines whether or not there is a next pass based on the print data acquired in step S12.

When the control program 82 determines that there is no next pass (S21: No), the control program 82 rotates the paper discharge roller 25 via the conveying motor 42 to carry out the paper discharge process of conveying the sheet 6 to the paper discharge tray 16. End the process. When the control program 82 determines that there is a next pass (S21: Yes), the process from step S12 onwards is executed again. When the print instruction instructs printing of a plurality of pages, the control program 82 determines whether or not there is a next page. Execute.

[Action and effect of the embodiment]
The control device 71 controls the pressure (first pressure) of the ink pressure that changes due to ejection of ink from the head 62 and the pressure (second pressure) that changes due to the inertial force caused by the acceleration/deceleration movement of the carriage 32 . to determine the ink pressure, which is the pressure exerted by the ink on the head 62 . Therefore, the ink pressure can be determined more accurately than determining the ink pressure without relying on the second pressure. As a result, in the printer 10 in which the head 62 ejects ink even in the acceleration/deceleration region of the carriage 32, the control device 71 can accurately determine the ink pressure without using a pressure sensor. Since the ink pressure can be accurately determined, the controller 71 can accurately determine whether the supply of ink to the head 62 is insufficient.

In addition, the control device 71 executes the first scanning process when the determined minimum ink pressure value, which is the minimum ink pressure value, is equal to or greater than the threshold value, and executes the first scanning process when the minimum ink pressure value is not equal to or greater than the threshold value. A second scanning process different from the scanning process of . The threshold is set such that the amount of ink supplied to the head 62 becomes insufficient when the minimum ink pressure value is less than the threshold. Therefore, the controller 71 can change the type of scanning process to be executed depending on whether the amount of ink supplied to the head 62 is sufficient or when the amount of ink supplied to the head 62 is insufficient. can.

Further, the control device 71 executes the first scanning process when the minimum ink pressure value is equal to or greater than the threshold value, and when the minimum ink pressure value is not equal to or greater than the threshold value, the ink to the head 62 is transferred to the head 62 rather than the first scanning process. Then, a second scanning process is executed in which a decrease in the supply amount of is suppressed. Therefore, the control device 71 can prevent an insufficient amount of ink from being supplied to the head 62, thereby preventing a decrease in printing accuracy, or the ink meniscus at the nozzle 67 can be destroyed and Air can be prevented from entering 62 .

[Modification 1]
In the above-described embodiment, in the second scanning process of step S20, the plurality of nozzles 67 are the nozzles 67 used in the first movement of the carriage 32 and the nozzles 67 used in the second movement of the carriage 32. I explained an example that can be divided into In this modification, instead of dividing the plurality of nozzles 67 into two, printing is performed in an area where an image is printed by the first movement of the carriage 32 and an area where an image is printed by the second movement of the carriage 32. An example in which an image is printed by dividing areas will be described.

The control program 82 executes the third scanning process shown in FIG. 7 instead of the second scanning process of step S20 described in the embodiment. Also, the control program 82 determines the boundary position and the discharge stop position shown in FIG. 8 after the process of step S17 and before executing the third scanning process. The boundary position is the position where the ink pressure determined in step S17 is less than the threshold value stored in the storage unit 73, and is the position that the carriage 32 reaches first. The ejection stop position is a position ahead of the boundary position by a predetermined distance (to the left in the illustrated example) in the direction of movement of the carriage 32 . The third scanning process is an example of a second type printing process.

First, when the control program 82 determines in step S18 that the minimum ink pressure value is not equal to or greater than the threshold (S18: No), it determines a position where the ink pressure determined in step S17 matches the threshold stored in the storage unit 73. do. Then, the control program 82 determines the first position to be reached by the carriage 32 among the determined positions as the boundary position. Next, the control program 82 reads out the predetermined distance stored in the ROM 66 or EEPROM 78 of the storage section 73 . The predetermined distance is a value pre-stored in the storage unit 73 before the printer 10 is shipped. The control program 82 determines a position a predetermined distance away from the boundary position in the direction opposite to the movement direction of the carriage 32 as the ejection stop position. Note that the discharge stop position is determined as a value (hereinafter referred to as a determination value) corresponding to the number of pulses input from the linear encoder 51 .

After determining the decision value, the control program 82 performs the third scanning process shown in FIG. First, the control program 82 executes the first movement of the carriage 32 (first scanning process) to move the carriage 32 from the first position to the second position while using all the nozzles 67 of the head 62 ( S31). Then, the control program 82 counts the number of pulses input from the linear encoder 51, and determines whether or not the count value has reached the above-described determined value (S32). That is, in step S32, it is determined whether or not the carriage 32 has reached the discharge stop value.

When the control program 82 determines that the count value has not reached the determination value (S32: No), it continues the first scanning process. When the control program 82 determines that the count value has reached the determination value (S32: Yes), the ink ejection from the head 62 is stopped without stopping the movement of the carriage 32 (S33). That is, the control program 82 prints the image in the area to the left of the ejection stop position in the print area.

Next, the control program 82 determines whether or not the carriage 32 has reached the second position and the first scanning process has ended (S34). The control program 82 moves the carriage 32 toward the second position until the carriage 32 reaches the second position (S34: No). That is, the control program 82 moves the carriage 32 to the second position without causing the head 62 to eject ink after stopping the ink ejection at the ejection stop position.

When the control program 82 determines that the carriage 32 has reached the second position and the first scanning process has been completed (S34: Yes), the carriage 32 is moved from the second position to the first position while using all the nozzles 67. A second movement of the carriage 32 to the position (second scanning process) is executed (S35). Then, the control program 82 determines whether or not the count value of the number of pulses input from the linear encoder 51 has reached the determination value (S36). That is, in step S36, it is determined whether or not the carriage 32 has reached the discharge stop position. For example, when the carriage 32 moves from the first position to the second position, the control program 82 adds and counts the number of pulses input from the linear encoder 51 so that the carriage 32 moves from the second position to the first position. When moving toward the position, the number of pulses input from the linear encoder 51 is subtracted and counted.

When the control program 82 determines that the count value has not reached the determination value (S36: No), it continues the second scanning process. On the other hand, when the control program 82 determines that the count value has reached the determination value (S36: Yes), the ink ejection from the head 62 is stopped without stopping the movement of the carriage 32 (S37). That is, the control program 82 prints an image in the second scanning process in the area where printing was not performed in the first scanning process, that is, in the area to the right of the ejection stop position.

The control program 82 determines whether the carriage 32 has reached the first position and the second scanning process has ended (S38). The control program 82 moves the carriage 32 toward the first position until the carriage 32 reaches the first position (S38: No). That is, the control program 82 moves the carriage 32 to the first position without causing the head 62 to eject ink after stopping the ink ejection at the ejection stop position.

When the control program 82 determines that the carriage 32 has reached the first position and the second scanning process has ended (S38: Yes), the third scanning process ends, and step S21 of the main process (FIG. 6) is executed. process.

In the above description, the carriage 32 is moved from the first position to the second position in the first scanning process, and the carriage 32 is moved from the second position to the first position in the second scanning process. However, the carriage 32 may be moved from the second position to the first position in the first scanning process, and the carriage 32 may be moved from the first position to the second position in the second scanning process.

[Effects of Modification 1]
In this modification, ink ejection is stopped at the ejection stop position, which is the position before the boundary position where the amount of ink supplied to the head 62 becomes insufficient. Therefore, insufficient supply of ink to the head 62 is reliably prevented. Note that the time from when the carriage 32 reaches the second position after ink ejection is stopped in the first scanning process of the carriage 32 to when the second scanning process is started determines the first scanning process. Ink pressure that was lost in the process is restored.

[Modification 2]
In the above-described embodiment, an example has been described in which insufficient supply of ink to the head 62 is suppressed by moving the carriage 32 twice. In this modified example, an example will be described in which the amount of ink supplied to the head 62 is suppressed from becoming insufficient by slowing the moving speed of the carriage 32 .

In this modification, the control program 82 executes a fourth scanning process (not shown) instead of the second scanning process in step S20 (FIG. 6). The storage unit 73 also stores the first speed function V1(t) and the second speed function V2(t). The first speed function V1(t) is a function that determines the acceleration/deceleration movement and movement speed of the carriage 32 in the first scanning process, and is the same function as the speed function V(t) described in the embodiment. be. The second speed function V2(t) is a function that determines the acceleration/deceleration movement and movement speed of the carriage 32 in the fourth scanning process. The moving speed of the carriage 32 in the constant-velocity moving region indicated by the second speed function V2(t) is slower than the moving speed of the carriage 32 in the constant-velocity moving region indicated by the first speed function V1(t). Note that the first speed function V1(t) and the second speed function V2(t) are pre-stored in the storage unit 73 when the printer 10 is shipped. The moving speed of the carriage 32 determined by the first speed function V1(t) is an example of the first speed. The moving speed of the carriage 32 determined by the second speed function V2(t) is an example of the second speed. The fourth scanning process is an example of the second type printing process.

In the main process shown in FIG. 6, the control program 82 reads the second velocity function V2(t) from the storage unit 73 when determining that the minimum ink pressure value is not equal to or greater than the threshold value (S18: No). Then, the control program 82 uses the read second speed function V2(t) to control the drive of the carriage motor 36 to move the carriage 32 at the speed indicated by the second speed function V2(t). The drive control of the carriage motor 36 using the second speed function V2(t) is performed in the same manner as the drive control of the carriage motor 36 using the speed function V(t) described in the embodiment.

In the fourth scanning process, the control program 82 moves the carriage 32 at the speed indicated by the second speed function V2(t) and causes the head 62 to eject ink to print an image on the print area of the sheet 6 .

[Effects of Modification 2]
In this modification, when it is determined that the minimum ink pressure value is not equal to or greater than the threshold value, the moving speed of the carriage 32 is made slower than the moving speed of the carriage 32 in the first scanning process, and an image is printed on the sheet 6. . Since the moving speed of the carriage 32 is slowed down, the amount of ink ejected by the head 62 per unit time, that is, the ink ejection frequency (print duty) is reduced. By reducing the frequency of ink ejection, it is possible to prevent an insufficient amount of ink from being supplied to the head 62 . That is, in the fourth scanning process, the time required for printing is longer than that in the first scanning process, but the decrease in the amount of ink supplied to the head 62 is suppressed. As a result, it is possible to prevent the print accuracy from deteriorating and the air to enter the head 62 due to the destruction of the meniscus of the ink in the nozzles 67 .

The second speed function V2(t) may be a function for accelerating and decelerating the carriage 32 in an acceleration/deceleration region having the same width as the first speed function V1(t). ) may be a function for accelerating and decelerating the carriage 32 in an acceleration/deceleration region narrower than ). When the second speed function V2(t) is a function that accelerates and decelerates the carriage 32 in an acceleration/deceleration region with the same width as the first speed function V1(t), the second speed function V2(t) is the first speed function V2(t). The inertial force acting on the ink due to the acceleration/deceleration of the carriage 32 is smaller than in the case of the function that accelerates/decelerates the carriage 32 in an acceleration/deceleration region narrower than the speed function V1(t). Therefore, if the second speed function V2(t) is a function that accelerates and decelerates the carriage 32 in the same acceleration/deceleration region as the first speed function V1(t), the amount of ink supplied to the head 62 is reduced. Insufficiency can be suppressed more effectively.

[Modification 3]
In this modified example, as shown in FIG. 9, an example will be described in which the print area is divided into a plurality of areas and the first pressure is determined. In the illustrated example, the print area is divided into eight areas from the first area to the eighth area. However, the print area may be divided into a plurality of areas of 9 or more or 7 or less.

The control program 82 determines the number of ink dots for each area from the first area to the eighth area based on the print data acquired in step S12 (FIG. 6). Then, the control program 82 determines the first pressure for each area based on the determined number of ink dots. Specifically, the ROM 66 or EEPROM 78 of the storage unit 73 stores in advance a table showing the correspondence between the number of ink dots and the first pressure, or a formula for calculating the first pressure from the number of ink dots. The control program 82 reads from the storage unit 73 the first pressure corresponding to the number of ink dots determined based on the print data, or uses the calculation formula read from the storage unit 73 and the number of ink dots to read the first pressure. is determined for each region.

The table or calculation formula stored in the storage unit 73 includes a pressure drop indicating the degree of pressure drop that ink exerts on the manifold 68 and the nozzle flow paths 69 of the head 62, and and a recovery pressure indicating the extent to which the pressure on 69 recovers over time. Specifically, for example, the greater the amount of ink ejected by the head 62 per unit time, the greater the degree of decrease in the first pressure. When the amount of ink ejected by the head 62 per unit time is small, or when no ink is ejected, the first pressure gradually recovers. The table or calculation formula stored in the storage unit 73 is set to reduce the ink pressure or restore the ink pressure according to the amount of ink ejected by the head 62 per unit time. For example, the storage unit 73 stores a linear function whose slope changes according to the number of ink dots. The control program 82 determines the slope of the linear function based on the number of ink dots determined for each area.

The control program 82 uses the final pressure value of the first pressure in the first region and the determined linear function to determine the first pressure in the second region. The control program 82 uses the final pressure value of the first pressure in the second region and the determined linear function to determine the first pressure in the third region. Similarly, the control program 82 determines the first pressures in the fourth to eighth regions. The final pressure value in each region is an example of an ink pressure related value.

The storage unit 73 stores a linear function whose slope is changed according to the number of ink dots. ing. In the example shown in FIG. 9, the number of ink dots in the second area is greater than the number of ink dots in the other areas, and ink is not ejected in the fourth area. The first pressure determined by the linear function of the slope of the pressure drop is an example of the drop pressure. The first pressure determined by the linear function of the slope of the pressure recovery is an example of the recovery pressure.

[Effects of Modification 3]
In this modification, the print area is divided into a plurality of areas (first area to eighth area), and the first pressure is determined for each area. Therefore, the minimum value of the first pressure can be determined more accurately than when the print area is not divided into a plurality of areas. More specifically, the thin line in FIG. 9 indicates the first pressure when the print area is not divided into a plurality of areas. When the print area is not divided into a plurality of areas, the first pressure is determined based on the number of ink dots in the entire print area as described in the embodiment. Therefore, for example, when the print area includes an area where a large amount of ink is ejected per unit time (second area) and an area where no ink is ejected (fourth area), the actual minimum value of the first pressure It is conceivable that a value greater than is determined as the minimum value of the first pressure. In this modification, the print area is divided into a plurality of areas, and the first pressure is determined for each area. Even if included, the first pressure can be accurately determined. Since the first pressure can be determined accurately, it is possible to more accurately determine whether the amount of ink supplied to the head 62 is insufficient. As a result, a decrease in printing accuracy is suppressed, or air is prevented from entering the head 62 due to destruction of the ink meniscus at the nozzle 67 .

In addition, in this modification, the first pressure is determined for each region based on the reduced pressure due to ejection of ink from the head 62 and the recovery pressure over time. Therefore, the first pressure can be determined more accurately than when the first pressure is determined based on the reduced pressure due to ejection of ink from the head 62 and not based on the recovery pressure over time. Since the first pressure can be determined accurately, it is possible to accurately determine whether the amount of ink supplied to the head 62 is insufficient. As a result, a decrease in printing accuracy is suppressed, or air is prevented from entering the head 62 due to destruction of the ink meniscus at the nozzle 67 .

[Other variations]
In the above-described embodiment, the example in which the control device 71 of the printer 10 is an example of the "control device" of the present invention has been described. However, the "control device" of the present invention may be a control device of a personal computer or a mobile terminal connected to the printer 10 via a communication line. In that case, the control program 82 is, for example, a printer driver. Alternatively, the control program 82 is incorporated as a module into the printer driver.

In the embodiment described above, an example in which the membrane sheet 50 is provided in the buffer tank 61 has been described. However, the present invention can also be applied to a printer in which the buffer tank 61 is not provided with the membrane sheet 50 . When the buffer tank 61 is not provided with the membrane sheet 50 , the pressure numerical value associated with the acceleration/deceleration movement of the carriage 32 in the above-described first table and second table is the same as when the buffer tank 61 is provided with the membrane sheet 50 . The value is different from the case where

In the above-described embodiment, the ink cartridge 18 detachable from the mounting case 17 was described as an example of the container. However, the container may also be a tank fixed to the printer 10 .

In the above-described embodiments, the carriage motor 36 has been described as an example of the drive source that moves the carriage 32 . However, other drive sources may be used as long as the control device 71 can control the drive.

In the above-described embodiments, the ink pressure minimum value has been described as an example of the ink pressure related value. However, the ink pressure-related value is a value related to the pressure exerted by the ink on the head 62. If it is possible to determine whether the amount of ink supplied to the head 62 is insufficient, other values may be used. There may be. For example, the ink pressure related value may be the amount of change in the negative direction of the ink pressure. In that case, the threshold stored in the storage unit 73 is the absolute value of the threshold described in the embodiment. In step S18, the control program 82 determines whether or not the amount of change in the negative direction of the ink pressure is equal to or less than a threshold. When the control program 82 determines that the amount of change is equal to or less than the threshold (S18: Yes), it executes the first scanning process. Execute the scanning process.

In the above-described embodiment, in the second scanning process of step S20, an example of printing one print area (FIG. 8) by moving the carriage 32 twice has been described. However, in the second scanning process of step S20, the image may be printed in one print area by moving the carriage 32 three times or more.

In the above-described embodiment, an example in which one threshold is stored in the storage unit 73 has been described. However, a plurality of threshold values corresponding to the environmental temperature in which the printer 10 is used and the ink viscosity and sedimentation degree may be stored in advance in the storage unit 73 . For example, printer 10 has a temperature sensor that outputs the ambient temperature in which it is used. The control program 82 reads from the storage unit a threshold corresponding to the temperature output by the temperature sensor, and executes the process of step S18. Alternatively, the control program 82 counts and acquires the elapsed time after the ink cartridge 18 is attached to the attachment case 17 . The longer the elapsed time, the higher the viscosity and sedimentation of the ink. The control program 82 reads the threshold corresponding to the elapsed time from the storage unit 73, and executes the process of step S18. Alternatively, the control program 82 may correct the threshold described in the embodiment using the environmental temperature or the elapsed time, and execute the process of step S18 using the corrected threshold. A calculation formula for correcting the threshold value is stored in advance in the storage unit 73 .

Reference Signs List 10 Printer 18 Ink cartridge 32 Carriage 36 Carriage motor 42 Transport motor 62 Head 63 Tube 67 Nozzle 70 Piezoelectric element 71 ... control device 73 ... storage unit 82 ... control program

Claims (11)

a tube having a first end connected to a container in which ink is stored;
a head to which the second end of the tube is connected, the head having a plurality of nozzles for ejecting ink and a plurality of drive elements provided corresponding to the nozzles;
a carriage for mounting the head, the carriage being movable between a first position and a second position;
a drive source for moving the carriage;
A control device for controlling a print execution unit comprising:
a control unit that controls driving of the drive element and the drive source;
with memory and
The control unit
Acquisition processing for acquiring print data;
While moving the carriage from one of the first position and the second position to the other by accelerating movement, constant velocity movement, and deceleration movement, the head is moved in the acceleration area, constant velocity movement area, and deceleration area of the carriage. determining an ink pressure relation value corresponding to the pressure exerted by the ink on the head when the ink is ejected from the nozzles, based on the obtained print data and the acceleration movement and deceleration movement of the carriage. processing;
determination processing for determining whether the determined ink pressure-related value reaches a threshold value stored in the memory;
a first type of print processing executed according to the print data in response to determination that the ink pressure-related value does not reach the threshold;
A second type of print processing that is executed according to the print data in response to determination that the ink pressure-related value reaches the threshold value, the second type of print processing that is different from the first type of print processing. Execute the print process and
In the determination process, the control unit divides the area from the first position to the second position into a plurality of areas, determines the ink pressure relation value in one of the areas, and determines the ink pressure relationship in the one area. using the values to determine said ink pressure related value for the next said region contiguous to said one region . a tube having a first end connected to a container in which ink is stored;
a head to which the second end of the tube is connected, the head having a plurality of nozzles for ejecting ink and a plurality of drive elements provided corresponding to the nozzles;
a carriage for mounting the head, the carriage being movable between a first position and a second position;
a drive source for moving the carriage;
A control device for controlling a print execution unit comprising:
a control unit that controls driving of the drive element and the drive source;
with memory and
The control unit
Acquisition processing for acquiring print data;
While moving the carriage from one of the first position and the second position to the other by accelerating movement, constant velocity movement, and deceleration movement, the head is moved in the acceleration area, constant velocity movement area, and deceleration area of the carriage. determining an ink pressure relation value corresponding to the pressure exerted by the ink on the head when the ink is ejected from the nozzles, based on the obtained print data and the acceleration movement and deceleration movement of the carriage. processing;
determination processing for determining whether the determined ink pressure-related value reaches a threshold value stored in the memory;
a first type of print processing executed according to the print data in response to determination that the ink pressure-related value does not reach the threshold;
A second type of print processing that is executed according to the print data in response to determination that the ink pressure-related value reaches the threshold value, the second type of print processing that is different from the first type of print processing. Execute the print process and
The control unit, in the determination process,
determining a first ink pressure relation value corresponding to the pressure exerted by the ink on the head, which decreases due to ejection of the ink from the nozzles, based on the print data;
determining a second ink pressure relation value corresponding to the pressure exerted by the ink on the head based on the acceleration movement and the deceleration movement of the carriage, which changes according to the acceleration movement and the deceleration movement of the carriage;
A controller for determining the ink pressure-related value by adding the first ink-pressure-related value and the second ink-pressure-related value. a tube having a first end connected to a container in which ink is stored;
a head to which the second end of the tube is connected, the head having a plurality of nozzles for ejecting ink and a plurality of drive elements provided corresponding to the nozzles;
a carriage for mounting the head, the carriage being movable between a first position and a second position;
a drive source for moving the carriage;
A control device for controlling a print execution unit comprising:
a control unit that controls driving of the drive element and the drive source;
with memory and
The control unit
Acquisition processing for acquiring print data;
While moving the carriage from one of the first position and the second position to the other by accelerating movement, constant velocity movement, and deceleration movement, the head is moved in the acceleration area, constant velocity movement area, and deceleration area of the carriage. determining an ink pressure relation value corresponding to the pressure exerted by the ink on the head when the ink is ejected from the nozzles, based on the obtained print data and the acceleration movement and deceleration movement of the carriage. processing;
determination processing for determining whether the determined ink pressure-related value reaches a threshold value stored in the memory;
a first type of print processing executed according to the print data in response to determination that the ink pressure-related value does not reach the threshold;
A second type of print processing that is executed according to the print data in response to determination that the ink pressure-related value reaches the threshold value, the second type of print processing that is different from the first type of print processing. Execute the print process and
The first type printing process is a process of printing in a printing range by one movement of the carriage from one of the first position and the second position to the other,
The second type of printing process is a process of printing in the printing range by moving the carriage two or more times between the first position and the second position,
The control unit
In the determining process, a boundary position, which is a position of the carriage at which the ink pressure-related value reaches the threshold value, is determined;
In the second type of printing process, the head ejects ink while the carriage moves from one of the first position and the second position to the other, and ink is discharged until the boundary position is reached. A control device in which ejection is stopped and the head ejects ink to an ejection stop position where ink ejection is stopped while moving from the other of the first position and the second position to one of the positions. a tube having a first end connected to a container in which ink is stored;
a head to which the second end of the tube is connected, the head having a plurality of nozzles for ejecting ink and a plurality of drive elements provided corresponding to the nozzles;
a carriage for mounting the head, the carriage being movable between a first position and a second position;
a drive source for moving the carriage;
A control device for controlling a print execution unit comprising:
a control unit that controls driving of the drive element and the drive source;
with memory and
The control unit
Acquisition processing for acquiring print data;
While moving the carriage from one of the first position and the second position to the other by accelerating movement, constant velocity movement, and deceleration movement, the head is moved in the acceleration area, constant velocity movement area, and deceleration area of the carriage. determining an ink pressure relation value corresponding to the pressure exerted by the ink on the head when the ink is ejected from the nozzles, based on the obtained print data and the acceleration movement and deceleration movement of the carriage. processing;
determination processing for determining whether the determined ink pressure-related value reaches a threshold value stored in the memory;
a first type of print processing executed according to the print data in response to determination that the ink pressure-related value does not reach the threshold;
A second type of print processing that is executed according to the print data in response to determination that the ink pressure-related value reaches the threshold value, the second type of print processing that is different from the first type of print processing. Execute the print process and
The control device, wherein the memory stores the threshold according to the diameter of the nozzle. In the determination process, the control unit determines, based on the print data, the reduced pressure corresponding to the decrease in the pressure exerted by the ink on the head and the recovery pressure of the pressure exerted by the ink on the head over time. 2. The controller of claim 1 , further determining the ink pressure-related value based on the reduced pressure and the recovery pressure. The control unit, in the determination process,
determining a first ink pressure relation value corresponding to the pressure exerted by the ink on the head, which decreases due to ejection of the ink from the nozzles, based on the print data;
determining a second ink pressure relation value corresponding to the pressure exerted by the ink on the head based on the acceleration movement and the deceleration movement of the carriage, which changes according to the acceleration movement and the deceleration movement of the carriage;
6. A controller according to claim 1 or 5 , wherein said ink pressure related value is determined by adding said first ink pressure related value and said second ink pressure related value. The first type printing process is a process of printing in a printing range by one movement of the carriage from one of the first position and the second position to the other,
6. The second type of printing process is a process of printing in the printing range by moving the carriage two or more times between the first position and the second position . 7. The control device according to any one of 6 . The control unit
In the determining process, a boundary position, which is a position of the carriage at which the ink pressure-related value reaches the threshold value, is determined;
In the second type of printing process, the head ejects ink while the carriage moves from one of the first position and the second position to the other, and ink is discharged until the boundary position is reached. 8. The processing according to claim 7 , wherein ejection is stopped and the head ejects ink to an ejection stop position where ink ejection is stopped while moving from the other of the first position and the second position to one of the positions. Control device as described. The first type printing process is a process in which the carriage performs printing in an acceleration region, a uniform movement region in which the carriage moves at a constant speed at a first speed, and a deceleration region,
6. The second type of printing process is a process in which printing is performed in a constant-velocity movement area in which the carriage moves at least at a second constant velocity that is lower than the first velocity. , and 6 . 10. The control device according to any one of claims 1 to 3 and 5 to 9 , wherein said memory stores said threshold according to the diameter of said nozzle. 11. The control device according to any one of claims 1 to 10 , comprising said print execution unit.

Images