JP4893766B2 - Liquid ejecting apparatus and control method thereof - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus that records an image by ejecting liquid onto a recording medium, and a control method therefor.

  For example, in an ink jet type ejection device, ejection performance may deteriorate due to bubbles or dust mixed in the ejection port from which ink is ejected, or dry ink adhering to the vicinity of the ejection port. . In order to prevent or recover from such deterioration in ejection performance, purge is performed to wipe the ejection surface after forcibly ejecting ink from the ejection port of the head, and ink droplets are forcibly ejected from the ejection port. A technique for performing flushing or the like is known.

  To perform flushing or the like, a member such as a cap covering the discharge port is required, a dedicated space for performing the operation is secured, it takes time to move the long head, Such inconvenience may occur. Therefore, in order to avoid such inconvenience, there has been a proposal to perform flushing while the head is held at the recording position without being moved to a space dedicated to flushing (see Patent Document 1). According to Patent Document 1, ink ejected from the head at the time of flushing is landed on a medium dedicated to flushing (empty ejection paper) different from the recording medium for image recording.

JP-A-9-57957

  As described above, the technique disclosed in Patent Document 1 is uneconomical because a medium dedicated to flushing is required. Furthermore, it is necessary to provide a space and a member for storing a medium dedicated to flushing (empty discharge paper storage unit), an empty discharge paper conveyance path, and the like in the apparatus, which increases the size of the apparatus and increases the manufacturing cost. Become.

  An object of the present invention is to provide a liquid ejection apparatus that does not require a flushing-dedicated medium and that can alleviate problems of an increase in the size of the apparatus and an increase in manufacturing cost, and a control method therefor.

  In order to achieve the above object, according to a first aspect of the present invention, a liquid channel that reaches a plurality of ejection ports, and a drive unit that applies energy to the liquid in the liquid channel to eject the liquid from the ejection port And a recording medium having a first surface and a second surface opposite to the first surface to a recording position by the liquid discharge head so that the first surface faces the discharge port. A first conveyance unit that conveys the liquid, and a recording medium in which liquid is ejected from the ejection port to the first surface at the recording position, to the recording position so that the second surface faces the ejection port. When the flushing of the second transport unit and the liquid discharge head is performed, the discharge is performed on the first surface of the recording medium that has reached the recording position by the transport by the first transport unit based on the flushing data relating to the flushing. Exit After the liquid is ejected, the liquid is ejected from the ejection port to the second surface of the recording medium that has reached the recording position by the transport by the second transport unit based on the recording data relating to the image recording. Recording data on the first surface of the recording medium that has reached the recording position by the first control for controlling the first transport unit, the second transport unit, and the drive unit, and transport by the first transport unit Then, the liquid is discharged from the discharge port based on the flushing data to the second surface of the recording medium that has reached the recording position by the transport by the second transport unit. Thus, there is provided a liquid ejecting apparatus comprising: a controller that performs any one of second control for controlling the first transport unit, the second transport unit, and the drive unit.

  According to the above configuration, at the time of performing the flushing, the liquid related to the flushing is discharged to one of the first surface and the second surface of the recording medium for recording by the first or second control of the controller. Therefore, a medium dedicated to flushing is not required, which is economical. In addition, since it is not necessary to provide a space or member for storing a medium dedicated to flushing, a conveyance path for the medium, and the like in the ejection device, problems of an increase in the size of the device and an increase in manufacturing cost can be reduced.

  When the controller determines to perform the flushing, it is preferable to perform the first control. For example, when performing single-side recording on a plurality of recording media, only a part of the recording media may be used for flushing, and the remaining recording media may be recorded on the first surface. In this case, when the controller performs the second control, the recording surface (the surface on which an image based on the recording data is formed) in the discharge portion in the recording medium used for flushing and the recording medium used for recording without flushing. The direction of is different. In order to avoid this, it is necessary to control the surface of the recording medium to be reversed before the recording medium used for flushing is discharged to the discharge unit. It is also conceivable for the user to align the orientation of the recording medium discharged manually to the discharge unit. On the other hand, when the controller performs the first control as described above, the recording surface of the recording medium is directed in the same direction at the discharge unit without performing the complicated control and processing as described above. Therefore, it is possible to improve the processing speed and the usability. In addition, even when performing double-sided recording on a plurality of recording media, flushing is performed at the same time as in the case of single-sided recording, so that the ejection performance at the plurality of ejection ports included in the head is made uniform at an early stage. Good image recording can be performed.

  When the controller receives a double-sided recording command, the controller controls the first transport unit to transport the recording medium to the recording position, and the recording medium that has reached the recording position by the transport by the first transport unit. The drive unit is controlled so that liquid is ejected from the ejection port on the first surface based on the recording data, and the recording medium on which the image is recorded on the first surface by driving by the drive unit is moved to the recording position. The second transport unit is controlled to transport, and the liquid is ejected from the ejection port on the second surface of the recording medium that has reached the recording position by the transport by the second transport unit based on recording data. It is preferable to perform double-sided recording control for controlling the drive unit. In this case, the practicality is enhanced by using the first and second transport units not only for the processing related to flushing but also for double-sided recording.

  When the controller receives a single-sided recording command and determines that the flushing is to be performed, the flushing data is ejected to one of the first and second surfaces, and the liquid based on only the recording data is ejected to the other. Either the first or second control may be performed. In this case, the deterioration of the recording quality is reduced as compared with the case where the liquid related to both recording and flushing is ejected on one surface of the recording medium. In addition, the flushing region can be set in a wider range than in the case where the liquid related to flushing is ejected to a partial region in the recording surface. As a result, the degree of freedom in designing the flushing data is improved, and it becomes easy to devise the data configuration so that the droplets related to flushing are less noticeable.

  When the controller receives a double-sided recording command and determines that the flushing is to be performed, the brightness, saturation, recording duty, and character size of the image to be recorded on each of the first and second surfaces Based on at least one, it is selected whether to perform the first or second control, and the brightness of the image to be recorded is lower than the other of the first and second surfaces, and the color of the image Recording data and flushing data on one surface satisfying at least one of the following conditions: the degree is higher than the other, the recording duty of the image is higher than the other, and the character size included in the image is larger than the other Based on the recording data, the drive unit is controlled so that the liquid is ejected from the ejection port based on the recording data, and the selected one of the first and second controls is selected. The may be carried out. As a result, even when flushing is performed on one side of the recording medium in double-sided recording, the droplets associated with flushing can be made inconspicuous, and deterioration in recording quality can be reduced.

  It is preferable that the controller performs one of the selected first and second controls so that the droplet based on the recording data and the droplet based on the flushing data do not overlap on the one surface. In this case, problems such as conspicuous droplets related to flushing, which may occur when the droplets overlap each other, lead to deterioration in recording quality, are alleviated.

  When the controller receives a recording command for the first time after turning on the power, or when another recording command is received after a lapse of a predetermined time from the time when the previous recording command was received, the controller determines that the flushing is performed, and the recording command It is preferable to perform either the first control or the second control for the recording medium that is first transported by the first transport unit after receiving the print. When recording is performed for the first time after the power is turned on, or when recording is resumed after not being performed for a predetermined time, it is highly necessary to restore the ejection performance by flushing due to an increase in the viscosity of the liquid. Therefore, it is possible to recover the ejection performance and maintain the recording quality satisfactorily by the control as described above. Further, flushing is performed on the recording medium other than the recording medium that is first transported by the first transport unit (that is, the second and subsequent recording media) (except for the case where flushing is performed for each nth recording medium described later). The recording speed can be improved by performing the recording.

  When the controller receives a recording command for continuously recording on a recording medium of n (n: a predetermined natural number of 2 or more) or more, the controller determines that the flushing is to be performed, and receives the recording command, It is preferable to perform one of the first and second controls so that the flushing is performed for each nth recording medium conveyed by one conveyance unit. When recording is continuously performed on a plurality of recording media, there is a high possibility that the ejection performance is deteriorated during the continuous recording. Therefore, the above control makes it possible to periodically recover the ejection performance during continuous recording and maintain good recording quality.

  It is preferable that the controller performs any one of the first and second controls so that the droplets based on the flushing data do not overlap each other on either the first or second surface. In this case, problems such as bleeding of droplets on the opposite surface, which may occur when the droplets overlap, are alleviated.

  The liquid discharge head may be a line head that is long in the width direction of the recording medium and discharges liquid to the recording medium in a fixed state. When using a line-type head, it is possible to secure a space dedicated to flushing at a position adjacent to the recording position, or to move the head to the space during flushing. The problem becomes more prominent. However, according to the above configuration, it is not necessary to secure a flushing-dedicated space and to move the head, so that problems such as an increase in the size of the apparatus and deterioration in processing efficiency can be reduced even when a line-type head is provided.

  According to a second aspect of the present invention, a liquid discharge head including a liquid channel that reaches a plurality of discharge ports, and a drive unit that applies energy to discharge the liquid from the discharge ports to the liquid in the liquid channel; A first transport unit that transports a recording medium having a first surface and a second surface opposite to the first surface to a recording position by the liquid ejection head so that the first surface faces the ejection port. And a second transport unit that transports the recording medium in which the liquid is ejected from the ejection port to the first surface at the recording position to the recording position so that the second surface faces the ejection port. In the control method for performing flushing of the liquid discharge head in the liquid discharge apparatus, the first transfer step for controlling the first transfer unit to transfer the recording medium to the recording position, the first transfer step Before by A first control unit that controls the driving unit to discharge liquid from the discharge port to the first surface of the recording medium that has reached the recording position based on one of flushing data relating to flushing and recording data relating to image recording. After the driving step and the first driving step, a second transporting step for controlling the second transporting unit so as to transport the recording medium on which the liquid is ejected to the first surface based on the one to the recording position. And controlling the driving unit so that liquid is ejected from the ejection port to the second surface of the recording medium that has reached the recording position by the second transport step based on the other of the flushing data and the recording data. There is provided a control method comprising the second driving step.

  According to the above configuration, as in the first aspect, when flushing is performed, the liquid related to flushing is ejected to one of the first surface and the second surface of the recording medium, and the other surface of the recording medium is ejected. Liquid for recording is discharged. Therefore, it is possible to obtain the same effect as in the first aspect (that is, an effect that the medium dedicated to flushing is unnecessary and economical, and the problem of increase in the size of the apparatus and increase in manufacturing cost is reduced). it can.

  According to the present invention, a medium dedicated to flushing is unnecessary and economical, and the problems of an increase in the size of the apparatus and an increase in manufacturing cost can be reduced.

1 is a side sectional view of an ink jet printer according to an embodiment of the present invention. FIG. 2 is a plan view showing a flow path unit of one inkjet head included in the printer of FIG. 1. 2 is a flowchart illustrating a method for controlling the printer of FIG. 1. It is a flowchart which shows the single-sided recording process of FIG. It is a flowchart which shows the double-sided recording process of FIG. It is a perspective view which shows the connection state of 1 inkjet head shown in FIG. 1, and a main tank.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  First, an overall configuration of an inkjet printer 1 according to an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the inkjet printer 1 of this embodiment has a rectangular parallelepiped housing 1a. A paper discharge unit 131 that receives the paper P discharged from the opening 130 is formed on the top plate of the housing 1a. The internal space of the housing 1a is divided into spaces A, B, and C in order from the top. In the space A, four ink jet heads 10 that eject inks of magenta, cyan, yellow, and black, a transport unit 122, A re-transport cassette 140 disposed below the transport unit 122 and a controller 100 that controls the operation of each unit of the printer 1 are disposed. The head 10 is arranged so that the longitudinal direction thereof is along the main scanning direction, and the transport unit 122 transports the paper P in the sub scanning direction immediately below the head 10. Each of the spaces B and C is a space in which a paper supply unit 1b and an ink tank unit 1c that can be attached to and detached from the housing 1a along the main scanning direction are arranged.

  The ink tank unit 1 c includes four main tanks 121 that store the respective color inks corresponding to the four heads 10. As shown in FIG. 6, each main tank 121 is connected to the corresponding head 10 via a tube.

  The paper feed unit 1 b includes a paper feed tray 123 that can store a plurality of sheets of paper P, and a paper feed roller 125 attached to the paper feed tray 123. The paper P in the paper feed tray 123 is sent out in order from the uppermost one by the paper feed roller 125, guided by the guides 127 a and 127 b, and sent to the transport unit 122 while being sandwiched by the feed roller pair 126. On the conveyance belt 8 of the conveyance unit 122 to be described later, the surface of the sheet P facing downward in the sheet feeding tray 123 faces upward.

  The conveyance unit 122 is in contact with two belt rollers 6 and 7, an endless conveyance belt 8 wound around the two rollers 6 and 7, and an inner peripheral surface of a lower loop of the conveyance belt 8. A tension roller 9 that applies tension to the conveyor belt 8 by being biased downward, and a support frame (not shown) that rotatably supports the rollers 6, 7, 9 are provided. When the belt roller 7 as a driving roller rotates clockwise in FIG. 1, the conveyor belt 8 travels, and the belt roller 6 as a driven roller also rotates clockwise in FIG.

  The upper loop of the conveyor belt 8 is arranged so that the belt surface extends in parallel with the lower surface of the four heads 10 while being separated from the lower surface of the four heads 10 (a surface on which a large number of ejection ports for ejecting ink are formed) by a predetermined distance. Is supported by The four heads 10 are juxtaposed along the sub-scanning direction and supported by the housing 1a via the frame 3.

  A weakly adhesive silicon layer is formed on the surface of the conveyor belt 8. The paper P sent to the transport unit 122 is pressed against the surface of the transport belt 8 by the pressing roller 4 and then held on the surface by the adhesive force on the surface of the transport belt 8 while being sub-scanned along the black arrow. It is conveyed in the direction. A sensor 15 that detects the paper P is provided immediately downstream of the pressing roller 4 in the sub-scanning direction so as to face the upper loop surface of the conveyor belt 8. The controller 100 grasps the position of the paper P based on the detection signal from the sensor 15 and controls the driving of the head 10.

  When the paper P is transported while being placed on the transport belt 8 and passes immediately below the four heads 10 (that is, the “recording position” facing the ejection openings formed on the lower surface of the heads 10), each head A color image is formed on the paper P by sequentially ejecting ink of each color from the ten ejection openings toward the paper P. The paper P is peeled off from the surface of the transport belt 8 by the peeling plate 5, guided by the guides 129a and 129b, and transported upward while being sandwiched between the two pairs of feed rollers 128.

  The paper P that has thus reached the vicinity of the opening 130 is discharged as it is to the paper discharge unit 131, or when performing flushing as will be described in detail later (see S14 to S16 in FIG. 4), it is outlined. It is conveyed in the reverse direction along the arrow, and is conveyed again to the conveyance unit 122 via the re-conveyance cassette 140.

  As shown in FIG. 1, the re-transport cassette 140 is disposed so as to be sandwiched between the transport unit 122 and the paper feed tray 123 of the paper feed unit 1b. The re-conveying cassette 140 is connected to the upstream side of the pair of feed rollers 126 via the guide 143. By this re-conveying cassette 140 functioning as a reverse conveying mechanism, the surface of the paper P facing downward in the paper feed tray 123 is directed upward at the recording position.

  Next, the configuration of the head 10 will be described with reference to FIGS. 1 and 2.

  The head 10 is long in the main scanning direction (the width direction of the paper P), and is a line type that performs recording on the paper P conveyed in the sub-scanning direction while being fixed to the housing 1a. Head. The head 10 has a substantially rectangular shape in plan view.

  As shown in FIGS. 1 and 2, the head 10 includes a flow path unit 10a and a reservoir unit 10b in order from the bottom. The reservoir unit 10b temporarily stores the ink supplied from the main tank 121 via the tube as shown in FIG. The flow path unit 10a distributes the ink supplied from the reservoir unit 10b to a plurality of ejection ports.

  As shown in FIG. 2, an opening 105b for receiving the ink sent from the reservoir unit 10b is formed on the upper surface of the flow path unit 10a. The openings 105b are arranged along two long sides of the flow path unit 10a having a rectangular shape in plan view. Inside the flow path unit 10a, there are formed an ink flow path from the opening 105b to the manifold flow path 105, the sub-manifold flow path 105a branched from the manifold flow path 105, and further to each discharge port on the lower surface via the aperture and the pressure chamber. The

  Four trapezoidal actuator units 21 are fixed on the upper surface of the flow path unit 10a so as to cover a large number of pressure chambers opened on the upper surface. The actuator units 21 are alternately arranged with the openings 105b along the main scanning direction. A region corresponding to the fixed region of the actuator unit 21 on the lower surface of the flow path unit 10a is a discharge region in which a large number of discharge ports are opened. In the flow path unit 10a, a plurality of individual ink flow paths are formed from the outlet of the sub-manifold flow path 105a to the discharge port via the pressure chamber. The actuator unit 21 includes a piezoelectric actuator corresponding to each discharge port. The piezoelectric actuator is driven under the control of the controller 100 to apply energy for ejecting ink from the ejection port to ink in the corresponding pressure chamber.

  The reservoir unit 10b is fixed to a portion of the upper surface of the flow path unit 10a where the actuator unit 21 is not bonded (a region including the opening 105b partitioned by a two-dot chain line in FIG. 2), and is slightly spaced from the actuator unit 21. Is facing through. The reservoir unit 10b supplies the temporarily stored ink to the flow path unit 10a through the opening 105b.

  As shown in FIG. 6, the flexible cable 52 on which the driver IC 50 is mounted is drawn upward from the gap between the reservoir unit 10 b and the actuator unit 21. One end of the flexible cable 52 is connected to the actuator unit 21, and the other end is electrically connected to the controller 100 via a substrate (not shown). The recording data from the controller 100 is supplied to the driver IC 50, where it is converted into a drive signal for driving the actuator unit 21 (piezoelectric actuator).

  Next, a control method of the printer 1 will be described with reference to FIGS. Each step shown in FIG. 3 to FIG. 5 indicates processing executed by the controller 100.

  The controller 100 includes a CPU (Central Processing Unit), an EEPROM (Electrically Erasable and Programmable Read Only Memory) that stores a program executed by the CPU and data used for the program in a rewritable manner, and temporarily stores data when the program is executed. A random access memory (RAM). Each functional unit constituting the controller 100 is constructed by cooperation of these hardware and software in the EEPROM.

  The controller 100 receives a recording command from, for example, a PC (personal computer) connected to the printer 1 via the interface of the printer 1. When the recording command is received (S1: YES), the controller 100 resets various parameters related to the recording process. By this reset processing, for example, the parameter m relating to the number of recorded sheets is set to an initial value 0. Further, the controller 100 transmits the recording data (for example, designation of single-sided recording and double-sided recording, the number of recordings, data on pixel positions, colors, and gradations in the recorded image) included in the command to the printer 1. And whether or not the command is a double-sided recording command (S2). The controller 100 performs a double-sided recording process (S4) if it is a double-sided recording command (S2: YES), and performs a single-sided recording process (S3) if it is not a double-sided recording command (S2: NO). End the routine.

  Here, the single-sided recording process (S3) will be described with reference to FIG.

  In the single-sided recording process (S3), the controller 100 first inputs “1” as the page number m of the paper P to be recorded (S10), and the recording command received for the first time after the printer 1 is turned on. It is determined whether or not it is a command (S11). If the recording command is not the recording command received for the first time after the printer 1 is turned on (S11: NO), the controller 100 determines whether or not a predetermined time (for example, 12 hours) has elapsed since the previous recording command was received. Is determined (S12).

  If the predetermined time has not elapsed since the previous recording command was received (S12: NO), the controller 100 determines whether the page number m is “10x (x: any natural number)” (that is, a multiple of 10). It is determined whether or not (S13).

  Here, among the criteria for determining whether or not the controller 100 performs flushing, the criteria for the page number m will be described. The standard for page number m corresponds to the time determined by the physical properties (characteristics) of the ink. As the property changes, such as thickening, progresses over time, the ink ejection performance changes, and a visible change (deterioration) in recording accuracy and quality is recognized. Therefore, in determining the above-mentioned standard, for example, the ink leaving time is changed, and the time until the change due to the thickening of the dot shape in the recorded image is recognized by microscopic observation is obtained. If ink is not ejected even within the time, the recording accuracy and quality are adversely affected. In the present embodiment, the time is obtained as described above, and a convenient numerical value that is close to the maximum number of sheets P that can be recorded within the time and that is convenient is “10”. Is stipulated.

  When the recording command is a recording command received for the first time after the printer 1 is turned on (S11: YES), when a predetermined time has elapsed since the previous recording command was received (S12: YES), or page number When m is a multiple of 10 (S13: YES), the controller 100 determines that flushing of the head 10 is to be performed, and a series including flushing as described below for the uppermost sheet P in the sheet feed tray 123. The processes (S14 to S17) are performed.

  That is, the controller 100 first controls each part of the printer to perform flushing on the paper P (S14). Here, “flushing” means that the actuator unit 21 is driven on the basis of previously generated flushing data, and ink is ejected from the ejection ports of the head 10. By performing the flushing, it is possible to prevent or recover the deterioration of the ink ejection performance of the head 10. In the present embodiment, the flushing is performed on the paper P, that is, the ink ejected based on the flushing data is landed on the surface of the paper P.

  In S14, the controller 100 first generates flushing data so that ink droplets based on the flushing data do not overlap on the surface of the paper P. The prevention of the overlapping of the ink droplets is considered for one head 10 or one type of ink, between different heads 10 or between different types of ink. As a result, the ink droplets that have landed on the paper P are dispersed on the paper P with little noticeability. The controller 100 then feeds a paper feed roller 125, a feed roller pair 126, and the like so that the uppermost paper P in the paper feed tray 123 is conveyed to the recording position below the head 10 along the black arrow in FIG. And the drive of the belt roller 7 is controlled. The sheet P thus transported is in a state where the surface facing downward in the paper feed tray 123 is facing upward on the transport belt 8. Further, the controller 100 is the surface of the paper P that has been conveyed by the belt roller 7 to the recording position (at this time, the surface that faces the discharge port on the lower surface of the head 10 and is opposite to the back surface that contacts the surface of the conveying belt 8. The actuator unit 21 of each head 10 is controlled so that ink is ejected from the ejection port based on the generated flushing data. The ink ejection timing from each head 10 is determined based on the detection result of the leading edge of the paper P by the sensor 15.

  Next, the controller 100 controls each unit so that the front and back of the paper P are reversed (S15). Specifically, the controller 100 controls the belt roller 7 and the feed roller pair 128 so that the paper P on which the ink droplets related to flushing land on the surface is conveyed upward from the conveyance unit 122 to the vicinity of the opening 130 in S14. Control the drive. When the paper P leaves the conveyance belt 8 and reaches the vicinity of the opening 130, the controller 100 reverses the rotation direction of the feed roller pair 128 near the opening 130. As a result, the transport direction is reversed, and the paper P is transported downward along the white arrow. Then, the controller 100 feeds the paper P to the re-conveying cassette 140 while being guided by the guide 141 and sandwiched by the feed roller pair 142, further guided by the guide 143, and sandwiched by the roller pair 126 again. The driving of the feed roller pair 128, the feed roller pair 142, and the roller pair 126 is controlled so as to be fed to the roller. The re-conveying cassette 140 is provided with a skew correcting mechanism for aligning the transport direction of the paper P such as a skew roller, and the paper P sent to the re-conveying cassette 140 is in a state where the skew is corrected. Then, it is carried out toward the roller pair 126. As a result, the paper P is turned upside down, that is, the surface on which the ink for flushing has landed in S14 faces downward on the transport belt 8 (that is, the state in contact with the surface of the transport belt 8). Become.

  Next, the controller 100 controls each unit so as to perform recording on the paper P (S16). Specifically, the controller 100 controls the driving of the belt roller 7 so that the paper P is transported along the transport belt 8. When the paper P reaches the recording position, the controller 100 controls the actuator unit 21 of each head 10 so that ink is ejected from the ejection port to the surface of the paper P based on the recording data in the memory. Also at this time, the ejection timing of the ink from each head 10 is determined based on the detection result of the leading edge of the paper P by the sensor 15.

  Next, the controller 100 drives the belt roller 7 and the feed roller pair 128 so that the paper P is transported further upward from the transport unit 122 to the vicinity of the opening 130 and further discharged from the opening 130 to the paper discharge unit 131. Control (S17). At this time, the paper P is discharged onto the paper discharge unit 131 with the image recording surface down.

  Next, the controller 100 refers to the memory to determine whether or not there is data for the next page to be recorded (S18). If there is no next page data (S18: NO), the process returns to FIG. To end the routine. If the next page data remains (S18: YES), the controller 100 returns to S10 as shown in FIG. Here, as the page number m of the paper P to be recorded next, the controller 100 adds 1 to the previous page number (S10), and performs the processes related to S11, S12, and S13. When the controller 100 determines YES in any of these three steps (S11 to S13), the controller 100 repeats the above-described series of processing (S14 to S17). On the other hand, if any of S11 to S13 is NO, the controller 100 records the uppermost sheet P in the sheet feed tray 123 on one surface of the sheet P and then discharges the sheet P. Each part is controlled to perform (S16 and S17). In this case, the processing (S14 and S15) related to flushing is omitted.

  The controller 100 repeats the above-described processing until there is no page data to be recorded. When there is no more page data to be recorded (that is, after the recording of all pages on the paper P is completed), the controller 100 ends the single-sided recording process (S3).

  Next, the double-sided recording process (S4) will be described with reference to FIG. Hereinafter, processes similar to those shown in FIG. 4 are denoted by the same step numbers, and detailed description thereof is omitted.

  In the double-sided recording process (S4), the controller 100 first performs the same processes as S10, S11, S12, and S13 of the single-sided recording process (S3: see FIG. 4). When the recording command is a recording command received for the first time after the printer 1 is turned on (S11: YES), when a predetermined time has elapsed since the previous recording command was received (S12: YES), or page number When m is a multiple of 10 (S13: YES), the controller 100 determines that flushing of the head 10 is to be performed, and a series including flushing as described below for the uppermost sheet P in the sheet feed tray 123. (S19 to S22 etc.) are performed.

  That is, the controller 100 first extracts data relating to brightness, saturation, recording duty, and character size relating to images to be recorded on both sides of the paper P from the recording data stored in the memory (S19).

  Here, the recording duty refers to the ratio of the number of pixels to be recorded with respect to the number of pixels in the recording area, and the recording duty relating to the image refers to the recording duty relating to the whole or a part of the image (the portion serving as the flushing area). Further, the lightness and saturation relating to the image refer to the lightness and saturation in the whole or a part of the image (a portion serving as a flushing region), respectively. The character size related to the image refers to the size of characters included in the entire image or a part of the image (the portion serving as the flushing area).

  Next, the controller 100 selects which side of the paper P is to be flushed based on the data extracted in S19 (S20). Specifically, out of both sides (first side and second side) of the paper P, the brightness related to the image to be recorded is lower than the other, the saturation related to the image is higher than the other, and the recording related to the image One surface satisfying at least one of the condition that the duty is higher than the other and the character size of the image is larger than the other is selected as a surface to be flushed.

  Further, the controller 100 generates flushing data so that the ink droplets based on the flushing data do not overlap each other on the surface of the paper P, and the ink droplets based on the recording data and the ink droplets based on the flushing data do not overlap. To do. The prevention of the overlapping of the ink droplets is considered for one head 10 or one type of ink, between different heads 10 or between different types of ink. As a result, the ink droplets that have landed on the paper P are dispersed on the paper P with little noticeability.

  Next, the controller 100 determines whether or not to perform flushing on the first surface (that is, the surface to be recorded first and currently facing downward in the paper feed tray 123) (S21). ). When performing flushing on the first surface (S21: YES), the controller 100 transports the uppermost paper P in the paper feed tray 123 to the recording position below the head 10 along the black arrow in FIG. The driving of the paper feed roller 125, the feed roller pair 126, and the belt roller 7 is controlled. Further, the controller 100 causes each head 10 to discharge ink from the discharge port to the surface (first surface) of the paper P conveyed by the belt roller 7 and reaching the recording position based on the flushing data and the recording data. The actuator unit 21 is controlled (S22). The ink ejection timing from each head 10 is determined based on the detection result of the leading edge of the paper P by the sensor 15.

  Next, the controller 100 performs the same processing as S15 and S16 in FIG. 4 to perform recording on the second surface following reversal of the paper P, and discharges the paper P (S17).

  On the other hand, when flushing is performed on the second surface (S21: NO), the controller 100 first performs the processing of S16 and S15 in FIG. Then, the paper P is reversed. Thereafter, as in S22, the controller 100 conveys the sheet P by driving the belt roller 7 and discharges the sheet P onto the surface (second surface) of the sheet P that has reached the recording position based on the flushing data and the recording data. The actuator unit 21 of each head 10 is controlled so that ink is ejected from the outlet (S22). Then, the controller 100 discharges the paper P by performing the same process as S17 in FIG.

  Next, as in S18 of FIG. 4, the controller 100 determines whether there is next page data. If there is no next page data (S18: NO), the controller 100 returns to FIG. 3 and ends the routine. If the next page data remains (S18: YES), the controller 100 returns to S10 as shown in FIG. Here, the controller 100 sets 2 (= 1 + 1) as the page number m of the paper P (S10), and performs the processes related to S11, S12, and S13. When the controller 100 determines YES in any of these three steps (S11 to S13), the controller 100 repeats the above-described series of processing (S19 to S22, etc.). On the other hand, if any of S11 to S13 is NO, the controller 100 records the uppermost paper P in the paper feed tray 123 on the first surface of the paper P (S16) and reverses the front and back (S15). Then, each unit is controlled so that the recording of the second surface (S16) and the discharge of the paper P (S17) are performed. In this case, processing related to flushing is omitted.

  As described above, according to the present embodiment, when the flushing is performed, the recording paper P is recorded by the processing of S14 to S17 (see FIG. 4) or S19 to S22 (see FIG. 5) by the controller 100. Ink for flushing is ejected on one surface. Therefore, a flushing-dedicated medium (such as a sheet different from the image recording sheet P) is not required, which is economical. In addition, since it is not necessary to provide a space or member for storing a medium dedicated to flushing, a conveyance path for the medium, and the like in the printer 1, problems of an increase in the size of the printer 1 and an increase in manufacturing cost are reduced.

  As shown in FIG. 4, when single-sided recording is continuously performed on a plurality of sheets P, only some of the sheets P (first and 10x pages in the present embodiment) are used for flushing. And in this embodiment, about the paper P utilized for flushing, after performing flushing on one side, it records on the other side (refer S14-S16 of FIG. 4). On the other hand, if the sheet P used for flushing is recorded on one side and then flushed on the other side, the sheet P used for flushing and the sheet P on which recording was performed without using flushing. , The direction of the recording surface (surface on which an image based on recording data is formed) in the paper discharge unit 131 is different. In order to avoid this, it is necessary to perform control to reverse the surface of the paper before the paper P used for flushing is discharged to the paper discharge unit 131. It is also conceivable for the user to align the orientation of the paper P discharged to the paper discharge unit 131 manually. In contrast, in the present embodiment, since flushing is performed on one side and then recording is performed on the other side, recording of the paper P is performed in the paper discharge unit 131 without performing the above complicated control and processing. The faces will face the same direction. Therefore, it is possible to improve the processing speed and the usability.

  As shown in FIG. 5, the controller 100 performs the same conveyance as in the case of S14 to S17 when flushing is not performed in double-sided recording (S12: NO or the like). Double-sided recording is performed while controlling the driving of the belt roller 7 and the feed roller pairs 126, 128, 141, etc. Thus, practicality is enhanced by using the transport mechanism not only for flushing but also for double-sided recording. In addition, the present invention can be realized by applying a series of processes including flushing (S14 to S17 or S19 to S22) in an apparatus that already has a duplex transport mechanism to support duplex recording.

  As shown in FIG. 4, when the controller 100 receives a single-sided recording command and determines to perform the flushing (S11: YES, S12: YES, S13: YES, etc.), one of the sheets P in S14. The actuator unit 21 is controlled such that ink based on only the flushing data is ejected on this surface and ink based on only the recording data is ejected on the other surface in S16. Thereby, compared with the case where the ink which concerns on both recording and flushing is discharged to one side of the paper P, the deterioration of recording quality is reduced. In addition, the flushing area is set to a wider range than when ink for flushing is ejected to a part of the recording surface of the paper P (that is, when recording and flushing is performed on the same surface of the paper P). be able to. As a result, the degree of freedom in designing the flushing data is improved, and it is easy to devise the data configuration so that the ink droplets related to flushing are less noticeable on the paper P.

  As shown in FIG. 5, when the controller 100 receives a double-sided recording command and determines to perform flushing (S11: YES, S12: YES, S13: YES, etc.), a predetermined condition is set in S20. After the surface to be filled is selected as the surface to be flushed, ink is ejected to the selected surface based on the recording data and the flushing data (S22), and to the other surface based on the recording data (S16). The actuator unit 21 is controlled. As a result, even when flushing one side of the paper P in double-sided recording, the droplets associated with flushing can be made inconspicuous, and deterioration in recording quality can be reduced. Specifically, when the brightness is low, the image is dark, when the saturation is high, the image is vivid, and when the recording duty is high, the number of pixels is large. Because of the size, the line of sight tends to concentrate on the recorded image, and the droplets related to flushing are less noticeable.

  In S <b> 22, the controller 100 performs control so that the ink droplet based on the recording data and the ink droplet based on the flushing data do not overlap on one surface of the paper P (the surface on which flushing and recording are performed). As a result, problems that may occur when the droplets overlap each other, such as the dots on the paper P relating to flushing being noticeable, leading to deterioration in recording quality, are alleviated.

  As shown in FIGS. 4 and 5, when the controller 100 receives a recording command for the first time after power-on (S11: YES), the controller 100 receives another recording command after a predetermined time has elapsed since the previous recording command was received. In this case (S12: YES), or when the page number m is a multiple of 10 (S13: YES), it is determined that flushing is to be performed, and the sheet P that is transported first from the paper feed tray 123 after receiving the recording command is received. A series of processing (S14 to S17 or S19 to S22 etc.) including flushing is performed. When recording is performed for the first time after the power is turned on, when recording is resumed after not being performed for a predetermined time, or when recording is continuously performed on paper P having a predetermined number of pages, due to an increase in ink viscosity, There is a high need to restore ejection performance by flushing. Therefore, it is possible to recover the ejection performance and maintain the recording quality satisfactorily by the control as described above. In addition, the recording speed is increased without performing flushing on sheets other than the sheet P first conveyed from the sheet feed tray 123 after receiving the recording command and the sheet P of the 10x page, thereby improving the processing speed. be able to.

  As shown in FIGS. 4 and 5, when the controller 100 receives a command to continuously record on a plurality of sheets P (S18: YES), the controller 100 is conveyed from the paper feed tray 123 after receiving the command. For each 10th page of paper P (S13: YES), a series of processes (S14 to S17 or S19 to S22, etc.) including flushing are performed. When recording is continuously performed on a plurality of sheets P, there is a high possibility that the ejection performance is deteriorated during the continuous recording. Therefore, the above control makes it possible to periodically recover the ejection performance during continuous recording and maintain good recording quality.

  In S <b> 14 and S <b> 22, the controller 100 performs control so that ink droplets based on the flushing data do not overlap on one side of the paper P. Thereby, problems such as bleeding of ink droplets on the other surface of the paper P, which may occur when the droplets overlap, are alleviated.

  When the printer 1 has the line type head 10, it is conceivable that a space dedicated for flushing is secured at a position adjacent to the recording position in the printer 1 or the head 10 is moved to the space at the time of flushing. Problems of enlargement of the printer 1 and deterioration of processing efficiency become more conspicuous. However, according to this embodiment, since flushing is performed on the paper P, it is not necessary to secure a flushing-dedicated space and to move the head 10, and even if the line-type head 10 is provided, the printer 1 can be increased in size and The problem of deterioration in processing efficiency is reduced.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments and modifications, and various design changes can be made as long as they are described in the claims. is there.

  For example, in the above-described embodiment, when performing flushing in single-sided recording, after performing flushing on one side, recording is performed on the other side (see S14 to S17 in FIG. 4). After recording on this surface, flushing may be performed on the other surface. In this case, the controller 100 may control the actuator unit 21 so that ink is ejected based on only the recording data on one side of the paper P and only the flushing data on the other side. Note that, from the viewpoint of aligning the recording surfaces in the paper discharge unit 131, the reversing process of S15 may be performed again after the flushing.

  In the above-described embodiment, control is performed so that the ink droplets based on the flushing data do not overlap on the surface of the paper P, but the ink droplets may overlap. When performing flushing in double-sided recording, control is performed so that ink droplets based on the recording data and ink droplets based on the flushing data do not overlap on the surface of the paper P, but the ink droplets may overlap.

  The controller 100 receives a recording command for the first time after turning on the power (S11: YES), receives another recording command after elapse of a predetermined time from the time when the previous recording command was received (S12: YES), or page It is not limited to the case where the number m is a multiple of 10 (S13: YES), and it may be determined that flushing is performed based on other conditions.

  In the above-described embodiment, when a continuous recording command is received, a series of processes including flushing (S14 to S17 or S19 to S22) is performed for each sheet P of the 10th page, but the number of pages is 10 pages. The natural number is not limited to 2 and may be any natural number of 2 or more. It should be noted that a series of processes including flushing need not be performed for pages in the middle of continuous recording.

  The printer 1 may be one that does not support double-sided recording, that is, one that does not receive a double-sided recording command.

  The number of liquid discharge heads included in the liquid discharge apparatus is not limited to four, and may be one or more.

  The liquid discharge head included in the liquid discharge apparatus according to the present invention may be either a line type or a serial type, and includes a drive unit of a method other than the piezoelectric method (electrostatic method, thermal jet method, etc.). It may be a thing. Furthermore, liquids other than ink may be ejected.

  The recording medium is not limited to paper as long as it has the first and second surfaces, and may be a cloth, for example.

  The structure of the 1st and 2nd conveyance part is not limited to the above-mentioned embodiment, It can change variously.

  The liquid ejection apparatus according to the present invention may be a facsimile, a copier, or the like other than a printer.

1 Inkjet printer (liquid ejection device)
10 Inkjet head (liquid discharge head)
10a Channel unit 10b Reservoir unit 21 Actuator unit (drive unit)
100 Controller 105 Manifold channel (liquid channel)
122 transport unit (first transport unit, second transport unit)
125 Paper feed roller (first transport unit)
126 Feed roller pair (first transport unit, second transport unit)
128 Feed roller pair (second transport section)
140 Re-conveying cassette 142 Feed roller pair (second conveying unit)
P paper (recording medium)

Claims (11)

A liquid discharge head including a liquid flow path that reaches a plurality of discharge openings, and a drive unit that applies energy for discharging the liquid from the discharge openings to the liquid in the liquid flow path;
A first transport unit that transports a recording medium having a first surface and a second surface opposite to the first surface to a recording position by the liquid ejection head so that the first surface faces the ejection port. When,
A second transport unit that transports the recording medium in which the liquid is ejected from the ejection port to the first surface at the recording position, to the recording position so that the second surface faces the ejection port;
When flushing the liquid ejection head, liquid was ejected from the ejection port to the first surface of the recording medium that reached the recording position by conveyance by the first conveyance unit based on flushing data relating to flushing. Thereafter, the first transport is performed such that liquid is ejected from the ejection port to the second surface of the recording medium that has reached the recording position by the transport by the second transport unit, based on recording data relating to image recording. The first control for controlling the recording unit, the second transport unit, and the drive unit, and the discharge on the first surface of the recording medium that has reached the recording position by the transport by the first transport unit based on the recording data. After the liquid is discharged from the outlet, the discharge port is formed on the second surface of the recording medium that has reached the recording position by conveyance by the second conveyance unit based on flushing data. Luo so that liquid is ejected, the first conveying unit, the second conveyance unit, and a liquid discharge apparatus characterized by comprising a controller for performing one of the second control for controlling the drive unit.   The liquid ejecting apparatus according to claim 1, wherein when the controller determines to perform the flushing, the controller performs the first control.   When the controller receives a double-sided recording command, the controller controls the first transport unit to transport the recording medium to the recording position, and the recording medium that has reached the recording position by the transport by the first transport unit. The drive unit is controlled so that liquid is ejected from the ejection port on the first surface based on the recording data, and the recording medium on which the image is recorded on the first surface by driving by the drive unit is moved to the recording position. The second transport unit is controlled to transport, and the liquid is ejected from the ejection port on the second surface of the recording medium that has reached the recording position by the transport by the second transport unit based on recording data. The liquid ejection apparatus according to claim 1, wherein double-sided recording control for controlling the driving unit is performed. The controller is
When receiving a single-sided recording command and determining to perform the flushing,
The first or second control is performed so that only the flushing data is ejected on one of the first and second surfaces, and the liquid based on only the recording data is ejected on the other. The liquid ejection apparatus according to any one of the above. The controller is
When receiving a double-sided recording command and determining to perform the flushing,
Select whether to perform the first or second control based on at least one of brightness, saturation, recording duty, and character size related to the image to be recorded on each of the first and second surfaces And
Of the first and second surfaces, the lightness related to the image to be recorded is lower than the other, the saturation related to the image is higher than the other, the recording duty related to the image is higher than the other, and One surface satisfying at least one condition that the character size of the image is larger than the other is based on the recording data and the flushing data, and the other surface is based on the recording data. 5. The liquid ejecting apparatus according to claim 1, wherein the driving unit is controlled so as to be ejected, and any one of the selected first and second controls is performed.   The controller performs one of the selected first and second controls so that a droplet based on recording data and a droplet based on flushing data do not overlap on the one surface. Item 6. The liquid ejection device according to Item 5.   When the controller receives a recording command for the first time after turning on the power, or when another recording command is received after a lapse of a predetermined time from the time when the previous recording command was received, the controller determines that the flushing is performed, and the recording command 7. The liquid according to claim 1, wherein the first control and the second control are performed on a recording medium that is first transported by the first transport unit after receiving the liquid. Discharge device.   When the controller receives a recording command for continuously recording on a recording medium of n (n: a predetermined natural number of 2 or more) or more, the controller determines that the flushing is to be performed, and receives the recording command, 8. The method according to claim 1, wherein one of the first control and the second control is performed so that the flushing is performed for each n-th recording medium transported by one transport unit. Liquid ejection device.   The controller performs any one of the first and second controls so that droplets based on flushing data do not overlap each other on either the first or second surface. The liquid ejection device according to claim 8.   10. The line head according to claim 1, wherein the liquid discharge head is a line head that is long in the width direction of the recording medium and discharges liquid to the recording medium in a fixed state. The liquid ejection device according to item. A liquid discharge head including a liquid flow path leading to a plurality of discharge openings; and a drive unit that applies energy for discharging the liquid from the discharge openings to the liquid in the liquid flow path; the first surface and the first surface; , A first transport unit that transports a recording medium having a second surface on the opposite side to a recording position by the liquid ejection head so that the first surface faces the ejection port, and the first transport unit at the recording position. The liquid ejection apparatus according to claim 1, further comprising: a second transport unit configured to transport a recording medium on which a liquid is ejected from the ejection port to the recording position so that the second surface faces the ejection port. In the control method when flushing the head,
A first transport step for controlling the first transport unit so as to transport the recording medium to the recording position;
The liquid is ejected from the ejection port to the first surface of the recording medium that has reached the recording position by the first conveying step based on one of flushing data relating to flushing and recording data relating to image recording. A first driving step for controlling the driving unit;
A second transporting step for controlling the second transporting unit so as to transport the recording medium on which the liquid is ejected to the first surface based on the one to the recording position after the first driving step; and
A second control unit configured to control the driving unit so that liquid is ejected from the ejection port to the second surface of the recording medium that has reached the recording position by the second transport step based on the other of the flushing data and the recording data; A control method comprising a driving step.

Images