Liquid dispensing device, its control method and program

Abstract

To suppress a sheet-like medium from contacting a nozzle surface and suppress a recording quality from deteriorating and a recording speed from decreasing.SOLUTION: After receiving a recording command (S1:YES) a CPU 101 of a printer determines a floating amount X in an area at an end part of a sheet (S2). Thereafter, the CPU determines whether the floating amount X is above a predetermined amount Xt or not (S3). When determining that the floating amount X is above the predetermined amount Xt (S3:YES), the CPU performs end-part control to the area at the end part of the sheet. When determining that the floating amount X is not above the predetermined amount Xt (S3:NO), the CPU does not perform the end-part control to the area at the end part of the sheet but performs control that is performed to a central area of the sheet.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a liquid ejection device that ejects liquid onto a sheet-like medium, a control method therefor, and a program.

Background Art

[0002] Patent Document 1 shows that if the recording paper (sheet-like medium) is not held by the upstream pressing part (upstream pressing member), the upstream end of the recording paper may lift up and the recording paper may come into contact with the ink ejection surface (nozzle surface). To suppress this problem, Patent Document 1 shows that as the last unit printing process, a second unit printing process (a process of transporting the recording paper by a distance slightly smaller than the nozzle shift amount compared to the transport amount of the recording paper P in the first transport process) (small transport) is executed, and then a skip transport process (large transport) is executed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The end control including the above small transport and large transport is effective in suppressing contact of the sheet-like medium with the nozzle surface. However, compared with the control that makes the transport amount constant, transport variations are likely to occur and the number of transports is likely to increase. The recording quality may deteriorate due to transport variations, and the recording speed may decrease due to an increase in the number of transports. Therefore, if end control is performed even when the possibility of the sheet-like medium coming into contact with the nozzle surface is low, deterioration of the recording quality and decrease in the recording speed may become problems.

[0005] The object of the present invention is to provide a liquid dispensing device, a control method therefor, and a program that can suppress contact of a sheet-like medium with the nozzle surface, as well as suppress a decrease in recording quality and recording speed. [Means for solving the problem]

[0006] According to a first aspect of the present invention, the present invention comprises a conveying mechanism for conveying a sheet-like medium in a conveying direction, a discharge unit having a nozzle surface on which a nozzle is formed and for discharging liquid from the nozzle onto the sheet-like medium conveyed by the conveying mechanism, and a control unit, wherein the conveying mechanism includes an upstream pressing member positioned upstream of the discharge unit in the conveying direction and pressing down on the sheet-like medium to prevent it from approaching the nozzle surface, and a downstream pressing member positioned downstream of the discharge unit in the conveying direction and pressing down on the sheet-like medium to prevent it from approaching the nozzle surface, and the control unit performs a determination process for determining the amount of floating in the end region of the sheet-like medium in the conveying direction, and a determination process for determining whether the amount of floating is greater than or equal to a predetermined amount, and if the determination process determines that the amount of floating is greater than or equal to the predetermined amount When the floating amount is determined in the determination process to be less than or equal to a predetermined amount, the liquid dispensing device is provided, characterized in that when only one of the upstream pressing member and the downstream pressing member is pressing down on the sheet-like medium, the conveying mechanism is made to perform a large conveying operation after multiple small conveying operations, and the liquid is discharged to the discharge section during the multiple small conveying operations, wherein the small conveying operation is made to have the conveying mechanism convey a small amount of the sheet-like medium, and the large conveying operation is made to have the conveying mechanism convey a large conveying operation that is greater than the small conveying operation, and when the determination process determines that the floating amount is not greater than or equal to a predetermined amount, the same control is performed on the conveying mechanism and the discharge section as when both the upstream pressing member and the downstream pressing member are pressing down on the sheet-like medium.

[0007] According to a second aspect of the present invention, a liquid dispensing device comprising: a conveying mechanism for conveying a sheet-like medium in a conveying direction; and a dispensing unit having a nozzle surface on which a nozzle is formed, for dispensing liquid from the nozzle onto the sheet-like medium conveyed by the conveying mechanism, wherein the conveying mechanism includes an upstream pressing member positioned upstream of the dispensing unit in the conveying direction and pressing down on the sheet-like medium to prevent it from approaching the nozzle surface; and a downstream pressing member positioned downstream of the dispensing unit in the conveying direction and pressing down on the sheet-like medium to prevent it from approaching the nozzle surface, and a control method for controlling the liquid dispensing device comprising: a determination process for determining the amount of floating in the end region of the sheet-like medium in the conveying direction; and a determination process for determining whether the amount of floating is greater than or equal to a predetermined amount, wherein in the determination process the amount of floating is greater than or equal to a predetermined amount A control method is provided in which, if it is determined that the amount is greater than the predetermined amount, when only one of the upstream pressing member and the downstream pressing member is pressing down on the sheet-like medium, the conveying mechanism is made to perform a large conveyance after multiple small conveyances, and liquid is discharged to the discharge section during the multiple small conveyances, wherein the small conveyance is made to convey the sheet-like medium in a small conveyance amount by the conveying mechanism, and the large conveyance is made to convey the sheet-like medium in a large conveyance amount greater than the small conveyance amount by the conveying mechanism, and if it is determined in the determination process that the amount of floating is not greater than the predetermined amount, when only one of the upstream pressing member and the downstream pressing member is pressing down on the sheet-like medium, the same control as when both the upstream pressing member and the downstream pressing member are pressing down on the sheet-like medium is performed on the conveying mechanism and the discharge section.

[0008] According to a third aspect of the present invention, a liquid dispensing device comprising a conveying mechanism for conveying a sheet-like medium in a conveying direction, and a dispensing unit having a nozzle surface on which a nozzle is formed, for dispensing liquid from the nozzle onto the sheet-like medium conveyed by the conveying mechanism, wherein the conveying mechanism includes an upstream pressing member positioned upstream of the dispensing unit in the conveying direction and pressing down on the sheet-like medium to prevent it from approaching the nozzle surface, and a downstream pressing member positioned downstream of the dispensing unit in the conveying direction and pressing down on the sheet-like medium to prevent it from approaching the nozzle surface, and the liquid dispensing device is configured to function as a determination means for determining the amount of floating in the end region of the sheet-like medium in the conveying direction, and a determination means for determining whether the amount of floating is equal to or greater than a predetermined amount, and the determination means determines whether the amount of floating is equal to or greater than the predetermined amount If it is determined that the floating amount is not equal to or greater than a predetermined amount, the program is provided which, when it is determined that only one of the upstream pressing member and the downstream pressing member is pressing down on the sheet-like medium, causes the conveying mechanism to perform a large conveyance after multiple small conveyances, and discharges liquid to the discharge section during the multiple small conveyances, wherein the small conveyance is caused by the conveying mechanism to convey a small amount of the sheet-like medium, and the large conveyance is caused by the conveying mechanism to convey a large amount of the sheet-like medium that is greater than the small conveyance amount, and if it is determined by the determination means that the floating amount is not equal to or greater than a predetermined amount, the program is provided which, when only one of the upstream pressing member and the downstream pressing member is pressing down on the sheet-like medium, causes the conveying mechanism and the discharge section to perform the same control as when both the upstream pressing member and the downstream pressing member are pressing down on the sheet-like medium. [Effects of the Invention]

[0009] According to the present invention, if it is determined that the amount of floating is greater than or equal to a predetermined amount, edge control can be performed to suppress contact of the sheet-like medium with the nozzle surface. On the other hand, if it is determined that the amount of floating is not greater than or equal to a predetermined amount, edge control can be not performed to suppress a decrease in recording quality and a decrease in recording speed. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic side view showing the internal structure of a printer according to the first embodiment of the present invention, and is a schematic side view showing the state in which the roll body is housed. [Figure 2] Figure 1 is a schematic side view showing the printer with cut paper loaded into it. [Figure 3] This is a partial cross-sectional view of the head. [Figure 4] This is a magnified view of region IV shown in Figure 1. [Figure 5] Figure 4 is a plan view of the area around the head. [Figure 6] (a) is a cross-sectional view along the VIA-VIA line in Figure 5. (b) is a side view taken from the direction of arrow VIB in Figure 5. [Figure 7] This is a block diagram showing the electrical configuration of the printer in Figure 1. [Figure 8] This figure corresponds to Figure 4, which is used to explain central control. [Figure 9] This figure corresponds to Figure 4, which illustrates edge control relative to the leading edge of the paper. [Figure 10] This figure corresponds to Figure 4, which illustrates edge control relative to the trailing edge of the paper. [Figure 11] Figure 1 is a flowchart showing the control details related to recording in the printer. [Figure 12] This graph shows the relationship between the leading edge position of the paper and the amount of lift. [Figure 13] This is a flowchart showing the control content related to recording in a printer according to the second embodiment of the present invention. [Modes for carrying out the invention]

[0011] <First Embodiment> As shown in Figures 1 and 2, the printer 1 (liquid ejection device) according to the first embodiment of the present invention comprises a housing 1a, paper feed trays 10 and 20 that are detachable from the housing 1a, and a paper output tray 6. Paper feed tray 10 corresponds to the "first storage section" and "storage section" of the present invention, and paper feed tray 20 corresponds to the "second storage section" of the present invention.

[0012] The paper feed trays 10 and 20 have a box shape that opens upward and are movable in the front-rear direction with respect to the housing 1a. The paper feed trays 10 and 20 are pulled out from the housing 1a by being moved forward with respect to the housing 1a and are attached to the housing 1a by being moved backward with respect to the housing 1a. The paper feed trays 10 and 20 can take a mounted position (see FIGS. 1 and 2) attached to the housing 1a and a pulled-out position (not shown) in front of the mounted position. When the paper feed trays 10 and 20 are in the mounted position, the paper feed tray 20 overlaps the paper feed tray 10 in the vertical direction and is disposed above the paper feed tray 10.

[0013] The paper discharge tray 6 is constituted by a side wall in front of the upper part of the housing 1a. The paper discharge tray 6 can take an open position (not shown) that opens the opening 1x of the housing 1a and a closed position (see FIGS. 1 and 2) that closes the opening 1x by rotating about an axis 6a along the left-right direction.

[0014] The printer 1 further includes a conveyance mechanism 3, a cutting mechanism 4, a head 5, and a control device 100. Elements of the conveyance mechanism 3 excluding rollers 14a and 14b described later, the cutting mechanism 4, the head 5, and the control device 100 are supported by the housing 1a.

[0015] The conveyance mechanism 3 is configured to selectively convey the paper P from the paper feed trays 10 and 20 and includes rollers 14a and 14b, rollers 32 and 35 and arms 33 and 36, roller pairs 37a, 37b, 38, and 39, a platen 9, a corrugated plate 31, a roller 34, and a conveyance motor 30 (see FIG. 7) for driving the respective rollers.

[0016] The paper P is a general term for a roll paper Pr (see FIG. 1) and a cut paper Pc (see FIG. 2) and corresponds to the "sheet-like medium" of the present invention. The cut paper Pc is shorter in length in the conveyance direction (the direction in which the paper P is conveyed by the conveyance mechanism 3) than the roll paper Pr.

[0017] In the transport mechanism 3, rollers 14a and 14b, roller 35 and arm 36, roller pairs 37a, 37b, 38, and 39, roller 34, and platen 9 constitute a transport path T1 through which roll paper Pr is transported from the paper feed tray 10, passing under the head 5, to the paper output tray 6 (see Figure 1). In the transport mechanism 3, rollers 32 and arm 33, roller pairs 37a, 38, and 39, roller 34, and platen 9 constitute a transport path T2 through which cut paper Pc is transported from the paper feed tray 20, passing under the head 5, to the paper output tray 6 (see Figure 2). The section from roller pair 37a to the paper output tray 6 is common to both transport paths T1 and T2.

[0018] As shown in Figure 1, the paper feed tray 10 is capable of accommodating a roll of paper R. The roll of paper R consists of a long roll of paper Pr wound around the outer circumference of a cylindrical core member Rc. The roll of paper R is housed in the paper feed tray 10 with its rotation axis Rx (the central axis of the core member Rc) aligned in the left-right direction.

[0019] Rollers 14a and 14b are positioned at the bottom of the paper feed tray 10. Rollers 14a and 14b are rotatable about an axis that runs in the left-right direction. When the roll body R is housed in the paper feed tray 10, the outer circumferential surface of its lower portion is supported by rollers 14a and 14b.

[0020] When setting the roll R, the roll R is manually rotated counterclockwise in the direction shown in Figure 1 to unwind the roll paper Pr from the roll R. The leading edge of the roll paper Pr (the downstream end in the transport direction) is then clamped between the roller 35 and the bottom wall 11 of the paper feed tray 10. In this state, when the transport motor 30 (see Figure 7) is driven by the control device 100, the rollers 14a, 14b, and 35 rotate, and the roll paper Pr is fed backward. The roll paper Pr fed from the paper feed tray 10 by the roller 35 comes into contact with the rear side wall 12 of the paper feed tray 10, moves along the side wall 12, and is guided to the cutting mechanism 4.

[0021] The roller 35 is supported at one end of the arm 36. The other end of the arm 36 is supported by the housing 1a via an axis 36a that runs in the left-right direction. The arm 36 is rotatable about the axis 36a. The arm 36 is biased by a biasing member (not shown) so that the roller 35 approaches the bottom wall 11.

[0022] The cutting mechanism 4 includes a cutter 4a and a cutting motor 40 (see Figure 7). The cutter 4a is positioned above the rear side wall 12 of the paper feed tray 10 and below the roller pair 37b. The cutter 4a consists of, for example, a disc-shaped rotating blade and a driven blade. Alternatively, the cutter 4a may consist of a rotating blade and a fixed blade. When the cutting motor 40 is driven by the control device 100, the rotating blade rotates and moves back and forth in the left-right direction. The roll paper Pr is cut in the left-right direction by the cutter 4a.

[0023] As shown in Figure 2, the paper feed tray 20 can accommodate multiple cut sheets Pc stacked vertically. The cut sheets Pc are supported on the upper surface of the bottom wall 21 of the paper feed tray 20.

[0024] When the paper feed tray 20 is mounted on the housing 1a and no cut paper Pc is placed in the paper feed tray 20, the roller 32 contacts the bottom wall 21 (see Figure 1). When the paper feed tray 20 is mounted on the housing 1a and cut paper Pc is placed in the paper feed tray 20, the roller 32 contacts the uppermost layer of cut paper Pc (see Figure 2). In this state, when the transport motor 30 (see Figure 7) is driven by the control device 100, the roller 32 rotates and the cut paper Pc is fed backward.

[0025] The roller 32 is supported at one end of the arm 33. The other end of the arm 33 is supported by the housing 1a via an axis 33a that runs in the left-right direction. The arm 33 is rotatable about the axis 33a (see Figures 1 and 2). The arm 33 is biased by a biasing member (not shown) so that the roller 32 approaches the bottom wall 21.

[0026] The head 5 (corresponding to the "discharge section" of the present invention) includes a flow path unit 51 and an actuator unit 52, as shown in Figure 3. Inside the flow path unit 51, a common flow path 51x communicating with an ink tank (not shown) and a plurality of individual flow paths 51y branching off from the common flow path 51x are formed. Each individual flow path 51y includes a pressure chamber 51c and a nozzle 51n. The nozzle 51n is located at the tip of the individual flow path 51y and opens to the lower surface of the flow path unit 51. The lower surface of the flow path unit is a nozzle surface 5a on which the plurality of nozzles 51n are formed. The pressure chamber 51c opens to the upper surface of the flow path unit 51. The actuator unit 52 includes a diaphragm 521 positioned on the upper surface of the flow path unit 51 so as to cover the plurality of pressure chambers 51c, a piezoelectric layer 522 positioned on the upper surface of the diaphragm 521, and a plurality of individual electrodes 523 positioned on the upper surface of the piezoelectric layer 522 so as to face each of the plurality of pressure chambers 51c. In the diaphragm 521 and piezoelectric layer 522, the portion sandwiched between each individual electrode 523 and each pressure chamber 51c functions as an individual unimorph-type actuator for each pressure chamber 51c, and can be independently deformed in response to the voltage applied to each individual electrode 523 by the driver IC 50 (see Figure 3). As the actuator deforms to become convex toward the pressure chamber 51c, the volume of the pressure chamber 51c decreases, pressure is applied to the ink in the pressure chamber 51c, and ink is ejected from the nozzle 51n.

[0027] The head 5 is held in a carriage 5c, as shown in Figures 4 and 5. The carriage 5c is movable in the left-right direction by the scanning mechanism 8 (see Figure 5) while holding the head 5. The left-right direction is perpendicular to the transport direction around the head 5 and parallel to the nozzle surface 5a, and corresponds to the "scanning direction" of the present invention.

[0028] As shown in Figure 5, the scanning mechanism 8 includes two guide rails 81 and 82 that support the carriage 5c, an endless belt 83 connected to the carriage 5c, and a scanning motor 80. The endless belt 83 is connected to the scanning motor 25. When the scanning motor 25 is driven by the control device 100, the endless belt 83 moves, and the carriage 5c and head 5 move in the scanning direction along the guide rails 81 and 82.

[0029] As shown in Figure 4, the platen 9 is positioned below the head 5 and carriage 5c, parallel to the nozzle surface 5a, and has a surface that supports the paper P. Six ribs 9a (see Figure 5) extending in the transport direction are formed in the upstream region of this surface. As shown in Figure 5, the six ribs 9a are arranged at equal intervals in the scanning direction.

[0030] Roller pairs 38 and 39 are positioned so as to sandwich the platen 9 in the conveying direction. As shown in Figure 4, roller pair 38 is positioned upstream of the head 5 in the conveying direction and includes an upper roller 38a and a lower roller 38b. Roller pair 39 is positioned downstream of the head 5 in the conveying direction and includes an upper roller 39a and a lower roller 38b.

[0031] The base of the corrugated plate 31 is positioned above the upper roller 38a of the roller pair 38. The tip of the corrugated plate 31 (downstream end in the conveying direction) faces the surface of the platen 9 with a slight gap between them. As shown in Figure 5, seven corrugated plates 31 are provided at equal intervals in the scanning direction. The six ribs 9a are positioned between adjacent corrugated plates 31 in the scanning direction.

[0032] As shown in Figure 5, the roller pair 39 has six sets, each consisting of an upper roller 39a and a lower roller 39b. The six sets are arranged at equal intervals in the scanning direction. Each of the six sets is positioned in the scanning direction, coinciding with the six ribs 9a.

[0033] As shown in Figure 4, rollers 34 are positioned downstream of the roller pairs 39 in the conveying direction. As shown in Figure 5, there are seven rollers 34, spaced equally apart in the scanning direction. The six pairs of rollers 39 are each positioned between adjacent rollers 34 in the scanning direction. The seven rollers 34 are aligned in the scanning direction with the seven corrugated plates 31.

[0034] Rollers 38a, 38b, and 39b are rubber rollers without protrusions on their outer surface, while rollers 34 and 39a are spur rollers with multiple protrusions on their outer surface. This makes it difficult for ink that lands on the surface of the paper P to adhere to rollers 34 and 39a.

[0035] As shown in Figure 6(a), the upper end of each rib 9a is positioned above the tip of each corrugated plate 31. In this positional relationship, the upper ends of the six ribs 9a support the paper P from below, and the tips of the seven corrugated plates 31 press against the paper P from above, thereby imparting a wave shape to the paper P along the scanning direction.

[0036] As shown in Figure 6(b), the contact point between the upper roller 39a and the lower roller 39b is located above the lower end of the roller 34. In this positional relationship, the six lower rollers 39b support the paper P from below, while the seven rollers 34 press down on the paper P from above, thereby imparting a wave shape to the paper P along the scanning direction.

[0037] As shown in Figures 6(a) and (b), the paper P is given a wave shape along the scanning direction, which gives the paper P rigidity and enables good transport.

[0038] Here, the corrugated plate 31 corresponds to the "upstream pressing member" of the present invention, and the upper roller 39a corresponds to the "downstream pressing member" of the present invention. As shown in Figure 4, the corrugated plate 31 is positioned upstream of the head 5 in the transport direction and presses the paper P to restrict the paper P from approaching the nozzle surface 5a. The upper roller 39a is positioned downstream of the head 5 in the transport direction and presses the paper P to restrict the paper P from approaching the nozzle surface 5a.

[0039] As shown in Figure 7, the control device 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, and an ASIC (Application Specific Integrated Circuit) 104 that includes various control circuits. The control device 100 is connected to an external device (not shown), such as a PC (Personal Computer), in a communicative manner. The CPU 101 and ASIC 104 correspond to the "control unit" of the present invention.

[0040] ROM102 stores programs and data for the CPU101 to control various operations. RAM103 temporarily stores data used by the CPU101 when executing the above programs. Based on recording commands received from external devices, the CPU101 issues commands to the ASIC104 according to the programs and data stored in ROM102 and RAM103.

[0041] The ASIC104 is connected to a transport motor 30, a driver IC 50, a scanning motor 80, and a cutting motor 40. The ASIC104 controls the transport motor 30, the driver IC 50, and the scanning motor 80 (and the cutting motor 40 if recording is to be done on roll paper Pr) according to commands from the CPU 101, and performs the recording process to record an image on the paper P.

[0042] In the recording process, the ASIC 104 alternately causes the transport mechanism 3 to transport the paper P in the transport direction and the scanning mechanism 8 to move the head 5 in the scanning direction while ejecting ink from the nozzle 51n. That is, during recording, the paper P is transported intermittently. The ejection operation is performed during the transport stop between one transport operation and the next transport operation. By repeatedly performing the transport operation and the ejection operation alternately, ink dots are formed on the surface of the paper P, and an image is recorded.

[0043] A single ink ejection operation can be performed in two ways, depending on the recording resolution and recording speed: (i) when the head 5 ejects ink while moving forward or backward in the scanning direction, or (ii) when the head 5 makes one or more reciprocating movements in the scanning direction, ejecting ink in both the forward and backward movements.

[0044] Now, referring to Figures 8-10, we will explain the transport control in the recording process.

[0045] As shown in Figure 8, when both the corrugated plate 31 and the upper roller 39a are holding the paper P, the ASIC 104 performs "central control" to cause the transport mechanism 3 to transport the paper P at a constant reference transport amount D0.

[0046] As shown in Figures 9 and 10, when only one of the corrugated plate 31 or the upper roller 39a is holding down the paper P, the ASIC 104, if it determines that the amount of floating X of the paper P is greater than or equal to a predetermined amount Xt, executes "edge control" which causes the transport mechanism 3 to perform a large transport after multiple small transports, and to perform an ejection operation between the multiple small transports.

[0047] Figure 9 shows edge control for the leading edge (downstream end in the transport direction) region of the paper. In Figure 9, the paper P, shown by the dashed line, is held down by the corrugated plate 31 but not by the upper roller 39a.

[0048] Figure 10 shows edge control for the rear end (upstream end in the transport direction) region of the paper. In Figure 10, the paper P shown by the dashed line is held down by the upper roller 39a but not by the corrugated plate 31.

[0049] Figures 9 and 10 illustrate the case where, in a single ejection operation, "(ii) the head 5 makes one or more reciprocating movements in the scanning direction, ejecting ink in both the forward and reverse movements." In this example, a large transport is performed after multiple small transports, and then multiple small transports are performed after the large transport.

[0050] Small transport is when the transport mechanism 3 transports paper P in small transport amounts D1a, D1b, D1a', D1b' (amounts smaller than the standard transport amount D0). Large transport is when the transport mechanism 3 transports paper P in large transport amounts D2a, D2a' (amounts larger than the small transport amounts D1a, D1b, D1a', D1b' and larger than the standard transport amount D0). The large transport amounts D2a, D2a' are shorter than the length of the nozzle area in the transport direction (the distance in the transport direction from the nozzle 51n located furthest upstream in the transport direction to the nozzle 51n located furthest downstream among the multiple nozzles 51n formed on the head 5).

[0051] The small transport quantities D1a, D1b, D1a', and D1b' are not limited to being the same as each other, but may be different. The large transport quantities D2a and D2a' are not limited to being the same as each other, but may be different. Furthermore, in multiple small transports performed consecutively, the transport quantity is constant in Figures 9 and 10, but the transport quantity is not limited to being constant.

[0052] The amount of lift X refers to the amount of lift (distance from the surface of the platen 9 to the highest point of the paper P) in the end region of the paper P in the transport direction (including the leading and trailing end regions; in Figure 9, the leading end region of the paper P). The end region is the region that includes the end (leading or trailing end) of the paper P, and the length of the end region in the transport direction is, for example, the sum of the length in the transport direction from the leading end of the corrugated plate 31 to the upper roller 39a and the length of the nozzle region in the transport direction. Note that in Figures 9 and 10, the leading and trailing end regions of the paper P are curved so as to be convex upwards, but they may also be convex downwards.

[0053] Next, referring to Figure 11, the control details related to recording will be explained.

[0054] First, the CPU 101 determines whether or not it has received a recording command from an external device (S1).

[0055] If the CPU 101 determines that it has not received a recording command from an external device (S1:NO), it repeats the process of S1.

[0056] If the CPU 101 determines that it has received a recording command from an external device (S1: YES), it determines the amount of floating X in the leading and trailing areas of the paper P (S2: Determination process).

[0057] Here, the amount of float X changes depending on the position of the leading or trailing end of the paper P in the transport direction. For example, as shown in Figure 12, the amount of float when the leading end of the paper P is in the same position as the leading end of the corrugated plate 31 (see Figure 9) in the transport direction is taken as the initial value X0, and the amount of float gradually increases as the leading end of the paper P moves downstream in the transport direction from that position. The amount of float X is at its maximum when the leading end of the paper P is in the same position as the roller 39a in the transport direction. Thereafter, as the leading end of the paper P moves downstream of the roller 39a in the transport direction, the amount of float gradually decreases, and becomes constant when the leading end of the paper P passes a predetermined position downstream of the roller 39a in the transport direction.

[0058] Furthermore, the amount of floating X changes based on parameters such as the amount of ink ejected to the edge region (leading or trailing region) of the paper P, the type of paper P, and the type of ink. For example, as shown in Figure 12, the larger the ejection amount, the larger the amount of floating X. In the example in Figure 12, when the ejection amount is small, the amount of floating X is smaller than a predetermined amount Xt regardless of the position of the leading edge of the paper P, but when the ejection amount is medium or large, it becomes larger than a predetermined amount Xt when the leading edge of the paper P is near the roller 39a. The predetermined amount Xt is, for example, the distance between the surface of the platen 9 and the nozzle surface 5a (see Figure 9).

[0059] To derive the discharge volume, the image data included in the recording command is converted into density data for each RGB color, and this density data is then converted into discharge data (data indicating the discharge volume in each discharge cycle for each nozzle 51n).

[0060] ROM103 stores functions (functions showing the relationship between the position of the leading or trailing end of the paper P in the transport direction and the amount of float X) and tables corresponding to each of the above parameters, as shown in Figure 12. These functions and tables are based on experiments conducted in advance.

[0061] In S2, the CPU 101 determines the maximum value of the amount of floating X in the leading edge region and trailing edge region (edge ​​region) of the paper P, based on the functions and tables stored in the ROM 103.

[0062] The printer 1 has a paper feed tray 10 for storing roll paper Pr and a paper feed tray 20 for storing cut paper Pc. In S2, when the transport mechanism 3 transports roll paper Pr from the paper feed tray 10, the amount of floating X is corrected to be larger compared to when the transport mechanism 3 transports cut paper Pc from the paper feed tray 20. Specifically, in the case of roll paper transport, the initial value X0 of the function shown in Figure 12 is made larger than in the case of cut paper transport.

[0063] After S2, the CPU 101 determines whether the amount of lift X is greater than or equal to a predetermined amount Xt (S3: determination process). In S2, the maximum value of the amount of lift X is determined for both the leading edge and trailing edge regions of the paper P. In S3, it is determined whether the maximum value of the amount of lift X for both the leading edge and trailing edge regions of the paper P is greater than or equal to a predetermined amount Xt.

[0064] If the CPU 101 determines that at least one of the maximum values ​​of the amount of lift X in the leading and trailing areas of the paper P is equal to or greater than a predetermined amount Xt (S3: YES), the CPU 101 controls the transport motor 30, driver IC 50, and scanning motor 80 (and the cutting motor 40 if recording is performed on roll paper Pr) via the ASIC 104 to execute the recording process. At this time, edge control (see Figures 9 and 10) is performed on the area of ​​the leading and trailing areas of the paper P where the amount of lift X is determined to be equal to or greater than a predetermined amount Xt (S4).

[0065] In S4, the larger the amount of float X determined in S2, the earlier the timing to start end control and the larger the large transport amounts D2a and D2a' (see Figures 9 and 10). To increase the large transport amounts D2a and D2a', the ASIC104 may, for example, start the small transport before the large transport earlier, start the small transport after the large transport later, or reduce the transport amounts of multiple small transports without changing the timing of starting the small transport before the large transport.

[0066] The start timing of the large-scale transport and the values ​​of the large-scale transport amounts D2a and D2a' are determined based on the function shown in Figure 12. For example, in Figure 12, when the discharge rate is large, the large-scale transport starts when the buoyancy amount X gradually increases from the initial value X0 and reaches a value slightly smaller than a predetermined amount Xt. The large-scale transport then ends when the buoyancy amount X gradually decreases from its maximum value and reaches a value slightly smaller than a predetermined amount Xt.

[0067] The number of small transfers and the values ​​of the small transfer amounts D1a, D1b, D1a', and D1b' are determined according to the recording resolution and recording speed.

[0068] Furthermore, in S4, after the small transport and before the large transport, the ASIC104 uses the scanning mechanism 8 (see Figure 5) to position the head 5 outside the transport area (the position of the head 5 shown in Figure 5). Then, with the head 5 positioned outside the transport area, the ASIC104 has the transport mechanism 3 perform the large transport. The transport area is the area in which the paper P is transported by the transport mechanism 3 (the area shown by the dashed line in Figure 5).

[0069] If the CPU determines that the maximum values ​​of the amount of lift X in both the leading and trailing areas of the paper P are not equal to or greater than a predetermined amount Xt (S3: NO), the CPU 101 controls the transport motor 30, driver IC 50, and scanning motor 80 (and the cutting motor 40 if recording is to be performed on roll paper Pr) via the ASIC 104 to execute the recording process. At this time, the ASIC 104 does not perform edge control (see Figures 9 and 10) on the leading and trailing areas of the paper P, but performs center control (see Figure 8) (S5). That is, when only one of the corrugated plate 31 or the upper roller 39a is pressing down on the paper P, the ASIC 104 performs the same control on the transport motor 30 and driver IC 50 as when both the corrugated plate 31 and the upper roller 39a are pressing down on the paper P.

[0070] After S4 or S5, CPU101 terminates the routine.

[0071] As described above, according to this embodiment, if it is determined that the amount of floating X is equal to or greater than a predetermined amount Xt (S3: YES), edge control (see Figures 9 and 10) can be performed to suppress contact of the paper P with the nozzle surface 5a. On the other hand, if it is determined that the amount of floating X is not equal to or greater than a predetermined amount Xt (S3: NO), edge control can be not performed to suppress a decrease in recording quality and a decrease in recording speed.

[0072] In S2 (decision process), the CPU 101 determines that the greater the amount of ink ejected from the nozzle 51n onto the paper P (ejection amount), the greater the amount of floating X (see Figure 12). In this case, the amount of floating X can be effectively determined based on the phenomenon of the paper P curling due to ink adhesion.

[0073] In S2 (decision processing), CPU 101 determines that the greater the amount of paper ejected to the edge region of the paper P rather than the entire paper P, the greater the amount of floating X. In this case, the amount of floating X can be determined more accurately.

[0074] When edge control is performed, ASIC104 increases the large transport amounts D2a and D2a' (see Figures 9 and 10) as the amount of lift X increases. In this case, contact of the paper P with the nozzle surface 5a can be suppressed more reliably.

[0075] When ASIC104 performs edge control, the greater the amount of lift X, the earlier the timing of initiating edge control. In this case, contact of the paper P with the nozzle surface 5a can be more reliably suppressed.

[0076] In edge control, after small-scale transport and before large-scale transport, the ASIC104 uses the scanning mechanism 8 (see Figure 5) to position the head 5 outside the transport area (the position of the head 5 shown in Figure 5), and then has the transport mechanism 3 perform large-scale transport with the head 5 positioned outside the transport area. In this case, contact of the paper P with the nozzle surface 5a can be more reliably suppressed.

[0077] When both the corrugated plate 31 and the upper roller 39a are holding down the paper P, the ASIC104 performs central control (see Figure 8) to keep the transport amount D0 constant. This ensures stable recording quality.

[0078] In S2, when the transport mechanism 3 transports roll paper Pr from the paper feed tray 10, the CPU 101 corrects the lift amount X to be greater than when the transport mechanism 3 transports cut paper Pc from the paper feed tray 20. Roll paper Pr is more prone to curling than cut paper Pc, and therefore the lift amount X is more likely to be greater. Therefore, by correcting the lift amount X to be greater when roll paper Pr is transported, edge control can be easily performed, and contact of the paper P with the nozzle surface 5a can be reliably suppressed.

[0079] <Second Embodiment> The printer (liquid ejection device) according to the second embodiment of the present invention has different control content from that of the first embodiment.

[0080] In the first embodiment (see Figure 11), in S2, when the transport mechanism 3 transports roll paper Pr from the paper feed tray 10, the CPU 101 corrects the amount of floating X to be larger compared to when the transport mechanism 3 transports cut paper Pc from the paper feed tray 20.

[0081] In contrast, in the second embodiment (see Figure 13), instead of performing the above correction in S2, the CPU 101 determines whether or not to have the transport mechanism 3 transport the roll paper Pr from the paper feed tray 10 after receiving the recording command and before S2 (S20). If it is determined that the transport mechanism 3 should transport the roll paper Pr from the paper feed tray 10 (S20: YES), the CPU 101 proceeds to S4 and executes the recording process with edge control via the ASIC 104. On the other hand, if it is determined that the transport mechanism 3 should not transport the roll paper Pr from the paper feed tray 10 (i.e., to transport the cut paper Pc from the paper feed tray 20) (S20: NO), the CPU 101 proceeds to S2 and selects whether or not to perform edge control according to the amount of float X, similar to the first embodiment.

[0082] This embodiment focuses on the fact that roll paper Pr is more prone to curling and has a larger amount of lift X compared to cut paper Pc. When roll paper Pr is transported (S20:YES), edge control is performed (S4) to reliably suppress contact of the paper P with the nozzle surface 5a.

[0083] <Variation> Although preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various design modifications are possible as long as they are within the scope of the claims.

[0084] In the above embodiment, the upstream retaining member is a corrugated plate 31, but is not limited to this, and may be a roller.

[0085] The downstream retaining member is a roller 39a in the above embodiment, but is not limited to this, and may be a plate.

[0086] In the above embodiment, the amount of float is determined based on the discharge amount, paper type, etc., but it may also be the discharge amount itself (the discharge amount may be determined in the determination process, and it may be determined in the judgment process whether the discharge amount is equal to or greater than a predetermined amount).

[0087] Positioning the discharge unit outside the transport area using a scanning mechanism after small-scale transport and before large-scale transport is performed when the amount of buoyancy is relatively large, but is not required when the amount of buoyancy is relatively small.

[0088] To reduce the amount of floating, the time interval between one transport operation and the next transport operation may be made longer than the predetermined time.

[0089] In the above embodiment, central control (control that transports the sheet-like medium at a constant reference transport amount) was exemplified as a control method when both the upstream and downstream pressing members are pressing down on the sheet-like medium, but the invention is not limited to this. For example, when both the upstream and downstream pressing members are pressing down on the sheet-like medium, the transport amount for each transport operation does not have to be constant.

[0090] Figures 9 and 10 show an example in which, in a single ejection operation, "(ii) the head 5 makes one or more reciprocating movements in the scanning direction, ejecting ink in both the forward and reverse movements," a large transport is performed after multiple small transports, and then multiple small transports are performed after the large transport, but the case is not limited to this. For example, depending on the recording resolution and recording speed, in a single ejection operation, "(i) the head 5 ejects ink while moving forward or backward in the scanning direction," multiple small transports are not required after the large transport.

[0091] The dispensing unit is not limited to a serial type that dispenses liquid from a nozzle while moving in the left-right direction, but may also be a line type that dispenses liquid from a nozzle while its position is fixed. In other words, the liquid dispensing device of the present invention is not limited to having a scanning mechanism.

[0092] The liquid dispensed from the nozzle is not limited to ink, but may be any liquid (for example, a processing solution that causes components in the ink to coagulate or precipitate, or a liquid in which metal particles are dispersed in a solvent, etc.).

[0093] The sheet-like medium is not limited to paper; it may also be cloth or plastic film. In other words, the sheet-like medium may be made of any material as long as it is in sheet form.

[0094] This invention is not limited to printers, but can also be applied to facsimile machines, copiers, multifunction devices, and the like.

[0095] The program according to the present invention can be recorded on removable recording media such as flexible disks or fixed recording media such as hard disks and distributed, as well as distributed via communication lines. [Explanation of symbols]

[0096] 1. Printer (liquid ejection device) 3. Conveying mechanism 5. Head (discharge part) 5a Nozzle surface 8 Scanning mechanism 10. Paper feed tray (first storage compartment; storage compartment) 20 Paper feed tray (second storage compartment) 31. Corrugated plate (upstream retaining member) 39a Upper roller (downstream pressing member) 51n nozzle 100 Control device 101 CPU (Control Unit) 104 ASIC (Control Unit) P paper (sheet-type media) R Roll Body

Claims

1. A conveying mechanism for conveying a sheet-like medium in the conveying direction, A discharge unit having a nozzle surface on which a nozzle is formed, which discharges liquid from the nozzle onto a sheet-like medium conveyed by the conveying mechanism, It comprises a control unit and, The aforementioned transport mechanism is An upstream pressing member is positioned upstream of the discharge section in the conveying direction and presses down on the sheet-like medium, restricting the sheet-like medium from approaching the nozzle surface. It includes a downstream pressing member positioned downstream of the discharge section in the conveying direction, which holds down the sheet-like medium and restricts the sheet-like medium from approaching the nozzle surface, The control unit, When both the upstream pressing member and the downstream pressing member are pressing down on the sheet-like medium, the conveying mechanism is controlled to convey the sheet-like medium at a constant standard conveying amount. A determination process for determining the amount of lift in the end region in the conveying direction of a sheet-like medium, Further, a determination process is performed to determine whether the amount of buoyancy is equal to or greater than a predetermined amount. When only one of the upstream pressing member and the downstream pressing member is pressing down on the sheet-like medium, If the floating amount is determined to be equal to or greater than the predetermined amount in the judgment process, the conveying mechanism is instructed to perform small conveying, in which a small conveying amount of the sheet-like medium is conveyed, and large conveying, in which a large conveying amount greater than the small conveying amount is conveyed, and the large conveying is performed after multiple small conveyings, and liquid is discharged to the discharge section between the multiple small conveyings, and end control is performed. A liquid dispensing device characterized in that, if it is determined in the judgment process that the amount of float is not equal to or greater than the predetermined amount, the central control is executed.

2. The liquid dispensing device according to claim 1, characterized in that the control unit determines in the determination process that the amount of liquid dispensed from the nozzle onto the sheet-like medium is greater, and the amount of floating is greater.

3. The liquid dispensing device according to claim 2, characterized in that the control unit determines in the determination process that the amount of liquid dispensed from the nozzle to the end region of the sheet-like medium is greater, and the amount of floating is greater.

4. The liquid dispensing device according to any one of claims 1 to 3, characterized in that when the control unit performs the end control, the larger the amount of float, the larger the amount of transported liquid.

5. The liquid dispensing device according to any one of claims 1 to 3, characterized in that when the control unit performs the end control, the timing for starting the end control is advanced as the amount of float increases.

6. The system further includes a scanning mechanism that moves the discharge unit in a scanning direction perpendicular to the transport direction and parallel to the nozzle surface. The liquid dispensing apparatus according to any one of claims 1 to 3, characterized in that the control unit, after the small transport and before the large transport in the end control, uses the scanning mechanism to position the dispensing unit outside the transport area of ​​the sheet-like medium by the transport mechanism, and causes the transport mechanism to perform the large transport while the dispensing unit is positioned outside the transport area.

7. The liquid dispensing device according to any one of claims 1 to 3, characterized in that the standard transport volume is greater than the small transport volume and less than the large transport volume.

8. A first storage section capable of accommodating a roll body in which a sheet-like medium is wound into a roll shape, It further comprises a second storage section capable of accommodating multiple sheet-like media in a stacked state, The liquid dispensing device according to any one of claims 1 to 3, characterized in that the control unit corrects the amount of floating to be greater when the conveying mechanism is transporting a sheet-like medium from the first storage unit compared to when the conveying mechanism is transporting a sheet-like medium from the second storage unit.

9. It further comprises a storage section capable of accommodating a roll body in which a sheet-like medium is wound into a roll shape, The liquid dispensing device according to any one of claims 1 to 3, characterized in that the control unit performs the end control when the transport mechanism transports the sheet-like medium from the storage unit.

10. A liquid dispensing device comprising a conveying mechanism for conveying a sheet-like medium in a conveying direction, and a dispensing unit having a nozzle surface on which a nozzle is formed, for dispensing liquid from the nozzle onto the sheet-like medium conveyed by the conveying mechanism, wherein the conveying mechanism includes an upstream pressing member positioned upstream of the dispensing unit in the conveying direction and pressing down on the sheet-like medium to prevent it from approaching the nozzle surface, and a downstream pressing member positioned downstream of the dispensing unit in the conveying direction and pressing down on the sheet-like medium to prevent it from approaching the nozzle surface, and a control method for controlling the liquid dispensing device, When both the upstream pressing member and the downstream pressing member are pressing down on the sheet-like medium, the conveying mechanism is controlled to convey the sheet-like medium at a constant standard conveying amount. A determination process for determining the amount of lift in the end region in the conveying direction of a sheet-like medium, Further, a determination process is performed to determine whether the amount of buoyancy is equal to or greater than a predetermined amount. When only one of the upstream pressing member and the downstream pressing member is pressing down on the sheet-like medium, If the floating amount is determined to be equal to or greater than the predetermined amount in the judgment process, the conveying mechanism is instructed to perform small conveying, in which a small conveying amount of the sheet-like medium is conveyed, and large conveying, in which a large conveying amount greater than the small conveying amount is conveyed, and the large conveying is performed after multiple small conveyings, and liquid is discharged to the discharge section between the multiple small conveyings, and end control is performed. A control method characterized in that, if the floating amount is determined to be less than or equal to a predetermined amount in the aforementioned determination process, the central control is executed.

11. A liquid dispensing device comprising a conveying mechanism for conveying a sheet-like medium in a conveying direction, and a dispensing unit having a nozzle surface on which a nozzle is formed, for dispensing liquid from the nozzle onto the sheet-like medium conveyed by the conveying mechanism, wherein the conveying mechanism includes an upstream pressing member positioned upstream of the dispensing unit in the conveying direction and holding down the sheet-like medium to prevent it from approaching the nozzle surface, and a downstream pressing member positioned downstream of the dispensing unit in the conveying direction and holding down the sheet-like medium to prevent it from approaching the nozzle surface, When both the upstream pressing member and the downstream pressing member are pressing down on the sheet-like medium, a central control means executes central control to cause the conveying mechanism to convey the sheet-like medium at a fixed standard conveying amount. A determination means for determining the amount of lift in the end region in the conveying direction of a sheet-like medium, and This serves as a means for determining whether the amount of buoyancy is equal to or greater than a predetermined amount. When only one of the upstream pressing member and the downstream pressing member is pressing down on the sheet-like medium, If the determination means determines that the amount of floating is equal to or greater than the predetermined amount, the conveying mechanism is instructed to perform small-scale conveying, in which a small amount of the sheet-like medium is conveyed, and large-scale conveying, in which a larger amount of the sheet-like medium is conveyed than the small amount, and to perform large-scale conveying after multiple small-scale conveyings, and to perform end control, in which liquid is discharged to the discharge section between the multiple small-scale conveyings. The program is characterized in that if the determination means determines that the amount of float is not equal to or greater than the predetermined amount, the central control is executed.

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