Liquid ejection apparatus and method of controlling same

Abstract

To shorten the time required to perform a wiping operation following a forming operation of ejecting a liquid to an object in a liquid ejection apparatus that performs an operation of wiping a head by a wiping mechanism.SOLUTION: A liquid ejection apparatus includes a wiping mechanism configured to perform a wiping operation for wiping an ejection surface provided with nozzles of a head while moving relative to a carriage. The carriage is movable to a formation position for performing a formation operation of ejecting liquid to an object and a wiping position for performing a wiping operation. The wiping mechanism is movable to a standby position, a start position for starting the wiping operation ad an end position for ending the wiping operation. The wiping mechanism is configured to perform the wiping operation by moving from the start position to the end position in a state in which the carriage is at the wiping position after moving from the standby position to the start position. When performing the wiping operation following a forming operation, the wiping mechanism moves from the standby position to the start position in parallel to the forming operation.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus and a control method thereof. [Background technology]

[0002] Some liquid ejection devices have a head that ejects liquid and form images by ejecting ink from the head onto a recording medium. Some liquid ejection devices have a wiping mechanism that wipes the surface of the head where the ejection ports are located to restore the ink ejection performance from the head. Patent Document 1 discloses a device that wipes the ejection surface of the head where the nozzles are located with a cloth, where the cloth is wrapped around a pressure roller, and the entire wiping mechanism, including the cloth supply and recovery rollers, is moved under the head to wipe the ejection surface of the head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-108594 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to reduce the time required to perform a wiping operation following a forming operation of discharging liquid onto an object in a liquid ejection device that performs a wiping operation of a head using a wiping mechanism. [Means for solving the problem]

[0005] The present invention relates to a liquid ejection head, a carriage on which the head is mounted; a wiping mechanism that performs a wiping operation to wipe an ejection surface of the head on which the ejection ports are provided while moving relatively to the carriage; a liquid ejection device that ejects the liquid from the ejection opening while moving the carriage in a main scanning direction relative to an object, the carriage is movable to a forming position for performing a forming operation of ejecting the liquid onto the object and to a wiping position for performing the wiping operation; the wiping mechanism is movable between a standby position, a start position where the wiping operation starts, and an end position where the wiping operation ends, and is configured to perform the wiping operation by moving from the standby position to the start position and then moving from the start position to the end position with the carriage at the wiping position; In the liquid ejection device, when the wiping operation is performed following the forming operation, the wiping mechanism moves from the standby position to the start position in parallel with the forming operation. [Effects of the Invention]

[0006] In a liquid ejection device that performs a wiping operation on a head using a wiping mechanism, the time required to perform the wiping operation following the forming operation of ejecting liquid onto an object can be reduced. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic perspective view of the printer from above. [Figure 2] FIG. 1 is a block diagram showing a schematic configuration of a system. [Figure 3] FIG. 2 is a schematic cross-sectional side view of the wiping mechanism and related components. [Figure 4] FIG. 10 is a diagram of a comparative example in which the printing operation and the operation of the wiping mechanism are not performed in parallel. [Figure 5] FIG. 10 is a diagram illustrating a case where the printing operation and the operation of the wiping mechanism are performed in parallel. [Figure 6] FIG. 10 is a diagram illustrating a case where a collision occurs when a printing operation and a wiping mechanism operation are performed in parallel. [Figure 7] 10 is a flowchart of a reciprocating printing operation. [Figure 8] 10 is a graph showing changes in carriage speed during reciprocating printing operations. [Figure 9] FIG. 2 is a view of the recording head as seen from the recording medium side. [Figure 10]FIG. 7 is a diagram showing details of the positional relationship in FIG. 6(g). DETAILED DESCRIPTION OF THE INVENTION

[0008] Example 1 Hereinafter, exemplary embodiments for carrying out the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in the following examples may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions, and the scope of the present invention is not intended to be limited to the following examples.

[0009] FIG. 1 is a perspective schematic diagram from above of a printer 100 according to one embodiment of the present invention. A print head 101 is mounted on a carriage 102, which moves along a carriage guide shaft 103. The direction in which the carriage 102 moves is called the main scanning direction (X direction in FIG. 1). The current position of the print head 101 can be detected by an encoder film 104. During printing, a print medium 106 is fed from the bottom of the printer 100 and transported intermittently. This transport direction is called the sub-scanning direction (Y direction in FIG. 1). In this embodiment, the main scanning direction and the sub-scanning direction intersect (are perpendicular to each other).

[0010] The printer 100 repeats an image forming operation in which ink is ejected from the print head 101 onto the recording medium 106 while transporting the recording medium 106 in the sub-scanning direction and moving the carriage 102 in the main scanning direction, thereby forming an image on the recording medium 106. The right side in Figure 1 is called the reference side, and the left side is called the non-reference side; forming an image while moving the carriage 102 from the reference side to the non-reference side is called forward printing, and forming an image while moving from the non-reference side to the reference side is called backward printing.

[0011] A flexible cable 105 is connected to the print head 101 via a contact surface inside the carriage 102. Signals are exchanged between the print head 101 and an electric board (not shown) through the flexible cable 105. The exchanged signals include ejection signals for the print head 101.

[0012] The wiping mechanism 107 is disposed in an area outside the conveyed recording medium 106, and is capable of moving along a wiping mechanism guide shaft 108. The detailed operation will be described later, but after the carriage 102 is moved above the wiping mechanism 107, the wiping mechanism 107 moves along the wiping mechanism guide shaft 108. As a result, the wiping mechanism 107 performs a wiping operation to wipe the ejection surface 111 (see FIGS. 3 and 9) on which the nozzles 110 of the recording head 101 are provided, while moving relatively to the carriage 102.

[0013] That is, the carriage 102 is movable between an image forming position for performing an image forming operation in which ink is ejected onto the recording medium 106, and a wiping position for performing a wiping operation. Here, the image forming position refers to the range in the main scanning direction in which the carriage 102 moves for forward printing and backward printing. The wiping position refers to a position of the carriage 102 in which the wiping mechanism 107 can perform a wiping operation on the recording head 101. Therefore, depending on the configuration of the printer 100, it is possible that the carriage 102 may be in a position (called a process position) in which neither an image forming operation nor a wiping operation is performed during the process of moving from the image forming position to the wiping position. When it is said that the carriage 102 is movable between the image forming position and the wiping position, this also includes the carriage 102 being movable to the process position.

[0014] A cleaning liquid application mechanism 109 is disposed above the wiping mechanism 107, and is a mechanism that can apply cleaning liquid to the sheet on the wiping mechanism 107 before wiping. Details will be described later.

[0015] FIG. 2 is a block diagram showing a schematic configuration of a system according to an embodiment of the present invention. Print data is sent from a host 200 to a printer 100. A printer control unit 202 controls the overall processing within the printer 100. An I / F 201 receives the print data from the host 200. A print control unit 203 stores the print data in a printer storage device 204. The print control unit 203 determines a printing method based on the print data sent from the host and information accompanying the print data. The printing method also includes the carriage movement width and print mode. In accordance with the determined printing method, the print control unit 203 repeatedly transports the recording medium 106 using a transport control unit 205 and moves the carriage 102 using a carriage control unit 206, thereby forming an image.

[0016] To prevent deterioration of ink ejection performance, the wiping mechanism control unit 207 is used to move the wiping mechanism 107 to wipe (also called wipe or wiping) the ejection surface 111 of the print head 101. This allows ink adhering to the ejection surface 111 to be wiped away. The timing of wiping is determined by the ink characteristics and the amount of ink ejected, but there may be times during image formation when wiping is necessary. The timing (frequency) of wiping can be, for example, periodically, such as once every five minutes. The wiping interval may be varied, for example, between 2 and 20 minutes, depending on the ink characteristics and head temperature.

[0017] 3 is a schematic cross-sectional side view of the wiping mechanism and related mechanisms according to an embodiment of the present invention. A carriage 102 carries a print head 101 and moves along a carriage guide shaft 103. This allows the print head 101 to move in the main scanning direction (toward or behind in FIG. 3). The print head 101 has multiple liquid ejection orifices on its underside (ejection surface 111) that eject ink.

[0018] The wiping mechanism 107 is equipped with a sheet 305, which is an absorbing means capable of absorbing ink, inside, and can wipe ink from the ejection surface 111 of the print head 101 by pressing the sheet 305 against the ejection surface 111. The wiping mechanism 107 supplies a new sheet 305 from a sheet supply mechanism 301. The wiping unit 302 presses the sheet 305 supplied from the sheet supply mechanism 301 against the ejection surface 111 of the print head 101 to wipe it. In order to press the sheet 305, the wiping unit 302 has a structure that protrudes above the ejection surface 111 of the print head 101.

[0019] The preliminary ejection receiving surface 303 is a receiving portion that receives ink when ink is ejected from the print head 101 (hereinafter referred to as preliminary ejection) to recover ejection performance, and is the surface on which the sheet 305 is exposed to the outside of the wiping mechanism 107. By winding up the ink-covered sheet 305 with a sheet winding mechanism 304, a sheet 305 without ink is supplied from the sheet supply mechanism 301 to the wiping unit 302 and the preliminary ejection receiving surface 303. The entire wiping mechanism 107 can be moved along a wiping mechanism guide shaft 108.

[0020] The cleaning liquid application mechanism 109 is an application unit that applies cleaning liquid to a sheet 305 on the wiping unit 302 before the wiping unit 302 wipes the ejection surface 111 of the recording head 101. The sheet 305 is made of a material that can absorb liquid, such as cloth. The operation of wiping off ink adhering to the ejection surface 111 is not limited to absorbing liquid by pressing the sheet 305 against the ejection surface 111, but may also be performed by wiping by moving a blade-shaped member (blade wiper) in contact with the ejection surface 111.

[0021] The application of cleaning liquid to the sheet 305 by the cleaning liquid application mechanism 109 may be performed each time a wiping operation is performed, or may be performed independently at a timing different from the timing of the wiping operation. When applying cleaning liquid every time a wiping operation is performed, the preparatory operations for the wiping operation may include the operation of applying cleaning liquid to sheet 305. Note that if it is necessary to wait a certain period of time for the cleaning liquid to penetrate into sheet 305 after applying cleaning liquid to sheet 305, the time required to perform the wiping operation can be shortened by applying the cleaning liquid at a timing separate from the execution of the wiping operation.

[0022] The series of wiping operations will be described in detail below. Figure 3(a) shows the wiping mechanism 107 in a standby position. When no wiping-related operations are being performed, the wiping mechanism 107 is in the standby position. When the wiping mechanism 107 is in the standby position, the carriage 102 will not collide with the wiping mechanism 107 even if it is moved above the wiping mechanism 107.

[0023] Before the wiping operation, the wiping mechanism 107 is moved from the standby position shown in FIG. 3(a) to the cleaning liquid application position shown in FIG. 3(b). With the wiping mechanism 107 positioned at the cleaning liquid application position, the cleaning liquid application mechanism 109 applies cleaning liquid to the sheet on the wiping unit 302. Even when the wiping mechanism 107 is positioned at the cleaning liquid application position, the wiping mechanism 107 and the carriage 102 do not collide even if the carriage 102 is moved above the wiping mechanism 107. Therefore, the position shown in FIG. 3(a) and the cleaning liquid application position can be collectively referred to as the standby position of the wiping mechanism 107. In this case, if the application of cleaning liquid is considered a preparatory operation for the wiping operation, the wiping mechanism 107 can also be said to perform the preparatory operation at the standby position.

[0024] Once the application of the cleaning liquid is complete, the wiping mechanism 107 moves from the cleaning liquid application position in FIG. 3(b) to the start position (pre-wiping standby position) where the wiping operation begins in FIG. 3(c). When moving, the carriage 102 is moved while not positioned above the wiping mechanism 107 (wiping position) so that the ejection surface 111 of the print head 101 is not wiped by the wiping unit 302. The reason why wiping is not performed when moving from the standby position (cleaning liquid application position) in FIG. 3(b) to the start position in FIG. 3(c) is as follows: It is desirable to remove ink that has entered the ejection orifices by preliminary ejection immediately after wiping, but in the state in FIG. 3(c), the preliminary ejection receiving surface 303 does not face below the print head 101, and preliminary ejection cannot be performed.

[0025] From the start position shown in FIG. 3(c), the carriage 102 is moved to a wiping position above the wiping mechanism 107, and then the wiping operation begins. The wiping mechanism 107 moves from the start position shown in FIG. 3(c) to the end position shown in FIG. 3(d), where the wiping operation ends, thereby wiping the ejection surface 111 of the print head 101 with the wiping unit 302. After the wiping operation ends, the print head 101 performs preliminary ejection at the end position shown in FIG. 3(d) to remove ink that has entered the ejection orifices, as described above. Therefore, the end position of the wiping operation can also be called the preliminary ejection position where the print head 101 performs preliminary ejection. Ink generated during preliminary ejection is absorbed by the sheet 305 on the preliminary ejection receiving surface 303. After preliminary ejection, the sheet 305 soiled with ink is wound up using the sheet winding mechanism 304, and the print head returns to the standby position shown in FIG. 3(a). This completes the wiping operation sequence.

[0026] The printer 100 of this embodiment is characterized in that, when a wiping operation is performed following a printing operation (image forming operation), the wiping mechanism 107 moves from the standby position to the start position in parallel with the printing operation of the recording head 101. Also, when a preparatory operation is performed at the standby position, the wiping mechanism 107 performs the preparatory operation and moves from the standby position to the start position in parallel with the printing operation of the recording head 101. To make it easier to understand the features of this embodiment, a comparative example will be described below in which the wiping mechanism 107 does not move from the standby position to the start position in parallel with the printing operation when a wiping operation is performed following a printing operation.

[0027] 4 is a diagram illustrating a comparative example in which the printing operation and the wiping operation of the wiping mechanism 107 are not performed in parallel. Fig. 4 is a schematic diagram of the printer 100 as seen from above, and shows the operations in chronological order from forward printing, conveyance of the recording medium 106, backward printing, to completion of preparation for the wiping operation.

[0028] FIG. 4(a) shows the relative positions of the carriage 102 and wiping mechanism 107 when forward printing begins. The wiping mechanism 107 is in the standby position. To form an image near the reference side of the recording medium 106, part of the carriage 102 must be above the wiping mechanism 107. In the standby position, the wiping unit 302 on the wiping mechanism 107 and the recording head 101 do not collide (see FIG. 3(a)). FIG. 4(b) shows the state in the middle of forward printing, with forward printing ending in FIG. 4(c). FIG. 4(d) shows the timing at which backward printing begins after the recording medium 106 has moved in the sub-scanning direction. FIG. 4(e) shows the state in the middle of backward printing, with backward printing ending in FIG. 4(f).

[0029] From FIG. 4(a) to FIG. 4(f), the wiping mechanism 107 remains stationary at the standby position and does not move at all. To move the wiping mechanism 107 from the state of FIG. 4(f) to the start position, the carriage 102 must be temporarily retracted from above the wiping mechanism 107. FIG. 4(g) shows the point in time when the carriage 102 has been retracted (moved in the forward direction) and the wiping mechanism 107 has been moved to the cleaning liquid application position (see FIG. 3(b)). FIG. 4(h) shows the movement of the wiping mechanism 107 to the start position, and FIG. 4(i) shows the carriage 102 being moved in the backward direction above the wiping mechanism 107 that has moved to the start position. At the start position, the wiping unit 302 on the wiping mechanism 107 does not collide with the print head 101 (see FIG. 3(c)). After this, the wiping operation by the wiping mechanism 107 becomes possible.

[0030] Here, when forming an image in an area that exceeds the size of the print head 101 in the sub-scanning direction (the width of an image in the sub-scanning direction that can be formed by one forward printing or backward printing), forward printing, backward printing, and conveying the print medium in the sub-scanning direction are repeated multiple times. When multiple round-trip printing operations are performed to form an image in such a wide area on the print medium, consider the case where a wiping operation is performed following at least one of the multiple round-trip printing operations (image forming operations). In this case, as described with reference to FIG. 4, if the carriage 102 is retracted and the wiping mechanism 107 is moved after the backward printing operation is completed, the printing throughput will decrease by the time.

[0031] 5 is a diagram showing a case where the printing operation and the operation of the wiping mechanism 107 are performed in parallel. As with FIG. 4, the operations up to the completion of preparation for wiping are shown in chronological order.

[0032] Like Figure 4(a), Figure 5(a) shows the relative positions of the carriage 102 and wiping mechanism 107 when forward printing begins. Figure 5(b) shows the wiping mechanism 107 moving to the cleaning liquid application position in parallel with the carriage 102 moving for forward printing. There is no problem if the carriage 102 moves over the wiping mechanism 107 while it is moving to the cleaning liquid application position, as there are no components that collide with it (see Figure 3(b)). Figure 5(c) shows the wiping mechanism 107 starting to move to the start position in parallel with the movement of the carriage 102 during forward printing. Figure 5(d) shows the state after forward printing has ended. Figure 5(e) shows the timing when the recording medium 106 moves in the sub-scanning direction and backward printing begins. Figure 5(f) shows the timing during backward printing. Figure 5(g) also shows the timing during backward printing, just before the carriage 102 moves over the wiping mechanism 107.

[0033] Here, between FIG. 5(c) and FIG. 5(g), the wiping mechanism 107 continues to move to the start position (see FIG. 3(c)). As a result, the wiping mechanism 107 has arrived at the start position at the time of FIG. 5(g), and in this state, the carriage 102 can be moved onto the wiping mechanism 107 consecutively with the backward printing operation (FIG. 5(h)). After this, the wiping operation is performed by the wiping mechanism 107. By operating in this manner, it is no longer necessary to retract the carriage 102 as shown in FIG. 4(g), and the movement time of the wiping mechanism 107 to the start position is included in the time of the printing operation. This makes it possible to prevent a decrease in printing throughput.

[0034] FIG. 6 shows a case where a collision occurs when the printing operation and the operation of the wiping mechanism 107 are performed in parallel. FIGS. 6(a) and 6(b) show the same operations as FIGS. 5(a) and 5(b), respectively. FIG. 6(c) shows the middle of forward printing, and FIG. 6(d) shows the state after forward printing has finished. What differs from FIG. 5 is that the width of the printed image in the sub-scanning direction is narrower. FIG. 6(e) shows the timing at which backward printing begins after the recording medium 106 has moved in the sub-scanning direction. FIG. 6(f) shows the middle of backward printing.

[0035] As in Figure 5, the wiping mechanism 107 moves in parallel with the printing operation. However, in the case of Figure 6, the print image width is narrow, so the printing operation time is short, and the carriage 102 tries to move above the wiping mechanism 107 before the wiping mechanism 107 reaches the start position. This results in the state shown in Figure 6(g), where the wiping unit 302 protrudes above the ejection surface of the recording head 101, causing the wiping unit 302 on the wiping mechanism 107 to collide with the recording head 101.

[0036] In this way, the printer 100 of this embodiment is configured such that when the wiping mechanism 107 is located halfway between the standby position and the start position, the carriage 102 may collide with the wiping mechanism 107 at a predetermined collision position during the printing operation (i.e., when it is located at the image forming position). Therefore, to avoid the collision, an adjustment is made to increase the time required for the printing operation so that the carriage 102 reaches the collision position after the wiping mechanism 107 has reached the start position.

[0037] The adjustment can be performed, for example, by increasing the range of movement in the main scanning direction of the carriage 102 beyond the default range of movement. In the case of an image forming operation (recording operation) in which an image is formed on the recording medium 106 with ink, the default range of movement of the carriage 102 is a range of movement determined according to the width of the image to be recorded in the main scanning direction.

[0038] Furthermore, the adjustment can be made, for example, by changing a default parameter related to the movement speed of the carriage 102 so as to increase the time required for the carriage 102 to move through a default movement range in the main scanning direction. In the case of an image forming operation, the default parameter related to the movement speed of the carriage 102 is a parameter that is set, for example, in accordance with a recording mode (print mode) related to the quality or speed of image recording. One such parameter is the speed at which the carriage 102 moves at a constant speed. In this case, the adjustment can be made by making the speed of the constant movement of the carriage 102 slower than the default speed.

[0039] The adjustment can also be performed by providing a stop period during the image forming operation in which no ink is ejected.

[0040] The adjustment can also be performed by combining increasing the movement range of the carriage 102, changing parameters related to the movement speed, and providing a stop period.

[0041] FIG. 7 is a flowchart of a reciprocating printing operation according to one embodiment of the present invention. The reciprocating printing operation collectively handles forward printing, backward printing, and associated operations. The flowchart in FIG. 7 is executed by the print control unit 203. The operations of the hardware in the flowchart in FIG. 7 are executed by the transport control unit 205, carriage control unit 206, and wiping mechanism control unit 207 in response to instructions from the print control unit 203.

[0042] When the reciprocating printing operation is started, it is determined whether or not wiping is necessary after the forthward printing and backward printing that will be performed (step S701). For example, it is determined that wiping is necessary when the cumulative amount of ink ejected since the previous wiping operation is equal to or greater than a threshold. Note that wiping is not necessary if a predetermined time has passed since the previous wiping operation. It can also be determined that this is the necessary timing.

[0043] If the determination in step S701 is No, a forward printing operation is performed (step S702), the recording medium is conveyed in the sub-scanning direction (step S703), a backward printing operation is performed (step S704), and the reciprocating printing operation is completed.

[0044] If the determination in step S701 is Yes, it is determined whether a collision (the situation in FIG. 6(g)) will occur when the carriage 102 is moved above the wiping mechanism 107 with the current print image width and print mode (step S705). The print mode (recording mode) is a value determined by, for example, a user specifying "fine," "normal," or "fast" as the image quality, combining the image quality designation with the type of recording medium. The speed of the carriage 102 during printing and the amount of transport of the recording medium 106 in the sub-scanning direction are determined by the print mode. The determination method in step S705 will be described in detail later.

[0045] If the determination in step S705 is Yes, the carriage movement width setting is increased to prevent collisions (step S706). This will also be described in detail later. Thereafter, the printing operation and the wiping mechanism 107 are operated in parallel.

[0046] If the determination in step S705 is No, the printing and wiping mechanism 107 operate in parallel without changing the settings. The printing operation is performed in the order of forward printing operation (step S707), conveying the recording medium in the sub-scanning direction (step S708), and backward printing operation (step S709). If the carriage movement width setting is increased in the processing of step S706, the forward printing operation (step S707) and backward printing operation (step S709) move the carriage accordingly.

[0047] The wiping mechanism 107, which operates in parallel with the printing operation, moves to the cleaning liquid application position (step S711), applies cleaning liquid, waits for it to penetrate (step S712), and then starts moving to the start position (step S713). Here, an example is shown in which the cleaning liquid application operations of steps S711 and S712 are performed as preparatory operations for the wiping operation. However, as described above, the cleaning liquid application operations do not need to be included in the preparatory operations for the wiping operation. In that case, the cleaning liquid application operation may be performed at a different timing, for example, during a reciprocating printing operation when wiping is not required, and the processes of steps S711 and S712 may be omitted for the wiping operation. In that case, the movement process for the wiping operation (step S713) can be performed in parallel with the process of step S707 during the image forming operation. In this case, to avoid collision between the wiping unit 302 and the print head 101, the movement process for the wiping operation (step S713) is performed after waiting for the carriage 102 to move to a position not above the wiping mechanism 107.

[0048] Following the backward printing operation in step S709, the carriage 102 is moved to above the wiping mechanism 107 (step S710). Even if it is determined in step S705 that a collision will occur, the adjustment process in step S706 causes the wiping mechanism 107 to arrive at the start position before the carriage 102 passes above the wiping mechanism 107. Therefore, the carriage 102 can be moved above the wiping mechanism 107 without a collision between the print head 101 and the wiping unit 302.

[0049] After step S710, the wiping mechanism 107 is moved under the carriage 102 to perform the actual wiping operation, and after preliminary ejection, the sheet with the ink attached thereto is wound up (step S714). Thereafter, the wiping mechanism 107 is moved to the standby position (step S715), and the reciprocating printing operation is completed.

[0050] In this way, in the method for controlling the reciprocating printing operation in this embodiment, the wiping mechanism 107 is first waited. The carriage 102 is placed in a standby position. Next, the image formation operation and the operation of moving the wiping mechanism 107 from the standby position to the start position are performed in parallel. Next, following the image formation operation, the carriage 102 is moved to a wiping position for performing the wiping operation by the wiping mechanism 107. Next, while the carriage 102 is in the wiping position, the wiping mechanism 107 is moved from the start position to the end position where the wiping operation ends, thereby wiping the ejection surface 111 of the recording head 101. If the carriage 102 reaches the collision position before the wiping mechanism 107 reaches the start position, an adjustment is made to increase the time required for the image formation operation, and the movement of the wiping mechanism 107 is performed in parallel while the image formation operation is performed with settings that prevent the wiping mechanism 107 and carriage 102 from colliding.

[0051] The processing of steps S705 and S706 in Figure 7 will be described in detail. Figure 8 is a graph showing changes in carriage speed during reciprocating printing operations. The vertical axis of Figure 8 represents carriage speed, and the horizontal axis represents time. Carriage speed during forward printing is a positive value, and carriage speed during backward printing is a negative value. Carriage speed Vcr is a value determined by the print mode. Figure 8(a) is a graph corresponding to the case where the printing operation of Figure 5 and the operation of the wiping mechanism 107 are performed in parallel, and Figure 8(b) is a graph corresponding to the case where the printing operation of Figure 4 and the operation of the wiping mechanism 107 are not performed in parallel.

[0052] The time on the horizontal axis in Figure 8(a) will be explained. Tac is the time it takes to accelerate the carriage speed to Vcr. Tpr is the time the carriage speed remains constant at Vcr, and printing (ink ejection operation) is performed during this period. The time it takes to decelerate after printing in the forward direction is finished is Tac, assuming that acceleration and deceleration are the same. Tlf is the time it takes to move the recording medium in the sub-scanning direction. Tlf is also a value determined by the print mode.

[0053] During backward printing, the carriage speed is a negative value, but it accelerates and moves at a constant speed, just like during forward printing. However, after printing is completed, the carriage continues to move up to above the wiping mechanism 107, so the time it takes to stop is Tre, which is greater than the deceleration time Tac during forward printing. Here, Tco is the time required from the start of constant speed movement during backward printing until the print head 101 moves to a position where there is a possibility of collision with the wiping mechanism 107 (see Figure 6(g)).

[0054] If the time required for the wiping mechanism 107 to move to the start position (the time required for steps S711 to S713 in FIG. 7) is Twp, the condition under which the wiping mechanism 107 and the carriage 102 do not collide is expressed by the following equation 1. Tpr+3Tac+Tlf+Tco≧Twp+m (Formula 1)

[0055] In Equation 1, m is a margin that takes various errors into consideration. In step S705 of FIG. 7, if Equation 1 is true, the result is No; if it is not true, the result is Yes. The left side of Equation 1 is a value determined by the print mode and image width. FIG. 8(a) shows Twp,m when the following equation is true: Tpr+3Tac+Tlf+Tco=Twp+m

[0056] The calculation method for Tpr, Tac, and Tco will be explained. The carriage speed determined by the print mode is Vcr, and the image width determined by the image data is Wp. Figure 9 shows the print head 101 as seen from the print medium 106 side. Nozzles 110, which are ink ejection ports, are arranged in the sub-scanning direction on the ejection surface 111 of the print head 101, and these are called nozzle rows. There are multiple nozzle rows in the main scanning direction, and different color inks are ejected from the nozzles 110 of each nozzle row. do.

[0057] In this way, nozzle rows that eject inks of different colors are arranged in the main scanning direction on the ejection surface 111 of the print head 101. Therefore, it is preferable that the direction in which the wiping mechanism 107 wipes the ejection surface 111 during the wiping operation is not parallel to the main scanning direction in order to prevent inks of different colors from mixing due to the wiping operation. In this embodiment, as shown in FIG. 3, the movement direction of the wiping mechanism 107 is parallel to the sub-scanning direction that intersects with the main scanning direction (orthogonal in this embodiment). Therefore, a configuration is achieved in which inks of different colors are less likely to mix due to the wiping operation.

[0058] When performing an image formation operation, the nozzle array of the ink color used in image formation must be brought to a position above the edge of the image on the recording medium 106. The distance in the main scanning direction between the nozzle array on the most non-reference side and the nozzle array on the most reference side used in image formation on the recording medium 106 is assumed to be Wn. For example, when forming an image using all the nozzle arrays of the recording head 101, the carriage 102 must be moved an additional distance Wn in addition to the image width Wp. Therefore, Tpr can be calculated using the following equation. Tpr=(Wp+Wn) / Vcr

[0059] If the acceleration of the carriage 102 is a (the deceleration is also a), Tac can be calculated by the following formula. Tac=Vcr / a

[0060] The position where the print head 101 and wiping mechanism 107 collide in Figure 6(g) is a fixed position. Figure 10 is a diagram showing the details of the positional relationship in Figure 6(g). The position of the carriage 102 is based on the position of the nozzle row on the most non-reference side. The distance from the reference side edge of the print medium 106 to the position where the collision occurs is defined as Wc. If the margin to the image on the reference side is defined as Wm, Tco can be calculated using the following formula. Tco=((Wp+Wm-Wc)+Wn) / Vcr

[0061] Substituting each value into Equation 1, we obtain the following equation: (Wp+Wn) / Vcr+3Vcr / a+Tlf+((Wp+Wm-Wc)+Wn) / Vcr≧Twp+m

[0062] The processing of step S706 in Fig. 7 will be described. If formula 1 does not hold, the image width Wp is replaced with a value Wrp for which formula 1 holds, and the carriage is moved so as to pass through the area of ​​Wrp. In other words, Wrp is set so that the following formula holds: (Wrp+Wn) / Vcr+3Vcr / a+Tlf+((Wrp+Wm-Wc)+Wn) / Vcr≧Twp+m

[0063] After rearranging, we get the following formula: (2Wrp+2Wn+Wm-Wc) / Vcr≧Twp-3Vcr / a-Tlf+m Wrp≧(Vcr(Twp-3Vcr / a-Tlf+m)-2Wn-Wm+Wc) / 2

[0064] Figure 8(a) shows the result after adjusting the equation above to hold true.

[0065] FIG. 8(b) is a graph showing the case where the wiping mechanism 107 is operated after the printing operation shown in FIG. 4 is completed without adjusting the image width Wp. The time shown in FIG. 8(b) will be explained. Tac and Tlf are the same as in FIG. 8(a). The time corresponding to Tpr in FIG. 8(a) is Tprb in FIG. 8(b) because the image width Wp is not adjusted. Also, unlike FIG. 8(a), after printing is completed in the backward direction, the carriage 102 does not move continuously to above the wiping mechanism 107, so the time it takes for the carriage 102 to decelerate is Tac.

[0066] The time required for the operation of retracting the carriage 102 from above the wiping mechanism 107 after printing is completed (see FIGS. 4(f) and 4(g)) is defined as Tavo. After the carriage 102 is retracted, the time required for the wiping mechanism 107 to move to the start position is Twp. The time required for the operation of subsequently moving the carriage 102 above the wiping mechanism 107 (see FIGS. 4(h) and 4(j)) is defined as Tret.

[0067] Let's compare the time in Figure 8(a) and Figure 8(b). If the time until wiping can begin is Tready_a in Figure 8(a) and Tready_b in Figure 8(b), then it can be expressed by the following equations: Tready_a=Twp+m+(Tpr-Tco)+Tre Tready_b=4Tac+2Tprb+Tlf+Tavo+Twp+Tret

[0068] In FIG. 8B, the carriage speed when the carriage 102 is retracted and when it moves above the wiping mechanism 107 is set to the same as the speed during printing, and in this case, the following formula holds: Tret>m+(Tpr-Tco)+Tre

[0069] This is because Tret includes the acceleration time of the carriage 102. Therefore, the following equation holds true: Tready_b>Twp+Tret>Twp+m+(Tpr-Tco)+Tre=Tready_a

[0070] Therefore, the following formula always holds true: Tready_b>Tready_a

[0071] In other words, when the printing operation and the operation of the wiping mechanism 107 are performed in parallel, the time until the wiping operation can be started is shorter.

[0072] The carriage speed when the carriage 102 is retracted and moved onto the wiping mechanism 107 is set to the speed when printing. It is possible to shorten the Tavo and Tret times by making the speed faster than . In that case, the following formula usually holds. (Time required for forward and reverse printing) > m + (Tpr - Tco) + Tre

[0073] That is, the following equation holds: 4Tac+2Tprb+Tlf>m+(Tpr-Tco)+Tre

[0074] Therefore, the following formula holds: Tready_b>Tready_a

[0075] In Figure 8, the recording medium moves in the sub-scanning direction after the carriage movement for forward printing has stopped, and then reverse printing begins after the movement is complete. To improve throughput, the operation of decelerating forward printing and accelerating reverse printing, during which ink is not being ejected, may be performed in parallel with the movement of the recording medium in the sub-scanning direction. In this case, the time for which parallel operation is performed can be subtracted from Tlf. Also, for simplicity's sake, Figure 8 shows that ink is ejected during a constant carriage speed interval at Vcr, but ink may also be ejected during acceleration or deceleration. Furthermore, the acceleration or deceleration may be changed during acceleration or deceleration.

[0076] Also, in Figure 8, the carriage speed was changed in a trapezoidal fashion, but to avoid sudden changes in speed, a moving average can be taken to make the change more gradual. In these cases, the basic idea is the same, and the calculations described so far are possible because the area of ​​the graph in Figure 8 is the movement distance. Also, for these cases, although it is not an accurate value, it is possible to use Equation 1 simply by taking into account the calculation error in the margin m.

[0077] As described above, according to the first embodiment, in a liquid ejection device that performs a wiping operation of a head using a wiping mechanism, it is possible to reduce the time required to perform a wiping operation following a forming operation of ejecting liquid onto a target (recording medium). It is possible to prevent the time required for one scan from fluctuating significantly from scan to scan, and as a result, it is possible to reduce color unevenness between scans in an image.

[0078] Example 2 In the second embodiment, the carriage speed is changed to a carriage speed different from the carriage speed determined by the print mode, instead of the large carriage movement width setting in step S706 in Fig. 7 in the first embodiment. If the carriage speed after the change is Vrcr, it is sufficient to set Vrcr so that the following formula holds. (Wp+Wn) / Vrcr+3Vrcr / a+Tlf+((Wp+Wm-Wc)+Wn) / Vrcr≧Twp+m

[0079] Normally, the carriage speed during printing is not an arbitrary value, but one of several predetermined values. The Vrcr that satisfies the above formula is found, and this is used as the carriage speed during forward printing and reverse printing, and is applied during the processing of steps S707 and S709 in Figure 7.

[0080] Example 3 In the third embodiment, the carriage movement width setting in step S706 in Fig. 7 in the first embodiment is increased, but this is changed to a calculation of the waiting time between forward printing and backward printing. Before or after step S708 in Fig. 7, a process of pausing for the calculated waiting time is inserted. If the waiting time is Twait, it is sufficient to wait for the Twait time for which the following formula is true. (Wp+Wn) / Vcr+3Vcr / a+Tlf+((Wp+Wm-Wc)+Wn) / Vcr+Twait≧Twp+m

[0081] Example 4 In the fourth embodiment, the processing of step S706 in FIG. 7 is performed by combining two or more of the first to third embodiments. In the first embodiment, the carriage is moved beyond the image width, increasing the time during which ink is not ejected. By appropriately increasing the carriage movement range, it is possible to suppress thickening and solidification of ink in the nozzles, which is caused by an increase in the time during which ink is not ejected. In the second embodiment, there is a restriction that an arbitrary value cannot be set as the carriage speed, but by appropriately slowing the carriage speed, it is possible to suppress changes in image quality compared to areas printed at the normal carriage speed, which are caused by changing the carriage speed during printing. In the third embodiment, similar to the first embodiment, the time during which ink is not ejected increases. By appropriately setting the carriage stop period, it is possible to suppress thickening and solidification of ink.

[0082] The value after changing the carriage movement width is Wrp, the value after changing the carriage speed is Vrcr, and the waiting time is Twait. Adjust each value to suppress ink thickening / sticking and changes in image quality, and so that the following formula holds true. (Wrp+Wn) / Vrcr+3Vrcr / a+Tlf+((Wrp+Wm-Wc)+Wn) / Vrcr+Twait≧Twp+m

[0083] The above describes an embodiment in which the liquid ejection device of the present invention is applied to a recording device that records an image by ejecting ink onto a recording medium. However, the present invention is not limited to recording devices and can be applied to various liquid ejection devices, such as dispensers that eject liquid onto a target. In the above embodiment, the recording medium is an example of an object onto which a liquid is ejected. Furthermore, the image forming operation is an example of a forming operation in which a liquid is ejected onto a target. Ink is an example of a liquid. The present invention can also be applied to a liquid ejection device that ejects a liquid from ejection ports provided in a head while moving a carriage in the main scanning direction relative to the target. The liquid is not limited to ink; it can be any substance in a liquid phase that can be ejected toward a target from the ejection ports of the head. For example, liquids of various viscosities, sols, gels, solvents, solutions, liquid resins, liquid metals, and liquids in which solid particles such as pigments and metal particles are dissolved, dispersed, or mixed in a solvent are also acceptable.

[0084] <Other Examples> The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0085] The disclosure of this embodiment includes the following configuration. (Configuration 1) a head provided with a discharge port for discharging a liquid; a carriage on which the head is mounted; a wiping mechanism that performs a wiping operation to wipe an ejection surface of the head on which the ejection ports are provided while moving relatively to the carriage; a liquid ejection device that ejects the liquid from the ejection opening while moving the carriage in a main scanning direction relative to an object, the carriage is movable to a forming position for performing a forming operation of ejecting the liquid onto the object and to a wiping position for performing the wiping operation; the wiping mechanism is movable between a standby position, a start position where the wiping operation starts, and an end position where the wiping operation ends, and is configured to perform the wiping operation by moving from the standby position to the start position and then moving from the start position to the end position with the carriage at the wiping position; The liquid ejection device is characterized in that, when the wiping operation is performed following the forming operation, the wiping mechanism moves from the standby position to the start position in parallel with the forming operation. (Configuration 2) the wiping mechanism performs a preparatory operation for preparing for the wiping operation at the standby position; The liquid ejection device according to configuration 1, wherein when the wiping operation is performed following the forming operation, the wiping mechanism performs the preparation operation and movement from the standby position to the start position in parallel with the forming operation. (Configuration 3) the wiping mechanism includes an absorbing means capable of absorbing the liquid, the absorbing means being pressed against the ejection surface to wipe the liquid from the ejection surface, and an applying means applying a cleaning liquid to the absorbing means; 3. The liquid ejection device according to configuration 2, wherein the preparatory operation includes an operation in which the applying unit applies the cleaning liquid to the absorbing unit. (Configuration 4) When the wiping mechanism is located at a position midway between the standby position and the start position, the carriage may collide with the wiping mechanism at a collision position midway during the forming operation, The liquid ejection device according to any one of configurations 1 to 3, wherein an adjustment is made to increase the time required for the forming operation so that the carriage reaches the collision position after the wiping mechanism reaches the start position. (Configuration 5) 5. The liquid ejection apparatus according to configuration 4, wherein the adjustment is to make the movement range of the carriage in the main scanning direction larger than a predetermined movement range. (Configuration 6) the forming operation is a recording operation of recording an image on a recording medium, 6. The liquid ejection device according to configuration 5, wherein the predetermined movement range of the carriage is a movement range determined in accordance with the width of the image in the main scanning direction. (Configuration 7) The liquid ejection device according to configuration 4, wherein the adjustment is to change a predetermined parameter related to the movement speed of the carriage so as to increase the time required for the carriage to move through a predetermined movement range in the main scanning direction. (Configuration 8) the forming operation is a recording operation of recording an image on a recording medium, 8. The liquid ejection device according to configuration 7, wherein the predetermined parameter relating to the carriage movement speed is a parameter set in accordance with a recording mode relating to the quality or speed of recording the image. (Configuration 9) the parameter is a speed at which the carriage moves at a constant speed, 9. The liquid ejection device according to configuration 7 or 8, wherein the adjustment is to slow down the constant speed movement of the carriage below the predetermined speed. (Configuration 10) 5. The liquid ejection device according to configuration 4, wherein the adjustment is to provide a stop period during the forming operation in which the liquid is not ejected. (Configuration 11) The liquid ejection device of configuration 4, wherein the adjustment is performed by combining the following: increasing the range of movement of the carriage in the main scanning direction beyond a predetermined range of movement; changing a predetermined parameter related to the movement speed of the carriage so as to increase the time required for the carriage to move through the predetermined range of movement in the main scanning direction; and providing a stop period during the formation operation during which the liquid is not ejected. (Configuration 12) the wiping mechanism has, at the end position, a receiving portion capable of receiving the liquid ejected from the head of the carriage at the wiping position; 12. The liquid ejection device according to any one of configurations 1 to 11, wherein after the wiping operation is completed, preliminary ejection is performed to eject the liquid from the head to the receiving portion. (Configuration 13) by repeating a plurality of times the forming operation of ejecting the liquid from the ejection port while moving the carriage in the main scanning direction relative to the object, and the transport operation of moving the object in a sub-scanning direction intersecting the main scanning direction, the liquid can be ejected onto an area of ​​the object that exceeds the size of the head in the sub-scanning direction, 13. The liquid ejection device according to any one of configurations 1 to 12, wherein the wiping operation is performed following at least one of the forming operations performed multiple times. (Configuration 14) 14. The liquid ejection device according to any one of configurations 1 to 13, wherein the moving direction of the wiping mechanism is parallel to a sub-scanning direction that intersects with the main scanning direction. (Configuration 15) 15. The liquid ejection device according to any one of configurations 1 to 14, wherein the wiping operation is performed when the cumulative amount of ejection of the liquid since the previous wiping operation is performed reaches or exceeds a threshold value. (Configuration 16) 15. The liquid ejection device according to any one of configurations 1 to 14, wherein the wiping operation is performed when a predetermined time has elapsed since the wiping operation was previously performed. (Method 1) a head provided with a discharge port for discharging a liquid; a carriage on which the head is mounted; a wiping mechanism that performs a wiping operation to wipe an ejection surface of the head on which the ejection ports are provided while moving relatively to the carriage; A method for controlling a liquid ejection device, comprising: a step of placing the wiping mechanism at a standby position; a step of concurrently performing a forming operation of discharging the liquid from the discharge port while moving the carriage in a main scanning direction relative to the object at a forming position, and an operation of moving the wiping mechanism from the standby position to a start position where the wiping operation is started; moving the carriage to a wiping position for performing the wiping operation by the wiping mechanism following the forming operation; wiping the ejection surface by moving the wiping mechanism from the start position to an end position where the wiping operation ends, while the carriage is at the wiping position; A method for controlling a liquid ejection device, comprising: (Method 2) When the wiping mechanism is located at a position midway between the standby position and the start position, the carriage may collide with the wiping mechanism at a collision position midway during the forming operation, The method further comprises adjusting the time required for the forming operation so that the carriage reaches the impact position after the wiping mechanism reaches the start position. A method for controlling a liquid ejection device. [Explanation of symbols]

[0086] 100: printer, 101: recording head, 102: carriage, 107: wiping mechanism, 110: nozzle, 111: ejection surface

Claims

1. a head provided with a discharge port for discharging a liquid; a carriage on which the head is mounted; a wiping mechanism that performs a wiping operation to wipe an ejection surface of the head on which the ejection ports are provided while moving relatively to the carriage; a liquid ejection device that ejects the liquid from the ejection opening while moving the carriage in a main scanning direction relative to an object, the carriage is movable to a forming position for performing a forming operation of ejecting the liquid onto the object and to a wiping position for performing the wiping operation; the wiping mechanism is movable between a standby position, a start position where the wiping operation starts, and an end position where the wiping operation ends, and is configured to perform the wiping operation by moving from the standby position to the start position and then moving from the start position to the end position with the carriage at the wiping position; The liquid ejection device is characterized in that, when the wiping operation is performed following the forming operation, the wiping mechanism moves from the standby position to the start position in parallel with the forming operation.

2. the wiping mechanism performs a preparatory operation for preparing for the wiping operation at the standby position; The liquid ejection device according to claim 1 , wherein, when the wiping operation is performed following the forming operation, the wiping mechanism performs the preparation operation and movement from the standby position to the start position in parallel with the forming operation.

3. the wiping mechanism includes an absorbing means capable of absorbing the liquid, the absorbing means being pressed against the ejection surface to wipe the liquid from the ejection surface, and an applying means applying a cleaning liquid to the absorbing means; The liquid ejection apparatus according to claim 2 , wherein the preparatory operation includes an operation in which the applying unit applies the cleaning liquid to the absorbing unit.

4. When the wiping mechanism is located at a position midway between the standby position and the start position, the carriage may collide with the wiping mechanism at a collision position midway during the forming operation, A liquid ejection device described in any one of claims 1 to 3, which adjusts to increase the time required for the forming operation so that the carriage reaches the collision position after the wiping mechanism reaches the start position.

5. The liquid ejection apparatus according to claim 4 , wherein the adjustment is to make the movement range of the carriage in the main scanning direction larger than a predetermined movement range.

6. the forming operation is a recording operation of recording an image on a recording medium, The liquid ejection device according to claim 5 , wherein the predetermined movement range of the carriage is determined in accordance with the width of the image in the main scanning direction.

7. The liquid ejection device according to claim 4 , wherein the adjustment is to change a predetermined parameter relating to the movement speed of the carriage so as to increase the time required for the carriage to move through a predetermined movement range in the main scanning direction.

8. the forming operation is a recording operation of recording an image on a recording medium, The liquid ejection apparatus according to claim 7 , wherein the predetermined parameter relating to the carriage movement speed is a parameter set in accordance with a print mode relating to the quality or speed of printing the image.

9. the parameter is a speed at which the carriage moves at a constant speed, The liquid ejection device according to claim 7 , wherein the adjustment comprises slowing down the constant speed movement of the carriage below the predetermined speed.

10. The liquid ejection device according to claim 4 , wherein the adjustment is performed by providing a stop period during the forming operation during which the liquid is not ejected.

11. The liquid ejection device described in claim 4, wherein the adjustment is performed by combining the following: increasing the range of movement of the carriage in the main scanning direction beyond a predetermined range of movement; changing a predetermined parameter related to the carriage movement speed so as to increase the time required for the carriage to move through the predetermined range of movement in the main scanning direction; and providing a stop period during the formation operation during which the liquid is not ejected.

12. the wiping mechanism has, at the end position, a receiving portion capable of receiving the liquid ejected from the head of the carriage at the wiping position; 3. The liquid ejection device according to claim 1, wherein after the wiping operation is completed, a preliminary ejection is performed to eject the liquid from the head to the receiving portion.

13. by repeating a plurality of times the forming operation of ejecting the liquid from the ejection port while moving the carriage in the main scanning direction relative to the object, and the transport operation of moving the object in a sub-scanning direction intersecting the main scanning direction, the liquid can be ejected onto an area of ​​the object that exceeds the size of the head in the sub-scanning direction, The liquid ejection device according to claim 1 or 2, wherein the wiping operation is performed following at least one of a plurality of the forming operations.

14. 3. The liquid ejection apparatus according to claim 1, wherein the moving direction of the wiping mechanism is parallel to a sub-scanning direction that intersects with the main scanning direction.

15. The liquid ejection device according to claim 1 , wherein the wiping operation is performed when a cumulative amount of the liquid ejected since the previous wiping operation is equal to or greater than a threshold value.

16. The liquid ejection device according to claim 1 or 2, wherein the wiping operation is performed when a predetermined time has elapsed since the previous wiping operation.

17. a head provided with a discharge port for discharging a liquid; a carriage on which the head is mounted; a wiping mechanism that performs a wiping operation to wipe an ejection surface of the head on which the ejection ports are provided while moving relatively to the carriage; A method for controlling a liquid ejection device, comprising: a step of placing the wiping mechanism at a standby position; a step of concurrently performing a forming operation of discharging the liquid from the discharge port while moving the carriage in a main scanning direction relative to the object at a forming position, and an operation of moving the wiping mechanism from the standby position to a start position where the wiping operation is started; moving the carriage to a wiping position for performing the wiping operation by the wiping mechanism following the forming operation; wiping the ejection surface by moving the wiping mechanism from the start position to an end position where the wiping operation ends, while the carriage is at the wiping position; A method for controlling a liquid ejection device, comprising:

18. When the wiping mechanism is located at a position midway between the standby position and the start position, the carriage may collide with the wiping mechanism at a collision position midway during the forming operation, The method for controlling a liquid ejection device according to claim 17, further comprising the step of making an adjustment to increase the time required for the forming operation so that the carriage reaches the collision position after the wiping mechanism reaches the start position.

Images