Recording device and carriage control method

Abstract

To solve such a conventional problem that a movement length of a carriage became long in a main scanning direction, and improvement of through-put was difficult.SOLUTION: A recording device 10 comprises: a carriage 41 on which a recording head 20 for discharging a photocurable ink onto a medium B and a light source 30 for radiating light that cures the photocurable ink discharged during an approach path motion are mounted, and which is capable of reciprocating in a main scanning direction; and a control part 80 that controls the motion of the carriage 41. The control part 80 specifies a movement range at a step S140 and controls the movement of the carriage 41 so that the irradiation range of light by the light source 30 does not deviate from a region on the medium B to which the photocurable ink has been discharged, when reversing from the approach path motion to the return path motion.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a printing apparatus and a carriage control method, and more particularly to a printing apparatus and a carriage control method for printing using photocurable ink. [Background technology]

[0002] 2. Description of the Related Art A known recording apparatus for recording using photocurable ink is disclosed in Patent Document 1. The document discloses an inkjet recording device equipped with a carriage 3 that is configured to be able to move back and forth in the main scanning direction and that has a recording head 4 that ejects photocurable ink onto a recording medium and a light source 5. In this inkjet recording device, the carriage 3 moves in the forward direction while the recording head 4 ejects photocurable ink, and the light source 5 irradiates the photocurable ink with light for curing.

[0003] The carriage 3 turns back after the irradiation range of the light beam emitted from the light source 5 has passed over the recording medium, and moves in the return direction. In this way, the light source 5 moves in the forward direction until it passes over the recording medium, so that the photo-curable ink ejected by the recording head 4 is reliably fixed and cured. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-26970 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional inkjet recording devices, the carriage always moves until the light source passes over the recording medium during forward movement to ensure that the photocurable ink is cured. This increases the carriage movement distance in the main scanning direction, making it difficult to improve throughput. [Means for solving the problem]

[0006] The present invention is a recording device comprising a carriage that can move back and forth in the main scanning direction and that carries a recording head that ejects photocurable ink onto a medium and a light source that irradiates light to harden the photocurable ink ejected during an outward movement, and a control unit that controls the movement of the carriage, wherein the control unit controls the movement of the carriage so that the return movement from the outward movement to the return movement occurs at a position where the range of light irradiation by the light source does not deviate from the area on the medium where the photocurable ink was ejected.

[0007] The present invention also provides a carriage control method for a recording device that controls the operation of a carriage that can move back and forth in a main scanning direction and that is equipped with a recording head that ejects photocurable ink onto a medium and a light source that irradiates light to cure the photocurable ink ejected during a forward movement, and that includes the steps of: acquiring the area on the medium onto which the photocurable ink has been ejected; determining a turnaround position from the forward movement to the return movement at a position where the range of light irradiation by the light source does not deviate from the area onto which the photocurable ink has been ejected; and controlling the movement of the carriage at the turnaround position. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic block diagram of an inkjet printing apparatus to which the printing apparatus of the present invention is applied; [Figure 2] FIG. 2 is a schematic diagram showing the arrangement of a recording head and a light source mounted on a carriage. [Figure 3] 10 is a flowchart of a program for controlling the operation of the carriage. [Figure 4] 10A to 10C are diagrams illustrating a movement process of the carriage. [Figure 5] 10A to 10C are diagrams illustrating a movement process of the carriage. [Figure 6] 10A to 10C are diagrams illustrating a movement process of the carriage. [Figure 7] 10A and 10B are diagrams illustrating the distance from the light source of the carriage to the medium and the range of movement of the carriage. [Figure 8] 10A and 10B are diagrams illustrating the distance from the light source of the carriage to the medium and the range of movement of the carriage. [Figure 9] FIG. 10 is a diagram showing a table for looking up the range of carriage movement based on the distance of the carriage from the light source to the media. [Figure 10] 10 is a flowchart of a program according to a modified example for controlling the operation of the carriage. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram showing an ink jet recording apparatus to which the recording apparatus of the present invention is applied.

[0010] The recording device 10 includes a carriage unit 40 that carries a recording head 20 and a light source 30 and moves back and forth in the main scanning direction, a transport unit 50 that transports the medium in a direction roughly perpendicular to the main scanning direction, a PG sensor 60, and a control unit 80 that receives print data via an interface unit 70 and controls printing.

[0011] The recording head 20 is controlled by a control unit 80, and ejects photocurable ink onto the medium transported by a transport unit 50. The carriage unit 40 includes a carriage 41 that carries the recording head 20 and the light source 30, in that order, from the front side to the rear side during forward movement, and is driven back and forth along a predetermined guide by a drive unit 42. The light source 30 irradiates light that cures the photocurable ink ejected from the forward recording head 20 during forward movement. The control unit 80 moves the medium in the sub-scanning direction by the transport unit 50, and controls the ejection of photocurable ink by the recording head 20 and the fixing of the ink by the light source 30 while controlling the forward movement and return movement of the carriage unit 40.

[0012] FIG. 2 is a schematic diagram showing the arrangement of the recording head and light source mounted on the carriage. The carriage 41 carries head 21 and head 22 as the recording head 20. Heads 21 and 22 each have nozzle rows A to H, each of which has 180 nozzles extending parallel to the sub-scanning direction, arranged in parallel in the main scanning direction. Head 21 is arranged upstream of head 22 in the sub-scanning direction, and head 21 is arranged downstream of head 22 in the main scanning direction. The downstream side in the main scanning direction is the forward side during forward movement.

[0013] The light source 30 is disposed downstream of the heads 21 and 22 in the main scanning direction, and its length is long enough to cover all of the nozzles of the heads 21 and 22, which are disposed offset in the sub-scanning direction. The light source 30 is divided into areas 1 to 8 in the length direction and into five in the width direction. One LED that irradiates ultraviolet light is disposed in each section.

[0014] The distance from row H of the head 22 to the light source 30 is 95.2 mm in the case of an A3 model recording device 10. The A4 model recording device 10 has only one head, and the distance from row H, which is closest to the light source 30, to the light source 30 is 105.3 mm. The LEDs of the light source 30 are arranged in two rows and five columns for each area, with each LED measuring 3.5 mm x 3.5 mm, spaced 0.9 mm apart in the sub-scanning direction (vertical direction) and 1.1 mm apart in the main scanning direction (horizontal direction). Therefore, the width of each area is 21.9 mm.

[0015] During forward movement, predetermined nozzles of the heads 21 and 22 eject photocurable ink, and once the photocurable ink adheres to the medium, ultraviolet light emitted from the LEDs of the light source 30 located downstream in the main scanning direction illuminates and fixes the photocurable ink. The travel distance until all five rows of LEDs of the light source 30 face the photocurable ink ejected from the nozzles in row H of the head 22 located furthest downstream in the main scanning direction is 117.1 mm, which is the sum of the distance from row H to the light source (95.2 mm) and the length of the five rows of LEDs that make up the light source 30 (21.9 mm). In other words, after photocurable ink is ejected from row H of nozzles, when the carriage 41 is moved a further 117.1 mm, all five rows of LEDs of the light source 30 will be irradiated onto the photocurable ink.

[0016] FIG. 3 shows a flowchart of a program for controlling the operation of the carriage, and FIGS. 4 to 6 illustrate the process of carriage movement. The control unit 80 performs control in accordance with the flowchart shown in Fig. 3. First, in step S100, the control unit 80 acquires print data. Once the control unit 80 acquires the print data, it generates control data for each pass to move the carriage 41 back and forth to proceed with printing. Then, in step S110, the processing from step S120 onwards is repeated until it is determined that printing for all passes has been completed.

[0017] In step S120, the control unit 80 calculates the printing area for the next pass. This printing area refers to the area from when the carriage 41 starts at the rightmost end of its movable range as shown in Fig. 4, until it moves leftward on the outward path and finishes ejecting photo-curable ink from the recording head 20. Next, in step S130, the control unit 80 acquires the platen gap PG from the PG sensor 60.

[0018] 7 and 8 illustrate the light source to media distance of the carriage and the range of carriage movement. The platen gap PG represents the distance between the recording head 20 and the medium B. In this recording device 10, the distances from the heads 21 and 22 of the recording head 20 and from the light source 30 to the medium are all the same. That is, the distance from the light source 30 to the medium is also the platen gap PG. The recording ink ejected from the nozzles of the heads 21 and 22 lands on the medium in a direction and at a speed indicated by a resultant vector of the movement component in the forward direction of the carriage 41 and the movement component in the ejection direction of the ink ejected from the nozzles. Meanwhile, the ultraviolet light emitted from each LED of the light source 30 has a predetermined spread angle. For example, in the case of the platen gap PG' shown in FIG. 7, in order for the irradiation range to extend beyond the edge of the medium B, the center of the light source 30 must be moved to a position a distance LP' from the edge of the medium B. In contrast, in the case of the platen gap PG" shown in FIG. 8, in order for the irradiation range to extend beyond the edge of the medium B, the center of the light source 30 must be moved to a position a distance LP" from the edge of the medium B. That is, when the platen gap PG is smaller, the movement amount of the carriage 41 in the main scanning direction is smaller at the turnaround position.

[0019] Thus, when there is a platen gap PG, for example, the movement distance (from the edge of medium B) of light source 30 required to irradiate up to the edge of medium B varies depending on the platen gap PG. This relationship can be calculated from the divergence angle from light source 30 as shown in the figure and the platen gap PG. Note that, as will be described later, the platen gap is used as one of the parameters in calculating the return position. This distance LP is called the adjustment amount. This means that even if light source 30 is located at a position not exceeding a predetermined position on the medium, ultraviolet light can be irradiated up to a range downstream by this distance LP.

[0020] In step S140, the control unit 80 obtains the required movement amount of the carriage 41. The information required to obtain this movement amount is the position of the printing edge based on the printing area calculated in step S120, the overlap amount which is the width of the light source 30 that overlaps the inside of the printing area beyond the edge of the printing area, using the edge of the printing area as a reference, the size and number of LEDs mounted on the carriage 41, and the arrangement positions of the heads 21 and 22.

[0021] As a specific example, the calculation is performed as follows. The most downstream nozzle that ejects photocurable ink is in row H of the head 22. The distance from this position to the light source 30 is 95.2 mm in an A3 model, and the width of all LEDs in the light source 30 is 21.9 mm. It has been found that in certain environments, sufficient fixation can be ensured even if the light from all LEDs does not irradiate the final photocurable ink. In the case of the light source 30 of this embodiment, an irradiation range of four LEDs was sufficient for the final photocurable ink. This means that the carriage 41 can return from its forward movement to its backward movement, leaving an overlap amount OW equivalent to the width of one LED.

[0022] The absence of an overlap amount means that the range of light emitted by the light source 30 is outside the area on medium B where the photo-curable ink has been ejected, and the printing area does not overlap with the light source 30. Furthermore, the presence of an overlap amount means that the movement of the carriage 41 is controlled so that the range of light emitted by the light source 30 moves forward to a position where it does not deviate from the area on medium B where the photo-curable ink has been ejected, and then returns to the homeward movement. However, as described above, the distance LP, which is an adjustment amount based on the spread angle from the light source 30 and the platen gap PG, is finally reflected.

[0023] In this way, if the edge of the printing area is used as the base point, the distance traveled is the position of the nozzle row H of the head 22 plus the width of the light source 30, minus the overlap amount OW for one LED.

[0024] The overlap amount OW changes depending on the fixing conditions, and can be adjusted in units of the number of LEDs. In other words, it is possible to adjust the turn-around position in units of the number of LEDs. If a large overlap OW can be achieved, the movement range of the carriage 41 can be shortened, and throughput can be improved.

[0025] In this way, when the light source 30 has a plurality of rows of optical elements in the scanning direction, the control unit 80 adjusts the return position in units of the width of the optical elements.

[0026] In step S150, the control unit 80 performs printing while moving the carriage 41 so as to achieve the above movement distance. Referring to the figure, first, carriage 41 is moved to the rightmost end of its movable range shown in Fig. 4 to the start position, and starts from this position. During the process, as shown in Fig. 5, carriage 41 moves based on control data for the current printing pass, which is based on the print data, and the heads 21 and 22 of recording head 20 eject a predetermined photocurable ink, and then light source 30 irradiates the ink with ultraviolet light to fix it. Fig. 6 shows the state after carriage 41 has moved the required movement amount calculated in step S140, and at this position carriage 41 returns from its forward movement to its return movement.

[0027] The turning position is a position where, by setting the overlap amount OW as described above, the range of light emitted by the light source 30 does not deviate from the area where the photo-curable ink has been ejected on the medium B. After the forward movement to this position, the turning position is changed to the return movement.

[0028] When specifying this turning position, as described above, the control unit 80 changes it based on the platen gap PG, which is the distance between the light source 30 and the medium B. This is because the light emitted from the light source 30 diffuses, and the irradiation range changes based on the distance to the medium B.

[0029] Since it is no longer necessary to always move the carriage 41 until the light source 30 passes the edge of the medium B as in the conventional method, it is possible to achieve both curing of the photo-curable ink and improvement of throughput. FIG. 9 graphically illustrates a table for looking up the range of carriage travel based on the carriage's light source to media distance.

[0030] The adjustment amount movement amount LP can be calculated each time based on the platen gap PG, or can be obtained by referencing the table shown in Figure 9. This table allows the adjustment amount movement amount LP to be referenced by referencing the table based on two parameters, the platen gap PG and the number of LEDs, so that adjustment based on the number of LEDs according to the fixing status can also be performed simultaneously. In this way, the control unit 80 determines the turn-back position by referencing a predetermined table using the distance between the light source 30 and the medium B as a parameter.

[0031] In addition, in the carriage control method of the recording device 10, step S120 corresponds to a process of acquiring the area on the medium B onto which the photocurable ink has been ejected, steps S130 and S140 correspond to processes of determining a turnaround position from the forward operation to the return operation at a position where the light irradiation range from the light source 30 does not deviate from the area onto which the photocurable ink has been ejected, and step S150 corresponds to a process of controlling the movement of the carriage 41 at the turnaround position.

[0032] FIG. 10 is a flowchart showing a modified example of a program for controlling the operation of the carriage. In the above-described embodiment, the movement range of the carriage 41 was determined based on the edge of the printing area where the photocurable ink is actually ejected, but it is also possible to use the edge of the printing medium B as the reference, regardless of the printing area. Even in this case, if the overlap amount OW is determined and the paper is turned back at that position, the turning back position can be made earlier than before, which contributes to improving throughput.

[0033] 3 is that in step S220 instead of step S120, the control unit 80 acquires the medium width, and in step S240 instead of step S140, the control unit 80 acquires the amount of movement based on the medium width instead of the print area. Note that, as shown by the dashed line in Fig. 1, a medium sensor 61 is provided, and the medium width is acquired in step S220 by obtaining the output of the medium sensor 61.

[0034] Furthermore, by folding back the sheet in a range from a position that does not deviate from the print area as in the previous embodiment to a position that does not deviate from the print medium as in this modified example, throughput is improved compared to the conventional method.

[0035] The recording device 10 may also be provided with an adjustment mechanism for adjusting the platen gap PG. For example, the adjustment mechanism may be a moving unit that adjusts the distance to the medium B by moving the recording head 20, or a moving unit that moves the position of a support unit that supports the medium B.

[0036] It goes without saying that the present invention is not limited to the above-described embodiments. The mutually replaceable components and configurations disclosed in the above embodiments may be appropriately changed and applied. Although not disclosed in the above embodiments, members and configurations that are publicly known and can be mutually substituted for the members and configurations disclosed in the above embodiments may be appropriately substituted, and their combinations may be changed and applied. Although not disclosed in the above embodiments, members and configurations may be substituted by those skilled in the art based on publicly known techniques as substitutes for the members and configurations disclosed in the above embodiments, and the combinations may be changed and applied. is disclosed as an embodiment of the present invention. [Explanation of symbols]

[0037] 10...recording device, 20...recording head, 21, 22...head, 30...light source, 40...carriage unit, 41...carriage, 42...drive unit, 50...conveying unit, 60...PG sensor, 61...medium sensor, 70...interface unit, 80...control unit.

Claims

1. a carriage that is capable of reciprocating in a main scanning direction and that carries a recording head that ejects photocurable ink onto a medium and a light source that irradiates light to cure the photocurable ink ejected during a forward movement; a control unit for controlling the operation of the carriage, The control unit controls the movement of the carriage so that the return movement from the forward movement to the backward movement is performed at a position where the irradiation range of the light from the light source does not deviate from the area on the medium where the photo-curable ink is ejected. A recording device characterized by:

2. 2. The recording apparatus according to claim 1, wherein the control unit changes the turning position based on a distance between the light source and the medium.

3. 3. The recording apparatus according to claim 2, wherein the control unit calculates the turning position using a distance between the light source and the medium as a parameter.

4. 3. The recording apparatus according to claim 2, wherein the control unit determines the turning position by referring to a predetermined table using the distance between the light source and the medium as a parameter.

5. 2. The recording apparatus according to claim 1, wherein the control unit is capable of adjusting the folding position.

6. 6. The recording apparatus according to claim 5, wherein the light source has a plurality of rows of optical elements in a scanning direction, and the control unit adjusts the return position in units of the width of the optical elements.

7. A carriage control method for a recording device, comprising: controlling the operation of a carriage that is mounted with a recording head that ejects photocurable ink onto a medium and a light source that irradiates light to cure the photocurable ink ejected during a forward movement, and that is capable of reciprocating in a main scanning direction, the method comprising: acquiring an area on the medium onto which the photocurable ink has been ejected; determining a return position from the forward movement to the backward movement at a position where the irradiation range of light from the light source does not deviate from the area where the photo-curable ink is ejected; and a step of controlling the movement of the carriage at the return position.

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