Heating device, liquid ejection device, printing device

Abstract

To efficiently dry a sheet material by controlling wrinkles from generating in the sheet material.SOLUTION: A heating device includes: heat irradiation means 421 for heating a sheet material P imparted with liquid; and UV irradiation means 431 for heating the sheet material P. The heat irradiation means 421 and the UV irradiation means 431 are respectively disposed upstream and downstream in a transportation direction of the sheet material P. The heating device includes heating control means 801 for controlling switching output between the heat irradiation means 421 and the UV irradiation means 431 on the basis of a thickness of the sheet material P.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a heating device, a liquid ejecting device, and a printing device. [Background technology]

[0002] 2. Description of the Related Art Printing devices that perform printing by applying liquid to a printing target such as a sheet material include a printing device that is equipped with a heating device that heats the sheet material to which the liquid has been applied, thereby accelerating drying of the applied liquid.

[0003] Conventionally, a method is known in which water-based ink applied to a blanket cylinder from a head is irradiated with infrared rays from a first lamp to heat-dry or heat-cure it, the ink on the blanket cylinder is transferred to a printing sheet, and the ink on the printing sheet is irradiated with ultraviolet rays from a second lamp to UV-dry or UV-cure it (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5579030 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the entire sheet material is heated by infrared irradiation, if the sheet material is thin, wrinkles are likely to occur when the heated sheet material cools down. On the other hand, when the sheet material is heated by ultraviolet irradiation, if the sheet material is thick, the sheet material itself does not heat up, resulting in a shortage of heating energy, which causes problems such as a long drying time and a long transport distance required for drying.

[0006] The present invention has been made in consideration of the above problems, and has an object to suppress the occurrence of wrinkles in a sheet material and to enable efficient drying. [Means for solving the problem]

[0007] In order to solve the above problems, the heating device according to the present invention comprises: A heat irradiation means for heating the sheet material to which the liquid has been applied; an ultraviolet ray irradiation means for heating the sheet material; and a conveyor belt for conveying the sheet material. the heat irradiation means and the ultraviolet ray irradiation means are disposed adjacent to each other in a conveying direction of the sheet material, In a conveying direction of the sheet material, the heat irradiation means is disposed on an upstream side, and the ultraviolet ray irradiation means is disposed on a downstream side, the conveyor belt is disposed so as to linearly cross the heat irradiation means and the ultraviolet ray irradiation means, The heat irradiation means and the ultraviolet ray irradiation means are switched on and off based on the thickness of the sheet material. death, The control means includes: the heat irradiation means is set to a first output when the thickness of the sheet material is a first thickness, and is set to a second output greater than the first output when the thickness of the sheet material is a second thickness that is greater than the first thickness; The ultraviolet ray irradiation means is set to a third output when the thickness of the sheet material is the first thickness, and is set to a fourth output smaller than the first output when the thickness of the sheet material is the second thickness. The composition was as follows.

[0008] According to the present invention, the occurrence of wrinkles in the sheet material can be suppressed, and efficient drying can be achieved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic explanatory diagram of a printing apparatus as a liquid ejecting apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view illustrating a discharge unit of the printing apparatus. [Diagram 3] FIG. 2 is an explanatory diagram of the drum and its surroundings in the printing unit of the printing device. [Figure 4] FIG. 1 is an explanatory diagram of a heating device according to a first embodiment of the present invention. [Diagram 5] FIG. 2 is a perspective view illustrating an example of an ultraviolet ray irradiation means. [Figure 6] FIG. 2 is an explanatory diagram for explaining a first example of a thickness detection means. [Figure 7]FIG. 11 is an explanatory diagram for explaining a second example of a thickness detection means. [Figure 8] FIG. 4 is a block diagram illustrating a portion related to heating control of a drying unit. [Figure 9] 11 is an explanatory diagram illustrating an example of a relationship between the thickness of a sheet material stored in a storage means and the outputs of a heat irradiation means and an ultraviolet ray irradiation means; FIG. [Figure 10] 13 is an explanatory diagram illustrating an example of a relationship between the sheet material thickness stored in the storage means, the presence or absence of the sheet material, and the outputs of the heat irradiation means and the ultraviolet ray irradiation means; FIG. [Figure 11] FIG. 2 is an explanatory diagram of an example of an operation panel including an input unit. [Figure 12] FIG. 3 is a flow diagram illustrating an example of heating control in the first embodiment of the present invention. [Figure 13] FIG. 11 is a block diagram illustrating a portion relating to heating control in a second embodiment of the present invention. [Figure 14] FIG. 4 is a flow diagram illustrating an example of heating control in the embodiment. [Figure 15] FIG. 4 is an explanatory diagram for explaining the operation and effect of the embodiment. [Figure 16] FIG. 11 is a block diagram illustrating a portion relating to heating control according to a third embodiment of the present invention. [Figure 17] 11 is an explanatory diagram illustrating an example of a determination as to whether or not an image pattern is a pattern that is likely to cause waviness in a sheet material P. FIG. [Figure 18] An example of heating control in this embodiment will be described with reference to a flow chart. [Figure 19] FIG. 13 is a flow diagram illustrating an example of heating control in a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. A printing device as a device for discharging liquid according to a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a schematic explanatory diagram of the printing device, Fig. 2 is a plan explanatory diagram of the discharging unit of the printing device, and Fig. 3 is an explanatory diagram of the drum and the surrounding area of ​​the printing section of the printing device.

[0011] The printing apparatus 1 includes an input section 10 for inputting a sheet material P, a pre-processing section 20 which is a coating section, a printing section 30, a drying section 40, a reversing mechanism section 60, and an output section 70.

[0012] The printing device 1 applies (coats) a pretreatment liquid as a coating liquid to the sheet material P transported (supplied) from the transport section 10 in the pretreatment section 20 as necessary, and then applies the required liquid to the sheet material P in the printing section 30 to perform the required printing.

[0013] Then, after drying the liquid adhering to the sheet material P in the drying section 40, the printing device 1 discharges the sheet material P to the discharge section 70 via the inversion mechanism section 60, either as is or after printing on both sides of the sheet material P.

[0014] The loading section 10 includes an input tray 11 (lower input tray 11A, upper input tray 11B) that stores multiple sheet materials P, and a feeding device 12 (12A, 12B) that separates and sends out the sheet materials P one by one from the input tray 11, and supplies the sheet materials P to the pre-processing section 20.

[0015] The pre-treatment section 20 includes, for example, an application section 21 which is a treatment liquid application section that applies a treatment liquid having an effect of agglomerating ink and preventing show-through to the printing surface of the sheet material P.

[0016] The printing unit 30 includes a drum 31 which is a support member (rotating member) that supports the sheet material P on its circumferential surface and rotates, and a liquid ejection unit 32 which ejects liquid toward the sheet material P supported by the drum 31.

[0017] The printing section 30 includes a transfer cylinder 34 which receives the sheet material P sent from the pre-treatment section 20 and transfers the sheet material P between the drum 31, and a transfer cylinder 35 which receives the sheet material P transported by the drum 31 and transfers it to the first drying section 41.

[0018] The sheet material P transported from the pre-processing section 20 to the printing section 30 has its leading edge gripped by a gripping means (sheet gripper) provided on the transfer cylinder 34, and is transported as the transfer cylinder 34 rotates. The sheet material P transported by the transfer cylinder 34 is delivered to the drum 31 at a position opposite to the drum 31.

[0019] A gripping means (sheet gripper) is also provided on the surface of the drum 31, and the leading end of the sheet material P is gripped by the gripping means (sheet gripper). A plurality of suction holes are formed in a dispersed manner on the surface of the drum 31, and the suction means generates a suction airflow that flows inward from the required suction holes of the drum 31.

[0020] Then, the sheet material P transferred from the transfer cylinder 34 to the drum 31 has its leading edge gripped by the sheet gripper, and is adsorbed and supported on the drum 31 by the suction airflow of the suction means, and is transported as the drum 31 rotates.

[0021] The liquid discharge section 32 includes discharge units 33 (33A to 33E) which are liquid discharge means serving as liquid application means. For example, the discharge unit 33A discharges cyan (C) liquid, the discharge unit 33B discharges magenta (M) liquid, the discharge unit 33C discharges yellow (Y) liquid, and the discharge unit 33D discharges black (K) liquid. The discharge unit 33E discharges special liquids such as white and gold (silver).

[0022] 2, the ejection unit 33 has a head array 100 including a full-line head in which a plurality of liquid ejection heads (hereinafter simply referred to as "heads") 101, each having a plurality of nozzle rows in which a plurality of nozzles 111 are arranged, are arranged in a staggered pattern on a base member 103. The ejection unit 33 also has a sub-tank (liquid storage container) that stores liquid to be supplied to each head 101 of the head array 100.

[0023] The discharge operation of each discharge unit 33 of the liquid discharge section 32 is controlled by a drive signal corresponding to the printing information. When the sheet material P supported on the drum 31 passes through an area facing the liquid discharge section 32, liquid of each color is discharged from the discharge unit 33, and an image corresponding to the printing information is printed.

[0024] 3, multiple (three in this example) discharge receivers 300 are arranged at approximately equal angles on the drum 31. When performing maintenance and recovery of the head 101 of the discharge unit 33, a blank discharge operation is performed to discharge liquid (blank discharge droplets) that is not applied to the sheet material P to the discharge receiver 300. The discharge receiver 300 also receives liquid that spills over the sheet material P when performing borderless printing, for example.

[0025] Further, a thickness detection means 831 for detecting the thickness of the sheet material P is disposed upstream of the most upstream discharge unit 33A.

[0026] The drying section 40 includes a first drying section 41 and a second drying section 42.

[0027] The first drying section 41 includes a heat irradiating section 402 as a heating means such as an IR heater, and irradiates infrared rays to the sheet material P to which the liquid has been applied and which is being transported by the transport mechanism section 401, thereby heating and drying it.

[0028] The second drying section 42 is equipped with an ultraviolet ray irradiation section 403 as a heating means, and irradiates ultraviolet rays to heat and dry the sheet material P to which the liquid has been applied, which has passed through the first drying section 41 and is transported by the transport mechanism section 401.

[0029] The reversing mechanism 60 includes a reversing section 61 that reverses the sheet material P using a switchback method when performing double-sided printing on the sheet material P that has passed through the drying section 40 and has had liquid applied to one side and been dried, and a double-sided conveying section 62 that sends the reversed sheet material P back upstream of the transfer drum 34 of the printing section 30.

[0030] The discharge section 70 includes a discharge tray 71 on which a plurality of sheet materials P are stacked. The sheet materials P conveyed from the reversing mechanism section 60 are successively stacked and held on the discharge tray 71.

[0031] In this embodiment, an example is described in which the sheet material is cut sheet material, but the present invention can also be applied to devices that use continuous bodies (webs) such as continuous paper or rolled paper, and devices that use sheet materials such as wallpaper.

[0032] Next, the heating device according to the first embodiment of the present invention will be described with reference to Fig. 4. Fig. 4 is an explanatory side view of the heating device.

[0033] The heating device 400 includes a transport mechanism 401, which is a transport means, a heat irradiating section 402, and an ultraviolet ray irradiating section 403. The heating device 400 constitutes the drying section 40.

[0034] The conveying mechanism 401 has a conveying belt 411 that carries and conveys the sheet material P. The conveying belt 411 is looped around a driving roller 412 and a driven roller 413 and moves in a circular motion. In this embodiment, the conveying mechanism 401 is a mechanism that conveys the sheet material P from the printing unit 30 to the reversing mechanism 60 as shown in FIG.

[0035] The conveyor belt 411 is, for example, a belt having a plurality of openings that is sucked by a suction chamber 414 disposed inside. For example, a mesh belt or a flat belt having suction holes is used. The suction chamber 414 performs suction using a suction blower, a fan, or the like. The conveyor is not limited to a conveyor using a suction method, and may be a conveyor that conveys the sheet material P using, for example, an electrostatic adsorption method or a gripper gripping method.

[0036] The heat irradiation unit 402 has a housing 420 and a plurality of heat irradiation means 421, each of which is made up of an IR heater, arranged along the conveying direction. The heat irradiation means 421 irradiates infrared rays to heat the sheet material P conveyed by the conveying mechanism 401. The heat irradiation unit 402 includes a temperature detection means 422 that detects the temperature of the heat irradiation means 421.

[0037] The ultraviolet irradiating section 403 has a plurality of ultraviolet irradiating means 431 arranged along the conveying direction in a housing 430. The ultraviolet irradiating means 431 irradiates the sheet material P conveyed by the conveying mechanism section 401 with ultraviolet light to heat it.

[0038] In this manner, in the conveying direction of the sheet material P, the heat irradiation means 421 is disposed on the upstream side, and the ultraviolet ray irradiation means 431 is disposed on the downstream side.

[0039] Further, sheet material presence / absence detection means 832 (832A to 832C) for detecting the presence or absence of sheet material P are respectively disposed on the upstream side of heat irradiation section 402, between heat irradiation section 402 and ultraviolet ray irradiation section 403, and on the downstream side of ultraviolet ray irradiation section 403.

[0040] Next, an example of the ultraviolet ray irradiation means will be described with reference to Fig. 5. Fig. 5 is a perspective explanatory view of the example of the ultraviolet ray irradiation means.

[0041] The ultraviolet irradiation means 431 has granular UV-LED light emitting elements 433 arranged in a lattice pattern on an irradiation surface 432. Each UV-LED light emitting element 433 emits light with the same illuminance, resulting in a state in which light is emitted uniformly along the irradiation surface 432 as a whole. The ultraviolet light (UV light) used has a peak wavelength of 395 nm and a wavelength distribution with a full width at half maximum of approximately 15 nm.

[0042] By irradiating with ultraviolet light, selective heating is possible, with the effect of heating only the image areas (areas where liquid has been applied) and not excessively raising the temperature of blank areas (areas where liquid has not been applied).

[0043] The results of comparing UV-LED with IR heaters (IR lamps) were as follows:

[0044] The heating conditions (output settings of the IR lamp and UV-LED) were varied and the surface temperature of the sheet material after it passed through the drying section was measured. The temperatures of the image area and the blank area were confirmed. When the temperature of the image area rose to around 90°C, the water and solvent in the water-based ink began to evaporate and the ink began to dry.

[0045] When heating with an IR lamp, the temperature of the image area was set to 90°C, and at the same time the temperature of the blank area was 105°C. In contrast, when heating with a UV-LED, when the temperature of the image area was similarly set to 90°C, the temperature of the blank area was 45°C, approximately 60°C lower than with an IR lamp.

[0046] Due to this difference in temperature of the blank part, when heated with an IR lamp, the moisture content of the blank part dropped from 6.1% to 1.4%, whereas when heated with a UV-LED, the moisture content of the blank part dropped only from 6.1% to 2.9%. In other words, it was confirmed that by heating with ultraviolet light, the blank part can retain more moisture after drying.

[0047] Next, a different example of a thickness detection means for detecting the thickness of the sheet material P will be described with reference to Figures 6 and 7. Figures 6 and 7 are explanatory diagrams for explaining the thickness detection means.

[0048] The thickness detection means 831 of the first example shown in Fig. 6 includes a light emitting element 831A that emits light La to the sheet material P, and a light receiving element 831B that receives reflected light Lb from the sheet material P. The amount of light received by the light receiving element 831B changes when the sheet material P is thin paper Pa as shown in Fig. 6(a) and when the sheet material P is thick paper Pb as shown in Fig. 6(b). This makes it possible to detect the thickness of the sheet material P.

[0049] The thickness detection means 831 of the second example shown in Fig. 7 includes a projection means 831C that irradiates parallel light Lc parallel to the in-plane direction of the sheet material P, and a CCD light receiving element 831D that receives the parallel light Lc. As shown in Fig. 7(a), part of the parallel light Lc is blocked depending on the thickness of the sheet material P, and as shown in Fig. 7(b), the amount of light received by each CCD constituting the CCD light receiving element 831D changes. This makes it possible to detect the thickness of the sheet material P.

[0050] Next, the part related to the heating control of the drying part will be described with reference to Fig. 8. Fig. 8 is a block explanatory diagram of the part related to the heating control.

[0051] The heating control means 801 controls the output of each heat irradiation means 421 in the heat irradiation section 402 and controls the output of each ultraviolet ray irradiation means 431 in the ultraviolet ray irradiation section 403.

[0052] The storage means 802 stores relationship information between the thickness of the sheet material P and the output of the heat irradiation means 421 and the output of the ultraviolet ray irradiation means 431. The storage means 802 also stores relationship information between the detection result of the presence or absence of the sheet material P and the output of the heat irradiation means 421 and the output of the ultraviolet ray irradiation means 431.

[0053] The input means 811 is a user interface for inputting the thickness of the sheet material P.

[0054] The status display means 812 is a means for displaying various statuses.

[0055] The heating control means 801 controls to change the output of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 in accordance with the detection result of the thickness of the sheet material P by the thickness detection means 831 and the related information stored in the memory means 802 based on the thickness of the sheet material P input by the input means 811.

[0056] The heating control means 801 controls the output of the heat irradiation means 421 based on the detection result of the temperature detection means 422 .

[0057] The heating control means 801 performs control to change the outputs of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 in accordance with the related information stored in the storage means 802 based on the detection result of the sheet material presence / absence detection means 832 .

[0058] Next, an example of the relationship between the thickness of the sheet material stored in the storage means and the outputs of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 will be described with reference to the explanatory diagram of FIG.

[0059] 9, the temperature inside the unit refers to the temperature inside the heat irradiation section 402 of the first drying section 41 and the temperature inside the ultraviolet ray irradiation section 403 of the second drying section 42. The IR heater refers to the heat irradiation means 421, and the UV LED irradiation refers to the ultraviolet ray irradiation means 431.

[0060] In this example, the basis weight (thickness) of the sheet material P is 128 gms, and the thickness is divided into less than the predetermined value and greater than the predetermined value. The unit internal temperature of 150° C. is the predetermined value (predetermined temperature) for each thickness of the sheet material P, and the thickness is divided into greater than the predetermined value and less than the predetermined value. The outputs of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 are determined for each category of thickness of the sheet material P and temperature within the unit.

[0061] In this way, the outputs of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 are changed based on the thickness of the sheet material P. The change in output (output adjustment) includes OFF (0% in FIG. 9).

[0062] As a result, thick sheet material P (cardboard) that does not wrinkle due to moisture absorption can be dried by applying sufficient heat energy using heat irradiation means 421. On the other hand, thin sheet material P (thin paper) that is prone to wrinkles can be dried while suppressing the occurrence of wrinkles by using ultraviolet irradiation means 431 to dry only the portions where liquid has been applied.

[0063] In this example, for thin paper (basis weight less than 128 gsm), when the temperature inside the unit is less than 150° C., the output of the heat irradiation means 421 is set to 50%. This is to prevent the moisture in the sheet material P from evaporating, thereby suppressing the occurrence of wrinkles.

[0064] Next, an example of the relationship between the sheet material thickness and the presence or absence of a sheet material stored in the storage means and the outputs of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 will be described with reference to the explanatory diagram of FIG.

[0065] 10, the presence or absence of a sheet material refers to the detection result of the sheet material presence / absence detection means 832. The IR heater refers to the heat irradiation means 421, and the UV LED irradiation refers to the ultraviolet ray irradiation means 431.

[0066] In this example, the basis weight (thickness) of the sheet material P is set to 128 gms, and the sheets are divided into those below the predetermined value and those above the predetermined value. The thickness of each sheet material P is divided into those with and without the sheet material. The outputs of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 are determined for each category of the thickness of the sheet material P and the presence or absence of the sheet material.

[0067] In other words, when the thickness of the sheet material P is less than the predetermined thickness and the presence / absence detection means 832 detects the presence of the sheet material, the heat irradiation means 421 does not irradiate heat (output is set to 0%). On the other hand, when the thickness of the sheet material P is less than the predetermined thickness and the presence / absence detection means 832 detects the absence of the sheet material, and when the thickness of the sheet material P is equal to or greater than the predetermined thickness, the heat irradiation means 421 irradiates heat.

[0068] Here, by irradiating heat with the heat irradiation means 421 when there is no sheet material, the heat irradiation means 421 is used as an auxiliary (pre)heater. In this case, the temperature inside the unit is kept at a temperature at which the moisture in the sheet material P does not evaporate, and idling time is prevented from occurring, thereby preventing a decrease in printing speed. In this case, the output of the heat irradiation means 421 is made different when the thickness of the sheet material P is less than a predetermined thickness and when it is equal to or greater than the predetermined thickness.

[0069] In addition, when using thick paper (basis weight 128 gsm or more), the outputs of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 are set to 100%. This is because, in the case of thick paper, wrinkles do not occur even if it is dried strongly.

[0070] Next, an example of the input means will be described with reference to Fig. 11. Fig. 11 is an explanatory diagram of an example of an operation panel including the input means.

[0071] On the operation panel 900, there are arranged an input unit 811 for inputting the thickness (basis weight) of the sheet material P, a print start key 901 for instructing the start of printing, and the like.

[0072] Next, an example of heating control in this embodiment will be described with reference to the flow chart of FIG.

[0073] First, the thickness (t0) of the sheet material P is set by the input means 811, and the thickness (t0) of the sheet material P set in the heating control means 801 is input (step S1, hereinafter referred to as "S1").

[0074] Then, the user instructs the printing start by pressing the print start key 901 (S2).

[0075] Here, the heating control means 801 adjusts the output of each of the heat irradiation means 421 and the ultraviolet ray irradiation means 431 in accordance with the thickness (t0) of the sheet material P (S3).

[0076] Thereafter, printing is started (S4), the thickness (t1) of the sheet P is detected by the thickness detection means 831, and is input to the heating control means 801 (S5).

[0077] The heating control means 801 determines whether or not the difference between the input thickness (t0) of the sheet material P and the detected thickness (t1) of the sheet material P is less than a predetermined value x (t1 - t0 < x). The predetermined value x is set to, for example, 0.85 mm.

[0078] Here, if (t1 - t0 < x), the detected thickness (t1) of the sheet material P is given priority over the input thickness (t0) of the sheet material P. That is, based on the relationship information stored in the storage means 802 corresponding to the thickness (t1) of the sheet material P, the outputs of the heat irradiation means 421 and the ultraviolet irradiation means 431 are adjusted (S7). Thereafter, printing is continued (S8).

[0079] At this time, as described above, for the thick sheet material P (cardboard), sufficient thermal energy is applied using the heat irradiation means 421 for drying, and for the thin sheet material P (thin paper), generation of wrinkles is suppressed using the ultraviolet irradiation means 431 for drying. Thereby, generation of wrinkles in the sheet material can be suppressed and drying can be performed efficiently.

[0080] On the other hand, if (t1 - t0 |) x, that is, when the detected thickness (t1) of the sheet material P is thicker than the predetermined value x than the input thickness (t0) of the sheet material P, it is determined as a jam (JAM) (S9). Then, the conveyance operation of the conveyance belt 411 is stopped (S10), and the display lamp of the state display means 812 is lit (S12).

[0081] In other words, when the set value for the thickness of the sheet material P is larger than the actual measurement value (detection result of the thickness detection means 831), the drying output becomes strong and wrinkles are generated in the sheet material P, but no damage is done to the printing device. On the other hand, when the set value for the thickness of the sheet material P is smaller than the actual measurement value (detection result of the thickness detection means 831), the drying output is weak and the liquid does not dry, causing damage to the printing device, so the sheet material transport operation is stopped and the printing operation (liquid application operation) is stopped.

[0082] Next, a second embodiment of the present invention will be described with reference to Fig. 13. Fig. 13 is a block diagram illustrating a portion related to heating control in the second embodiment.

[0083] When the heat irradiation means 421 and the ultraviolet irradiation means 431 are used in combination as in the first embodiment, if an image pattern that is likely to cause waving of the sheet material P is printed on a sheet material of a predetermined thickness (for example, a thickness of about 128 gsm), using the heat irradiation means may not be able to completely suppress the waving. On the other hand, if the heat irradiation means is not used, the drying energy will be insufficient, resulting in a decrease in productivity. An example of an image pattern that is likely to cause waving is a pattern in which multiple pages of a manuscript containing a mixture of images and text, such as a magazine, are imposed.

[0084] Therefore, when the thickness of the sheet material P is a predetermined thickness, the heating control means 801 controls to switch the output of at least the heat irradiation means 421 based on the transport speed obtained from the transport mode setting information.

[0085] In this embodiment, the conveying modes include a low-speed mode in which the sheet material P is conveyed at a first speed (first conveying speed), and a high-speed mode in which the sheet material P is conveyed at a second speed (second conveying speed) that is faster than the first speed. In this embodiment, the user can manually input conveying mode setting information from an operation panel of the printing device 1 or the like to specify the conveying mode (conveying speed).

[0086] Note that the input of the conveyance mode setting information can also be performed by the input means 811. Further, the conveyance mode setting information includes not only information for setting the conveyance mode itself, but also information correlated with the conveyance mode (conveyance speed). Further, the "conveyance speed" means the sheet material conveyance linear speed (process linear speed) of the entire printing apparatus 1 (including not only drying but also printing, etc.).

[0087] And in the present embodiment, the heating control means 801 controls such that the output of the heat irradiation means 421 when the conveyance speed of the sheet material P is the first speed is made smaller (lower) than the output of the heat irradiation means 421 when the conveyance speed of the sheet material P is the second speed faster than the first speed.

[0088] Next, an example of the heating control in the present embodiment will be described with reference to the flowchart of FIG. 14. In FIG. 14, the description of the heat irradiation means 421 as an IR heater and the ultraviolet irradiation means 431 as a UVLED is the same as in the first embodiment.

[0089] When printing is started (S20), the heating control means 801 captures the thickness t1 of the sheet material P detected by the thickness detection means 831 (S21), and determines whether the thickness t1 of the sheet material P is less than a predetermined thickness A (t1 < A) (S22).

[0090] Here, when the thickness t1 of the sheet material P is less than the predetermined thickness A, the output of the heat irradiation means 421 is set to 0 to 50%, and the output of the ultraviolet irradiation means 431 is set to 100% (S23).

[0091] On the other hand, when the thickness t1 of the sheet material P is not less than the predetermined thickness A, that is, when the thickness t1 of the sheet material P is greater than or equal to the predetermined thickness A (t ≧ A), it is determined whether the thickness t1 of the sheet material P is less than a predetermined thickness B (B > A) (S24).

[0092] Here, when the thickness t1 of the sheet material P is not less than a predetermined thickness A and less than a predetermined thickness B (B > A), that is, when the thickness t1 of the sheet material P is not less than the predetermined thickness B, the output of the heat irradiation means 421 is set to 100%, and the output of the ultraviolet irradiation means 431 is set to 100% (S28).

[0093] On the other hand, when the thickness of the sheet material P is not less than the predetermined thickness A and less than the predetermined thickness B (A ≤ t1 < B), it is determined whether the conveyance mode is the low-speed mode (first speed) or the high-speed mode (second speed) (S25). In the present embodiment, as described above, the conveyance mode is set by the user.

[0094] Here, when the conveyance mode is set to the low-speed mode, the output of the heat irradiation means 421 is set to 0 to 60%, and the output of the ultraviolet irradiation means 431 is set to 70 to 100% (S26). Note that it is preferable to satisfy the combination of (output of heat irradiation means 421) / (output of ultraviolet irradiation means 431) ≤ 0.60.

[0095] When the conveyance mode is set to the high-speed mode, the output of the heat irradiation means 421 is set to 100%, and the output of the ultraviolet irradiation means 431 is set to 100% (S27).

[0096] Note that the control of the heat irradiation means 421 and the ultraviolet irradiation means 431 in steps S23, 27, and 28 can also apply the control described with reference to FIGS. 9 and 10 in the first embodiment.

[0097] Next, the operation and effect of the present embodiment will be described with reference to FIG. 15 as well. FIG. 15 is an explanatory diagram for this description.

[0098] FIG. 15 shows the results of verifying the drying property and the undulation of the sheet material P with an inkjet printer. Here, in the high-speed mode, the sheet material P was conveyed at a speed of 1270 mm / s, and in the low-speed mode, the sheet material P was conveyed at a speed of 889 mm / s. Then, an image in which photos and characters are mixed as in a magazine was printed on both sides with four pages attached, and the drying property of the image and the undulation of the blank part were evaluated.

[0099] In the high-speed mode, the IR output of the heat irradiation means 421 and the UV output of the ultraviolet ray irradiation means 431, which achieved dryness but poor waviness, were set to 100%. Based on this output, the results are shown when the IR output of the heat irradiation means 421 and the UV output of the ultraviolet ray irradiation means 431 were lowered in various combinations in the low-speed mode.

[0100] In FIG. 15(a), the points marked with "x" indicate that the drying ability was not achieved in the low speed mode (the drying was not achieved to the predetermined dry state).

[0101] From the results in FIG. 15(a), it can be seen that if the total drying energy of the IR output of the heat irradiation means 421 and the UV output of the ultraviolet ray irradiation means 431 is insufficient, the drying performance will not be achieved.

[0102] In addition, in FIG. 15(a), "R1 to R5" are ranks of waviness, and when waviness in high-speed mode is taken as the standard of R3, R1 and R2 indicate that the waviness has worsened, while R4 and R5 indicate that the waviness has improved.

[0103] From the results in FIG. 15(a), it can be seen that waviness can be improved by not reducing the UV output of the ultraviolet irradiating means 431 too much, but by significantly reducing the IR output of the heat irradiating means 421 and increasing the proportion of UV drying in the drying process.

[0104] In order to achieve both drying performance and waviness reduction in the low-speed mode, it is found that it is effective to select drying conditions in either the R4 or R5 region enclosed by the thick frame in FIG. 15(a).

[0105] FIG. 15(b) shows a list of ratios of (IR output of heat irradiation means 421 / UV output of ultraviolet irradiation means 431) under drying conditions in the low-speed mode.

[0106] In this example, it can be understood that in the low-speed mode, if the drying condition is such that the ratio (IR output of the heat irradiation means 421 / UV output of the ultraviolet irradiation means 431) is 0.60 or less, the undulation can be significantly improved compared to the high-speed mode.

[0107] As described above, when the thickness t of the sheet material P is a predetermined thickness (A ≤ t < B), at least the output of the heat irradiation means 421 is switched based on the conveyance speed of the sheet material P. At this time, the output of the heat irradiation means 421 when the conveyance speed of the sheet material P is the first speed is made smaller than the output of the heat irradiation means 421 when the conveyance speed of the sheet material P is the second speed faster than the first speed.

[0108] Thereby, for the sheet material P having a thickness of about 128 gsm, for example, when an image pattern where undulation of the sheet material P is likely to occur is printed, even if the productivity slightly decreases, the undulation can be suppressed by using the heat irradiation means. On the other hand, for an image pattern where undulation is less likely to occur originally, the productivity can be increased.

[0109] Next, a third embodiment of the present invention will be described with reference to FIG. 16. FIG. 16 is a block explanatory diagram of a part related to the heating control of the embodiment.

[0110] When the thickness of the sheet material P is a predetermined thickness, the conveyance control means 821 performs control to switch the conveyance speed of the sheet material P by the conveyance belt 411 of the conveyance mechanism unit 401 via the conveyance control means 821 based on the liquid application amount (liquid adhesion amount) of the sheet material P.

[0111] Here, the conveyance control means 821 takes in the print data and determines whether or not the variation amount of the liquid application amount for each predetermined region of the print pattern on the sheet material P exceeds a threshold value, and determines whether or not the printed image pattern is a pattern where undulation of the sheet material P is likely to occur.

[0112] When the amount of variation does not exceed the threshold and the image pattern is not likely to cause waving of the sheet material P, the transport control means 821 sets the transport mode to the high-speed mode and the transport speed of the sheet material P to a high speed. On the other hand, when the amount of variation exceeds the threshold and the image pattern is likely to cause waving of the sheet material P, the transport control means 821 sets the transport mode to the low-speed mode and the transport speed of the sheet material P to a low speed.

[0113] Next, an example of a determination as to whether or not an image pattern is a pattern that is likely to cause waviness in the sheet material P will be described with reference to Fig. 17. Fig. 17 is an explanatory diagram for the same description.

[0114] In this example, as shown in Fig. 17(b), photographs G1 to G4 are arranged on a 585 mm x 750 mm long grain (T grain) sheet material P. This sheet material P was divided into 10 areas 1 to 10 at 75 mm intervals in the grain direction, and the total amount of liquid applied to each area was calculated.

[0115] In this case, as shown in FIG. 17(a), areas 2, 3, 7, and 8 in which photographs G1 to G4 are arranged are areas where the total amount of liquid applied is large, while areas 1, 5, 9, and 10 which only have blank space or text are areas where the total amount of liquid applied is small.

[0116] In this embodiment, the amount of liquid applied is calculated from the printing data (image data), but it may also be possible to detect or count the amount of liquid droplets ejected from each head, or to calculate it by reading an image of the sheet material P.

[0117] Therefore, the (maximum-minimum of the total amount of liquid applied) for each of these regions 1 to 10 is taken as the amount of variation, and if this amount of variation exceeds a threshold S, it is determined that the image pattern is prone to waviness.

[0118] Specifically, the total liquid application amount for each of the regions 1 to 10 is normalized by the sheet material area of ​​each of the regions 1 to 10, and the liquid application amount is expressed in units of "μl / cm 2 " and the amount of variation = (maximum - minimum) is 0.30 [μl / cm 2When it exceeded the threshold value (S), it was determined as an image pattern in which undulations were likely to occur.

[0119] In this determination, when the image pattern is a pattern in which undulations of the sheet material P are likely to occur, the sheet material P is conveyed at a low speed, and the ratio of ultraviolet irradiation (UV drying) is increased for drying. On the other hand, when the printed pattern does not correspond to a pattern in which undulations of the sheet material P are likely to occur, the sheet material P is conveyed at a high speed to give priority to productivity.

[0120] Next, an example of the heating control in the present embodiment will be described with reference to the flowchart of FIG. 18.

[0121] When printing is started (S30), the heating control means 801 takes in the thickness t1 of the sheet material P detected by the thickness detection means 831 (S31), and determines whether the thickness t1 of the sheet material P is less than a predetermined thickness A (t1 < A) (S32).

[0122] Here, when the thickness t1 of the sheet material P is less than the predetermined thickness A, the output of the heat irradiation means 421 is set to 0 to 50%, and the output of the ultraviolet irradiation means 431 is set to 100% (S33).

[0123] On the other hand, when the thickness t1 of the sheet material P is not less than the predetermined thickness A, that is, when the thickness t1 of the sheet material P is greater than or equal to the predetermined thickness A (t ≦ A), it is determined whether the thickness t1 of the sheet material P is less than a predetermined thickness B (B > A) (S34).

[0124] Here, when the thickness t1 of the sheet material P is greater than or equal to the predetermined thickness A and not less than the predetermined thickness B (B > A), that is, when the thickness t1 of the sheet material P is greater than or equal to the predetermined thickness B, the output of the heat irradiation means 421 is set to 100%, and the output of the ultraviolet irradiation means 431 is set to 100% (S40).

[0125] On the other hand, when the thickness of the sheet material P is equal to or greater than a predetermined thickness A and less than a predetermined thickness B (A ≤ t1 < B), the conveyance control means 821 determines whether the maximum - minimum of the total liquid application amount exceeds a threshold value S (S35), i.e., whether (the maximum - minimum of the total liquid application amount) > S1.

[0126] Here, when (the maximum - minimum of the total liquid application amount) > S1, the conveyance control means 821 sets the conveyance mode by the conveyance mechanism unit 401 to the low - speed mode and conveys the sheet material P at the first speed (S36). Then, the heating control means 801 sets the output of the heat irradiation means 421 to 0 - 60% and the output of the ultraviolet irradiation means 431 to 70 - 100% (S37). As described above, it is preferable to satisfy the combination of (the output of the heat irradiation means 421) / (the output of the ultraviolet irradiation means 431) ≤ 0.60.

[0127] On the contrary, when (the maximum - minimum of the total liquid application amount) > S1 is not satisfied, the conveyance control means 821 sets the conveyance mode by the conveyance mechanism unit 401 to the high - speed mode and conveys the sheet material P at the second speed (S38). Then, the heating control means 801 sets the output of the heat irradiation means 421 to 100% and the output of the ultraviolet irradiation means 431 to 100% (S39).

[0128] Note that for the control of the heat irradiation means 421 and the ultraviolet irradiation means 431 in steps S23, 39, and 40, the control described in FIGS. 9 and 10 in the first embodiment can also be applied.

[0129] In this way, since the conveyance speed can be automatically set, compared with the second embodiment, the setting operation of the conveyance mode by the user becomes unnecessary.

[0130] Next, an example of the heating control in the fourth embodiment of the present invention will be described with reference to the flowchart of FIG. 19.

[0131] This embodiment combines the second embodiment and the third embodiment. Note that the step numbers are the same as those in the same parts of the third embodiment.

[0132] That is, in step S34, when the thickness of the sheet material P is equal to or greater than a predetermined thickness A and less than a predetermined thickness B (A ≤ t1 < B), step S41 is executed. In step 41, it is determined whether the conveyance mode is set to any one of a low-speed mode, a high-speed mode, and automatic setting by the user.

[0133] If the conveyance mode is set to the low-speed mode, the process proceeds to step S37. If the conveyance mode is set to the high-speed mode, the process proceeds to step S39. When the conveyance mode is instructed to be automatically set, the process proceeds to step 35. After setting the conveyance mode according to the determination result (S36 or S38), the process proceeds to step S37 or step S38.

[0134] In the present application, the liquid to be ejected only needs to have a viscosity and surface tension that can be ejected from the head, and is not particularly limited. However, it is preferably a liquid whose viscosity becomes 30 mPa·s or less at normal temperature and normal pressure, or by heating or cooling. More specifically, it includes solutions, suspensions, emulsions, etc. containing solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functional additive materials such as surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium, and edible materials such as natural pigments. These can be used, for example, in applications such as inkjet inks, surface treatment liquids, components of electronic elements and light-emitting elements, and liquids for forming electronic circuit resist patterns, and material liquids for three-dimensional modeling.

[0135] As an energy generation source for ejecting the liquid, those using piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators using electrothermal conversion elements such as heating resistors, and electrostatic actuators composed of a diaphragm and a counter electrode are included.

[0136] In addition, the "device for ejecting a liquid" includes not only a device capable of ejecting a liquid onto an object to which the liquid can adhere, but also a device for ejecting the liquid into the air or into a liquid.

[0137] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0138] For example, examples of "devices that eject liquid" include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder in order to create a three-dimensional object (a three-dimensional model).

[0139] In addition, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves and devices that create three-dimensional images.

[0140] The above-mentioned "object to which liquid can adhere" means an object to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or to which the liquid adheres and penetrates, etc. Specific examples include media such as paper, recording paper, film, cloth, and other recording media, electronic boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects to which liquid can adhere.

[0141] The material of the above-mentioned "object to which liquid can adhere" may be any material to which liquid can adhere even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics.

[0142] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object to which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, a line type device in which a liquid ejection head does not move, etc.

[0143] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0144] In the present application, the terms image formation, recording, printing, copying, printing, modeling, and the like are all synonymous. [Explanation of symbols]

[0145] 1 Printing device 10 Loading section 20 Pretreatment section 30 Printing Department 40 Drying section 41 1st drying section 42 2nd drying section 60 Reversing mechanism 70 Unloading section 400 Heating device 401 Conveyor mechanism 402 Heat irradiation part 403 Ultraviolet irradiation unit 421 Heat irradiation means 431 Ultraviolet irradiation means 801 Heating control means 831 Thickness detection means 832 Means for detecting the presence or absence of sheet material

Claims

1. A heat irradiation means for heating the sheet material to which the liquid has been applied; an ultraviolet ray irradiation means for heating the sheet material; a conveyor belt for conveying the sheet material; the heat irradiation means and the ultraviolet ray irradiation means are disposed adjacent to each other in a conveying direction of the sheet material, In a conveying direction of the sheet material, the heat irradiation means is disposed on an upstream side, and the ultraviolet ray irradiation means is disposed on a downstream side, the conveyor belt is disposed so as to linearly cross the heat irradiation means and the ultraviolet ray irradiation means, a control unit for switching the outputs of the heat irradiation unit and the ultraviolet ray irradiation unit based on a thickness of the sheet material, The control means includes: the heat irradiation means is set to a first output when the thickness of the sheet material is a first thickness, and is set to a second output greater than the first output when the thickness of the sheet material is a second thickness that is greater than the first thickness; The ultraviolet ray irradiation means is set to a third output when the thickness of the sheet material is the first thickness, and is set to a fourth output smaller than the first output when the thickness of the sheet material is the second thickness. A heating device characterized by:

2. A thickness detection means is provided for detecting the thickness of the sheet material.

2. The heating device according to claim 1 .

3. A means for inputting the thickness of the sheet material is provided.

2. The heating device according to claim 1 .

4. a thickness detection means for detecting a thickness of the sheet material; and a means for inputting the thickness of the sheet material.

2. The heating device according to claim 1 .

5. The control means compares the input thickness with the detected thickness, and when the input thickness differs from the detected thickness, controls based on the detected thickness.

5. The heating device according to claim 4.

6. When the difference between the input thickness and the detected thickness is equal to or greater than a predetermined value, at least one of an operation of conveying the sheet material and an operation of applying liquid to the sheet material is stopped.

6. The heating device according to claim 4 or 5.

7. When the thickness of the sheet material is a predetermined thickness, the output of the heat irradiation means is switched based on the conveying speed of the sheet material.

7. The heating device according to claim 1, wherein the heating device is a heater.

8. The output of the heat irradiation means when the conveying speed of the sheet material is a first speed is made smaller than the output of the heat irradiation means when the conveying speed of the sheet material is a second speed that is faster than the first speed.

8. The heating device according to claim 7.

9. A means for switching the conveying speed of the sheet material based on the amount of liquid applied to the sheet material is provided.

9. The heating device according to claim 7 or 8.

10. A liquid applying means for applying a liquid to the sheet material; and a heating device for heating the sheet material according to any one of claims 1 to 9. A liquid ejection device comprising:

11. A liquid applying means for applying a liquid to the sheet material; and a heating device for heating the sheet material according to any one of claims 1 to 9. A printing device comprising:

Images