JP2012131103A - Recorder, control device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently obtain a bleeding prevention effect by a pre-treatment liquid.SOLUTION: Two pre-coat heads 41 and 42 are provided at further upstream side than an ink jet head 10 in the direction of conveyance, and UV emitting devices 62 and 63 are provided at further downstream side than the respective heads 41 and 42 in the direction of the conveyance. The pre-treatment liquid is applied to paper P two times by the two pre-coat heads 41 and 42. Also, the illuminance of an ultraviolet ray emitted from the UV emitting device 62 corresponding to the head 41 on the upstream side is made larger than the illuminance of an ultraviolet ray emitted from the UV emitting device 63 corresponding to the head 42 on the downstream side.

Description

  The present invention relates to a recording apparatus that performs recording using a liquid that is cured by ultraviolet irradiation, a control apparatus that controls the recording apparatus, and a program.

  In a recording apparatus, a technique is known in which recording is performed using a liquid (UV ink or the like) that is cured by irradiation with ultraviolet rays. For example, an image forming apparatus 10 (recording apparatus) described in Patent Document 1 is disposed on the downstream side in the sheet transport direction of each head with inkjet heads 12K, 12M, 12C, and 12Y (recording heads) that discharge UV ink (recording liquid). The four light sources 16A, 16B, 16C, 18 (ultraviolet irradiation unit) and the like. In Patent Document 1, in order to prevent the recording liquid from bleeding into the recording medium, an ultraviolet irradiation unit is disposed immediately downstream in the transport direction of each head.

Japanese Patent Laying-Open No. 2005-280346 (particularly FIG. 1)

  However, even with the configuration as disclosed in Patent Document 1, bleeding may not be sufficiently prevented depending on the type of the recording medium. For example, if the recording medium is processed to prevent penetration of a resin film or recording liquid, bleeding is unlikely to occur. However, in the case of plain paper (paper that has not been processed in particular), The recording liquid easily permeates, and bleeding cannot be sufficiently prevented.

Therefore, a pretreatment liquid (a liquid having a function of preventing the recording liquid from bleeding into the recording medium) is ejected in advance on the recording liquid landing area of the recording medium to form a layer made of the pretreatment liquid. Conceivable. In this case, since the layer made of the pretreatment liquid exists in the surface layer portion of the recording medium, the recording liquid overlapping therewith remains in the surface layer portion, and an image having a desired quality can be obtained.
However, if the pretreatment liquid also penetrates into the recording medium and the backflow of the pretreatment liquid occurs (a phenomenon in which the liquid that has landed on the surface of the recording medium penetrates the recording medium layer and oozes out to the back surface), the pretreatment liquid The amount of the pretreatment liquid remaining on the surface layer portion of the recording medium is small relative to the liquid discharge amount, and, for example, blurring occurs, making it impossible to obtain desired image quality.
On the other hand, if the discharge amount of the pretreatment liquid is reduced to prevent the back-through and the like, the amount of the pretreatment liquid becomes insufficient, and in this case as well, the effect of preventing bleeding by the pretreatment liquid cannot be obtained sufficiently.

  An object of the present invention is to provide a recording apparatus, a control apparatus, and a program capable of sufficiently obtaining a bleeding prevention effect by a pretreatment liquid.

  In order to achieve the above object, according to a first aspect of the present invention, a transport unit that transports a recording medium in a transport direction, a recording head that discharges a recording liquid that is cured by irradiation of ultraviolet rays onto the recording medium, A plurality of pretreatment heads that discharge a pretreatment liquid that is cured by irradiation of ultraviolet rays onto the recording medium upstream of the recording head in the transport direction, the downstream pretreatment head and the downstream pretreatment A plurality of pre-processing heads including an upstream pre-processing head disposed upstream of the head in the transport direction, and a first unit that irradiates the recording medium with ultraviolet rays downstream of the recording head in the transport direction. A second ultraviolet ray that irradiates the recording medium with ultraviolet rays between the one ultraviolet irradiation unit and the upstream preprocessing head and the downstream preprocessing head in the transport direction; A third ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays between the irradiation unit, the downstream preprocessing head and the recording head with respect to the conveyance direction, the conveyance unit, the recording head, and the front A control unit that controls the processing head, the first ultraviolet irradiation unit, the second ultraviolet irradiation unit, and the third ultraviolet irradiation unit, and the control unit is irradiated from the second ultraviolet irradiation unit. A recording apparatus is provided, wherein the second ultraviolet irradiation unit and the third ultraviolet irradiation unit are controlled so that the illuminance of ultraviolet rays is greater than the illuminance of ultraviolet rays emitted from the third ultraviolet irradiation unit. Is done.

  According to a second aspect of the present invention, a transport unit that transports a recording medium in a transport direction, a recording head that discharges a recording liquid that is cured by irradiation of ultraviolet rays onto the recording medium, and the transport direction from the recording head. A plurality of pretreatment heads that discharge a pretreatment liquid that is cured by irradiation of ultraviolet rays onto the recording medium on the upstream side, upstream of the downstream pretreatment head and the downstream pretreatment head in the transport direction; A plurality of preprocessing heads including an upstream preprocessing head disposed on the side, a first ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays on the downstream side in the transport direction from the recording head, and A second ultraviolet irradiation unit for irradiating the recording medium with ultraviolet rays between the upstream preprocessing head and the downstream preprocessing head with respect to the conveyance direction; A control device used in a recording apparatus including a third ultraviolet irradiation unit that irradiates the recording medium with ultraviolet light between the downstream pre-processing head and the recording head, Controlling the second ultraviolet irradiation unit and the third ultraviolet irradiation unit so that the illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit is larger than the illuminance of ultraviolet rays irradiated from the third ultraviolet irradiation unit. A control device is provided.

  According to a third aspect of the present invention, a transport unit that transports a recording medium in the transport direction, a recording head that discharges a recording liquid that is cured by irradiation of ultraviolet rays onto the recording medium, and the transport direction from the recording head. A plurality of pretreatment heads that discharge a pretreatment liquid that is cured by irradiation of ultraviolet rays onto the recording medium on the upstream side, upstream of the downstream pretreatment head and the downstream pretreatment head in the transport direction; A plurality of preprocessing heads including an upstream preprocessing head disposed on the side, a first ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays on the downstream side in the transport direction from the recording head, and A second ultraviolet irradiation unit for irradiating the recording medium with ultraviolet rays between the upstream preprocessing head and the downstream preprocessing head with respect to the conveyance direction; Then, a recording apparatus including a third ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays is irradiated from the second ultraviolet irradiation unit between the downstream pretreatment head and the recording head. It functions as a control means for controlling the second ultraviolet irradiation unit and the third ultraviolet irradiation unit so that the ultraviolet irradiation intensity becomes larger than the ultraviolet irradiation intensity irradiated from the third ultraviolet irradiation unit. A program is provided.

According to the present invention, the pretreatment liquid is applied to the recording medium in a plurality of times by a plurality of pretreatment heads, and the illuminance of ultraviolet rays irradiated from the second ultraviolet irradiation unit corresponding to the upstream pretreatment head is set. The illuminance of the ultraviolet rays irradiated from the third ultraviolet irradiation unit corresponding to the downstream preprocessing head is set larger.
In this case, since the pretreatment liquid discharged from the upstream pretreatment head is quickly cured by ultraviolet rays having a large illuminance, the pretreatment liquid remains on the surface layer portion of the recording medium without penetrating into the recording medium so as to cause back-through. As a result, a thinly spread lower layer is formed on the surface layer portion of the recording medium. Thereafter, the pretreatment liquid discharged from the downstream pretreatment head hardly penetrates into the recording medium because the lower layer already exists in the recording medium (permeation is suppressed by the lower layer), and the surface direction of the recording medium Try to spread. Thereby, an upper layer without any gaps is uniformly formed on the lower layer.
That is, with the configuration as described above, a layer made of the pretreatment liquid can be formed on the surface layer portion of the recording medium, and the pretreatment liquid can be applied to a desired region of the recording medium. Therefore, the effect of preventing bleeding by the pretreatment liquid can be sufficiently obtained. Further, since it is not necessary to reduce the discharge amount of the pretreatment liquid in order to prevent the back-through and the like, the problem that the effect of preventing bleeding cannot be sufficiently obtained due to the insufficient amount of the pretreatment liquid is also suppressed. .

1 is a schematic side view showing an internal structure of an ink jet printer according to an embodiment of a recording apparatus of the present invention. It is a top view which shows the flow path unit and actuator unit of the head contained in the printer of FIG. FIG. 3 is an enlarged view showing a region III surrounded by an alternate long and short dash line in FIG. 2. FIG. 4 is a partial cross-sectional view taken along line IV-IV in FIG. 3. It is a longitudinal cross-sectional view of a head. FIG. 2 is a block diagram illustrating an electrical configuration of a printer. It is a graph which shows the electric potential change which the drive signal used for gradation control instruct | indicates. FIG. 4 is a conceptual diagram illustrating a state of pretreatment liquid and ink ejected on a sheet in a photo formation mode.

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

  First, an overall configuration of an ink jet printer 1 according to an embodiment of a recording apparatus of the present invention will be described with reference to FIG.

  The printer 1 has a rectangular parallelepiped casing 1a. A paper discharge unit 31 is provided on the top of the casing 1a. The internal space of the housing 1a can be divided into spaces A, B, and C in order from the top. In the space B, the paper feeding unit 1b is arranged. In the spaces A and B, a paper transport path from the paper feed unit 1b to the paper discharge unit 31 is formed.

  In the space A, two precoat heads 41, 42, one inkjet head 10, three UV irradiators 61, 62, 63, a transport unit 21, a guide unit, a control device 1p, and the like are arranged.

  The conveyance unit 21 includes belt rollers 6 and 7, an endless conveyance belt 8 wound between the rollers 6 and 7, a nip roller 4 and a separation plate 5 disposed outside the conveyance belt 8, and an inside of the conveyance belt 8. It has the platen 9 etc. which were arrange | positioned. The belt roller 7 is a drive roller, and is rotated by the drive of the transport motor 121 (see FIG. 6), and rotates clockwise in FIG. As the belt roller 7 rotates, the conveyor belt 8 travels in the direction of the thick arrow in FIG. The belt roller 6 is a driven roller and rotates clockwise in FIG. 1 as the transport belt 8 travels. The nip roller 4 is disposed to face the belt roller 6 and presses the sheet P supplied from the upstream guide portion (described later) against the outer peripheral surface 8 a of the transport belt 8. The peeling plate 5 is disposed so as to face the belt roller 7, and peels the paper P from the outer peripheral surface 8 a and guides it to the downstream guide portion (described later). The platen 9 is disposed so as to face the three heads 10, 41, 42, and supports the upper loop of the conveyor belt 8 from the inside. As a result, a predetermined gap suitable for recording is formed between the outer peripheral surface 8 a and the lower surfaces of the heads 10, 41, 42.

  Each head 10, 41, 42 is a line type head having a substantially rectangular parallelepiped shape that is long in the main scanning direction. The lower surface of each head 10, 41, 42 is a discharge surface in which a large number of discharge ports (see the discharge ports 14 a of the head 10 shown in FIGS. 3 and 4) are opened. During recording (image formation), black UV ink (ink cured by irradiation of ultraviolet rays) is discharged from the lower surface (discharge surface 10a) of the head 10. Further, depending on the situation, a pretreatment liquid that is cured by irradiation of ultraviolet rays is discharged from the lower surfaces of the precoat heads 41 and 42 onto the paper P before ink landing.

The pretreatment liquid refers to a liquid having at least an action for preventing ink from spreading on the paper P, and other actions (an action for improving the density, color developability, quick drying property, etc. of ink landed on the paper P, after ink landing) And the like to further suppress wrinkling and curling of the paper P.
The material of the pretreatment liquid can be appropriately selected from a liquid containing a polyvalent metal salt such as a cationic polymer or a magnesium salt.
The pretreatment liquid is preferably transparent from the viewpoint of recording quality.

  The UV irradiators 61, 62, and 63 are provided for the heads 10, 41, and 42, respectively. The transport direction of the paper P by the transport unit 21 (thick arrows in FIG. Direction (hereinafter simply referred to as “conveying direction”). The UV irradiators 61, 62, and 63 have the same configuration, are long in the main scanning direction, and have a substantially rectangular parallelepiped outer shape, similar to the head 10. A plurality of light sources (for example, a halogen lamp, a mercury lamp, a metal halide lamp, an LED element, and an LD element) arranged in the main scanning direction are provided on the lower surfaces of the UV irradiators 61, 62, and 63. During recording (image formation), ultraviolet rays are irradiated from the UV irradiators 61, 62, and 63, and the liquid (ink or pretreatment liquid that adheres to the paper P due to the irradiation). Are generally cured and fixed.

  The heads 10, 41, 42 and the UV irradiators 61, 62, 63 are the precoat head 41, UV irradiator 62, precoat head 42, UV irradiator 63, inkjet head 10, and UV irradiator 61 from the upstream side in the transport direction. In order, they are arranged at a predetermined pitch in the sub-scanning direction, and are supported by the housing 1 a via the frame 3.

  The guide unit includes an upstream guide portion and a downstream guide portion disposed with the transport unit 21 interposed therebetween. The upstream guide portion has two guides 27 a and 27 b and a pair of feed rollers 26. The upstream guide unit connects the paper feeding unit 1 b and the transport unit 21. The downstream guide portion has two guides 29 a and 29 b and two pairs of feed rollers 28. The downstream guide unit connects the transport unit 21 and the paper discharge unit 31.

  The paper feed unit 1 b includes a paper feed tray 23 and a paper feed roller 25. Among these, the paper feed tray 23 is detachable from the housing 1a. The paper feed tray 23 is a box that opens upward, and can store a plurality of types of paper P. The paper feed roller 25 feeds the uppermost paper P in the paper feed tray 23 and supplies it to the upstream guide unit.

The control device 1p controls the operation of each part of the printer 1 and controls the operation of the entire printer 1.
The control device 1p performs a preparatory operation for recording, and supplies and transports the paper P so that an image is formed on the paper P based on image data supplied from an external device (such as a PC connected to the printer 1). Control the discharge operation, the liquid discharge operation synchronized with the conveyance of the paper P, and the ultraviolet irradiation.

Based on the recording command received from the external device, the control device 1p feeds the paper feed motor 125 for the paper feed roller 25 (see FIG. 6), the feed motor 127 for the feed roller of each guide unit (see FIG. 6), and transports. The motor 121 (see FIG. 6), the heads 10, 41, and 42, the UV irradiators 61, 62, and 63 are driven.
The paper P sent out from the paper feed tray 23 is supplied to the transport unit 21 by the feed roller 26. When the paper P passes under the heads 10, 41, and 42 in the sub-scanning direction, ink (and pretreatment liquid from the precoat heads 41 and 42 depending on the situation) is ejected from the head 10, and further, UV. A color image is formed on the paper P when the liquid is cured by irradiating ultraviolet rays from the irradiators 61, 62, and 63. The liquid ejection operation and the ultraviolet irradiation are performed based on a detection signal from the paper sensor 32 that detects the leading edge of the paper P. The paper P is then peeled off by the peeling plate 5 and conveyed upward by the two feed rollers 28. Further, the paper P is discharged from the upper opening 30 to the paper discharge unit 31.

  Here, the sub-scanning direction is a direction parallel to the transport direction, and the main scanning direction is a direction parallel to the horizontal plane and orthogonal to the sub-scanning direction.

In the space C, the cartridge unit 1c is detachably attached to the housing 1a. The cartridge unit 1 c includes a tray 35 and three cartridges 38 and 39 accommodated in the tray 35 side by side. The cartridge 38 stores black UV ink, and the cartridge 39 stores pretreatment liquid, which communicate with the corresponding heads 10, 41, 42 via tubes (not shown). The liquid in the cartridges 38, 39 is supplied to the heads 10, 41, 42 as appropriate.
Note that the pretreatment liquid in the two cartridges 39 (that is, the pretreatment liquid discharged from the two precoat heads 41 and 42) may have the same composition.

Next, the configuration of the heads 10, 41, 42 will be described in more detail.
The heads 10, 41, and 42 have the same configuration except that they have different resolutions (the inkjet head 10 has a resolution of 600 dpi (dots per inch), the precoat head 41 has a resolution of 1200 dpi, and the precoat head 42 has a resolution of 300 dpi). Therefore, hereinafter, the configuration of the inkjet head 10 will be described with reference to FIGS. In FIG. 3, the pressure chamber 16 and the aperture 15 which are located below the actuator unit 17 and should be indicated by dotted lines are indicated by solid lines.

  As shown in FIG. 5, the head 10 is a stacked body in which the flow path unit 12, the actuator unit 17, the reservoir unit 11, and the substrate 64 are stacked. Among these, the actuator unit 17, the reservoir unit 11, and the substrate 64 are accommodated in a space formed by the upper surface 12 x of the flow path unit 12 and the cover 65. Within the space, an FPC (flat flexible substrate) 50 electrically connects the actuator unit 17 and the substrate 64. A driver IC 57 is mounted in the middle of the FPC 50.

  The cover 65 includes a top cover 65a and a side cover 65b as shown in FIG. The cover 65 is a box that opens downward, and is fixed to the upper surface 12 x of the flow path unit 12. The side cover 65b is made of an aluminum plate and also functions as a heat radiating plate. The driver IC 57 contacts the inner surface of the side cover 65b and is thermally coupled to the cover 65b.

  The reservoir unit 11 is a laminated body in which four metal plates 11a to 11d each having a through hole and a recess are bonded to each other. Convex portions are formed on the surface of the plate 11d. A channel including the reservoir 72 is formed inside the reservoir unit 11. One end of the flow path is connected to the cartridge 38 (the cartridge 39 in the case of the precoat heads 41 and 42) via a tube or the like, and the other end is opened on the lower surface of the reservoir unit 11. In the plate 11d, an outflow channel (a partial channel on the other end side of the channel of the reservoir unit 11) 73 communicating with the reservoir 72 is formed. The flow path 73 opens at the tip end surface of the convex portion of the plate 11d (that is, the joint surface with the upper surface 12x).

  The flow path unit 12 is a laminated body in which nine rectangular metal plates 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h, and 12i (see FIG. 4) having substantially the same size are bonded to each other. As shown in FIG. 2, an opening 12 y that faces the opening 73 a of the outflow channel 73 is formed on the upper surface 12 x. Inside the flow path unit 12, a flow path connecting from the opening 12y to the discharge port 14a is formed. 2, 3 and 4, the flow path includes a manifold flow path 13 having an opening 12y at one end, a sub-manifold flow path 13a branched from the manifold flow path 13, and a sub-manifold flow path 13a. The individual flow path 14 from the outlet to the discharge port 14a through the pressure chamber 16 is included.

  The manifold channel 13 and the sub-manifold channel 13a are channels common to the plurality of discharge ports 14a, as shown in FIGS. The individual flow path 14 is formed for each discharge port 14a, and as shown in FIG. 4, includes an aperture 15 that is a throttle for flow path resistance adjustment, and a pressure chamber 16 that opens to the upper surface 12x. As shown in FIG. 3, each of the pressure chambers 16 has a substantially rhombus shape and is arranged in a matrix. The pressure chambers 16 gather to occupy a substantially trapezoidal region in plan view, and constitute a total of eight pressure chamber groups 16G. Similarly to the pressure chambers 16, the discharge ports 14 a opened in the discharge surface 10 a are arranged in a matrix, thereby constituting a total of eight discharge port groups 14 G occupying a substantially trapezoidal region in plan view. The ejection port group 14G and the pressure chamber group 16G are arranged in two rows in a staggered pattern in the main scanning direction on the ejection surface 10a and the upper surface 12x, respectively.

As shown in FIG. 2, each actuator unit 17 has a trapezoidal planar shape, and is disposed on the trapezoidal region of the pressure chamber group 16G. In any actuator unit 17, the lower bottom portion of the trapezoid is close to the end of the flow path unit 12 in the sub-scanning direction. The actuator unit 17 is disposed in a gap created by the reservoir unit 11 and the flow path unit 12 while avoiding the convex portion on the lower surface of the reservoir unit 11.
Although not shown, each actuator unit 17 is a laminated body in which a diaphragm, a common electrode, a piezoelectric layer, and an individual electrode are sequentially laminated. Among the above members, the piezoelectric layer, the diaphragm, and the common electrode have a trapezoidal shape having a size that defines the outer shape of the actuator unit 17. The individual electrode is disposed on the upper surface of the piezoelectric layer so as to face each pressure chamber 16 and has a substantially similar shape to the pressure chamber 16. The same number of individual electrodes as the pressure chambers 16 in the corresponding pressure chamber group 16G are formed. The diaphragm is disposed between the common electrode and the flow path unit 12. The portions facing the individual electrodes of the actuator unit 17 function as independent piezoelectric actuators.

  The FPC 50 is provided for each actuator unit 17 and has wiring corresponding to each electrode of the actuator unit 17. Each wiring is connected to the output terminal of the driver IC 57. The FPC 50 transmits various drive signals adjusted by the substrate 64 to the driver IC 57 under the control of the control device 1p (see FIG. 1), and transmits the drive signals generated by the driver IC 57 to the actuator unit 17.

  Next, the electrical configuration of the printer 1 will be described with reference to FIG.

  As shown in FIG. 6, in addition to a CPU (Central Processing Unit) 101 that is an arithmetic processing unit, the control device 1p includes a ROM (Read Only Memory) 102, a RAM (Random Access Memory: including a nonvolatile RAM) 103, An ASIC (Application Specific Integrated Circuit) 104, an I / F (Interface) 105, an I / O (Input / Output Port) 106, and the like are included. The ROM 102 stores programs executed by the CPU 101, various fixed data (for example, data relating to four types of drive signals for gradation control described later), and the like. The RAM 103 temporarily stores data necessary for program execution. In the ASIC 104, rewriting and rearranging of image data (for example, signal processing and image processing) are performed. The I / F 105 performs data transmission / reception with an external device. The I / O 106 inputs / outputs detection signals of various sensors.

  The control device 1p is connected to the motors 121, 125, 127, the paper sensor 32, the control boards of the heads 10, 41, 42, the UV irradiators 61, 62, 63, and the like. The control device 1p controls the overall operation of the printer 1 by various functional units constructed by the program. Examples of the functional unit include a motor driving unit that controls the motors 121, 125, and 127, a head driving unit that controls the heads 10, 41, and 42, a light source driving unit that controls the UV irradiators 61, 62, and 63, and the like. Is included.

  Next, the gradation control of each head 10, 41, 42 will be described with reference to FIG.

  In the present embodiment, the number of gradations is 4, and four types of drive signals corresponding to zero (no discharge), small, medium, and large amounts of liquid forming one pixel are stored in the ROM 102. . Each drive signal changes the potential of the individual electrode with respect to the common electrode as shown by a thick line in FIG. The common electrode is always maintained at a low level (ground potential: 0 V).

  In the present embodiment, a so-called “pulling type” in which the liquid is supplied into the pressure chamber 16 before the liquid is discharged is employed as the actuator driving method. Specifically, before the control device 1p receives the recording command, in the actuator unit 17, all the individual electrodes are held at a high level (for example, 15V), and the common electrodes are held at a low level (ground potential: 0V). At this time, all the actuators of the actuator unit 17 are deformed in a convex state toward the pressure chamber 16. When the recording command is received, the control device 1p selects the drive signal based on the image data, and the voltage of the individual electrode is set so that a potential difference based on the drive signal is formed between the individual electrode and the common electrode. Start application.

  For example, when the amount of liquid is zero, the potential of the individual electrode remains at a high level. At this time, the actuator maintains a convex state toward the pressure chamber 16, and no liquid is discharged. When the amount of liquid is small, the potential of the individual electrode is changed once (change from high level to low level and then back again to high level). When the potential of the individual electrode becomes the same as the potential of the common electrode, the convex state changes to a state parallel to the ejection surface 10a (see FIG. 4), and the volume of the pressure chamber 16 increases. Along with this, liquid supply from the sub manifold channel 13a to the pressure chamber 16 is started. Thereafter, when the replenishing liquid reaches the pressure chamber 16, the potential of the individual electrode returns from the low level to the high level again. At this time, the actuator returns from the parallel state to the convex state, and the volume of the pressure chamber 16 decreases. Accordingly, pressure is applied to the liquid in the pressure chamber 16 and one drop of liquid is ejected.

  A series of operations including liquid replenishment into the pressure chamber 16 and liquid discharge from the discharge port 14a as described above is a pulse (a rectangular and pulse-like potential from the fall of the potential through the time width to the rise). This is done by the number of (changing parts). When the amount of liquid is small, medium, or large, the number of pulses is 1, 2, 3, respectively, and the above series of operations is performed 1, 2, 3 times, and 1, 2, and 3 drops of liquid are ejected. Is done. The discharged 1-3 drops of liquid form one pixel on the paper P. The size of pixels (dots) formed on the paper P is determined according to the number of ejected droplets.

  Note that the potential change shown in FIG. 7 is within one recording cycle (the time required for the paper P to move relative to the head 10 by a unit distance corresponding to the resolution of the image recorded on the paper P). . In the horizontal axis of FIG. 7, t0 means the start time of the recording cycle, and t1 means the end time of the recording cycle. The time width of the pulse is equal to AL (Acoustic Length: one-way propagation time length of the pressure wave in the individual flow path 14).

The control device 1p performs the gradation control as described above for each head 10, 41, 42 during recording.
Specifically, the control device 1p determines the number (total amount) of ink droplets ejected from the head 10 in units of pixels (that is, to form one dot) based on the image data included in the recording command. To do. Further, the control device 1p determines whether or not the heads 41 and 42 are driven according to the type of the paper P or the like. When the control device 1p drives the heads 41 and 42, the recording mode is a character formation mode (a mode for forming a line image such as letters, numbers, symbols) or a photo formation mode (a mode for forming an image such as a photograph or a painting). ), The number (total amount) of pretreatment droplets ejected from the heads 41 and 42 is determined in pixel units. That is, in the character forming mode, the control device 1p has the same number of droplets (total amount) ejected from the head 42 as the number (total amount) of droplets ejected from the head 41, and from the head 42. The transport unit 21 and the heads 41 and 42 are controlled so that the ejected droplets overlap the droplets ejected from the head 41 on the paper P. In the photo formation mode, the control device 1p has a larger number of droplets (total amount) ejected from the head 42 than a number (total amount) of droplets ejected from the head 41, and is ejected from the head 42. The transport unit 21 and the heads 41 and 42 are controlled so that the droplets overlap the droplets ejected from the head 41 on the paper P.

  Further, when driving the heads 41 and 42 at the time of recording, the control device 1p is configured so that the illuminance of ultraviolet rays emitted from the UV irradiator 62 is larger than the illuminance of ultraviolet rays emitted from the UV irradiator 63. The irradiators 62 and 63 are controlled.

As described above, according to the printer 1, the control device 1p, and the program according to the present embodiment, the pretreatment liquid is applied to the paper P twice by the two precoat heads 41 and 42, and The illuminance of ultraviolet rays emitted from the UV irradiator 62 corresponding to the upstream head 41 is made larger than the illuminance of ultraviolet rays emitted from the UV irradiator 63 corresponding to the downstream head 42.
In this case, as shown in FIG. 8, since the pretreatment liquid 41x discharged from the precoat head 41 is quickly cured by ultraviolet rays having a large illuminance, the paper P does not penetrate into the paper P so as to cause a back-through. It stays on the surface layer part. As a result, a thinly spread lower layer is formed on the surface layer portion of the paper P. Thereafter, the pretreatment liquid 42x discharged from the precoat head 42 does not easily penetrate into the paper P because the lower layer already exists in the paper P (the permeation is suppressed by the lower layer), and is in the surface direction of the paper P. Try to spread. Thereby, an upper layer without any gaps is uniformly formed on the lower layer.
That is, with the above-described configuration, a layer made of the pretreatment liquid can be formed on the surface layer portion of the paper P, and the pretreatment liquid can be applied to a desired region of the paper P. Therefore, it is possible to sufficiently obtain the effect of preventing bleeding due to the pretreatment liquid (that is, the effect of preventing the ink 10x that has landed on the portion of the paper P to which the pretreatment liquids 41x and 42x have been applied) from spreading on the paper P. Further, since it is not necessary to reduce the discharge amount of the pretreatment liquid in order to prevent the back-through and the like, the problem that the effect of preventing bleeding cannot be sufficiently obtained due to the insufficient amount of the pretreatment liquid is also suppressed. .

In the character forming mode, the control device 1p has the same amount of liquid droplets discharged from the head 42 as the total amount of liquid droplets discharged from the head 41 in units of pixels, and the liquid discharged from the head 42. The transport unit 21 and the heads 41 and 42 are controlled so that the droplets overlap the droplets ejected from the head 41 on the paper P. At this time, the sizes of dots formed by the pretreatment liquid discharged from both heads 41 and 42 are the same. In the photo formation mode, the control device 1p is configured such that the total amount of droplets ejected from the head 42 is larger than the total amount of droplets ejected from the head 41 in units of pixels, as shown in FIG. The transport unit 21 and the heads 41 and 42 are controlled so that the liquid droplets ejected from 42 overlap the liquid droplets ejected from the head 41 on the paper P. At this time, the size of the dots 42 x formed by the pretreatment liquid discharged from the head 42 is larger than the size of the dots 41 x formed by the pretreatment liquid discharged from the head 41.
Thus, by changing the total amount of droplets according to each mode, it is possible to apply a pretreatment liquid suitable for an image to be formed. Thereby, the bleeding prevention effect by the pretreatment liquid can be efficiently obtained according to each mode.
In particular, in the case of the photographic formation mode, the above effect (consisting of the pretreatment liquid) is caused by the small dots 41x by the small amount of pretreatment liquid discharged from the head 41 and the large dots 42x by the large amount of pretreatment liquid discharged from the head 42. The effect that the layer can be formed on the surface layer portion of the paper P) can be obtained more reliably. Therefore, it is possible to clearly form an image such as a photograph or a picture without bleeding.

  The resolution of the precoat head 41 (= 1200 dp) is higher than the resolution of the precoat head 42 (= 300 dp). As a result, the above-described effect (particularly the effect that a layer made of the pretreatment liquid can be formed on the surface layer portion of the paper P in the case of the photo formation mode) can be obtained more reliably.

  The resolution (= 1200 dp) of the precoat head 41 is higher than the resolution (= 600 dp) of the inkjet head 10. As a result, the above-described effect (particularly the effect that a layer made of the pretreatment liquid can be formed on the surface layer portion of the paper P in the case of the photo formation mode) can be obtained more reliably.

The resolution (= 300 dp) of the precoat head 42 is lower than the resolution (= 600 dp) of the inkjet head 10.
Increasing the resolution of the precoat head 42 increases the product cost. However, in the present embodiment, the above-described effect (e.g., an effect that a layer made of the pretreatment liquid can be formed on the surface layer portion of the paper P in the case of the photo formation mode) can be achieved without increasing the resolution of the precoat head 42. Obtainable. That is, it is possible to obtain the effect of preventing bleeding by the pretreatment liquid while reducing the product cost.

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

  The recording device may include any number of recording heads. When a plurality of recording heads are included, the ultraviolet irradiation unit may be provided on the downstream side in the transport direction of at least one recording head, and may not be provided on the downstream side in the transport direction of each recording head.

  The recording apparatus may include three or more pretreatment heads.

  In the present invention, the “recording liquid” refers to a liquid that directly contributes to image formation. The “pretreatment liquid” refers to a liquid having at least an action of preventing the recording liquid from bleeding into the recording medium.

The resolution of each head is not limited to that described above, and can be arbitrarily changed.
Although the heads having different resolutions are used in the above-described embodiment, the size and arrangement density (resolution) of the dots may be adjusted by using the heads having the same resolution and selecting an ejection port from which droplets are ejected. . For example, when three heads with a resolution of 1200 dpi are used, the upstream pre-processing head is driven as it is at 1200 dpi, the downstream pre-processing head is selectively driven so that dots are formed at 300 dpi, and the recording head is The ejection port is selectively driven so that dots are formed at 600 dpi. At this time, the number of droplets ejected from each head also changes in accordance with the size of the dots formed by each head.

  It is not necessary to change the number (total amount) of droplets ejected from each pretreatment liquid head in accordance with the recording mode.

  The present invention can be applied to both a line type and a serial type, and is not limited to a printer, and can also be applied to a facsimile, a copier, and the like. Furthermore, liquids other than ink may be ejected.

  The recording medium is not limited to the paper P, and may be various recording media.

  The conveyance unit is not limited to a pair of rollers that are spaced apart from each other and an endless conveyance belt wound around the rollers. For example, the conveyance unit may include a pair of a platen and a feed roller.

1 Inkjet printer (recording device)
1p control device (control means)
8 Conveyor belt (conveyor)
10 Inkjet head (recording head)
41 Precoat head (upstream pretreatment head)
42 Precoat head (downstream pretreatment head)
61 UV irradiator (first UV irradiation unit)
62 UV irradiator (second ultraviolet irradiation unit)
63 UV irradiator (third UV irradiation unit)
P paper (recording medium)

Claims (7)

A transport unit for transporting the recording medium in the transport direction;
A recording head that discharges a recording liquid that is cured by irradiation of ultraviolet rays onto the recording medium;
A plurality of pretreatment heads that discharge a pretreatment liquid that is cured by irradiation of ultraviolet rays onto the recording medium upstream of the recording head in the transport direction, the pretreatment heads on the downstream side and the front side of the downstream side. A plurality of pretreatment heads including an upstream pretreatment head disposed upstream of the treatment head in the transport direction;
A first ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays on the downstream side in the transport direction from the recording head;
A second ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays between the upstream preprocessing head and the downstream preprocessing head with respect to the transport direction;
A third ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays between the downstream pre-processing head and the recording head with respect to the transport direction;
Control means for controlling the transport unit, the recording head, the pretreatment head, the first ultraviolet irradiation unit, the second ultraviolet irradiation unit, and the third ultraviolet irradiation unit;
The control means includes the second ultraviolet irradiation unit and the third ultraviolet irradiation unit such that the illuminance of ultraviolet rays emitted from the second ultraviolet irradiation unit is larger than the illuminance of ultraviolet rays emitted from the third ultraviolet irradiation unit. A recording apparatus that controls an irradiation unit. The control means includes
In the character formation mode, the total amount of liquid droplets ejected from the downstream preprocessing head is the same as the total amount of liquid droplets ejected from the upstream preprocessing head and is ejected from the downstream preprocessing head. The transport unit and the preprocessing head are controlled so that the liquid droplets overlap the liquid droplets discharged from the upstream preprocessing head on the recording medium,
In the photographic formation mode, the total amount of droplets discharged from the downstream preprocessing head is larger than the total amount of droplets discharged from the upstream preprocessing head, and is discharged from the downstream preprocessing head. 2. The recording according to claim 1, wherein the transport unit and the preprocessing head are controlled so that the liquid droplets overlap the liquid droplets discharged from the upstream preprocessing head on the recording medium. apparatus.   The recording apparatus according to claim 2, wherein the resolution of the upstream preprocessing head is higher than the resolution of the downstream preprocessing head.   The recording apparatus according to claim 2, wherein a resolution of the upstream preprocessing head is higher than a resolution of the recording head.   The recording apparatus according to claim 4, wherein the resolution of the downstream preprocessing head is lower than the resolution of the recording head. A transport unit that transports the recording medium in the transport direction; a recording head that discharges a recording liquid that is cured by irradiation of ultraviolet rays with respect to the recording medium; and the recording medium upstream of the recording head in the transport direction A plurality of pretreatment heads for discharging a pretreatment liquid that is cured by irradiation with ultraviolet rays, and an upstream pretreatment disposed upstream of the downstream pretreatment head and the downstream pretreatment head in the transport direction. A plurality of preprocessing heads including a head, a first ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays on the downstream side in the transport direction from the recording head, and the upstream preprocessing head in the transport direction. A second ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays, and the downstream preprocessing head with respect to the transport direction. Wherein between the recording head, and a control apparatus for use in a recording apparatus including, a third ultraviolet irradiation unit for irradiating ultraviolet to the recording medium and,
Control of the second ultraviolet irradiation unit and the third ultraviolet irradiation unit is performed such that the illuminance of ultraviolet rays emitted from the second ultraviolet irradiation unit is larger than the illuminance of ultraviolet rays emitted from the third ultraviolet irradiation unit. A control device characterized by performing. A transport unit that transports the recording medium in the transport direction; a recording head that discharges a recording liquid that is cured by irradiation of ultraviolet rays with respect to the recording medium; and the recording medium upstream of the recording head in the transport direction A plurality of pretreatment heads for discharging a pretreatment liquid that is cured by irradiation with ultraviolet rays, and an upstream pretreatment disposed upstream of the downstream pretreatment head and the downstream pretreatment head in the transport direction. A plurality of preprocessing heads including a head, a first ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays on the downstream side in the transport direction from the recording head, and the upstream preprocessing head in the transport direction. A second ultraviolet irradiation unit that irradiates the recording medium with ultraviolet rays, and the downstream preprocessing head with respect to the transport direction. And between said recording head, the recording apparatus comprising, a third ultraviolet irradiation unit for irradiating ultraviolet to the recording medium,
Control of the second ultraviolet irradiation unit and the third ultraviolet irradiation unit is performed such that the illuminance of ultraviolet rays emitted from the second ultraviolet irradiation unit is larger than the illuminance of ultraviolet rays emitted from the third ultraviolet irradiation unit. Control means to perform,
A program characterized by functioning as

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