JP2018001425A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate discharge of ink adhered onto a platen toward an ink discharge portion.SOLUTION: A printer 1 comprises: a platen 2; a conveying mechanism 5 which conveys a recording paper 100 in a conveying direction; an inkjet head 4 which has a plurality of nozzles 16 and is arranged at the opposite side of the platen 2 with respect to the recording paper 100 to oppose to the platen 2; an ink discharge portion 20 provided closer to a downstream side in the conveying direction than an opposing region 300 of the platen 2 opposing to the plurality of nozzles 16 of the inkjet head 4; and a cover 30, arranged closer to the downstream side in the conveying direction than the opposing region 300, which covers a part between the opposing region 300 of the platen 2 and the ink discharge portion 20 with a clearance 39. This allows ink discharged into a region closer to outside than the recording paper 100 and then impacted on the platen 2 to be quickly absorbed into the clearance 39 by capillary force, so that discharge of the ink toward the ink discharge portion 20 is accelerated.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an image recording apparatus.

  As an example of a conventional image recording apparatus, Patent Document 1 describes an ink jet recording apparatus including a serial head that ejects ink while moving in the width direction of a recording medium. Japanese Patent Application Laid-Open No. 2004-151867 describes so-called borderless printing in which ink is also ejected to the edge of a recording medium to perform printing without margins.

  In the above-mentioned Patent Document 1, when performing borderless printing, in order to prevent margins from being generated at the edge of the recording medium, the ejection head is located not only at the edge of the recording medium but also outside the recording medium. Ink is also ejected to these areas. The ink ejected outside the recording medium lands on a platen that supports the recording medium. When the landed ink remains on the platen, there is a possibility that the ink adheres to the back surface of the recording medium transported on the platen and stains the recording medium.

  In order to solve such a problem, Patent Document 1 describes the following means. First, the platen includes a platen main body, a platen cover, and an ink absorbing member. An ink receiving portion is provided at the downstream end of the platen main body in the transport direction. The ink receiving part is further formed with an ink guide groove extending downstream in the transport direction.

  A concave portion connected to the ink receiving portion is provided further downstream of the ink receiving portion of the platen main body. An ink absorbing member is accommodated in the recess. A flat platen cover is attached on the recess. The platen cover covers only the ink absorbing member, and is provided to prevent the user from touching the ink absorbing member during work to keep his hands dirty.

  During borderless printing, ink is ejected from only some of the plurality of nozzles of the ejection head arranged downstream in the transport direction. Thereby, at the time of borderless printing, ink lands on the ink receiving portion of the platen main body. Further, the ink that has landed on the ink receiving portion flows on the platen by the capillary force generated in the ink guide groove, and is guided to the ink absorbing member on the downstream side in the transport direction.

JP 2006-206993 A

  In the image recording apparatus described in Patent Document 1, the ink that has landed on the platen is discharged to the ink absorbing member along the ink guide groove. However, it is sufficient that the ink on the platen flows promptly toward the ink discharge portion, but in some cases, the ink may not flow reliably. For example, when the viscosity of the ink is high, it becomes difficult to flow. In addition, in the case of ink that is easily dried, the ink may be dried before flowing to the ink absorbing member, and the color material contained in the ink may remain and accumulate on the platen. In this case, the recording medium that is subsequently conveyed on the platen comes into contact with the color material remaining on the platen, causing the recording medium to become dirty. Further, the ink guide groove is blocked by the accumulated color material, and there is a possibility that the discharge of the ink after that is hindered.

  An object of the present invention is to promote the discharge of ink attached on the platen to the ink discharge portion side.

  An image recording apparatus according to a first aspect of the present invention includes a platen that supports a recording medium, a conveyance unit that conveys the recording medium in a conveyance direction, and a plurality of nozzles, and the platen with respect to the recording medium On the opposite side, an ejection head disposed opposite to the platen, a first ink discharge portion provided outside the opposing area of the platen facing the plurality of nozzles of the ejection head, and the opposing area Is disposed closer to the first ink discharge portion than the opposed region in the discharge direction from the first ink discharge portion to the first ink discharge portion, and a gap is formed between the opposed region of the platen and the first ink discharge portion. And a first cover that covers the space.

When the ink ejected from the plurality of nozzles of the ejection head lands on the facing area of the platen facing the nozzle, the ink on the platen is the first so that the recording medium conveyed next is not soiled. It is desired that the ink is quickly discharged to the ink discharge portion side.
In the present invention, a portion of the platen between the facing region and the first ink discharge portion is covered with a first cover with a gap.
Therefore, the ink that has landed on the facing area is sucked into the gap by the capillary force generated in the gap, and quickly moves from the facing area to the outside. Therefore, the ink that has landed on the platen is prevented from adhering to the recording medium to be conveyed next.

  In the image recording apparatus according to a second aspect, in the first aspect, a plurality of grooves extending in the discharge direction are formed in a portion between the opposed region of the platen and the first ink discharge portion. It is characterized by this.

  By covering the plurality of grooves of the platen with the first cover, a plurality of elongated gaps are formed between the platen and the first cover. This ensures that a large capillary force acts on each gap, so that ink that has landed on the opposing area of the platen can easily escape from the opposing area.

  The image recording apparatus according to a third aspect is characterized in that, in the second aspect, a plurality of convex portions respectively accommodated in the plurality of grooves are formed on the platen side surface of the first cover. It is what.

  Since the first cover has a plurality of convex portions accommodated in the plurality of grooves of the platen, the cross-sectional area of each gap is further reduced, and the capillary force is further increased.

  According to a fourth aspect of the present invention, there is provided the image recording apparatus according to the first aspect, wherein a plurality of convex portions extending in the discharge direction are formed on the platen side surface of the first cover. is there.

  Since the first cover has a plurality of convex portions, a plurality of elongated gaps are formed between the platen and the first cover. As a result, a large capillary force acts on each gap, and it becomes easy for the ink to escape out of the opposing area.

  The image recording apparatus according to a fifth aspect of the present invention is the image recording apparatus according to any one of the first to fourth aspects, wherein the gap between the first cover and the platen is opened on both sides in the discharge direction, and the discharge A first drive unit that moves the first cover between the second position where the gap at the end on the opposite region side in the direction is narrower than the first position. .

  All of the ink sucked into the gap between the platen and the first cover may be discharged to the first ink discharge portion, but in practice, some ink may remain in the gap. In this case, when the remaining ink is solidified by drying, the gap is closed, and there is a possibility that the discharge of the ink after that is hindered. In the present invention, the first cover has a first position where a gap with the platen is opened, and a second position where the gap at the end portion on the opposite region side in the discharge direction is narrower than the first position. Can be moved between. When the ink needs to be discharged, the first cover is set to the first position to open the gap. When the ink discharge is completed, the first cover is moved to the second position, and the gap is blocked from the facing area side, so that drying of the ink in the gap can be suppressed.

  According to a sixth aspect of the present invention, in the fifth aspect of the invention, the first ink discharge section includes a storage section and an ink absorbing member stored in the storage section, and at least the first cover includes the first cover. When in the second position, a gap between the first cover and the platen communicates with a space in the housing portion.

  Since the ink absorbing member that has absorbed ink is accommodated in the accommodating portion of the first ink discharge portion, the space in the accommodating portion is filled with moist air. In addition, since the gap between the first cover and the platen communicates with the space in the accommodating portion, the humidity in the gap is kept high, and drying of ink remaining in the gap is suppressed.

  According to a seventh aspect of the present invention, in the fifth or sixth aspect of the invention, the first drive unit positions the first cover at the first position when ink is ejected from the ejection head, and the ejection is performed. The first cover is moved from the first position to the second position after ink ejection from the head is completed.

  In the present invention, when ink is ejected, the first cover is in the first position and the gap between the platen and the platen is open on both sides. It is sucked and discharged to the ink discharge section. On the other hand, after the ink discharge is completed, the first cover moves to the second position, and the gap becomes small at the end on the opposite area side, so that drying of the ink remaining in the gap is suppressed.

  The image recording apparatus according to an eighth aspect of the present invention is the image recording apparatus according to any one of the first to seventh aspects, wherein the first cover is opposed to the platen in the discharge direction after ink discharge of the discharge head is completed. It has the 2nd drive part moved to the area | region side, It is characterized by the above-mentioned.

  In the present invention, the first cover moves to the facing area side after the ink ejection is completed. As a result, it is possible to quickly collect the ink that has landed on the facing area.

  An image recording apparatus according to a ninth aspect is the image recording apparatus according to the seventh aspect, wherein the first cover is moved to the platen prior to the movement of the first cover to the second position after ink ejection of the ejection head is completed. The second drive unit is moved to the opposite region side in the discharge direction.

  In the present invention, after the ink discharge is completed, the first cover moves to the facing area side, and then moves to the second position. As a result, it is possible to quickly collect the ink that has landed on the opposing region and to suppress drying of the remaining ink.

  According to a tenth aspect of the present invention, in the eighth or ninth aspect, the second drive unit is a position where at least a part of the first cover covers the facing region of the platen in the discharge direction. Until the first cover is moved.

  When the first cover moves to a position where at least a part of the first cover covers the opposing area, the ink that has landed on the opposing area can be collected more quickly.

  An image recording apparatus according to an eleventh aspect of the present invention is the image recording apparatus according to any one of the first to tenth aspects, wherein after the ink discharge of the discharge head is finished, the first cover is swung with respect to the platen. It has a 3rd drive part which changes the width of the crevice between the 1st cover and the platen periodically.

  After the ink discharge is finished, the first cover swings and the width of the gap between the first cover and the platen changes periodically, so that the ink sandwiched between the platen is the first ink discharge section. Pushed to the side. Therefore, the ink remaining in the gap can be sent out to the first ink discharge unit side.

  The image recording apparatus according to a twelfth aspect of the present invention is the image recording apparatus according to the seventh or ninth aspect, wherein the first cover is moved to the second position after the discharge of the ink from the discharge head is completed. And a third drive unit that periodically changes the width of the gap between the first cover and the platen.

  After the ink discharge is finished, the first cover swings and the width of the gap between the first cover and the platen changes periodically, so that the ink sandwiched between the platen is the first ink discharge section. Pushed to the side. Thereafter, the first cover moves to the second position. Therefore, the ink remaining in the gap can be sent out to the first ink discharge portion side, and drying of the remaining ink can be suppressed.

  According to a thirteenth aspect of the present invention, in any one of the first to twelfth aspects, the gap between the first cover and the platen is at least in a state where ink is ejected from the ejection head. It is characterized by becoming narrower toward the first ink discharge portion side in the discharge direction.

  In the present invention, since the gap between the platen and the first cover becomes narrower toward the first ink discharge portion in the discharge direction, a force toward the first ink discharge portion acts on the ink sucked into the gap. . As a result, the ink discharge performance is enhanced, and the ink remaining in the gap is also suppressed.

  An image recording apparatus according to a fourteenth aspect of the present invention is the image recording apparatus according to any one of the first to thirteenth aspects, wherein the second ink discharge portion is disposed on the opposite side of the opposed region to the first ink discharge portion. A second cover that is disposed closer to the second ink discharge portion than the opposite region and covers a portion of the platen between the opposite region and the second ink discharge portion through a gap. It is characterized by having.

  In the present invention, a second ink discharge portion is provided on the opposite side to the first ink discharge portion with respect to the opposite region in the discharge direction, and the outer side between the opposite region of the platen and the second ink discharge portion is provided by the second cover. Part is covered. Therefore, the ink that has landed on the opposite side of the opposing region with respect to the first ink discharge portion can be quickly discharged toward the second ink discharge portion.

1 is a schematic plan view of a printer according to an embodiment. (A) is a top view of a platen and its peripheral part, (b) is a top view of a platen. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a perspective view of a platen and a cover. (A) is V (a) -V (a) sectional drawing of Fig.2 (a), (b) is V (b) -V (b) sectional drawing of Fig.2 (a). (A) is a plan view showing printing on the front end of the recording paper, and (b) is a plan view showing printing on the rear end of the recording paper. FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6A, where FIG. It is VIII-VIII sectional drawing of FIG.6 (b). It is a perspective view of a platen and a cover of a modification. (A) is sectional drawing of the upstream part along the conveyance direction of the platen and cover of FIG. 9, (b) is sectional drawing of a downstream part, (c) is sectional drawing of another modification. (A) is a perspective view of the platen and cover of another modification, (b) is a sectional view when the cover is in the first position, and (c) is a sectional view when the cover is in the second position. FIG. 10 is a cross-sectional view of the printer in the paper width direction according to another modification, where (a) shows before the cover operation and (b) shows the cover operation. (A) is a perspective view of a platen and a cover according to another modification, (b) is a plan view of the platen and cover (before cover advancement), and (c) is a plan view of the platen and cover (after cover advancement). 14A and 14B are cross-sectional views of the printer of FIG. 13 in the paper width direction, where FIG. (A) is a top view which shows the printing to the front-end part of the recording paper of another modification, (b) is a top view which shows the printing to the rear-end part of a recording paper. (A) is XVI (a) -XVI (a) sectional drawing of FIG. 15, (b) is XVI (b) -XVI (b) sectional drawing of FIG. (A) is a top view of a platen and its peripheral part, (b) is sectional drawing of a paper width direction. It is a top view of a platen and its peripheral part.

  Next, an embodiment of the present invention will be described. In FIG. 1, the conveyance direction in which the recording paper 100 is conveyed is defined as the front-rear direction of the printer 1. Further, the paper width direction of the recording paper 100 is defined as the left-right direction of the printer 1. Further, the vertical direction of the drawing in FIG.

(Schematic configuration of the printer)
As shown in FIG. 1, the printer 1 includes a platen 2, a carriage 3, an inkjet head 4, a transport mechanism 5, a cartridge holder 6, a control device 7, and the like.

  On the upper surface of the platen 2, a recording sheet 100 as a recording medium is placed. Details of the configuration of the platen 2 and its periphery will be described later.

  The carriage 3 is configured to be capable of reciprocating in the left-right direction (hereinafter also referred to as the scanning direction) along the two guide rails 11 and 12 in a region facing the platen 2. An endless belt 14 is connected to the carriage 3. When the endless belt 14 travels by the carriage drive motor 15, the carriage 3 moves in the scanning direction.

  The inkjet head 4 (the ejection head of the present invention) is attached to the carriage 3 and moves together with the carriage 3. A plurality of nozzles 16 are formed on the lower surface of the inkjet head 4. The plurality of nozzles 16 are arranged along the transport direction to form four nozzle rows 17.

  The transport mechanism 5 (the transport unit of the present invention) includes two transport rollers 18 and 19 disposed so as to sandwich the platen 2 in the front-rear direction, and a transport motor (not shown) that drives the transport rollers 18 and 19 in synchronization. Have The transport mechanism 5 transports the recording paper 100 placed on the platen 2 forward by two transport rollers 18 and 19.

  Ink cartridges 10 of four colors (black, yellow, cyan, magenta) are mounted on the cartridge holder 6. The cartridge holder 6 is connected to the inkjet head 4 by four tubes (not shown). The inkjet head 4 ejects ink of each color from the corresponding nozzle row 17.

  The control device 7 includes a ROM (Read Only Memory), a RAM (Random Access Memory), an ASIC (Application Specific Integrated Circuit) including various control circuits, and the like. The control device 7 executes various processes such as printing on the recording paper 100 by the ASIC according to the program stored in the ROM. For example, in the printing process, the control device 7 controls the ink jet head 4, the carriage drive motor 15, the transport motor, and the like based on a print command input from an external device such as a PC, and the like on the recording paper 100. To print. Specifically, an ink discharge operation for discharging ink while moving the inkjet head 4 in the scanning direction and a transport operation for transporting the recording paper 100 to the downstream side by the transport rollers 18 and 19 are alternately performed. As a result, an image or the like is printed on the recording paper 100.

<Detailed configuration of the platen and its surroundings>
Hereinafter, the detailed configuration of the platen 2 and its periphery will be described. First, the platen 2 will be described. As shown in FIG. 2B, the platen 2 is a synthetic resin member formed in a substantially rectangular shape in plan view.

  As shown in FIGS. 2 and 3, a plurality of ribs 35 extending in the transport direction are formed on the upstream side of the upper surface of the platen 2 in the transport direction. The plurality of ribs 35 are formed at intervals in the left-right direction. As shown in FIG. 3, the rib 35 supports the recording paper 100 being conveyed from below, and keeps the gap between the lower surface (ink ejection surface) of the inkjet head 4 and the recording paper 100 constant.

  For convenience of the following description, a region of the platen 2 that faces the plurality of nozzles 16 when the inkjet head 4 moves in the scanning direction is referred to as a facing region 300. In the present embodiment, specifically, in FIG. 2, a band-like region that is long in the scanning direction indicated by a one-dot chain line is the opposing region 300. At this time, the rib 35 extends over the entire width in the transport direction upstream portion with respect to the transport direction. The upstream end of the rib 35 is located outside the inkjet head 4, and the downstream end is located in the middle of the facing region 300.

  As shown in FIGS. 2 to 5, a plurality of grooves 33 extending in the transport direction are formed in the facing region 300 of the platen 2 and the downstream portion in the transport direction. Each groove 33 is formed in a V-shaped cross section and is closely adjacent to each other. As shown in FIG. 2B, the formation range of the groove 33 avoids the rib 35 and includes the facing region 300. Most of the grooves 33 extend across the facing region 300 in the transport direction, and the upstream end thereof is adjacent to the boundary of the facing region 300 from the upstream side (rear side). The downstream end extends to the front end of the platen 2. In the left-right direction, several grooves 33 are also arranged on the outside from the boundary of the facing region 300. As shown in FIG. 2B, in the present embodiment, flat portions are left at both ends of the platen 2. As shown in FIGS. 5A and 5B, the depth of the groove 33 is shallower toward the downstream side in the transport direction.

  As shown in FIGS. 2A and 3, a cover 30 (the first cover of the present invention) is disposed on the downstream side of the facing region 300 in the transport direction. The cover 30 is a substantially rectangular resin member in plan view. The rear side portion of the cover 30 overlaps with the downstream side portion of the platen 2 in the transport direction except for the facing region 300. That is, the rear end of the cover 30 is adjacent to the boundary of the facing area 300 from the front side (outside of the present invention) and does not overlap with the facing area 300 in the vertical direction.

  As shown in FIGS. 4 and 5, the lower surface of the rear side portion of the cover 30 is flat and has a gap 39 between the platen 2 and the lower surface. As described above, a plurality of grooves 33 are formed in the platen 2. In the present embodiment, the lower surface of the cover 30 is in contact with the ridge line portion of the convex portion that defines the groove 33 and constitutes an individual tunnel (flow path) having the groove 33 as a hollow portion. This hollow portion is the gap 39. Each tunnel has an upstream opening in the vicinity of the boundary of the facing region 300 and a downstream opening at the front end of the platen 2 in the transport direction. Further, as described above, the groove 33 of the platen 2 becomes shallower toward the downstream side in the transport direction. Each groove 33 has a size capable of expressing a capillary force with respect to the ink, so that the ink is moved downstream by the capillary force. Further, each groove 33 is covered with the cover 30 in the upward opening, so that a stronger capillary force can be obtained.

  A plurality of ribs 31 extending in the front-rear direction are also provided on the upper surface of the cover 30. The plurality of ribs 31 are formed at intervals in the left-right direction. Each rib 31 corresponds to the rib 35 of the platen 2 in a one-to-one relationship along the front-rear direction. Each rib 31 also supports the recording paper 100 conveyed downstream from below. As shown in FIG. 3, the rear end (upstream end) of the rib 31 is the rear end of the cover 30. The front end (downstream end) of the rib 31 is located outside the inkjet head 4. As a result, the interval between the recording paper 100 being conveyed and each nozzle 16 is maintained at a distance suitable for printing over the entire area of the opposed area 300. In addition, the front side part of the cover 30 is being fixed to the upper surface of the top plate 24 of the case 22 mentioned later.

  As shown in FIGS. 2A and 3, the ink discharge unit 20 (the first ink discharge unit of the present invention) is disposed downstream of the platen 2 in the transport direction. The ink discharge unit 20 includes a case 22 (housing portion of the present invention) and an ink absorbing foam 8 (ink absorbing member of the present invention).

  As shown in FIG. 3, the case 22 has a rectangular parallelepiped shape as a whole, and includes a case main body 23 that opens upward and a top plate 24 that covers the case main body 23 from above. The case main body 23 contains the ink absorbing foam 8. The upper part of the rear wall portion of the case body 23 is fixed to the front end surface of the platen 2. At this time, the upper end of the rear wall portion is at the same height level as the valley bottom of the groove 33 of the platen 2. The lower surface of the top plate 24 is at the same height level as the lower surface of the cover 30. Therefore, there is a gap (opening 26) between the upper end of the rear end and the lower surface of the top plate 24. The opening 26 is connected to the front end of all the grooves 33. That is, all the gaps 39 communicate with the substantially sealed internal space 27 (the space of the present invention) formed by the case main body 23 and the top plate 24 of the case 22 through the opening 26.

  The ink absorbing foam 8 is a porous member made of, for example, polyurethane foam. The ink absorbing foam 8 is for collecting ink landed on the platen 2 as will be described later.

  In the printer 1 having the above-described configuration, ink is hardly landed on the platen 2 for normal printing. However, ink may land on a part of the platen 2 when performing the borderless printing described below.

  Normally, an image is printed by providing a margin portion at the edge of the recording paper 100 (printing with a border). However, in marginless printing, an image is printed on the entire surface of the recording paper 100 without providing a margin portion. The control device 7 selects whether to perform bordered printing or borderless printing according to an input command from the external device.

  The control of borderless printing will be described with reference to FIGS. A description will be given separately for borderless printing on the edge in the scanning direction of the recording paper 100 and borderless printing on the edge in the transport direction.

  First, borderless printing on the edge of the recording paper 100 in the scanning direction will be described. The control device 7 controls the carriage drive motor 15 to move the carriage 3 in the scanning direction, and ejects ink from the inkjet head 4 during the movement. At that time, the control device 7 also causes ink to be ejected from the inkjet head 4 even when the carriage 3 is in the vicinity of the edge of the recording paper 100. At this timing, ink is ejected from the nozzles 16 on both sides sandwiching the edges (left and right ends) of the recording paper 100 in the left-right direction. Ink from the nozzles 16 facing the platen 2 lands on the platen 2. In the present embodiment, there is a groove 33 on the outside of the facing region 300, and the ink that has landed on the platen 2 travels along the groove 33 toward the case 22. The case 22 accommodates the ink absorbing foam 8, and the ink is collected in this case.

  Next, borderless printing on the front edge of the recording paper 100 in the conveyance direction will be described. The control device 7 controls the amount of paper transported by the transport mechanism 5 and positions the front end of the recording paper 100 in the middle of the facing area 300. Specifically, as shown in FIGS. 6A and 7A, a region sandwiched between the front end of the rib 35 and the rear end of the rib 31, the front end of the facing region 300 in the transport direction. The front end of the recording paper 100 is disposed in the section. In this state, the control device 7 controls the carriage drive motor 15 to eject the ink (ink 400 in FIG. 7A) from the nozzles 16 while moving the carriage 3. At this time, ink is ejected from the nozzles 16 on both sides sandwiching the front end of the recording paper 100 in the transport direction. Ink from the nozzles 16 facing the platen 2 lands on the platen 2. In this embodiment, the groove 33 extends across the facing region 300, and the ink that has landed on the platen 2 travels along the groove 33 toward the case 22.

  Further, in borderless printing on the edge on the rear side in the transport direction, the control device 7 causes the rear end of the recording paper 100 to be within the front end in the transport direction of the facing area 300 as shown in FIGS. Place. In this state, the control device 7 moves the carriage 3. At that time, ink (ink 400 in FIG. 8) is ejected only from the nozzles 16 belonging to the nozzle group 21. The nozzle group 21 includes nozzles 16 that face the front end of the facing region 300 in the transport direction. In this case as well, ink is ejected from the nozzles 16 on both sides sandwiching the rear end of the recording paper 100 in the transport direction. Ink from the nozzle 16 facing the platen 2 lands on the platen 2, but travels along the groove 33 toward the case 22.

  In the borderless printing described above, when the nozzle group 21 and the front end of the recording paper 100 face each other, ink lands on the hatched portion 28 in FIG. In addition, when the nozzle group 21 and the rear end of the recording paper 100 face each other, ink lands on the hatched portion 29 in FIG.

  The ink that has landed on the platen 2 is discharged toward the ink discharge unit 20 and is collected by the ink absorbing foam 8. However, at this time, if the ink is not discharged promptly, the ink remains in the middle of the groove 33 by drying. In particular, a pigment ink in which a pigment is dispersed as a color material is easier to dry than a dye-based ink, and the discharge performance itself is poor.

  Therefore, in the present embodiment, the groove 33 is formed in the platen 2 in order to improve the discharge performance of the ink that has landed on the facing region 300. Due to the capillary force generated in the groove 33, the ink (the ink 405 in FIGS. 7A and 8) easily moves downstream in the transport direction (the discharge direction of the present invention).

  Further, the cover 30 is arranged so as to cover the downstream side portion of the groove 33 in the transport direction. A gap 39 is generated between the cover 30 and the platen 2. Therefore, a capillary force further acts on the ink in the groove 33 (ink 405 in FIG. 7B), and the ink is sucked into the gap 39. As ink is sucked into the gap 39 one after another, the ink hardly remains in the facing region 300. Note that the cover 30 is desirably disposed as close to the facing region 300 as possible in order to promptly suck the ink on the facing region 300 into the gap 39. However, it is desirable to dispose the cover 30 slightly away from the facing region 300 so that the upper surface of the cover 30 is not soiled by ink mist or the like. The rear end position of the cover 30 is, for example, 1 to 2 mm from the front end of the facing region 300.

  In addition, since a plurality of grooves 33 are formed on the platen 2 side, and the plurality of grooves 33 are covered with the cover 30, a plurality of elongated tunnel-shaped gaps 39 are provided between the platen 2 and the cover 30. Is formed. This ensures that a large capillary force acts on each gap 39 and the ink easily enters the gap 39.

  Further, since the gap 39 becomes narrower toward the downstream side in the transport direction, a capillary force that is sucked further downstream in the transport direction acts on the ink that has entered the gap 39. As a result, ink discharge performance is improved, and ink remaining in the gap 39 is also suppressed.

  With the above configuration, the ink that has landed on the platen 2 is quickly discharged to the ink discharge unit 20 side. The present invention can be said to be particularly effective for pigment inks that are likely to remain and accumulate upon drying.

  Next, a modified example in which the above embodiment is modified will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

(1) The configuration of the platen and cover can be changed as appropriate. For example, in the above embodiment, the depth of the groove 33 is shallower toward the downstream side in the transport direction, but the depth of the groove 33 may be constant in the transport direction.

  9 and 10A and 10B, the cover 46 may include a plurality of convex portions 47 corresponding to the plurality of grooves 43 of the platen 42. Specifically, a plurality of convex portions 47 extending in the transport direction are formed on the lower surface of the rear side portion of the cover 46. When the cover 46 is put on the platen 42, the top of one convex portion defining the groove 43 abuts on one valley bottom formed by the convex portion 47. The protrusions 47 are accommodated in the corresponding grooves 43, but a slight gap 49 remains between the grooves 43 and the protrusions 47. Compared with the case where the lower surface of the cover is flat, the cross-sectional area of each gap 49 is further reduced, and the capillary force acting on the ink is further increased.

  10A and 10B, the protruding height of each convex portion 47 is higher on the downstream side than on the upstream side. Thereby, the clearance gap between the groove | channel 43 and the convex part 47 is so narrow that it goes to the conveyance direction downstream. However, this is not essential, and as with the groove 43, the height of the convex portion 47 may be constant in the transport direction.

  The shape of the groove on the platen 42 side and the shape of the convex portion on the cover side are not particularly limited. For example, the cross-sectional shape of the groove 43 or the convex portion 47 may be various such as a U shape and a wave shape.

  On the other hand, it is not essential that the groove 43 is formed on the platen 42 side. For example, as shown in FIG. 10C, the upper surface of the platen 42 may be flat, and the cover 46 may be disposed so as to cover the upper surface of the flat platen 42. Furthermore, a plurality of convex portions 47 may be formed on the lower surface of the cover 46 that covers the upper surface of the flat platen 42. Also in this case, a plurality of elongated gaps 49 are formed between the platen 42 and the cover 46 as in the above embodiment.

(2) If the ink sucked into the gap between the platen and the cover is dried and solidified, the gap may be blocked. Therefore, there may be a device for suppressing this. For example, when it is not necessary to discharge ink, if the gap is reduced, drying of the ink in the gap can be suppressed.

  In FIG. 11A described below, the upper surface of the downstream portion of the platen 52 in the conveyance direction and the lower surface of the rear portion of the cover 56 are shown as flat examples, but a groove is formed on the platen 52 side. Or the structure by which the convex part is formed in the cover 56 side may be sufficient. As shown in FIGS. 11B and 11C, a rotation shaft is provided at the center in the front-rear direction of the cover 56, and the cover 56 is driven to swing around the rotation shaft by the drive unit 201.

  Although the structure of the drive part 201 is not specifically limited, For example, the following structures are employable. 11 includes an eccentric cam 204 that contacts the upper surface of the front end of the cover 56, a motor 202 that rotates the eccentric cam 204, and an elastic body 203 such as a spring provided at the rear end of the cover 56. Have The rear end portion of the cover 56 is urged downward by the elastic body 203. FIG. 11B shows a state where the rotating shaft of the eccentric cam 204 and the upper surface of the cover 56 are farthest from each other. The lower surface of the cover 56 is parallel to the upper surface of the platen 52. When the motor 202 is driven, the eccentric cam 204 rotates and the distance between the rotation shaft and the upper surface of the cover 56 is reduced. The cover 56 is tilted and its rear end is pushed down. When the eccentric cam 204 is rotated 180 ° from the state shown in FIG. 11B, the rotation shaft and the upper surface of the cover 56 are closest (abut). When the eccentric cam 204 rotates, the cover 56 is substantially parallel to the upper surface of the platen 52 and the state in which the rear end of the cover 56 is close to (abuts) the upper surface of the platen 52 (the state in FIG. 11C: the second position). It swings between the states (the state in FIG. 11B: the first position). The elastic body 203 is not limited to a member that urges in the vertical direction, such as a coil spring, and a torsion spring provided on a rotating shaft may be employed.

  In the configuration as described above, the control device 7 moves the cover 56 between the first position and the second position in combination with the printing operation. Specifically, it is as follows.

  When executing borderless printing, the control device 7 first controls the motor 202 to place the cover 56 at the first position in FIG. In this state, the ink jet head 4 is controlled to discharge ink. In the first position, as shown in FIG. 11B, the gap 59 between the platen 52 and the cover 56 is open on both sides in the transport direction. Therefore, ink that has landed on the platen 52 during borderless printing is sucked into the gap 59.

  Immediately after the end of printing or after several seconds, the control device 7 controls the motor 202 to rotate the eccentric cam 204 and move the cover 56 to the second position in FIG. In the second position, as shown in FIG. 11C, the rear end portion of the cover 56 is inclined downward by the urging force of the elastic body. As a result, the rear end portion of the cover 56 contacts the platen 52 and the gap 59 is closed. Therefore, even if ink remains in the gap 59, drying of the residual ink 410 can be suppressed. Here, as in the above embodiment, the gap 59 communicates with the internal space 27 of the ink discharge unit 20 (see FIG. 3). The case 22 accommodates the ink absorbing foam 8 and the humidity of the internal space 27 is kept high, so that drying of the ink in the gap 59 is effectively suppressed.

  Thereafter, the cover 56 is maintained in the second position while printing (ink ejection) by the inkjet head 4 is not performed.

  In FIG. 11, in the second position, the rear end portion of the cover 56 contacts the platen 52 and the gap 59 is closed at the rear end portion, but the gap 59 does not necessarily have to be completely closed. . That is, when the cover is in the second position, the ink drying prevention effect can be obtained even if the gap 59 on the rear end side becomes narrower than when the cover is in the first position. For example, as in the above-described embodiment (see FIG. 4), when there are a plurality of grooves on the downstream side in the conveyance direction of the platen 52, the gap 59 is not completely closed even if the cover 56 contacts the platen 52. . Further, the rear end portion of the cover 56 may not be brought into contact with the platen but may be approached.

  The motor 202 that swings the cover 56 may be a dedicated motor for the cover 56, but may also be used as a motor for displacing other components. The motor 202 may be a conveyance motor, for example. Since the conveyance motor is not used after the printing process, the connection destination can be switched and the cover 56 can be moved. Alternatively, the carriage drive motor 15 may be used in conjunction with the movement of the carriage 3 to the home position.

(3) A configuration for positively discharging the ink sucked into the gap between the platen and the cover toward the ink discharge portion may be employed.

  For example, a configuration in which ink is pushed out by swinging the cover may be employed. In FIG. 12, as in FIG. 11, the cover 56 is swung by the drive unit 221 (the third drive unit of the present invention). The drive unit 221 includes a motor 222, an elastic body 223, and a cam 224. The configuration of the drive unit 221 is the same as that of the drive unit 201 in FIG.

  The control device 7 controls the motor 222 after the end of printing (after the end of ink ejection), and rotates the cam 224 for a predetermined time. As a result, the cover 56 periodically swings, and the width of the gap 59 between the cover 56 and the platen 52 periodically varies. The swinging motion of the cover 56 is preferably combined with the platen 2 described above. The platen 2 has a groove 33 on the downstream side in the transport direction. The groove 33 has a shallower bottom as it goes downstream. Therefore, the capillary force that the groove 33 develops is stronger toward the downstream side. Here, as shown in FIG. 12, when the cover 56 is in the first position and the state before and after the first position, the movement (discharge) of ink toward the case 22 proceeds with a strong capillary force on the downstream side. When the cover 56 is in the second position and the state before and after the second position, the capillary force on the upstream side is strengthened, and the ink collecting force from the opposing region 300 and its vicinity increases. By swinging the cover 56, the ink discharge and the ink collection are repeated, so that the ink can be discharged more reliably. Even when the upper surface is flat like the platen 52, the effect when the cover 56 takes the second position can be enjoyed.

  In addition, the cover swinging after ink ejection (FIG. 12) and the cover closing (FIG. 11) are performed by one driving unit having the function of the driving unit 201 of FIG. 11 and the function of the driving unit 221 of FIG. May be. That is, the control device 7 causes the cover 56 to swing by a single drive unit for a certain period of time, then moves the cover 56 to the second position, and makes the cover 56 stand by in that state.

(4) As shown in FIG. 6A of the above-described embodiment, the ink may adhere to a considerably far side (rear) region in the opposed region of the platen 2. Since this region is far away from the ink discharge portion 20, ink is easily left behind. A configuration in which the cover moves in the front-rear direction may be employed so that the ink adhering to such a region can be quickly collected. Specifically, it is as follows.

  In FIGS. 13 and 14, the cover 60 can be moved in the front-rear direction with respect to the platen 52 by the drive unit 211 (second drive unit of the present invention). Here, when the cover 60 moves rearward, the entire facing region 301 can be covered. The cover 60 has a size and a shape that can cover the facing region 301 and a region from the opposing region 301 to the front end of the platen 52. This size and shape may be realized by a combination of the cover 60 and the top plate 24 of the case 22.

  The configuration of the drive unit 211 that moves the cover 60 in the front-rear direction is not particularly limited. FIGS. 13 and 14 show, as an example, a so-called rack and pinion mechanism including a rack 213 provided on the cover 60, a pinion gear 214 that meshes with the rack 213, and a motor 212 that rotates the pinion gear 214. .

  A plurality of recesses 67 are formed on the lower surface of the rear side portion of the cover 60 as shown in FIG. In addition, guides (not shown) are arranged along the front-rear direction on both the left and right sides of the cover 60 to define the vertical position of the cover 60. These are configurations for preventing the plurality of ribs 55 of the platen 52 and the cover 60 from interfering when the cover 60 moves to the upstream side in the transport direction as will be described later.

  The control device 7 drives the motor 212 to rotate the pinion gear 214 after completion of printing (after completion of ink ejection). As a result, the entire cover 60 is moved upstream in the transport direction. More specifically, the control device 7 moves the cover 60 to a position where the rear side portion of the cover 60 covers the entire facing region 301 of the platen 52. Therefore, the ink that has landed on both the left and right ends of the facing region 301 is sucked into the gap 69, and the ink can be quickly collected.

  Until the next printing starts after the movement of the cover 60, the control device 7 may return the cover 60 to the downstream side in the transport direction, but may remain on the upstream side. Alternatively, the cover 60 may be further displaced by the drive unit 201 after being returned to the downstream side in the transport direction. In this case, after returning the cover 60 to the downstream side in the transport direction, the control device 7 rotates the eccentric cam 204 by the motor 202 and moves the cover 60 to the second position.

  The concave portion 67 of the cover 60 is not an essential configuration. For example, the ribs 55 may be formed low so that the cover 60 and the ribs 55 do not interfere with each other. Moreover, the structure of the drive part 211 is not limited to the above-mentioned thing, What is necessary is just to be able to move the cover 60 to the front-back direction. For example, the cover 30 may be configured to be movable with respect to the platen 2 shown in FIGS. The cover 30 can be approached until the rib 31 contacts the rib 35. Even if the ribs 31 and 35 do not contact each other, the rear end of the cover 30 may overlap the front portion from the rib 35 of the facing region 300. In any case, the cover does not require the above-described recess 67, and the degree of freedom with respect to the height of the rib is high. Of course, the ink can be effectively discharged from the facing region 300. This is an example in the case of having a groove on the platen side, but the effect of making the cover movable is obtained even if the groove is on the cover side or both without the groove.

(5) In the embodiment, borderless printing is performed using the nozzle group 21 on the front side of the inkjet head 4, but borderless printing can also be performed using the nozzle group on the rear side. In that case, as shown in FIGS. 15 and 16, it is preferable that the platen 72 is disposed in the reverse direction of the previous embodiment, and the cover 80 and the ink discharge portion 82 are provided upstream in the transport direction.

  Note that borderless printing at both ends in the transport direction using the rear nozzle group is as shown in FIGS. 15 and 16. First, at the front end portion of the recording paper 100, the control device 7 applies ink from the inkjet head 4 in a state where the nozzle group 71 composed of the plurality of nozzles 16 on the rear side faces the front end portion of the recording paper 100. Discharge. At that time, ink is ejected from only the plurality of nozzles 16 belonging to the nozzle group 71. Further, at the rear end of the recording paper 100, the control device 7 ejects ink in a state where the nozzle group 71 and the rear end of the recording paper 100 face each other. The ink that has landed on the platen 72 is discharged to the ink discharge portion 82 side upstream in the transport direction.

  In addition, a cover and an ink discharge unit may be provided on both sides in the transport direction. Specifically, for example, as shown in FIG. 17, a cover 80 (second cover of the present invention) is arranged on the platen 88 on the upstream side of the facing region 303, and a gap 90 is formed. An ink discharge portion 82 (second ink discharge portion of the present invention) is also arranged upstream of the platen 88 in the transport direction. Therefore, the ink can be quickly discharged to both sides in the transport direction. In the platen 88, the rib 91 is formed inside the facing region 303, and the rib 91 is not formed on the front side portion and the rear side portion of the facing region 303. Accordingly, borderless printing can be performed on the front end portion of the recording paper 100 using the front nozzle 16, and borderless printing can be performed on the rear end portion using the rear nozzle 16. Therefore, even in borderless printing, ink can be ejected from all the nozzles 16 at all times, leading to an improvement in printing speed.

  Further, as shown in FIG. 18, for example, covers 96 and 97 and ink discharge portions 98 and 99 may be provided on the left and right sides of the facing region 304 of the platen 94, respectively. About the both ends of the opposing area | region 301 in the left-right direction, compared with the case where an ink discharge part exists in the front-back direction, the discharged ink can be efficiently guide | induced to the outer side (ink discharge part 98, 99) of a platen. In this case, it is preferable that at least one of the platen 94 and the covers 96 and 97 has a groove extending from the facing region 301 toward the ink discharge portions 98 and 99. Furthermore, if the covers 96 and 97 can move to a position overlapping the facing region 301, ink can be discharged more effectively.

(6) In the above-described embodiment, the ink ejected from the inkjet head is all pigment ink, but only some of the color inks may be pigments and the rest may be dyes. For example, black ink may be a pigment, and yellow, cyan, and magenta inks may be dyes.

2, 42, 52, 62, 72, 88, 94 Platen 4 Inkjet head 8, 87 Ink absorbing foam 20, 82, 98, 99 Ink discharge part 22, 83 Case 27 Internal space 30, 46, 56, 60, 80, 96, 97 Cover 33, 43 Groove 39, 49, 59, 69, 86, 89, 90 Gap 47 Protruding part 201, 211, 221 Driving part 300, 301, 302, 303, 304 Opposite region

Claims (14)

A platen that supports the recording medium;
A transport unit for transporting the recording medium in the transport direction;
An ejection head having a plurality of nozzles and disposed opposite to the platen with respect to the recording medium and facing the platen;
A first ink discharge portion provided outside the platen facing region facing the plurality of nozzles of the ejection head;
A portion that is disposed closer to the first ink discharge portion than the counter region in the discharge direction from the counter region toward the first ink discharge portion, and that is between the counter region of the platen and the first ink discharge portion. A first cover covering the gap with a gap;
An image recording apparatus comprising:   The image recording apparatus according to claim 1, wherein a plurality of grooves extending in the discharge direction are formed in a portion between the facing region of the platen and the first ink discharge portion.   The image recording apparatus according to claim 2, wherein a plurality of convex portions respectively accommodated in the plurality of grooves are formed on the platen side surface of the first cover.   The image recording apparatus according to claim 1, wherein a plurality of protrusions extending in the discharge direction are formed on a surface of the first cover on the platen side.   A first position where a gap between the first cover and the platen is opened on both sides in the discharge direction; and a second position where the gap at the end on the opposite region side in the discharge direction is narrower than the first position. The image recording apparatus according to claim 1, further comprising a first drive unit that moves the first cover between positions. The first ink discharge section includes a storage section and an ink absorbing member stored in the storage section.
The image according to claim 5, wherein at least when the first cover is in the second position, a gap between the first cover and the platen communicates with a space in the housing portion. Recording device. The first driving unit includes:
When discharging ink from the discharge head, the first cover is disposed at the first position;
The image recording apparatus according to claim 5, wherein the first cover is moved from the first position to the second position after ink ejection of the ejection head is completed.   8. The apparatus according to claim 1, further comprising: a second driving unit configured to move the first cover to the opposite region side in the discharge direction with respect to the platen after ink discharge of the discharge head is completed. The image recording apparatus according to any one of the above.   After the ink discharge of the discharge head is completed, the first cover is moved to the opposite area side in the discharge direction with respect to the platen prior to the movement of the first cover to the second position. The image recording apparatus according to claim 7, further comprising a drive unit.   The said 2nd drive part moves the said 1st cover to the position which at least one part of the said 1st cover covers the said opposing area | region of the said platen in the said discharge direction. The image recording apparatus described.   A third driving unit configured to swing the first cover with respect to the platen after the discharge of the ink from the discharge head is completed and periodically change a width of a gap between the first cover and the platen; The image recording apparatus according to claim 1, comprising:   After the ink ejection of the ejection head is completed, the first cover is swung with respect to the platen before the first cover is moved to the second position, and the first cover and the platen are moved. The image recording apparatus according to claim 7, further comprising a third driving unit that periodically changes the width of the gap.   2. The gap between the first cover and the platen is narrower toward the first ink discharge portion in the discharge direction at least in a state where ink is discharged from the discharge head. The image recording apparatus according to any one of 12. A second ink discharge portion disposed on the opposite side of the opposed region to the first ink discharge portion;
A second cover that is disposed closer to the second ink discharge portion than the counter region and covers a portion between the counter region of the platen and the second ink discharge portion via a gap. The image recording apparatus according to claim 1, wherein the image recording apparatus is an image recording apparatus.

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