JP4432416B2 - Recording device - Google Patents

Description

  The present invention relates to a recording apparatus, and more specifically, an inkjet recording apparatus that performs recording by discharging ink onto a recording medium, and an output device such as a facsimile, a copier, a printer complex machine, and a workstation having those functions. The present invention relates to a recording apparatus.

  In recent years, the spread of color documents in offices is remarkable, and various output devices have been proposed. In particular, a small-sized and low-cost inkjet method is used in various output devices.

  A recording head used in an ink jet system includes an energy generation unit, an energy conversion unit that converts energy generated by the energy generation unit into an ink discharge force, an ink discharge port that discharges an ink droplet by the ink discharge force, and an ink discharge port And an ink supply path for supplying ink. As the energy generation means, bubbles are generated by heating ink by means of discharging ink droplets using an electromechanical converter such as a piezo element or an electrothermal conversion element having a heating resistor, and the ink is generated by generating the bubbles. There are means for discharging droplets.

  In a recording head that uses an electrothermal conversion element, since the electrothermal conversion element is small, it is possible not only to arrange the ink discharge ports at a high density, but also to divert semiconductor integrated circuit manufacturing technology as its manufacturing technology. Therefore, it is possible to reduce the size of the recording head having a large number of high-precision ink discharge ports and to manufacture it at low cost.

  However, at present, a printing method called serial scan in which printing is performed one band at a time by reciprocating a recording head while conveying a recording medium is prevalent. This method is small and low in cost, but has a drawback that the printing speed is slow because the recording head needs to be scanned a plurality of times in order to form an image over the entire recording medium. In order to improve the printing speed, it is necessary to reduce the number of scans, and it is essential to lengthen the recording head. A non-scanning printing method performed by a recording head having a recording medium width has advanced this to the limit. This printing method is an ink jet recording apparatus having a recording head corresponding to a recording medium width in which a large number of ejection openings are arranged over a length substantially the same as the width of the recording medium. Recording is performed by moving.

  As described above, there has been proposed an ink jet recording apparatus that performs printing while continuously transporting a recording medium by a non-scanning recording head corresponding to the recording medium width.

Incidentally, in the recording apparatus, the recording medium may be clogged in the apparatus. In order to remove the jammed recording medium and restore it in a short time, it is desired to have a structure that can easily remove the jammed recording medium. Many ink jet recording apparatuses include a first casing having a recording head and a second casing that is disposed opposite to the recording head and forms a conveyance path of the recording medium. In many cases, it is easy to remove the recording medium by relatively rotating the one housing and the second housing (so-called “crocodile mouth”). For example, Patent Document 1 discloses an image forming apparatus in which an upper frame is attached to a lower frame provided with a recording head so that the upper frame can be opened and closed around a rotation center.

  Generally, the recording head of an ink jet recording apparatus is designed so that the ink inside does not overflow to the outside by keeping the inside of the recording head within a certain negative pressure range with respect to the external atmospheric pressure. However, when the recording head is disposed inside the above-described upper housing or the like, if the above-described rotation operation is performed carelessly, the negative pressure in the recording head becomes excessive, and the ink discharge port The meniscus may be destroyed. Due to the destruction of the meniscus, air may be drawn into the recording head from the ink discharge port and flow back to the ink tank.

In order to prevent such meniscus destruction, it may be possible to close the ink supply path for supplying ink to the recording head and seal the inside of the recording head before moving the upper housing, but the configuration is complicated. Turn into.
Japanese Patent Laid-Open No. 9-86014

  In view of the above fact, an object of the present invention is to provide a recording apparatus capable of removing a recording medium without destroying a meniscus at an ink discharge port.

In order to solve the above-described problem, in the invention described in claim 1, a first housing having a recording head having an ink discharge port formed on an ink discharge surface, and a recording medium is conveyed facing the ink discharge surface. A second housing constituting a transport path to be moved, and the first housing can be separated from the second housing by rotating about a predetermined housing rotation axis . Moving means for moving the first housing so that the water head difference falls within a predetermined range, ink holding means for holding ink supplied to the recording head, provided in the first housing, and the ink holding And a supporting means for supporting the means with respect to the first casing so as to be rotatable around a suspension axis parallel to the casing rotation axis .

  In this recording apparatus, an ink droplet is ejected from the ink ejection port of the recording head while the recording medium is conveyed on a conveyance path formed between the first casing and the second casing, and an image is recorded on the recording medium. Is done. Since the first casing can be separated from the second casing by the moving means, it is possible to easily remove, for example, a recording medium that is jammed in the conveyance path. In addition, the first housing is separated so that the water head difference in the recording head is within a predetermined range. For this reason, the negative pressure in the recording head is also maintained within a certain range, and the meniscus is prevented from being destroyed at the ink discharge port.

Movement of the first housing by the moving means is effected by rotation around the shaft Jo Tokoro enclosure times. The axial direction of the rotation shaft may be a direction (including a normal direction of the ink discharge surface) intersecting with the ink discharge surface on which the ink discharge port is formed, but should be a direction parallel to the ink discharge surface. Is preferred. As a result, the first housing and the second housing are separated in a so-called “crocodile mouth” shape, so that the conveyance path is greatly opened and the paper can be easily removed. Note that this movement may include a parallel movement as described in claim 2 . By making the parallel movement in this way, it is possible to prevent the first housing and the second housing (or various members provided in these housings) from inadvertently contacting each other during the separation operation.
Furthermore, in the first aspect of the invention, the first housing is provided with ink holding means for holding the ink supplied to the recording head.
As described above, by providing the ink holding unit in the first housing, it is possible to efficiently supply ink to the recording head. In this configuration, the invention described in claim 1 further includes support means for supporting the ink holding means with respect to the first casing so as to be rotatable around a suspension axis parallel to the casing rotation axis. is doing. Thereby, even if the first housing is rotated, the posture of the ink holding unit does not change, and thus it is possible to reliably prevent the meniscus from being destroyed at the ink discharge port of the recording head.

In the invention described in claim 3, in the invention of claim 1 or claim 2, wherein the ink discharge port of the recording head is formed with a plurality so as to extend in a predetermined extending direction, the casing times The moving shaft and the extending direction of the ink discharge port are parallel to each other.

Therefore, even if the first housing rotates about the housing rotation axis with respect to the second housing, there is no difference in the vertical direction in the direction in which the ink discharge ports extend. As described above, the meniscus can be reliably prevented from being broken at the ink discharge port with a simple configuration in which the casing rotation shaft and the extending direction of the ink discharge port are made parallel to each other.

  The extending direction of the ink discharge ports coincides with the arrangement direction when the ink discharge ports are arranged in a straight line. Further, when the ink discharge ports are two-dimensionally arranged (so-called matrix arrangement or the like), the maximum difference among the height differences generated between the respective ink discharge ports in the separated state of the first housing is taken into consideration. If the direction connecting the respective ink discharge ports having the largest height difference is the extending direction, the meniscus can be reliably prevented from being broken at the ink discharge ports.

According to a fourth aspect of the present invention, the ink holding means is arranged so that a longitudinal direction of the ink holding means when viewed in plan is parallel to the casing rotation axis. Thereby, the pressure fluctuation inside the ink holding means can be further reduced.

The invention according to claim 5 is the invention according to any one of claims 1 to 4 , wherein the second casing is provided with maintenance means for maintaining the recording head. To do.

  This makes it possible to maintain the recording head and maintain the best ink ejection state.

  The “recording medium” that is the target of image recording in the recording apparatus of the present invention includes a wide range of objects as long as the recording apparatus ejects ink droplets. In addition, the dot pattern on the recording medium obtained by attaching the ink droplets on the recording medium is widely included in the “image” or “recorded image” obtained by the recording apparatus of the present invention. Therefore, the recording apparatus of the present invention is not limited to that used for recording characters and images on recording paper. In addition, the recording medium includes a recording sheet, an OHP sheet, and the like. In addition, for example, a substrate on which a wiring pattern or the like is formed is included. The “image” includes not only general images (characters, pictures, photographs, etc.) but also the above-described wiring patterns, three-dimensional objects, organic thin films, and the like. The liquid to be discharged is not limited to colored ink. For example, production of a color filter for display performed by discharging colored ink on a polymer film or glass, formation of bumps for component mounting performed by discharging molten solder onto the substrate, and organic EL solution on the substrate For general liquid droplet ejecting devices intended for various industrial applications, such as the formation of EL display panels that are ejected onto the substrate and the formation of bumps for electrical mounting that are performed by ejecting molten solder onto the substrate. The recording apparatus of the invention can be applied.

  Since the present invention is configured as described above, the recording medium can be removed without destroying the meniscus at the ink discharge port.

[Basic configuration]
First, the basic configuration of the recording apparatus of the present invention will be described. The basic configuration shown in FIGS. 1 to 3 is an example (reference example) that is a premise for understanding the present invention. On the other hand, the basic configuration shown in FIGS. 4 and 5 is an example according to the present invention.

  As shown in FIG. 1, the ink jet recording apparatus 10 includes a sheet supply unit 12 that feeds out a sheet, a registration adjustment unit 14 that controls the attitude of the sheet, a recording head unit 16 that forms an image on a sheet by ejecting ink droplets. The recording unit 20 includes a maintenance unit 18 that performs maintenance of the recording head unit 16, and a discharge unit 22 that discharges a sheet on which an image is formed by the recording unit 20.

  The sheet supply unit 12 includes a stocker 24 in which sheets are stacked and stocked, and a transport device 26 that transports the sheets one by one from the stocker 24 to the registration adjusting unit 14.

  The registration adjusting unit 14 includes a loop forming unit 28 and a guide member 30 that controls the posture of the paper. By passing through this portion, the skew is corrected using the stiffness of the paper and the conveyance timing is controlled. In this configuration, the recording unit 20 is entered.

  The discharge unit 22 stores the paper on which the image is formed by the recording unit 20 in the tray 32 via the discharge belt 31.

  FIG. 2 shows the configuration of the recording unit 20. The recording unit 20 includes a first housing 288 provided with the recording head unit 16 and a second housing 290 provided with the maintenance unit 18, and the first housing 288 and the second housing are provided. 290 is rotatable about the casing rotation shaft 292. As shown by a two-dot chain line in FIG. 2, the first housing is generally parallel to the second housing 290 at a position close to the second housing (hereinafter, this position is referred to as “recordable position”). In addition, a sheet conveyance path 104 is formed between the recording head unit 16 and the maintenance unit 18 (the conveyance direction is indicated by an arrow H). The paper is continuously conveyed (without stopping) while being pinched by the star wheel 70 and the conveying roll 100 (both see FIG. 1). Then, ink droplets are ejected from the recording head unit 16 to the paper, and an image is formed on the paper. When the first housing 288 is rotated with respect to the second housing 290, the first housing 288 moves upward (so-called “crocodile mouth”) as shown by a solid line in FIG. The separation position separated from the body 290 is reached. In this state, in the case of paper jam, the jammed paper can be easily taken out.

  As can be seen from FIG. 2, one or a plurality of recording heads 44 are arranged in the first casing 288 along the paper conveyance direction. For example, at least four recording heads are arranged corresponding to each color of YMCK for recording a so-called full-color image. In the example shown in FIG. 2, a total of eight recording heads 44 are arranged for each of the two colors. Each recording head 44 has a plurality of ink ejection ports 84 arranged in the same direction as the axial direction of the housing rotation shaft 292. The length of the ink discharge ports 84 in the arrangement direction, that is, the print area width is set to be longer than the maximum sheet width PW of the sheet P on which image recording by the inkjet recording apparatus 10 is assumed. The image can be recorded over the entire width of the paper P without being moved to (see FIG. 7).

  A predetermined amount of ink is stored in the recording head 44, and this ink is ejected from the ink ejection port 84 toward the paper. At the ink ejection port 84, the meniscus of the ink liquid level is maintained by a predetermined negative pressure, and inadvertent ink leakage is prevented. By making the arrangement direction of the ink discharge ports 84 coincide with the axial direction of the casing rotation shaft 292, the water head difference in the recording head 44 when the first casing 288 is in the separation position is recorded in each recording. It becomes constant at the ink discharge port 84 of the head 44. Since the negative pressure in the recording head 44 is maintained within a certain range and the meniscus in the ink discharge port 84 is maintained, inadvertent ink leakage is surely prevented.

  In addition, a sealing mechanism or the like for maintaining the negative pressure in the recording head 44 within a certain range is unnecessary, and the configuration can be simplified.

  FIG. 3 shows a recording unit 20 ′ having a sub tank 34 in addition to the configuration shown in FIG. 2 as a basic configuration of the present invention.

  The first casing 288 of the recording unit 20 ′ includes sub tanks 34 that correspond one-to-one to the recording heads 44. Ink stored in advance in a main tank 68 (see FIG. 6 described later) is sent to the sub tank 34 and temporarily held therein, and ink is further sent from the sub tank 34 to the corresponding recording head 44. As described above, when the sub tank 34 is provided in the first housing 288, the height difference between the corresponding recording head 44 and the sub tank 34 is within a certain range when the first housing 288 is moved to the separation position. Therefore, the water head difference between the ink discharge port 84 and the liquid level of the sub tank 34 can also be maintained within a certain range.

  Further, as can be seen from FIG. 3, the sub tank 34 has a substantially rectangular shape when seen in a plan view, and is attached to the first housing 288 so that the longitudinal direction thereof coincides with the axial direction of the housing rotation shaft 292. It has been. Therefore, the pressure fluctuation in the sub-tank 34 can be reduced with the first housing 288 moved to the separation position.

  FIG. 4A shows a recording unit 20 ″ in which the sub tank 34 is attached to the first housing 288 so as to be rotatable by the sub tank suspension shaft 294 in the basic configuration shown in FIG. 3. The sub tank suspension shaft 294 is parallel to the casing rotation shaft 292 and is inserted through a pair of holding pieces 34H extending upward from the sub tank main body 34B. When the first housing 288 is in the recordable position, the sub tank 34 maintains the posture in which the sub tank main body 34B is positioned vertically below the housing rotating shaft 292 due to gravity. Then, when the first casing 288 is moved to the separation position, the sub tank 34 is rotated around the sub tank suspension shaft 294 relative to the first casing 288 by gravity, and the sub tank main body 34B is rotated around the casing. The posture positioned vertically below the moving shaft 292 is maintained. Thereby, the water head difference between the ink discharge port 84 and the liquid level of the sub tank 34 in a state where the first housing 288 is in the rotating position can be maintained within a certain range.

  The sub-tank suspension shaft 294 is preferably located on an extension line in the extending direction of the ink discharge port 84, but even if it is not on the extension line, the deviation from the extension line is within a predetermined range. For example, the water head difference between the ink discharge port 84 and the liquid level of the sub tank 34 can be maintained within a certain range.

  FIG. 5 shows a basic configuration of the recording unit 21 which is further different from that shown in FIGS. In the recording unit 21, the first housing 288 is further supported by the lifting guide post 296 with respect to the recording unit 20 ″ illustrated in FIG. 4. And it moves (elevates and lowers in this example) while maintaining a state parallel to the second housing 290 along the elevating guide post 296.

  Therefore, for example, it is possible to first raise the first housing 288 and then rotate it around the housing rotation shaft 292 to move it to the separated position. If the first housing 288 is rotated without being raised with respect to the second housing 290, there is a possibility that the respective housings or members in the housing may interfere with each other. When the first housing 288 is raised, the interference of members can be prevented. Further, by raising the first housing 288, it is possible to greatly separate the second housing 290 from the configuration in which only the rotation is performed, and it is easy to remove the jammed paper. .

  Note that the first casing 288 can be rotated and raised and lowered independently, and the first casing 288 can be rotated with respect to the second casing 290 and then lifted. Good.

[Embodiment]
Next, an embodiment of the present invention will be described. In this embodiment, the basic configuration shown in FIG. 5 is adopted.

  FIG. 6 shows the ink supply unit 64, the maintenance unit 18, and the recording head unit 16 of the inkjet recording apparatus 10 of the present embodiment. 16 to 19 show a specific configuration of the recording unit 21 of the ink jet recording apparatus 10.

  As illustrated in FIGS. 16 to 19, the recording unit 21 includes a first housing 288 and a second housing 290. The second housing 290 is installed on an installation surface such as a floor surface, and a maintenance unit 18 is provided therein (in FIGS. 16 to 19, a part of the maintenance unit 18 is provided). Some maintenance devices 81 are partially shown). A pair of elevating guide posts 296 is erected from both sides of the second casing 290 in the sheet conveying direction, and the first casing 288 is supported by the elevating guide posts 296 via the holder 289 so as to be movable up and down. Yes. Further, a pair of lifting drive screw shafts 298 driven by a drive motor (not shown) is erected from both sides of the second casing 290 in the sheet conveyance direction, and is screwed into the holder 289. Accordingly, the first casing 288 is raised (see FIGS. 18 and 19) or lowered (see FIGS. 16 and 17) while maintaining the parallel state with the second casing 290 by the rotation of the lifting drive screw shaft 298. See).

  Between the holders 289, a case rotation shaft 292 is stretched in a direction orthogonal to the paper transport direction, and the first case 288 is rotatably supported by the case rotation shaft 292. Yes. As shown in FIG. 19, the first housing 288 is rotated from the raised position to have a predetermined inclination angle (separated position). When the first housing 288 is in the recordable position, a paper transport path 104 through which the paper P is transported is configured between the first housing 288 and the second housing 290. Note that it is preferable to provide a damper (not shown) between the holder 289 and the first housing 288 to reduce the load when the first housing 288 is rotated. As this damper, a gas damper, a coil spring, a leaf spring or the like can be applied. Further, it is preferable that the first housing 288 can be selected and fixed at a predetermined rotation angle (30 °, 45 °, etc.), for example, and can be fixed at an arbitrary rotation angle. More preferred.

  Therefore, the first housing 288 is raised with respect to the second housing 290 by the rotation of the lifting / lowering drive screw shaft 298 and then rotated around the housing rotation shaft 292 to be in the separated position. Is possible. Thus, by first raising the first casing 288 relative to the second casing 290, the first casing 288 and the second casing 290, or the members provided in these casings, are connected to each other. Interference can be prevented when the casing 288 is rotated. The rising stroke of the first housing 288 is sufficient as long as interference can be prevented in this way. For example, in the case of the present embodiment, the upper limit of the ascending stroke is about 200 mm, but the interference can be prevented if it is 50 mm or more. Basically, it is sufficient if there is a further upward stroke, and it is preferable to be able to stop (fix) at an arbitrary position.

  A plurality of recording heads 44 are fixed to the first housing 288 along the paper transport direction. As will be described later, each recording head 44 is provided with a plurality of unit heads 40 in a direction orthogonal to the paper transport direction (that is, parallel to the casing rotation shaft 292). A plurality of ink discharge ports 84 are formed in 40 along a direction orthogonal to the paper transport direction (see FIGS. 8 to 13). An image is recorded on the paper P by ejecting ink droplets from the ink ejection port 84 onto the paper P that is continuously transported through the paper transport path 104.

  As shown in FIG. 6, the ink supply unit 64 includes a main tank 68 in which ink is stored in advance, and a sub tank 34 to which ink is sent from the main tank 68 and temporarily held. The sub tanks 34 are provided in the first housing 288 so as to correspond one-to-one with each of the recording heads 44. In the inkjet recording apparatus 10 of the present embodiment, four color (or more, eight in the present embodiment) recording heads 44 are arranged at predetermined intervals in the transport direction, and yellow (Y), magenta (M), It is configured to eject ink droplets of cyan (C) and black (K), and can record a full color image, and the sub tank 34 is provided for each recording head 44 or the recording head array 42A. , 42B, and the main tank 68 is provided for each color (and therefore at least four).

  As shown in FIG. 16, the sub-tank 34 includes a substantially box-shaped sub-tank main body 34B that holds ink, and a pair of holding pieces 34H that protrude upward from the sub-tank main body 34B. On the other hand, from the first housing 288, a sub tank suspension shaft 294 parallel to the housing rotation shaft 292 is extended on an extension line in the extending direction of the ink discharge port 84, and the sub tank suspension is supported on the holding piece 34H. A shaft 294 is inserted. The sub tank 34 is rotatable (free rotation) around the sub tank suspension shaft 294, and the sub tank main body 34 </ b> B is positioned vertically below the sub tank suspension shaft 294 by its own weight regardless of the inclination angle of the first housing 288.

  As can be seen from FIG. 6, the main tank 68 and the sub tank 34 communicate with each other through a main supply path 72 and a main return path 74, and a main pump 76 provided in the main supply path 72 allows the main tank 68 to be connected to the sub tank 34. Ink can be sent back to the main tank 68 from the sub tank 34.

  An ink circulation path 36 is connected to the sub tank 34 via an ink supply path 35 and an ink return path 37, and the ink in the sub tank 34 can be circulated into the ink circulation path 36 by driving the sub pump 38. .

  An overflow wall 62 is erected in the sub tank 34 and is divided into an ink holding chamber 34S and an ink return chamber 34R. The main supply path 72, the ink supply path 35, and the main return path 74 are connected below the ink holding chamber 34S, and the main return path 74 is connected below the ink return chamber 34R.

  An air communication hole 50 is formed in the upper lid of the sub tank 34 so that the inside of the sub tank 34 is maintained at atmospheric pressure. Then, the recording head 44 and the sub tank 34 are arranged so as to provide a predetermined height difference between the ink discharge port 84 (see FIG. 8 and the like) of the unit head 40 and the liquid level of the ink holding chamber 34S of the sub tank 34. Thus, a water head difference is generated between them. In particular, in the present embodiment, since the overflow wall 62 is provided, the ink liquid level in the ink holding chamber 34S does not reach higher than this, so that the water head difference is always stably maintained. be able to.

  As shown in FIG. 6, the ink holding chamber 34S of the sub tank 34 is provided with a liquid level sensor 78 for detecting the liquid level of the ink. Information on the liquid level detected by the liquid level sensor 78 is sent to the ink supply controller 60, and the main pump 76 is controlled based on this information.

  The main supply path 72, the main return path 74, the ink supply path 35, the ink circulation path 36, the ink return path 37, and the individual flow path 48 are ink-resistant, and pressure from ink (in some cases, negative pressure) It is preferable that the tube is made of a material having a rigidity that does not collapse carelessly. Furthermore, when a roller pump is used as the main pump 76 or the sub pump 38, it is necessary to have flexibility (elasticity) to such an extent that the tube is appropriately crushed (locally dented or bent) by an external force. There is. Specific examples of tube materials include various types of rubber and resin tubes. PVD tubes with excellent ink resistance, Tygon tubes ("Tygon" is a product name of Saint-Gobain Norton), latex tubes, A polyethylene tube or the like is preferable. In addition, as described above, in the case of using a tube-type pump such as a roller pump, it is preferable to use a soft silicon tube. In addition, you may use properly the material of the tube suitable for each of the main supply path 72, the main return path 74, the ink circulation path 36, and the separate flow path 48.

  As long as the recording head 44 is an inkjet recording head capable of ejecting ink droplets from the nozzle surface 40A of the recording head 44, the type of ink and the ink droplet ejection method are not limited. Note that the ink droplet ejection method of the unit head 40 is not limited to the ink jet method, and any method may be used as long as the color material is directly transferred to the paper without contact. An inkjet method is typical, but any method can be applied as long as it is a known method. In addition, the ink jet method is not limited to a method such as a thermal ink jet method, a piezo ink jet, a continuous flow ink jet, or an electrostatic suction ink jet.

  The ink to be used may be any of water-based ink, oil-based ink, so-called solid ink that is solid at room temperature, solvent ink, and the like. The coloring material in the ink may be any pigment or dye.

  As shown in FIG. 7, the print area of the recording head 44 is set corresponding to the maximum paper width PW of the paper P to be printed. Here, the printing area is basically the maximum of the recording area obtained by subtracting the margin not to be printed from both ends of the sheet, but is generally larger than the maximum sheet width PW to be printed. This is because there is a possibility that the sheet is conveyed at an angle (skew) with respect to the conveyance direction, and there is a high demand for borderless printing.

  The recording head 44 may be composed of a monolithic long recording head chip or a plurality of short recording head chips (hereinafter referred to as unit heads).

  For example, if the unit head 40 is a type in which the nozzles 58 are formed up to the end in the nozzle arrangement direction (see FIG. 8), the unit heads 40 are continuously arranged in the nozzle arrangement direction as shown in FIG. A compact recording head 44 can be constructed. When the unit head 40 (see FIG. 10) in which the nozzles 58 are not formed at both ends is used, a recording head in which a plurality of unit heads 40 are arranged on the common substrates 46A and 46B at regular intervals in the nozzle arrangement direction. By arranging a plurality of arrays 42A and 42B in the transport direction (see FIG. 11), it is possible to obtain a recording head 44 capable of printing without interruption corresponding to the paper width. In this case, the recording head arrays 42A and 42B are formed on both surfaces of the single common substrate 46 (see FIG. 12), so that the size can be further reduced.

  In addition, although the nozzle arrangement of the unit head 40 is a straight line, it is not limited to this. For example, as shown in FIG. 13, the nozzles 58 can be arranged in a staggered manner.

  As shown in FIG. 6, each unit head 40 is provided with a connection channel 56 connected to the individual channel 48. A detachment unit 122 is provided at each connection portion of the individual channel 48 and the connection channel 56 so that the unit heads 40 can be easily detached from the individual channel 48 independently of each other.

  On the other hand, as shown in FIG. 14, the maintenance device 81 arranged to face the recording head 44 includes a cap unit (ink storage unit) 80 that can store ink droplets corresponding to each unit head 40, and a recording head. Cleaning means 88 capable of cleaning 44 nozzle surfaces 40A. The cap unit 80 has a function of containing and holding droplets ejected from the recording head 44. For this purpose, for example, a receiving member 82 having a recess 82A formed so as to correspond to the nozzle surface 40A (see FIG. 6 and the like) of the recording head 44, and an ink disposed on the bottom of the recess 82A of the receiving member 82 are provided. The holding member 82 can be brought into close contact with the nozzle surface 40A to be in an airtight state.

  As shown in FIG. 6, a first chamber 212 common to the entire recording head 44 is disposed below the receiving member 82, and the receiving member 82 and the first chamber 212 are connected to the discharge path opening / closing valve 216. Are connected by a first waste ink flow path 214.

  From the first chamber 212, a second chamber 218 and a third chamber 220 are sequentially connected by a second exhaust ink flow path 222 and an intake flow path 224. For the waste ink in the first chamber 212, the feedback valve 228 provided in the ink return path 226 is opened, and the switching valve 229 is switched to return to the main tank 68 (or the sub tank 34), or the second waste ink. After being sent to the second chamber 218 by the flow path 222, the discharge valve 230 can be opened and discharged from the discharge path 232 to the outside.

  An intake pump 236 is connected to the inside of the third chamber 220 via an intake pipe 234, and a negative pressure is generated in the third chamber 220 by opening and closing the intake valve 238. This negative pressure is applied to the receiving member 82 through the second chamber 218 and the first chamber 212.

The first chamber 212 and the third chamber 220 are provided with air release valves 240 and 242, and the inside of these chambers can be opened to atmospheric pressure.

The discharge path opening / closing valve 216, the return valve 228, the discharge valve 230, the intake valve 238, and the atmosphere release valves 240 and 242 are all controlled by the maintenance controller 244.
The cleaning unit 88 is for removing dust, dust, and ink from the nozzle surface 40A of the recording head 44 to maintain a constant ink droplet ejection performance.

  As shown in FIG. 14, the cleaning unit 88 includes a wiper 92, a holding member 90 that holds the wiper 92, and a moving unit 312 (see FIG. 15) that moves the cleaning unit 88 up and down and in the width direction. .

  The moving means 312 moves the wiper 92 along the nozzle surface 40A while slidingly contacting the nozzle surface 40A of the recording head 44 (see FIG. 15C), thereby cleaning the entire nozzle surface. At this time, since the cap unit 80 is disposed at a position facing the recording head 44, the cleaning unit 88 moves between the recording head 44 (nozzle surface 40 </ b> A) and the cap unit 80. For example, as shown in FIG. 14, a configuration in which the holding member 90 of the cleaning unit 88 is an arch type and the wiper 92 is moved across the cap unit 80 in a state of being pressed against the nozzle surface 40 </ b> A of the recording head 44 can be considered.

  The movement (sliding contact) direction of the wiper 92 may be, for example, a paper conveyance direction or a width direction orthogonal to the paper conveyance direction. Further, the movement may be performed not only in one direction but also in a reciprocating manner.

  In the present embodiment configured as described above, the main circulation path formed by the main supply path 72, the main return path 74, and the main pump 76 causes the ink in the main tank 68 to be circulated between the sub tank 34, It is supplied to the sub tank 34.

  Further, the ink in the sub tank 34 is circulated by the sub circulation means constituted by the ink supply path 35, the ink circulation path 36, the ink return path 37 and the sub pump 38, and is supplied to each unit head 40. Then, while continuously transporting the paper in the paper transport path, ink droplets are ejected from the ink ejection port 84 of the unit head 40 to record an image on the paper.

  In addition, since the second housing 290 includes the maintenance unit 18, a predetermined maintenance operation (wiping, dummy jet, ink suction, etc.), capping at the time of non-image recording, etc. is performed on the recording head 44. As a result, the recording head 44 can be maintained in a good ejection state.

  In the middle of the image recording, the paper may be jammed in the paper conveyance path 104. In this case, first, the first drive case 288 is raised by rotating the lifting drive screw shaft 298, and then the case. It is rotated around the rotation shaft 292 and moved to a separated position separated from the second housing 290. Since the space between the first housing 288 and the second housing 290 is greatly opened, the jammed paper can be easily removed.

  Here, in the present invention, the extending direction of the ink discharge port 84 of the recording head 44 is made to coincide with the axial direction of the casing rotation shaft 292. For this reason, even when the first housing 288 is moved to the separated position, there is no difference in height between the both ends of the ink ejection port 84. Generally, the meniscus is maintained at the ink discharge port so that the ink does not overflow during non-printing, so that the inside of the recording head 44 is designed to be maintained at a predetermined negative pressure (for example, 0.45 kPa to 1.00 kPa). . When this negative pressure increases, the meniscus formed at the ink discharge port 84 is destroyed, air is drawn into the print head 44 from the ink discharge port, and in some cases, there is a possibility that it will flow back to the sub tank 34. is there. However, in the present invention, as described above, even when the first housing 288 is in the separated position, there is no difference in height between the both ends of the ink discharge port 84, and the same negative pressure is maintained. For this reason, destruction of the meniscus is prevented and air is not drawn. In particular, in the configuration using the recording head 44 having a width equal to or larger than the maximum paper width PW (see FIGS. 2 to 5 and 7) as in the present invention, the rotation in the direction intersecting with the arrangement direction of the ink discharge ports 84. When the first casing is rotated around the axis, a difference in height is generated at the ink discharge ports 84 at both ends, so that different negative pressures are generated and the meniscus is easily broken. However, according to the present invention, the meniscus can be reliably prevented from being destroyed even though the recording head 44 has a width equal to or larger than the maximum paper width PW.

  Further, since the longitudinal direction of the sub tank 34 is parallel to the axial direction of the casing rotation shaft 292 when viewed in plan, the pressure in the sub tank 34 when the first casing 288 is set to the separated position. It is possible to reduce the fluctuation (substantially hardly occur).

  In addition, the sub tank 34 is freely rotatable around a sub tank suspension shaft 294 that is parallel to the casing rotation shaft 292 and coincides with the extending direction of the ink discharge port 84. Even if the first housing 288 is rotated around the housing rotation shaft 292, the posture of the sub tank 34 does not change, and the distance between the sub tank suspension shaft 294 and the ink liquid level in the sub tank 34 (this distance is equal to the water head difference). Therefore, it is possible to reliably prevent meniscus destruction at the ink discharge port 84.

  In order to achieve such an effect, the sub-tank suspension shaft 294 does not necessarily coincide exactly with the extending direction of the ink discharge port 84. This point will be described in detail below.

  FIG. 20 shows the water head difference WH originally desired to be given to the nozzle surface 40A. As can be seen, the difference in height between the nozzle surface 40A where the ink discharge port 84 of the unit head 40 is formed and the ink liquid level LS in the sub tank 34 is the water head difference WH. Further, in FIG. 21, when the first housing 288 is in the recordable position (see FIG. 17), the housing rotation shaft 292 that is the rotation center of the sub tank 34 is moved in the horizontal direction from the ink discharge port 84. , A state in which the sheet is separated by z in the vertical direction is shown (here, the y-axis is taken in the direction in which the paper P is conveyed, and the z-axis is taken up vertically). In FIG. 21, the state where y = 0 and z = 0 is a state where the casing rotation shaft 292 coincides with the extending direction of the ink discharge port 84. In this case, the water head difference WH is the sub tank. This corresponds to the distance D from the suspension shaft 294 to the ink liquid level in the sub tank 34. Hereinafter, the case of y = 0 is excluded from the calculation.

First, as can be seen from FIG. 21, when considering a line segment L1 connecting the ink discharge port 84 and the sub-tank suspension shaft 294, the length of the line segment L1 is √ (y ² + z ² ). Further, if the angle formed by the line segment L1 with the y-axis is θ, θ = tan ⁻¹ (z / y).

Here, as shown in FIG. 19, when the first housing 288 is rotated about the housing rotation shaft 292 by an angle Θ, the height of the ink discharge port 84 and the sub-tank suspension shaft 294 is changed as shown in FIG. The difference d is d = [√ (y ² + z ² )] × sin (Θ−θ). Therefore, the water head difference WHR acting on the ink discharge port 84 is
WHR = D + d
= D + [√ (y ² + z ² )] × sin (Θ−θ)
It becomes. From the above, when the upper limit value of the design water head difference WH is set to WHU and the lower limit value is set to WHL, the sub tank suspension shaft 294 is rotated when the first casing 288 is rotated.
WHL ≦ WHR ≦ WHU
It can be seen that the position (y, z) satisfying the above relationship is sufficient.

  In the present embodiment, the overflow wall 62 provided in the sub tank 34 overflows the excess ink in the ink holding chamber 34S so that the liquid level is maintained constant. Regardless of the shape, a constant water head difference WH can always be obtained from the ink ejection surface of the recording head 44. Since the ink meniscus at the ink discharge port is stable, the ink discharge state (discharge direction, ink droplet volume, etc.) is also stable, and a high-quality image can be recorded.

  In addition, since the ink can be continuously supplied from the main tank 68 to the sub tank 34, the ink level in the sub tank 34 (ink holding chamber 34S) is not vibrated.

  The overflowed ink is returned from the ink return chamber 34R to the main tank 68 and can be reused in the ink jet recording apparatus 10, so that no ink is wasted.

  In order to maintain the water head difference WH within a certain range, it is necessary to prevent the ink amount in the ink holding chamber 34S from becoming too small. In the present embodiment, the ink level is detected by the liquid level sensor 78 provided in the ink holding chamber 34S. Therefore, the main surface of the ink holding chamber 34S does not fall below a predetermined height as necessary. The pump 76 can be driven to supply ink from the main tank 68. For example, the water head pressure that can form a meniscus stably at the ink discharge port is generally in the range of 0.45 kPa to 1.00 kPa as described above, and therefore the ink holding chamber 34S can accommodate this range. It is only necessary to have a certain depth. Then, the ink level in the ink holding chamber 34S is detected by the liquid level sensor 78, and the main pump 76 is driven to supply ink from the main tank 68 to the sub tank 34 so that the lower limit thereof does not fall below the above range. The ink liquid level in the ink holding chamber 34S may be maintained within a certain range.

It is a schematic block diagram which shows the recording device of this invention. It is a conceptual diagram which shows an example of the fundamental structure of the recording device of this invention. It is a conceptual diagram which shows the fundamental structure different from FIG. 2 of the recording device of this invention. It is a conceptual diagram which shows the fundamental structure different from FIG.2 and FIG.3 of the recording device of this invention. It is a conceptual diagram which shows the fundamental structure different from FIGS. 2-4 of the recording device of this invention. It is a schematic block diagram which shows the recording device of this invention. It is explanatory drawing of the printing area | region of the recording device which concerns on embodiment of this invention. It is explanatory drawing of the variation of the unit head which concerns on embodiment of this invention. It is explanatory drawing of the variation of the recording head which concerns on embodiment of this invention. It is explanatory drawing of the variation of the unit head which concerns on embodiment of this invention. It is explanatory drawing of the variation of the recording head which concerns on embodiment of this invention. It is explanatory drawing of the variation of the recording head which concerns on embodiment of this invention. It is explanatory drawing of the variation of the unit head which concerns on embodiment of this invention. It is a perspective view which shows the maintenance apparatus applicable with the recording device of this invention. (A)-(C) are operation | movement explanatory drawings of the maintenance apparatus shown in FIG. It is a front view which shows the recording part of the recording device of embodiment of this invention. It is a side view which shows the recording part of the recording device of embodiment of this invention in a recordable state. FIG. 3 is a side view showing a recording unit of the recording apparatus according to the embodiment of the present invention in a state where a first housing is raised. It is a side view which shows the recording part of the recording device of embodiment of this invention in a separation state. It is explanatory drawing which shows the water head pressure which arises with the height difference of the nozzle surface in which the ink discharge port was formed, and the ink liquid level of a sub tank. It is explanatory drawing which shows the positional relationship of an ink discharge port and the ink liquid level of a sub tank in the state which has a 1st housing | casing in a recordable position. It is explanatory drawing which shows the positional relationship of an ink discharge port and the ink liquid level of a sub tank in the state which has a 1st housing | casing in a separation position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet recording device 16 Recording head part 18 Maintenance part 20 Recording part 21 Recording part 34 Sub tank (ink holding means)
34B Sub tank main body 34H Holding piece 40A Nozzle surface (ink discharge surface)
40 Unit head 44 Recording head 58 Nozzle 80 Cap means (maintenance means)
81 Maintenance device (maintenance means)
84 Ink discharge port 88 Cleaning means (maintenance means)
104 Paper transport path 288 First housing 290 Second housing 292 Housing rotation shaft 294 Subtank suspension shaft 296 Lifting guide post 298 Lifting drive screw shaft D Water head difference LS Ink liquid level P Paper PW Paper maximum width WH Water head difference

Claims (5)

A first housing including a recording head having an ink discharge port formed on an ink discharge surface;
A second housing constituting a conveyance path for conveying a recording medium facing the ink ejection surface;
The first casing is rotated about a predetermined casing rotation axis so as to be separated from the second casing, and the first head is set so that the water head difference in the recording head is within a predetermined range in the separated state. Moving means for moving the housing;
An ink holding means provided in the first housing for holding ink supplied to the recording head;
Support means for supporting the ink holding means with respect to the first casing so as to be rotatable around a suspension axis parallel to the casing rotation axis;
A recording apparatus comprising: The recording apparatus according to claim 1 , wherein the movement of the first casing by the moving unit includes a parallel movement with respect to the second casing. A plurality of the ink discharge ports of the recording head are formed so as to extend in a predetermined extending direction,
The recording apparatus according to claim 1, wherein the casing rotation shaft and the extending direction of the ink discharge port are parallel to each other. The recording apparatus according to claim 1, wherein the ink holding unit is arranged so that a longitudinal direction of the ink holding unit in a plan view is parallel to the casing rotation axis . The recording apparatus according to claim 1 , wherein a maintenance unit that maintains the recording head is provided in the second casing.

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