JP4144386B2 - Recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus that performs recording by discharging ink from a recording means to a recording medium, and a recording apparatus that is used as an output device such as a facsimile, a copying machine, a printer complex machine, or a workstation having these functions.
[0002]
[Prior art]
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.
[0003]
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 generating means, means that heats ink by means using an electromechanical transducer such as a piezo element or an electrothermal transducer having a heating resistor generates air bubbles, and ejects ink droplets by generating the bubbles. Etc.
[0004]
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.
[0005]
However, at present, a printing method called serial scan, in which printing is performed line by line by reciprocating the recording head while conveying the recording paper, is widely used. 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 sheet. 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 paper width has been advanced to the limit. This printing method is an ink jet recording apparatus having a recording head corresponding to a paper width in which a large number of ejection openings are arranged over almost the same length as the recording paper, and the recording paper moves relative to a fixed recording head. Recording is performed.
[0006]
As described above, in order to improve the printing speed and cope with office use, an inkjet recording apparatus that performs printing while continuously conveying a sheet by a non-scanning recording head corresponding to the sheet width has been proposed (for example, Patent Documents). 1, 2, hereinafter referred to as Conventional Examples 1 and 2).
[0007]
On the other hand, in order to maintain good ink ejection performance in inkjet recording devices, the maintenance device ejects ink droplets during non-printing (dummy jets), cleans nozzle surfaces (wiping), and prevents ink drying (capping). ) Etc. are needed.
[0008]
For example, if the non-printing state continues for a long time, the dried ink thickens and the nozzles are clogged, or dust adheres to the nozzle surface. As a result, the ink droplets cannot be ejected (dot missing) or the ejection direction of the ink droplets changes, so that the print quality is lowered or the printing is impossible.
[0009]
Therefore, when printing is suspended for a certain period, the recording head is moved from the printing position to the maintenance position in the ink jet recording apparatus, dust and the like adhering to the nozzle surface of the recording head is removed with a wiper, and the nozzle surface is refreshed. To do.
[0010]
Further, in order to prevent the ink droplet ejection performance from being changed due to the change in the viscosity of the ink or the generation of bubbles, the ink droplets are ejected from the recording head to the receiving member when not printing.
[0011]
Further, a cap member is disposed to prevent the nozzle surface (nozzle) of the recording head from drying. The cap member seals the nozzle surface (nozzle) from the outside by pressing the rubber part against the nozzle surface.
[0012]
The ink jet recording apparatus according to Conventional Example 1 is provided with a long recording head having a length substantially the same as the width of the recording paper, and an apparatus for recovering the recording head. The recovery operation is performed by stopping and moving the recording head or the recovery device to a predetermined location.
[0013]
The ink jet recording apparatus according to Conventional Example 2 has a long recording head that is almost the same as the width of the recording paper, a recording head that is disposed facing the recording head, conveys the recording paper, and has a plurality of through holes on the surface. A formed belt and an ink receiving portion disposed to face the recording head across the belt are provided. Therefore, when the through hole of the belt is at a position facing the recording head, the ink droplet ejected from the recording head is landed on the ink receiving portion through the through hole by ejecting the ink droplet from the recording head. That is, a dummy jet can be performed.
[0014]
Further, the recording head surface is cleaned and capped by moving the recording head to the position of the cleaning device and the cap device.
[0015]
[Patent Document 1]
Japanese Patent Laid-Open No. 02-179754
[Patent Document 2]
Japanese Patent Laid-Open No. 03-092358
[0016]
[Problems to be solved by the invention]
However, in the conventional example 1, when performing the dummy jet, cleaning and capping of the recording head, it is necessary to move the recording head or the recovery device once to a predetermined position, which makes the configuration of the apparatus complicated and returns to printing. There was an inconvenience that it took time.
[0017]
Further, in the configuration of the conventional example 2, the dummy jet can be performed during printing, but the cleaning and capping of the recording head moves the recording head to a predetermined position, so that the apparatus configuration becomes complicated as in the conventional example 1. In addition, there is a disadvantage that it takes time to return to printing.
[0018]
Accordingly, an object of the present invention is to provide a recording apparatus capable of forming a high-quality image while ensuring productivity in order to solve the above-described disadvantages. Another object of the present invention is to provide a recording apparatus that can achieve a maintenance operation with a relatively easy configuration.
[0019]
[Means for Solving the Problems]
  The recording apparatus according to claim 1, wherein the recording apparatus forms an image by discharging droplets onto a recording medium,A plurality of recording head arrays composed of a plurality of unit recording heads arranged in the width direction are combined,A recording head that discharges droplets from the droplet discharge surface, and a maintenance unit that is disposed opposite to the droplet discharge surface of each recording head and performs maintenance of the recording head;An endless belt, and a holding means for holding the recording medium on the surface of the endless belt,A transport unit that is disposed before and after the recording head in the transport direction of the recording medium, and transports the recording medium between the droplet discharge surface of the recording head and the maintenance unit;A conveyance assisting means that is disposed between the recording head and the maintenance means and between the plurality of unit recording heads to ensure flatness of the recording medium;ThePreparedIt is characterized by that.
[0020]
The operation of the recording apparatus according to claim 1 will be described.
[0021]
Since the conveying means for conveying the recording medium under the recording head is arranged on the upstream side and the downstream side of the recording head in the conveying direction, a maintenance means is provided at a position facing the droplet discharge surface of the recording head. Can do. Therefore, the recording head can be maintained without moving the recording head or maintenance means. As a result, it is possible to avoid misalignment associated with the movement of the recording head and productivity reduction associated with the movement. In particular, the dummy jet can be performed before the recording medium passes and reaches the subsequent recording medium during continuous printing, so that both improvement in productivity and maintenance of high image quality can be satisfied.
[0022]
  Further, when the recording medium passes between the recording head and the maintenance means, it is difficult to ensure flatness because the leading edge and the trailing edge of the recording medium are separated from the conveying means. Therefore, the flatness of the recording medium at the printing position is ensured satisfactorily, and printing can be performed with high image quality. Then, by configuring a recording head by combining a plurality of recording head arrays in which a plurality of unit recording heads are arranged in the width direction, the degree of freedom of arrangement of the unit recording heads is improved. Furthermore, a recording head can be configured at low cost by configuring a recording head by combining a plurality of unit recording heads with low unit prices. Further, by arranging a conveyance auxiliary means, for example, a spur, between the plurality of unit recording heads constituting the recording head, the conveyance auxiliary means can be easily arranged. further,Since the recording medium is conveyed and held on the endless belt by electrostatic force or non-electrostatic force, it is possible to print with high image quality.
[0023]
The recording apparatus according to claim 4 is the recording apparatus according to any one of claims 1 to 3, wherein the endless belt of the recording medium is located at a position facing the endless belt in a recording medium holding range of the endless belt. It is characterized in that a lifting prevention means is provided for preventing the lifting from the lift.
[0024]
The operation of the recording apparatus according to claim 4 will be described.
[0025]
The recording medium is conveyed between the recording medium and the maintenance means in a state in which the recording medium is reliably prevented from floating from the endless belt by the lifting prevention means. Therefore, high-quality printing is realized without damaging the droplet discharge surface of the recording head.
[0026]
A recording apparatus according to a fifth aspect is the recording apparatus according to any one of the first to fourth aspects, wherein the conveying means includes a belt cleaning means for cleaning the endless belt.
[0027]
The operation of the recording apparatus according to claim 5 will be described.
[0028]
The endless belt becomes soiled by liquid mist accompanying droplet discharge, adhesion of droplets accompanying borderless printing, and the like. Therefore, after the endless belt conveys the recording medium, the endless belt is removed by the belt cleaning unit, and the endless belt is prevented from adhering to the subsequent recording medium.
[0029]
The recording apparatus according to claim 6 is the recording apparatus according to any one of claims 1 to 5, wherein an interval between conveying means disposed on the upstream side and the downstream side in the conveying direction of the recording medium with the recording head interposed therebetween. Is shorter than the minimum transport direction length of the recording medium.
[0030]
The operation of the recording apparatus according to the sixth aspect will be described.
[0031]
The recording medium sent out from the conveying means on the upstream side in the conveying direction of the recording head passes under the recording head and is held by the conveying means on the downstream side. In this case, if the sheet is not held by the downstream conveyance unit before being peeled from the upstream conveyance unit, the conveyance becomes impossible. Accordingly, a recording medium having a short length in the conveyance direction can be reliably conveyed by making the interval of the conveyance means shorter than the minimum conveyance direction length of the recording medium.
[0032]
  8. A recording apparatus according to claim 7.Is, ClaimsAny one of 1-6In the recording device described,The conveyance auxiliary means is provided at both ends in the width direction of the maintenance means.It is characterized by that.
[0033]
The operation of the recording apparatus according to claim 7 will be described.
[0034]
  Since the back surface of the paper is supported by the guide member, the paper is prevented from being pushed into the maintenance means.
[0035]
  The recording apparatus according to claim 8 is the recording apparatus according to claim 7,The conveyance assist means includes a guide member that supports the non-recording surface side of the recording medium.It is characterized by that.
[0036]
The operation of the recording apparatus according to claim 8 will be described.
[0037]
  Since the conveyance auxiliary means provided on the maintenance means side is a guide member that supports the drawing recording surface side of the recording medium, the recording medium is reliably prevented from entering the maintenance means, and the recording medium is stably conveyed. At the same time, the flatness of the recording medium can be reliably maintained at the recording position.
[0038]
  The recording apparatus according to claim 9 is the recording apparatus according to claim 8, wherein the conveyance assisting means is a spur that contacts the recording surface side of the recording medium.WithIt is characterized by being.
[0039]
The operation of the recording apparatus according to claim 9 will be described.
[0040]
Since the spur comes into contact with the recording surface side of the recording medium, the distance from the droplet discharge surface of the recording head is kept constant, and printing is performed with high image quality. Further, since it is a spur that abuts the recording surface on the recording medium, the influence on the image quality is suppressed to a minimum, and printing is performed with high image quality.
[0041]
  The recording apparatus according to claim 10 is the claim.Any one of 1-9In the recording device described,The recording head has a printing width larger than a recording medium width.It is characterized by that.
[0042]
The operation of the recording apparatus according to claim 10 will be described.
[0043]
  Since the recording head has a printing width larger than the recording medium width, printing can be performed over the entire width of the recording medium simply by ejecting droplets onto the recording medium conveyed from the fixed recording head. Therefore, high-speed printing (printing with high productivity) becomes possible.
[0059]
  Claim11The recording apparatus according to claim 1.105. The recording apparatus according to claim 1, wherein the maintenance unit is capable of approaching and separating from the droplet discharge surface of the recording head, and presses against the droplet discharge surface to make the droplet discharge surface airtight. In addition, it is characterized by comprising cap means for landing droplets discharged during non-printing and cleaning means for wiping the droplet discharge surface.
[0060]
  Claim11The operation of the described recording apparatus will be described.
[0061]
Since the maintenance means has a cap means and a cleaning means, the nozzle surface of the recording head and the liquid are dried by bringing the cap means into pressure contact with the droplet ejection surface of the recording head arranged oppositely to make the droplet ejection surface airtight. In addition, it is possible to receive droplets (dummy jets) ejected from the recording head while being separated from the recording head.
[0062]
Further, by wiping the droplet discharge surface by the cleaning means, the stain on the droplet discharge surface can be removed, and the droplet discharge performance can be maintained favorably.
[0063]
  Claim12The recording device as claimed in claim11In the recording apparatus described above, the cleaning unit is configured to be close to and away from the droplet discharge surface of the recording head, and is in contact with the droplet discharge surface during cleaning.
[0064]
  Claim12The operation of the described recording apparatus will be described.
[0065]
The cleaning means can be surely removed by contacting the droplet discharge surface of the recording head during cleaning.
[0066]
  Claim13The recording apparatus according to claim 1.12The recording apparatus according to claim 1, wherein a plurality of the recording heads are arranged along a conveyance direction of the recording medium.
[0067]
  Claim13The operation of the described recording apparatus will be described.
[0068]
By arranging a plurality of recording heads along the conveyance direction of the recording medium, various types of printing can be performed.
[0069]
  Claim14The recording device as claimed in claim13In the recording apparatus described above, liquids of different colors are ejected from the plurality of recording heads.
[0070]
  Claim14The operation of the described recording apparatus will be described.
[0071]
By arranging a plurality of recording heads that discharge liquids of different colors, multicolor printing can be performed.
[0072]
  Claim15The recording apparatus according to claim 1.14The recording apparatus according to claim 1, wherein the recording head, the maintenance unit, and a transport unit disposed on the upstream side or the downstream side of the recording head are unitized.
[0073]
  Claim15The operation of the described recording apparatus will be described.
[0074]
In this way, the recording head, the maintenance means, and the conveying means arranged on the upstream side or the downstream side of the recording head are unitized, so that a single color, a full color, or a special color can be obtained by arranging one or a plurality of the units. It is possible to easily configure an image forming apparatus that meets various requirements including the above. Further, the unit maintenance improves the maintainability of the apparatus.
[0075]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
An ink jet recording apparatus according to a first embodiment of the present invention will be described.
(Overall configuration of inkjet recording apparatus)
First, the overall configuration of the ink jet recording apparatus will be briefly described.
[0076]
As shown in FIG. 1, the ink jet recording apparatus 10 basically includes a sheet supply unit 12 that sends out a sheet, and a recording unit 20 that forms an image on the sheet supplied from the sheet supply unit 12 and discharges the image to the outside. Is done.
[0077]
The sheet supply unit 12 is configured to pull out sheets one by one from the tray 14 by the feed roller 16 and supply the sheet to the recording unit 20 via the guide member 18.
[0078]
The recording unit 20 is arranged at regular intervals, and recording heads 44Y, 44M, 44C, 44K (hereinafter, the other reference numerals 44Y to 44K are also the same) that print yellow, magenta, cyan, and black, respectively. The conveying belt units 19A to 19E arranged on the upstream side and the downstream side in the paper conveying direction of each recording head, that is, the recording belts 44Y to 44K and the maintenance units arranged to face the recording heads 44Y to 44K, respectively. It is comprised from 18Y-18K.
[0079]
That is, the ink droplets are ejected from the recording heads 44Y to 44K onto the paper continuously conveyed (without stopping) by the conveying belt units 19A to 19E, and an image is formed on the paper. Since the recording unit 20 will be described later, detailed description thereof will be omitted.
(Conveyor belt unit configuration)
Since the conveyor belt units 19A to 19E have the same configuration, only the conveyor belt unit 19A will be described as a representative example, and other description will be omitted.
[0080]
As shown in FIG. 2, the conveying belt unit 19A includes a driving roller 100, driven rollers 102A and 102B, an endless belt 104 stretched between the driving roller 100 and the driven rollers 102A and 102B, and an endless belt 104. It basically includes a charging roll 106 that is a holding means for holding the paper, and a lift prevention member 108 that prevents the paper from lifting from the endless belt 104.
[0081]
The drive roller 100 rotates the endless belt 104 that is stretched. As a material of the drive roller 100, all metals (SUS, aluminum material, etc.) can be used, and a predetermined strength is secured. Plastic materials can also be used. Further, in order to ensure friction between the back surface of the belt and the roller surface when the belt is wound around the roller, the surface of the metal roller may be coated with a rubber material.
[0082]
The driven rollers 102 </ b> A and 102 </ b> B are driven by the driving rotational force of the driving roller 100 transmitted through the endless belt 104, and support the endless belt 104 together with the driving roller 100.
[0083]
As the material of the driven rollers 102A and 102B, all metals (SUS, aluminum material, etc.) can be used, and a plastic material having a predetermined strength can also be used. Further, in order to ensure friction between the back surface of the belt and the roller surface when the belt is wound around the roller, the surface of the metal roller may be coated with a rubber material.
[0084]
In the present embodiment, the driving roller 100 and the driven rollers 102A and 102B are formed from a SUS material.
[0085]
The endless belt 104 is a seamless belt that is seamless and does not expand and contract so as to be stably conveyed and has durability. The endless belt 104 is given a predetermined tension and has flatness.
[0086]
The material of the endless belt 104 is a material that can hold paper (electrostatically holdable), for example, a polymer sheet such as polyester, polyethylene terephthalate, polyethersulfone, polyetherketone, polysulfone, polyimide, polyimideamide, and polyamide. Etc.
[0087]
In particular, polyimide and polyimiamide are preferable in terms of ink resistance and stress resistance and crack resistance when wound around the driving roller 100 and the driven rollers 102A and 102B.
[0088]
In consideration of durability, the above materials and metal materials (general materials) are used for the base material, and the surface is covered with a semiconductive material (such as the above materials) capable of electrostatically holding paper, and two layers Can be structured.
[0089]
In this embodiment, the endless belt 104 is made of a semiconductive polyimide resin material, has a rotation direction length of 300 mm, a width of 380 mm (corresponding to the width of the paper A4), and a thickness of 300 μm.
[0090]
Further, a sheet holding means, a lifting prevention means, and a belt cleaning means are provided along the rotation direction of the endless belt 104 stretched around the transport belt unit 19A. These will be described below.
[0091]
The paper holding means holds the paper supplied to the transport belt unit 19Y by the guide member 17 of the paper supply unit 12 on the endless belt 104, and may be based on electrostatic force or non-static. It may be due to electric force.
[0092]
In this embodiment, a means using electrostatic force is employed, and a charging roll 106 disposed opposite to the driven roll 102 is used. Therefore, the sheet conveyed from the sheet supply unit 12 is charged by the charging roll 106 and the sheet charged by pressing with a predetermined pressure is surely electrostatically adsorbed on the endless belt 104.
[0093]
The charging roll 106 has a roll surface in which conductive carbon is dispersed in a rubber roll such as silicone rubber, and its volume resistivity is 10⁸Ω · cm to 10¹³It is adjusted to about Ω · cm. For example, conductive carbon is dispersed to have a volume resistivity of 10⁸Ω · cm to 10¹³A roll in which silicone rubber (thickness of about 100 μm) adjusted to about Ω · cm is coated on the surface of a SUS core is used.
[0094]
When the sheet is held by electrostatic force, a voltage 1 kv (constant voltage control) is applied to the endless belt 104 while applying a pressing force of 1 kgf to the endless belt 104 and the sheet by the charging roll 106, and the sheet is placed on the endless belt 104. It is configured to be held. In general, in consideration of the influence on the endless belt 104, the applied voltage is preferably about 0.5 to 2 kv (constant voltage control), and the pressing force of the charging roll 106 is preferably about 0.5 to 3.0 kgf.
[0095]
In the present embodiment, the charging roll has been described, but a corotron or a brush may be used. The applied voltage in this case is also performed under substantially the same conditions as the roll.
[0096]
By the way, although this embodiment demonstrated the holding method by an electrostatic force, the holding method by a non-electrostatic force may be used. For example, there may be mentioned a method in which an adhesive material (for example, a vulcanized rubber whose degree of vulcanization is adjusted) or the like is applied to the surface of the endless belt 104 and the paper is pressed and held with a roll or the like. In addition, a method of arranging a gripper on the belt and gripping and conveying the leading end of the sheet, a method of sucking and conveying with air from the lower side of the sheet conveying path, and the like can be considered.
[0097]
By the way, the sheet held on the endless belt 104 by the holding means is peeled from the endless belt 104 at a position where the curvature of the endless belt 104 becomes large on the driven roll 102B, and is inserted between the recording head 44Y and the maintenance unit 18Y. It is a configuration. Here, in the conveyance belt unit 19A, a range from the charging roll 106 to the sheet peeling position is referred to as a sheet conveyance section.
[0098]
A paper detection sensor 107 (for example, a transmissive fiber sensor) is disposed on the downstream side of the charging roll 106 in the paper conveyance direction so as to face the endless belt 104, and the recording head is detected by detecting the leading edge of the paper. The ink droplet ejection timing at 44Y is controlled. Note that the paper detection sensor 107 controls the ink droplet ejection timing of the recording head 44 disposed immediately downstream in the paper transport direction, so that the transport disposed downstream of the recording head 44K in the transport direction. The unit 19E is not provided.
[0099]
Further, a lifting prevention means is disposed on the downstream side of the sheet detection sensor 107 in the conveyance direction so as to face the sheet conveyance section of the endless belt 104. This is to prevent the sheet from lifting from the endless belt 104, and rolls, plates, spurs, and the like are conceivable. In the present embodiment, the plate 108 extends from the bottom of the charging roll 106 to the end of the recording head 44. Specifically, the plate 108 is made of SUS and has a thickness of 1 mm, a width of 380 mm, and a length of 100 mm.
[0100]
The belt cleaning means is disposed opposite to the endless belt 104 at a position outside the paper conveyance section of the endless belt 104 and can approach and separate from the endless belt 104. Cleaning is performed. Generally, there are cleaning rolls, brushes, blades, and the like. However, since the purpose of the present invention is to remove ink, the cleaning roll 116 in which an ink absorber is wound around the roll surface is preferable.
[0101]
The material of the ink absorber wound around the surface of the cleaning roll 116 is preferably a polyester felt fiber material or an acrylonitrile felt fiber material, and further, a mixture of a polyester felt fiber material and an acrylonitrile felt fiber material. Is also preferable. By appropriately changing the fiber diameter, fiber length, arrangement direction, etc. of the used fiber material, the ink holding capacity of the ink absorber is finely adjusted.
[0102]
Other examples include polyamide fiber materials, polypropylene fiber materials, polyvinyl alcohol fiber materials, polyvinylidene chloride fiber materials, polyurethane fiber materials, and the like.
[0103]
In view of absorbability of ink or the like, a polyester fiber material is more preferable, and a material system in which the above materials are mixed may be used.
[0104]
The ink absorber of this embodiment is formed from polypropylene and polyethylene.
[0105]
Note that the interval between the conveyance belt units 19 adjacent in the conveyance direction, for example, the interval between the conveyance belt units 19A and 19B, is shorter than the minimum sheet conveyance direction length (A4 short length in this embodiment). This is to enable the downstream conveyance belt unit to start holding the sheet before the holding of the sheet in the upstream conveyance belt unit is completed regardless of the sheet size.
(Configuration of recording head)
Next, the recording head portions 44Y to 44K will be described in detail with reference to FIGS. FIG. 3 is a schematic view of the recording head unit 16 as viewed from the paper transport position.
[0106]
Each of the recording heads 44Y to 44K ejects ink droplets of cyan, magenta, yellow, and black, and as shown in FIG. 1, the paper transport direction (arrow X direction; hereinafter referred to as the transport direction). ), The conveying belt unit 19 is interposed between the recording heads.
[0107]
Since the recording heads 44Y to 44K have the same configuration, only one recording head 44 will be described below.
[0108]
Each recording head 44 is constituted by a combination of a plurality of unit recording heads 40.
[0109]
As shown in FIG. 4, the unit recording head 40 has nozzles 58 that eject ink on a nozzle surface 40A formed in a straight line, and ejects ink droplets by a well-known thermal ink jet method.
[0110]
The unit recording head 40 has both sides of a common substrate 46 to be described later in a straight line so that the nozzle arrangement direction coincides with the paper width direction (arrow Y direction; hereinafter referred to as width direction) orthogonal to the paper transport direction. Each of the six unit recording heads 40 is attached to form recording head arrays 42YA and 42YB.
[0111]
As shown in FIG. 3, each of the recording head arrays 42YA and 42YB has six unit recording heads 40 arranged at regular intervals. In the recording head arrays 42YA and 42YB, the unit recording heads 40 are arranged. Are arranged so as to be shifted from each other in the width direction, so that a part of the nozzle row of the unit recording head 40 has an overlapping region OL that overlaps between the recording head arrays 42A and 42B. By providing the overlap area OL in this way, it is possible to prevent an area that cannot be printed from occurring in the print area. That is, printing of one color on the paper is performed by ejecting ink droplets from the nozzles 58 of the unit recording heads 40 of the recording head array pairs 42A and 42B. In the present embodiment, the combination of the pair of recording head arrays 42YA and 42YB is referred to as a recording head 44.
[0112]
The print area is basically the largest of the recording areas obtained by subtracting the margin for non-printing from both ends of the paper, but is generally larger than the maximum paper width PW to be printed. Also in this embodiment, the print area may be larger than the maximum paper width PW because there is a possibility that the paper may be conveyed at a predetermined angle with respect to the conveyance direction (skewed) and there is a high demand for borderless printing. Is set (see FIG. 3). The recording head 44 of the present embodiment has a printing area of 12 inches, and the maximum paper width PW is 297 mm, which is an A3 short width (A4 long width).
[0113]
The recording head 44 is configured so that yellow (Y), magenta (M), cyan (C), and black (K) are printed in this order from the upstream side in the transport direction, and full-color printing is possible. The reference numerals of the heads are distinguished by adding symbols Y, M, C, and K (44Y, 44M, 44C, and 44K) (see FIG. 1). Hereinafter, the same applies to other members.
[0114]
In the recording head arrays 42A and 42B, a star wheel 70 is disposed next to each unit recording head 40 (see FIG. 3). The star wheel 70 is elastically supported on the common substrate 46 via a leaf spring. The star wheel 70 is elastically brought into contact with a guide member 94 described later, and presses the sheet against the guide member 94.
[0115]
As shown in FIG. 5A, the star wheel 70 includes a cylindrical resin holding body 76 in which a hole 74 is formed, and a stainless steel wheel 78 held by the holding body 76. .
[0116]
The holding body 76 includes a first member 76A that is reduced in diameter in the center in the axial direction so that the wheel can be inserted, and a second member 76B that fits in the reduced diameter portion and sandwiches the wheel 78 together with the first member 76A. ing. The wheel 78 has a large number of teeth 79 formed at regular intervals on the outer periphery. The tip shape of the tooth 79 is obtuse and R-shaped (see FIG. 5B). However, the contact area only needs to be as small as possible because it contacts the undried ink on the paper. Or an acute angle (see FIG. 5C).
[0117]
Further, in this embodiment, the thickness of the wheel 78 is 0.1 mm, and the thickness of the tip (tooth tip) is reduced to about 0.01 to 0.02 mm by taper processing. The wheel 78 is formed by simultaneously processing the outer shape and the tapered shape of the tip from a SUS631EH material by double-sided step etching, and has a water-repellent coating on the surface.
(Maintenance department configuration)
The configuration of the maintenance units 18Y to 18K arranged to face the recording heads 44Y to 44K will be described with reference to FIGS. FIG. 6 is a plan view of the maintenance unit 18 from the paper transport position. Since the maintenance units 18Y to 18K have the same configuration, only one maintenance unit 18 will be described.
[0118]
The maintenance unit 18 is disposed to face the recording head 44 (see FIG. 1). As shown in FIG. 6, the maintenance unit 18 includes a maintenance device 81 including a cap member 80 and a wiping member 88 corresponding to each unit recording head 40.
As shown in FIG. 7, the cap member 80 includes a plastic receiving portion 82 in which a rectangular recess 82 </ b> A is formed, a rubber portion 84 disposed on the receiving portion 82 and having an opening 84 </ b> A, The ink absorber 86 is made of polypropylene and polyethylene disposed on the bottom surface of the recess 82A. Therefore, in the case of a dummy jet, which will be described later, ink droplets are ejected from the nozzles 58 of the unit recording heads 40 into the recesses 82A through the openings 84A of the cap member 80 and absorbed by the ink absorber 86. .
[0119]
The rubber portion 84 covers the entire nozzle surface 40A when capping, which will be described later, and is configured such that the nozzle 58 is positioned in the opening portion 84.
[0120]
Here, the plastic material constituting the receiving portion 82 includes POM, PET, PBT, PPS, nylon 66, acrylic, bakelite, etc., but PBT is preferable in terms of moldability, heat resistance, impact resistance, and the like.
[0121]
The rubber material constituting the rubber portion 84 includes various natural rubbers such as raw rubber, isoprene rubber, butadiene rubber, olefin rubber, ether rubber, polysulfide rubber, urethane rubber, fluorine rubber, and silicone rubber. Various elastic members such as various elastomers (rubber elastic bodies), blend rubbers of these rubber-based materials, or blend rubbers of these rubber-based materials and various plastics can be used, and combinations of these materials can be used. good.
[0122]
Among these materials, hydrogenated nitrile butadiene rubber, ethylene propylene rubber (EPDM), polydimethyl silicone rubber, methyl vinyl silicone rubber, methyl in terms of heat resistance, weather resistance, chemical resistance, abrasion resistance and processability. Phenyl silicone rubber, fluorosilicone rubber and the like are preferable.
[0123]
Further, the material of the ink absorber 86 is preferably a polyester felt fiber material or an acrylonitrile felt fiber material, and more preferably a mixture of a polyester felt fiber material and an acrylonitrile felt fiber material. By appropriately changing the fiber diameter, fiber length, arrangement direction and the like of the used fiber material, the ink holding capacity of the ink absorber 86 can be finely adjusted.
[0124]
Other examples include polyamide fiber materials, polypropylene fiber materials, polyvinyl alcohol fiber materials, polyvinylidene chloride fiber materials, polyurethane fiber materials, and the like.
[0125]
Considering the absorbability of recording liquid such as ink, a polyester fiber material is more preferable, and it is also preferable to use a material system in which the above materials are mixed.
[0126]
Further, as shown in FIG. 8, the cap member 80 is unitized by attaching six cap members 80 respectively corresponding to the unit recording heads 40 constituting the recording head array 42 to the common substrate 300, and the elevating mechanism. 302 is configured to be able to approach and separate from the nozzle surface 40A of the unit recording head 40 integrally.
[0127]
The elevating mechanism 302 includes a drive motor 304 and an eccentric cam 308 that is attached to the drive shaft 306 of the drive motor 304 and is in contact with the lower surface of the common substrate 300. Accordingly, the eccentric cam 308 is rotated by driving the drive motor 304, and the common substrate 300 with which the eccentric cam 308 is in contact is moved closer to and away from the nozzle surface 40 </ b> A of the unit recording head 40.
[0128]
A spring 87 that adjusts the pressure contact force when pressed against the nozzle surface 40A is disposed below the cap member 80 (see FIGS. 2 and 9). Therefore, at the time of a capping operation described later, the cap member 80 is raised and the rubber portion 84 is pressed against the nozzle surface 40A to seal the nozzle surface 40A including the nozzle 58, thereby preventing ink drying and preventing dust, dust, etc. Prevent adhesion. Further, during the wiping operation described later, the cap member 80 is lowered so that the wiping member 88 can be moved in the width direction.
[0129]
On the other hand, a wiping member 88 for cleaning the nozzle surface 40A of each unit recording head 40 is disposed at a position adjacent to each cap member 80 in the width direction.
[0130]
As shown in FIG. 7, the wiping member 88 includes a holding member 90 that has an arch shape when viewed in the width direction, and a wiper 92 that is disposed above the holding member 90 and extends in the transport direction. Is.
[0131]
The holding member 90 is made of a metal material having strength such as aluminum or SUS.
[0132]
On the other hand, the wiper 92 is formed to have a rubber hardness of 30 to 80 in order to obtain a predetermined rigidity, the longitudinal (conveyance) direction length (L1) is 10 mm, and the short (width) direction width (W1) is 0.8 mm and high. The thickness is 6 mm and the contact amount is 1.5 mm.
[0133]
The wiper 92 is made of raw rubber, isoprene rubber, butadiene rubber, olefin rubber, ether rubber, polysulfide rubber, urethane rubber, fluorine rubber, silicone rubber, and other natural rubbers, and various elastomers (rubber elastics). In addition, various elastic members such as blend rubbers of these rubber materials or blend rubbers of these rubber materials and various plastics can be used, and a combination of these materials may be used.
[0134]
Among these materials, hydrogenated nitrile butadiene rubber, ethylene propylene rubber (EPDM), polydimethyl silicone rubber, methyl vinyl silicone rubber, methyl in terms of heat resistance, weather resistance, chemical resistance, abrasion resistance and processability. Phenyl silicone rubber, fluorosilicone rubber and the like are preferable.
[0135]
In addition, an excellent thermoplastic elastomer or the like is preferable in terms of fatigue resistance, moldability, rubber characteristics, and the like.
[0136]
Further, the surface of the wiper 92 can be covered with a protective layer. The protective layer is preferably a fluorine resin excellent in liquid repellency and low frictional properties. Various plastic materials are also applicable.
[0137]
As specific materials, molded articles such as polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyvinyl chloride resins, polyvinylidene chloride resins, epoxy resins, polycarbonate resins, polyethylene resins, polypropylene resins and polystyrene resins may be used. .
[0138]
Furthermore, a film obtained by laminating and bonding these film materials may be cut with high accuracy. At this time, an acrylic polymer, a rubber polymer, or the like is suitable as the adhesive.
[0139]
As shown in FIG. 8, the wiping members 88 are unitized by attaching six wiping members 88 corresponding to the unit recording heads 40 constituting the recording head array 42 to the common substrate 310, and are moved by the moving mechanism 312. The unit recording head 40 is configured to be movable toward and away from the nozzle surface 40A of the unit recording head 40 and in the width direction.
[0140]
The moving mechanism 312 basically includes a slider 314 that supports the common substrate 310 so as to be movable in the width direction, a drive motor 316 that moves the common substrate 310 in the width direction on the slider 314, and a drive motor 318 that moves the slider 314 up and down. Constructed. The slider 314 includes guides 320 provided at both ends in the transport direction and extending in the width direction, and the common substrate 310 guided by the guides 320 is movable in the width direction. Further, a convex portion 324 in which a rack 322 is formed is formed on one side surface of the common substrate 310 and meshes with a drive gear 326 of a drive motor 316 attached to the slider 314. Therefore, the common substrate 310 can be moved in the width direction on the slider 314 by driving the drive motor 316.
[0141]
Further, a convex portion 332 provided with a rack 330 extending in the vertical direction is formed below the slider 314, and the drive gear 334 of the drive motor 318 is engaged. Therefore, the slider 314 can be moved up and down by the drive motor 318. That is, the common substrate 310 and the wiping member 88 supported by the slider 314 are configured to move up and down integrally.
[0142]
As described above, the wiping member 88 is configured to be movable toward and away from the nozzle surface 40A by the moving mechanism 312 (up and down) and is movable in the width direction. That is, the wiping member 88 (wiper 92) is located at a position lower than the cap member 80 so as not to interfere with the conveyed paper at the home position (see FIG. 10A), but rises during wiping. Thus, the wiping is performed by moving in the transport direction across the cap member 80 lowered from the home position (see FIG. 10C).
[0143]
In the maintenance unit 18, guide members 94 are disposed at both ends in the width direction of each maintenance device 81 so that the sheet does not enter the recess 82A of the cap member 80 during sheet conveyance (see FIGS. 6 and 7). ).
[0144]
The guide member 94 is made of SUS material, and as shown in FIG. 7, a horizontal portion 94A extending in the conveying direction, two vertical portions 94B extending vertically downward from both ends of the horizontal portion 94A, and a horizontal portion It comprises guide portions 94C and 94D extending obliquely downward in the transport direction from both ends in the transport direction of the portion 94A.
[0145]
The horizontal portion 94A of the guide member 94 is disposed so as to face the star wheel 70 disposed between the unit recording heads (see FIGS. 3 and 6). Therefore, the transported paper is pressed against the guide member 94 (horizontal portion 94A) by the star wheel 70 at the printing position in the transport direction, and the paper that is deformed by ink adhesion or the like is kept at a certain distance from the nozzle surface 40A. It is.
[0146]
The operation of the inkjet recording apparatus 10 configured as described above will be described.
[0147]
The paper drawn from the tray 14 of the paper supply unit 12 by the drawing roller pair 16 is supplied by the guide member 18 to the transport belt unit 19A.
[0148]
On the other hand, in the conveyor belt 19Y, the driving roller 100 is driven, and the endless belt 104 is rotated in the arrow X direction.
[0149]
Therefore, the sheet that contacts the endless belt 104 is conveyed in the direction of the arrow X together with the endless belt 104, and is charged by the charging roll 106 and pressed against the endless belt 104, so that the sheet is reliably electrostatically attracted to the endless belt 104. become. When the electrostatically attracted paper is conveyed together with the endless belt 104, the front edge of the paper is detected by the paper detection sensor 107, and the ink droplet ejection timing from each unit recording head 40 of the recording head 44Y is controlled. Further, the sheet electrostatically adsorbed on the endless belt 104 is prevented from being lifted from the endless belt 104 by the plate 108 which is a lift prevention means, and the flatness is maintained, and the curvature becomes large at the position of the driven roller 102B. It peels from the endless belt 104 and is conveyed between the recording head 44Y and the maintenance unit 18Y.
[0150]
The leading edge of the sheet reaches the horizontal portion 94A by being guided by a guide portion 94C of a guide member 94 provided adjacent to the maintenance device 81 in the width direction in the maintenance portion 18Y. That is, it is avoided that the back surface of the paper is supported by the guide member 94 and thrust into the maintenance device 81.
[0151]
Further, the paper is pressed against the horizontal portion 94A by the star wheel 70 of the recording head 44Y that elastically contacts the horizontal portion 94A to prevent the paper from being lifted, and the recording head 44Y (the nozzle surface 40A of each unit recording head 40). Is a fixed distance.
[0152]
In this state, when the sheet passes under the recording head 44Y, ink is supplied from the nozzles 58 of the unit recording heads 40 of the recording head array 42YA constituting the recording head 44Y and subsequently to the unit recording heads 40 of the recording head array 42YB. Drops are ejected to form a yellow image on the paper.
[0153]
Since the interval between the conveyance belt units 19A and 19B is shorter than the minimum conveyance direction length of the sheet, the conveyance belt unit 19A is separated before the trailing end of the sheet is peeled from the endless belt 104 of the conveyance belt unit 19A. The endless belt 104 of 19B can hold the leading edge of the paper and can be reliably conveyed.
[0154]
Hereinafter, magenta, cyan, and black ink droplets are ejected from the unit recording heads 40 constituting the recording heads 44M, 44C, and 44K onto the paper that is held and conveyed on the endless belt 104, thereby providing full color. Are formed on the paper.
[0155]
The paper on which the color image is formed is peeled off from the endless belt 104 of the transport belt unit 19E and discharged to the outside.
[0156]
Next, the operation of the dummy jet will be described.
[0157]
The dummy jet is performed before the leading edge of the succeeding sheet arrives at the time of non-printing or whenever a predetermined number of sheets are printed during continuous printing of a plurality of sheets. That is, ink droplet ejection (so-called dummy jet) is performed from an arbitrary nozzle 58 toward the cap member 80 among all the unit recording heads 40 constituting the recording heads 44Y to 44K. The dummy jet may be performed by all nozzles of all unit recording heads 40, or may be performed by selected unit recording heads 40 or all nozzles 58 of recording head array 42, and further, ink droplets are ejected for a predetermined time. Only the nozzle 58 that is not used may be used.
[0158]
For example, the distance between the nozzle surface 40A and the upper surface of the cap member 80 at the time of dummy jet for continuous printing of a plurality of sheets is set to 3 mm, and the leading end of the succeeding sheet is reached after passing the preceding sheet every 30 pages (A4). 1000 drops are discharged from all nozzles at the previous timing.
[0159]
At this time, since the ink absorbing member 86 is disposed on the bottom surface of the concave portion 82A of the cap member 80, the discharged ink does not overflow or scatter from the concave portion 82A.
[0160]
In this way, by ejecting ink droplets (dummy jets) from all the nozzles of the unit recording head 40, it is possible to initialize the ejection performance by drying ink (particularly water-based ink, solvent ink). In addition, even if the ink is oily ink or solid ink that hardly dries, it is possible to eliminate bubbles adhering to the ink flow path or the like inside the head by printing or to remove dust adhering to the nozzle surface. The discharge performance can be initialized.
[0161]
As in this embodiment, dummy printing can be performed without moving the recording head 44 and the cap member 80 during printing of a plurality of sheets that are continuously printed (conveyed). Improvement) is achieved. Further, the printing performance of the recording head 44 is maintained constant by the dummy jet, and high-quality printing is possible.
[0162]
Next, the wiping operation will be described.
[0163]
The wiping operation is performed before starting printing. The wiping member 88 of the maintenance unit 18 wipes the recording head 40 (nozzle surface 40A). A specific operation will be described based on the schematic diagram shown in FIG.
[0164]
First, the drive motor 304 of the lifting mechanism 302 shown in FIG. 8 is driven, and the common substrate 300 is lowered by the rotation of the eccentric cam 308. Further, the drive motor 318 of the moving mechanism 312 is driven, and the common substrate 310 supported by the slider 314 and the slider 314 is raised. That is, the six cap members 80 attached to the common substrate 300 are lowered from the home position (moved in a direction away from the recording head 40), and the six wiping members 88 attached to the common substrate 310 are moved to the home position. (Moves toward the nozzle surface 40A side of the recording head 40) (see FIG. 10A → FIG. 10B).
[0165]
In the present embodiment, the cap member 80 descends to a position 6 mm from the nozzle surface 40A of the unit recording head 40, and the tip (upper end) of the wiper 92 of the wiping member 88 is 1.5 mm higher than the nozzle surface 40A (hereinafter referred to as “the nozzle surface 40A”). The contact amount is 1.5 mm).
[0166]
As a result, the holding member 90 of the wiping member 88 can move in the width direction across the cap member 80. Further, the wiper 92 of the wiping member 88 overlaps the nozzle surface 40A of the recording head 40 in the vertical direction (FIG. 10, arrow Z direction) (see FIG. 10B).
[0167]
In this state, by driving the drive motor 316 of the moving mechanism 312 shown in FIG. 8, the common substrate 310 moves in the width direction on the slider 314 via the rack 322 meshed with the drive gear 326. Accordingly, the wiping member 88 attached to the common substrate 310 moves in the width direction, and the wiper 92 of the wiping member 88 whose tip is positioned higher than the nozzle surface 40A is in sliding contact with the nozzle surface 40A of the unit recording head 40. Moving. As a result, dust attached to the nozzle surface 40A, dried ink, and the like are removed (see FIG. 10C). At this time, the wiping member 88 moves so as to straddle the lowered cap member 80.
[0168]
In this embodiment, since the wiper 92 is in sliding contact with the nozzle surface 40A while maintaining the contact amount of 1.5 mm, dirt attached to the nozzle surface 40A is reliably removed.
[0169]
Further, the wiping member 88 escapes from the lower portion of the nozzle surface 40A, and the movement of the wiping member 88 and the guide member 94 in the width direction is completed (see FIG. 10D). Subsequently, the common substrate 310, that is, the wiping member 88 is lowered by driving of the driving motor 318 of the moving mechanism 312 and moved to the height of the home position (see FIG. 10E).
[0170]
Subsequently, the common substrate 310, that is, the wiping member 88 is moved together in the width direction by driving the drive motor 318 of the moving mechanism 312 shown in FIG. 8 to return to the home position (see FIG. 10F). . Further, the wiping operation is completed by driving the drive motor 304 of the elevating mechanism 302 to raise the cap member 80 and returning it to the home position close to the nozzle surface 40A of the recording head 40 (see FIG. 10G). .
[0171]
Next, the capping operation will be described.
[0172]
The capping operation is performed when the non-printing state continues for a long time or when the power is turned off. Specifically, the common substrate 300 is raised by driving the drive motor 304 of the lifting mechanism 302 shown in FIG. 8, and the rubber portion 84 of the cap member 80 attached to the common substrate 300 is moved to the nozzle surface 40 </ b> A of the recording head 40. (See FIG. 9A → FIG. 9B). As a result, the air tightness of the nozzle surface 40 (nozzle 58) is ensured, ink thickening and drying are prevented, and dust is prevented from adhering.
[0173]
As described above, in the inkjet recording apparatus 10 according to the present embodiment, the conveying belt units 19A to 19E are disposed on the upstream side and the downstream side of the recording heads 44Y to 44K, so that the positions facing the recording heads 44Y to 44K. The maintenance units 18Y to 18K are disposed in the main body. Therefore, it is not necessary to move the recording heads 44Y to 44K and the maintenance device 81, and a maintenance operation can be performed quickly, and a decrease in productivity can be suppressed to a minimum. In addition, misalignment due to movement of the recording head is prevented, and high-quality printing can be performed. Furthermore, since the moving mechanism is unnecessary, the apparatus configuration is simplified.
[0174]
On the other hand, since the sheet is conveyed by holding the sheet on the endless belt 104 of the conveying belt units 19A to 19E, the sheet is reliably held on the endless belt 104 and stably conveyed. In addition, since the lifting prevention means (for example, the plate 10) is provided to face the endless belt 104, paper that may be lifted from the endless belt 104 due to ink adhesion or the like is reliably held by the endless belt 104. It is conveyed between the recording head 44 and the maintenance unit 18.
[0175]
Further, in the present embodiment, the conveying means does not exist under the recording heads 44Y to 44K, but the guide member 94 is present, so that the paper is prevented from being pushed into the maintenance device 81. Further, the star wheel 70 elastically abutting against the guide member 94 prevents the sheet from floating from the guide member 94, and the sheet is maintained at a certain distance from the nozzle surface 40A of the unit recording head 40. Therefore, the paper is printed at a high distance with a certain distance from the nozzle surface 40A at the printing position.
[0176]
By the way, since the interval between the conveyance belt units 19 is shorter than the minimum conveyance direction length of the sheet, the sheet on the downstream side is separated before the sheet is peeled off by the conveyance belt unit on the upstream side when any size sheet is conveyed. The leading edge of the sheet is held by the conveyor belt unit. Therefore, the sheet is reliably conveyed in the recording unit 20.
[0177]
Further, as shown in FIG. 3, the recording head 44 of the present embodiment is configured by attaching recording head arrays 42 </ b> A and 42 </ b> B in which a plurality of short unit recording heads 40 are arranged on both surfaces of the common substrate 46. Therefore, the recording head 40 can be shared with an inexpensive device (recording head) produced in large quantities, and the recording head 40 capable of full width printing can be configured at a low price. Further, since a space is generated between the recording head 44 and the unit recording head 40, there is an advantage that the star wheel 70 can be disposed.
[0178]
In addition, by configuring the recording head arrays 42A and 42B on both surfaces of the common substrate 46, the configuration of each recording head array 42A and 42B is simplified (miniaturized), and manufacturing and high-precision adjustment become easier. In particular, there is an effect that the transport direction distance of the recording head 44 can be shortened. Further, there is an advantage that the configuration of the maintenance device 81 (cap member 80, wiping member 88) can be shared with that used in a short recording head.
[0179]
However, the recording head 44 is not limited to such a configuration, and as shown in FIG. 11, six unit recording heads 40 are attached to two common substrates 46A and 46B, respectively, and the recording head array 42A, 42B can also be configured.
[0180]
Furthermore, the recording head 44 is configured by continuously arranging the unit recording head 110 (see FIG. 12) in which the nozzles 58 of the unit recording head 40 are formed to the end in the nozzle arrangement direction in the width direction on a common substrate (not shown). You may do it (refer FIG. 13). In order to adjust the nozzle pitch at the connection portion between the unit recording heads, it is necessary to manufacture the end of the unit recording head 110 with high accuracy. However, the recording head 44 can be most miniaturized.
[0181]
Although the nozzle arrays of the unit recording heads 40 and 110 are linear, the description has been given above, but the present invention is not limited to this. For example, as shown in FIG. 14, it is possible to arrange the nozzles in a staggered manner.
[0182]
In this embodiment, the ink droplet ejection method of the unit recording head 40 is described as the thermal ink jet method. However, any method may be used as long as the color material is directly transferred to the sheet without contact. . An inkjet method is typical, but any method can be applied as long as it is a known method. Also, the ink jet method is not limited to the multi ink jet method, and may be a piezo ink jet, a continuous flow ink jet, an electrostatic suction ink jet, or the like.
[0183]
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.
[0184]
Furthermore, in this embodiment, the cap member 80 is provided corresponding to the unit recording head 40, but one cap member 80 may be associated with the plurality of unit recording heads 40.
[0185]
In this embodiment, the recording head arrays 42A and 42B and the maintenance unit 18 and the conveyance belt unit 19 disposed on the upstream side of the recording head arrays 42A and 42B are configured as one image forming unit.
[0186]
By arranging one or a plurality of the image forming units, it is possible to easily configure an image forming apparatus according to each request including single color, full color and special color. Further, the unit maintenance improves the maintainability of the apparatus.
[Second Embodiment]
An ink jet recording apparatus according to a second embodiment of the present invention will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, the description will focus on the different parts of the first embodiment.
[0187]
As shown in FIG. 15, the conveying belt unit 19 is different from the first embodiment in that an endless belt 104 is stretched around one driving roller 100 and a driven roller 102. The endless belt 104 is configured to be tensioned from the driven rollers 102A and 102BA by the elastic force of the spring 120.
[0188]
Further, instead of the star wheel 70 of the first embodiment, a roller is provided in this embodiment. The roller is a hollow roller made of SUS.
[0189]
Note that the cap member 80 and the wiping member 88 in the present embodiment are configured in the same manner as in the first embodiment. That is, a plurality of cap members and wiping members arranged in the width direction are unitized by being attached to a common substrate, and are driven integrally by a lifting mechanism and a moving mechanism, respectively.
[0190]
In the present embodiment, means for sucking ink from the recess 82A of the receiving portion 82 of the cap member 80 is provided. Specifically, as shown in FIG. 15, a first waste ink recovery tank 132 (in communication with a recess 82 </ b> A of the rubber portion 82 of each cap member 80 via a flow path 130 is provided below each cap member 80. The capacity is 4 cc). Furthermore, six first waste ink collection tanks 130 respectively corresponding to the six cap members 80 arranged in a line in the width direction and the second waste ink collection tanks 136 (capacity is communicated) through the flow paths 134. 60 cc) is provided.
[0191]
Further, a third waste ink collection tank 140 that is in communication with all the eight second waste ink collection tanks 136 through the flow path 138 is provided.
[0192]
The third waste ink recovery tank 140 can discharge the waste ink from the flow path 142 to the outside, and is communicated with the vacuum pump 146 via the filter 144.
[0193]
Further, the third waste ink recovery tank 140 is configured to measure the negative pressure by the negative pressure measuring device 148.
[0194]
Note that a first electromagnetic on-off valve 150, a second electromagnetic on-off valve 152, and a third electromagnetic on-off valve 154 are disposed in the flow paths 130, 134, 142, respectively, and can be selectively opened and closed.
[0195]
Therefore, the waste ink accumulated in the cap member 80 (recess 82A) is recovered by driving the vacuum pump 146 and opening / closing operations of the electromagnetic on / off valves 150, 152, 154, or ink in the nozzle surface 40A or the nozzle 58 by vacuum described later. Can be sucked.
[0196]
The operation of the inkjet recording apparatus 10 configured as described above will be described. Only the vacuum operation will be described, and detailed description of the same operations (printing, dummy jet, wiping, capping) as in the first embodiment will be omitted.
[0197]
The vacuum is performed at the timing of the non-printing state. Accordingly, the conveyance belt unit 19 stops driving, and the opening 112 is located at a position facing the recording head 44 and the maintenance device 81.
[0198]
Here, as in the first embodiment, by driving the elevating mechanism, the cap member 80 at the home position moves up and presses against the nozzle surface 40A of the unit recording head 40 (see FIG. 9B). As a result, the rubber part 82 of the cap member 80 covers the nozzle surface 40A to make it airtight.
[0199]
In this state, a negative pressure is supplied to the cap member 80. Specifically, it is as follows.
[0200]
First, the first electromagnetic open / close valve 150 provided in the flow path 130 and the third electromagnetic open / close valve 154 provided in the flow path 142 are closed. Next, the vacuum pump 146 is driven until the value measured by the negative pressure measuring device 148 reaches a predetermined value. When the measured value reaches a predetermined value (for example, −70 kPa) of about −30 kPa to −100 kPa with respect to the atmospheric pressure, the driving of the vacuum pump 146 is stopped. As a result, the first to third waste ink collection tanks 132, 136, and 140 are set to a predetermined negative pressure. Further, the second electromagnetic opening / closing valve 152 is closed.
[0201]
Here, the first electromagnetic opening / closing valve 150 disposed in the flow path 130 that communicates the cap member 80 or the unit recording head 40 for collecting ink and the corresponding first waste ink collection tank 132 is opened. As a result, the first waste ink recovery tank 132 having a predetermined negative pressure communicates with the concave portion 82A of the cap member 80, and the nozzle surface that is airtight with the ink and rubber portion 84 accumulated in the concave portion 82A of the receiving portion 82. The ink and dust adhering to the ink 40 and the thickened ink existing inside the nozzle 58 are sucked at a negative pressure and collected in the first waste ink collecting tank 132.
[0202]
Subsequently, as in the first embodiment, the elevating mechanism is driven to lower the cap member 80 to return to the home position (separate from the nozzle surface 40A), and all the first electromagnetic on-off valves 150 and the second electromagnetic By opening the on-off valve 152, the waste ink is collected from the cap member 80, the first waste ink collection tank 132, and the second waste ink collection tank 136 in the third waste ink collection tank 140 that is set to a negative pressure. Become.
[0203]
In this way, by applying a negative pressure to the concave portion 82A of the recording head 80, the ink (exhaust ink) collected in the concave portion 82A of the cap member 80 can be collected, and the ink can be ejected from the nozzle 58 by suction. This eliminates bubbles in the nozzle 58, thickened ink, and the like.
[0204]
After performing the vacuum operation in this way, wiping is performed as in the first embodiment.
[0205]
Therefore, the ink jet recording apparatus according to the present embodiment has the same effects as the first embodiment, and can perform a vacuum operation without moving the recording heads 44Y to 44K.
[0206]
In addition, since the endless belt 104 is wound between the pair of rollers of the driving roller 100 and the driven roller 102, the curvature of the endless belt 104 at the position of the driving roller 100 of the endless belt is further increased, and the peelability of the paper is improved. .
[0207]
Note that the vacuum operation and mechanism described in the present embodiment can also be applied to the first embodiment.
[0208]
【The invention's effect】
In the recording apparatus according to the present invention, since it is not necessary to move the recording head or the like for maintenance, it is possible to prevent deterioration in print image quality due to misalignment due to movement of the recording head or decrease in print productivity due to movement of the recording head. Productivity is high and high-quality printing can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating a recording apparatus according to a first embodiment of the invention.
FIG. 2 is a schematic side view showing a conveyor belt unit according to the first embodiment of the present invention.
FIG. 3 is a schematic plan view of the recording head according to the first embodiment of the invention.
FIG. 4 is a plan view of a unit recording head according to the first embodiment of the invention.
5A is a cross-sectional view of a star wheel according to the first embodiment, FIG. 5B is a side view of the star wheel, and FIG. 5C is a side view of a star wheel according to another example. .
FIG. 6 is a schematic plan view of a maintenance unit according to the first embodiment of the present invention.
FIG. 7 is a perspective view for explaining a main part of the maintenance device according to the first embodiment of the present invention.
FIG. 8 is an explanatory diagram of a drive mechanism of the recording apparatus according to the first embodiment of the invention.
FIGS. 9A and 9B are explanatory diagrams of a capping operation in the recording apparatus according to the first embodiment of the invention.
10A to 10G are explanatory diagrams of a wiping operation in the recording apparatus according to the first embodiment of the invention.
FIG. 11 is a diagram showing a variation of the recording head array.
FIG. 12 is a diagram showing a variation of a unit recording head.
FIG. 13 is a diagram illustrating a variation of a recording head.
FIG. 14 is a diagram showing variations of unit recording heads.
FIG. 15 is a schematic configuration diagram showing a recording apparatus according to a second embodiment of the invention.
[Explanation of symbols]
10 Inkjet recording device (recording device)
19 Conveying belt unit (conveying means)
40 unit recording head
42 Recording head array
44 Recording head
70 Starwheel (conveying aid, spur)
80 Cap member (cap means)
81 Maintenance device (maintenance means)
88 Wiping member (cleaning means)
94 Guide member (transport assisting means)
104 Endless belt
106 Charging roll (holding means)
108 Plate (lifting prevention means)
116 Cleaning roll (belt cleaning means)

Claims (15)

A recording apparatus that forms an image by discharging droplets onto a recording medium,
A recording head configured by combining a plurality of recording head arrays including a plurality of unit recording heads arranged in the width direction, and discharging droplets from a droplet discharge surface;
Maintenance means arranged opposite to the droplet discharge surface of each recording head, and performing maintenance of the recording head;
An endless belt and holding means for holding the recording medium on the surface of the endless belt, and disposed before and after the recording head in the conveyance direction of the recording medium. Conveying means for conveying the recording medium in between,
A conveyance assisting means that is disposed between the recording head and the maintenance means and between the plurality of unit recording heads to ensure flatness of the recording medium;
Recording apparatus characterized by comprising a.   The recording apparatus according to claim 1, wherein the holding unit holds the recording medium on the endless belt by an electrostatic force.   The recording apparatus according to claim 1, wherein the holding unit holds the recording medium on the endless belt by a non-electrostatic force.   4. A lifting prevention means for preventing the recording medium from lifting from the endless belt is provided at a position facing the endless belt in the recording medium holding range of the endless belt. The recording apparatus according to 1.   The recording apparatus according to claim 1, wherein the conveying unit includes a belt cleaning unit that cleans the endless belt.   6. The interval between the conveying means disposed on the upstream side and the downstream side in the conveyance direction of the recording medium across the recording head is shorter than the minimum conveyance direction length of the recording medium. The recording apparatus according to 1. The recording apparatus according to claim 1, wherein the conveyance assisting unit is provided at both ends in the width direction of the maintenance unit. The recording apparatus according to claim 7, wherein the conveyance assisting unit includes a guide member that supports a non-recording surface side of the recording medium . The recording apparatus according to claim 8, wherein the conveyance assisting unit includes a spur that contacts the recording surface side of the recording medium . The recording apparatus according to claim 1, wherein the recording head has a printing width larger than a recording medium width. The maintenance means is capable of approaching and separating from the droplet discharge surface of the recording head, presses against the droplet discharge surface to make the droplet discharge surface airtight, and drops discharged during non-printing Cap means to land,
Cleaning means for wiping the droplet discharge surface;
The recording apparatus according to claim 1 , further comprising: The recording apparatus according to claim 11, wherein the cleaning unit is configured to be movable toward and away from a droplet discharge surface of the recording head, and contacts the droplet discharge surface during cleaning . The recording apparatus according to claim 1, wherein a plurality of the recording heads are arranged along a conveyance direction of the recording medium . The recording apparatus according to claim 13, wherein liquids of different colors are ejected from the plurality of recording heads . Wherein the recording head, and the maintenance unit, the recording of any one of claims 1 to 14, characterized in that it is unitized and conveying means upstream or disposed downstream of said recording head apparatus.

Images