JP2004277023A - Recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder capable of achieving high quality printing while ensuring high productivity. <P>SOLUTION: This recorder 10 is provided with non-scanning type recording heads 44Y to 44K corresponding to width of paper and maintenance parts 18Y to 18K at positions opposing to each recording head. Consequently, maintenance operation can be performed without moving the recording heads to increase productivity. Since the recording heads 44 are not moved, deviation in alignment is prevented to achieve high quality printing. Since conveyance belt units 19A to 19E are arranged on the upstream side and the downstream side of the recording heads 44 to hold paper and planeness of paper is ensured by a guide member and star wheel at a printing position, high quality printing is performed on paper. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet recording apparatus that performs recording by ejecting ink from a recording unit to a recording medium, and a recording apparatus having such functions and used as an output device such as a facsimile, a copier, a multifunction printer, or a workstation.
[0002]
[Prior art]
In recent years, the spread of color documents in offices has been remarkable, and various output devices have been proposed. In particular, a low-priced inkjet system that can be reduced in size is used for various output devices.
[0003]
The recording head used in the ink jet system includes an energy generating unit, an energy converting unit that converts the energy generated by the energy generating unit into an ink ejection force, an ink ejection port that ejects ink droplets by the ink ejection force, and an ink ejection port. And an ink supply path for supplying ink in communication with the ink supply path. As the energy generating means, a means using an electromechanical transducer such as a piezo element or an electrothermal transducer having a heating resistor heats ink to generate bubbles, and a means for ejecting ink droplets by generating the bubbles. Etc.
[0004]
In a print head using an electrothermal transducer, the small size of the electrothermal transducer enables not only high-density arrangement of ink discharge ports, but also diverts a semiconductor integrated circuit manufacturing technique to its manufacturing technique. Therefore, it is possible to reduce the size of a recording head having many high-precision ink ejection ports, and it is possible to manufacture the recording head at low cost.
[0005]
At present, however, a printing method called serial scan, which mainly prints one line at a time by reciprocating a printing head while transporting printing paper, is mainly used. This method is small and low-cost, but has the disadvantage that the recording head needs to be scanned a plurality of times in order to form an image over the entire sheet, and the printing speed is slow. In order to improve the printing speed, it is necessary to reduce the number of scans, and it is necessary to lengthen the recording head. A non-scanning printing method that uses a paper-width recording head to push this to the limit is considered. This printing method is an ink jet recording apparatus having a recording head corresponding to a paper width in which a number of ejection ports are arranged over a length substantially equal to the paper width of the recording paper, and the recording paper moves relative to a fixed recording head. The recording is thus performed.
[0006]
As described above, in order to improve the printing speed and cope with office use, there has been proposed an ink jet recording apparatus that performs printing while continuously conveying a sheet by a non-scanning type recording head corresponding to a sheet width (for example, Patent Document 1). 1, 2; hereinafter, Conventional Examples 1 and 2).
[0007]
On the other hand, in an ink jet recording apparatus, in order to maintain good ink ejection performance, a maintenance device ejects ink droplets (dummy jet) during non-printing, cleans nozzle surfaces (wiping), and prevents ink from drying (capping). ) Is needed.
[0008]
For example, if the non-printing state continues for a long time, the dried ink thickens and the nozzles become clogged, or dust adheres to the nozzle surfaces. As a result, the ink droplets cannot be ejected (missing dots) or the ejection direction of the ink droplets changes, so that the print quality deteriorates or printing becomes impossible.
[0009]
Therefore, when printing is suspended for a certain period of time, the recording head is moved from the printing position to the maintenance position in the ink jet recording apparatus, dust and the like attached to the nozzle surface of the recording head are removed with a wiper, and the nozzle surface is refreshed. Do what you want.
[0010]
Further, in order to prevent a change in the ejection performance of the ink droplet due to a change in the viscosity of the ink or the generation of bubbles, the recording head ejects the ink droplet to the receiving member during non-printing.
[0011]
Further, a cap member is provided to prevent drying of the nozzle surface (nozzle) of the recording head. The cap member presses the rubber portion against the nozzle surface to make the nozzle surface (nozzle) airtight from the outside.
[0012]
The ink jet recording apparatus according to the conventional example 1 includes a long recording head having a length substantially equal to the paper width of the recording paper, and a device 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 having a length substantially equal to the paper width of the recording paper, a plurality of through-holes formed on the surface while conveying the recording paper disposed opposite the recording head. The printing apparatus includes a formed belt, and an ink receiving portion disposed to face the recording head with the belt therebetween. Accordingly, when the through hole of the belt is located at a position facing the recording head, the ink droplet is discharged from the recording head, and the ink droplet discharged from the recording head lands on the ink receiving portion via the through hole. That is, a dummy jet can be performed.
[0014]
The cleaning and capping of the recording head surface is performed by moving the recording head to the positions of the cleaning device and the cap device.
[0015]
[Patent Document 1]
JP-A-02-179754
[Patent Document 2]
JP-A-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, the recording head or the recovery device needs to be once moved to a predetermined position, which complicates the device configuration and returns to printing. It takes time.
[0017]
Further, in the configuration of the second conventional example, the dummy jet can be performed during printing, but since the recording head is moved to a predetermined position for cleaning and capping of the recording head, the apparatus configuration becomes complicated as in the first conventional example. At the same time, there is an inconvenience that it takes time to return to printing.
[0018]
Therefore, an object of the present invention is to provide a recording apparatus capable of forming a high-quality image while securing productivity while solving the above-mentioned inconvenience. Another object of the present invention is to provide a recording apparatus that can perform 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, wherein the recording head discharges droplets from a droplet discharge surface, and a liquid of each recording head is formed. A maintenance unit that is arranged to face the droplet ejection surface and performs maintenance of the recording head; and a maintenance unit that is arranged before and after the recording head in the transport direction of the recording medium, and performs recording between the droplet ejection surface of the recording head and the maintenance unit. Transport means for transporting the medium, wherein the transport means comprises an endless belt and a holding means for holding the recording medium on the surface of the endless belt.
[0020]
The operation of the recording apparatus according to claim 1 will be described.
[0021]
Since the transport means for transporting the recording medium under the recording head is disposed upstream and downstream of the recording head in the transport direction, the maintenance means is provided at a position facing the droplet discharge surface of the recording head. Can be. Therefore, maintenance of the recording head can be performed without moving the recording head and the maintenance unit. As a result, it is possible to avoid misalignment due to the movement of the recording head and decrease in productivity due to the movement. In particular, it is possible to perform the dummy jet before the recording medium passes and the subsequent recording medium arrives during the continuous printing, thereby satisfying both the improvement of the productivity and the maintenance of the high image quality.
[0022]
Further, since the recording medium is conveyed by being held on the endless belt by an electrostatic force or a non-electrostatic force, it is possible to print with high image quality.
[0023]
5. The recording apparatus according to claim 1, 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. A lifting preventing means for preventing the floating from rising.
[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 where the recording medium is reliably prevented from rising 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 transporting unit includes a belt cleaning unit that cleans the endless belt.
[0027]
The operation of the recording apparatus according to claim 5 will be described.
[0028]
The endless belt is contaminated by liquid mist accompanying droplet ejection and attachment of droplets accompanying borderless printing. Therefore, after the endless belt has conveyed the recording medium, the belt cleaning means removes the dirt from the endless belt, thereby preventing the endless belt from being adhered to the subsequent recording medium.
[0029]
7. The recording apparatus according to claim 1, wherein the distance between the conveying units disposed upstream and downstream of the recording medium in the conveying direction of the recording medium with respect to the recording head. Is shorter than the minimum length of the recording medium in the conveying direction.
[0030]
The operation of the recording apparatus according to claim 6 will be described.
[0031]
The recording medium sent 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, the sheet cannot be transported unless it is held by the downstream transport means until it is separated from the upstream transport means. Therefore, by making the interval of the conveying means shorter than the minimum length of the recording medium in the conveying direction, a recording medium having a short length in the conveying direction can be surely conveyed.
[0032]
8. The recording device according to claim 7, wherein a conveyance assisting device is provided between the recording head and the maintenance device to ensure flatness of a recording medium. It is characterized by having.
[0033]
The operation of the recording apparatus according to claim 7 will be described.
[0034]
When the recording medium passes between the recording head and the maintenance unit, it is difficult to secure the flatness because the leading end and the rear end of the recording medium are separated from the conveying unit. Therefore, the flatness of the recording medium at the printing position is sufficiently ensured, and high-quality printing can be performed.
[0035]
An eighth aspect of the present invention is the recording apparatus according to the seventh aspect, wherein the transport assisting means is provided on the recording head side.
[0036]
The operation of the recording apparatus according to claim 8 will be described.
[0037]
Since the transport assisting means is provided on the recording head side, the distance between the droplet discharge surface of the recording head and the recording medium is maintained constant, and high-quality printing can be performed on the recording medium.
[0038]
According to a ninth aspect of the present invention, in the recording apparatus according to the eighth aspect, the transport assisting means is a spur which comes into contact with a recording surface of the recording medium.
[0039]
The operation of the recording apparatus according to claim 9 will be described.
[0040]
Since the spur abuts on the recording surface side of the recording medium, the distance from the droplet ejection surface of the recording head is kept constant, and printing is performed with high image quality. Further, since the spur comes into contact with the recording surface of the recording medium, the influence on the image quality is minimized, and the image is printed with high image quality.
[0041]
According to a tenth aspect of the present invention, in the recording apparatus of the seventh aspect, the transport assisting means is provided on the maintenance means side.
[0042]
The operation of the recording apparatus will be described.
[0043]
Since the conveyance assisting means is provided on the maintenance means side, it is possible to prevent the leading end and the rear end of the recording medium separated from the conveying means from entering the maintenance means and making the conveyance state unstable. That is, the recording medium can be stably conveyed.
[0044]
The recording apparatus according to an eleventh aspect is characterized in that, in the recording apparatus according to the tenth aspect, the transport assisting unit is a guide member that supports a non-recording surface side of the recording medium.
[0045]
The operation of the recording apparatus according to claim 11 will be described.
[0046]
Since the transport assisting means provided on the maintenance means side is a guide member for supporting the drawing surface of the recording medium, the recording medium is reliably prevented from entering the maintenance means, and the recording medium is stably transported. At the same time, the flatness of the recording medium can be reliably maintained at the recording position.
[0047]
According to a twelfth aspect of the present invention, in the recording apparatus according to any one of the first to eleventh aspects, the recording head has a printing width larger than a recording medium width.
[0048]
The operation of the recording apparatus will be described.
[0049]
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 only by discharging droplets onto the recording medium conveyed from the fixed recording head. Therefore, high-speed printing (printing with high productivity) becomes possible.
[0050]
A recording apparatus according to a thirteenth aspect is the recording apparatus according to any one of the first to twelfth aspects, wherein the recording head includes a plurality of unit recording heads.
[0051]
The operation of the recording apparatus according to claim 13 will be described.
[0052]
By configuring a print head by combining a plurality of unit print heads with low unit prices, a print head can be configured at low cost.
[0053]
A recording apparatus according to a fourteenth aspect is the recording apparatus according to the thirteenth aspect, wherein the recording head is configured by combining a plurality of recording head arrays each including a plurality of unit recording heads arranged in a width direction. It is characterized by the following.
[0054]
The operation of the recording apparatus will be described.
[0055]
By configuring a printhead by combining a plurality of printhead arrays in which a plurality of unit printheads are arranged in the width direction, the degree of freedom of arrangement of the unit printheads is improved.
[0056]
The recording apparatus according to claim 15, wherein the transport assisting unit is disposed between a plurality of the unit recording heads in the recording apparatus according to any one of claims 8, 9, 13, and 14. It is characterized by.
[0057]
The operation of the recording apparatus according to claim 15 will be described.
[0058]
By arranging a transport assisting unit, for example, a spur, between a plurality of unit recording heads constituting the recording head, the transporting assisting unit can be easily arranged.
[0059]
The recording apparatus according to claim 16, wherein the maintenance unit is capable of approaching and separating from the droplet discharge surface of the recording head, and The liquid ejecting apparatus includes a cap unit on which a droplet ejected during non-printing lands, and a cleaning unit for wiping the droplet ejecting surface, while being in pressure contact with the surface to make the droplet ejection surface airtight. .
[0060]
The operation of the recording apparatus will be described.
[0061]
Since the maintenance unit has a cap unit and a cleaning unit, the cap unit is pressed against the droplet discharge surface of the recording head that is arranged opposite to the liquid droplet discharge surface to make the droplet discharge surface airtight, so that the nozzle surface of the recording head and the liquid are dried. Can be prevented, and droplets (dummy jets) ejected from the recording head can be received while being separated from the recording head.
[0062]
In addition, by wiping the droplet discharge surface by the cleaning means, dirt on the droplet discharge surface can be removed, and the droplet discharge performance can be favorably maintained.
[0063]
17. The recording apparatus according to claim 17, wherein the cleaning unit is configured to be able to freely approach and separate from a droplet discharge surface of the recording head, and the cleaning unit is configured to clean the droplet discharge surface during cleaning. Contact with
[0064]
The operation of the recording apparatus according to claim 17 will be described.
[0065]
When the cleaning means contacts the droplet discharge surface of the recording head during cleaning, dirt can be reliably removed.
[0066]
According to a eighteenth aspect of the present invention, in the recording apparatus according to any one of the first to seventeenth aspects, a plurality of the recording heads are arranged along a conveying direction of the recording medium. .
[0067]
The operation of the recording apparatus will be described.
[0068]
By arranging a plurality of recording heads along the recording medium conveyance direction, various printings and the like can be performed.
[0069]
A recording apparatus according to a nineteenth aspect is the recording apparatus according to the eighteenth aspect, wherein the plurality of recording heads discharge liquids of different colors.
[0070]
The operation of the recording apparatus according to claim 19 will be described.
[0071]
By arranging a plurality of recording heads that discharge liquids of different colors, multicolor printing can be performed.
[0072]
20. The recording apparatus according to claim 1, wherein the recording head, the maintenance unit, and a transport disposed upstream or downstream of the recording head. And means are unitized.
[0073]
The operation of the recording apparatus will be described.
[0074]
By unitizing the recording head, the maintenance unit, and the conveying unit disposed on the upstream side or the downstream side of the recording head in this manner, by arranging one or a plurality of the units, a single color, a full color or a special color can be obtained. It is possible to easily configure an image forming apparatus that meets various requirements including the above. In addition, the maintenance of the device is improved by the unitization.
[0075]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
An ink jet recording apparatus according to the first embodiment of the present invention will be described.
(Overall configuration of inkjet recording apparatus)
First, the overall configuration of the inkjet 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 for sending out a sheet, and a recording unit 20 for forming an image on a sheet supplied from the sheet supply unit 12 and discharging the sheet to the outside. Is done.
[0077]
The paper supply unit 12 is configured to draw out paper one by one from a tray 14 by a feed roller 16 and supply the paper to a recording unit 20 via a guide member 18.
[0078]
The recording units 20 are arranged at regular intervals, and perform recording heads 44Y, 44M, 44C, and 44K that perform printing of each color of yellow, magenta, cyan, and black (the same applies to other reference numerals 44Y to 44K). Transport belt units 19A to 19E arranged alternately with the recording heads 44Y to 44K on the upstream side and the downstream side in the sheet transport direction of each recording head, and a maintenance unit arranged opposite to the recording heads 44Y to 44K, respectively. 18Y to 18K.
[0079]
That is, ink droplets are ejected from the recording heads 44Y to 44K onto the paper continuously (without stopping) by the transport belt units 19A to 19E, and an image is formed on the paper. Since the recording unit 20 will be described later, a detailed description will be omitted.
(Conveyor belt unit configuration)
Since the transport belt units 19A to 19E have the same configuration, only the transport belt unit 19A will be described as a representative example, and other descriptions will be omitted.
[0080]
As shown in FIG. 2, the transport 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 as a holding means for holding the sheet, and a lifting prevention member 108 for preventing the sheet from floating from the endless belt 104.
[0081]
The drive roller 100 is for driving the stretched endless belt 104 to rotate. As a material of the drive roller 100, any metal (SUS, aluminum, etc.) can be used, and a predetermined strength is secured. Plastic materials can also be used. Further, in order to secure friction between the back surface of the belt and the surface of the roller when the belt is wound around the roller, a metal roller having a surface coated with a rubber material may be used.
[0082]
The driven rollers 102 </ b> A and 102 </ b> B are driven by the driving torque of the driving roller 100 being transmitted through an endless belt 104, and support the endless belt 104 together with the driving roller 100.
[0083]
As the material for the driven rollers 102A and 102B, any metal (SUS, aluminum, etc.) can be used, and a plastic material having a predetermined strength can also be used. Further, in order to secure the friction between the back surface of the belt and the surface of the roller when the belt or the like is wound around the roller, a metal roller having a surface coated with a rubber material may be used.
[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 without a seam, does not expand or contract so much so that it can be stably conveyed, and has durability. The endless belt 104 is given a predetermined tension to ensure flatness.
[0086]
As a material of the endless belt 104, a material capable of holding paper (statically holdable), for example, a polymer sheet such as polyester, polyethylene terephthalate, polyether sulfone, polyether ketone, polysulfone, polyimide, polyimide amide, polyamide, etc. And the like.
[0087]
In particular, polyimide and polyimide are preferable in terms of ink resistance, stress resistance when the film is wound around the drive roller 100 and the driven rollers 102A and 102B, and transport resistance, and crack resistance.
[0088]
In consideration of durability, the base material is made of the above materials or metal materials (all materials), and the surface is coated with a semiconductive material (such as the above materials) capable of electrostatically holding the paper, thereby forming two layers. Can be structured.
[0089]
In the present embodiment, the endless belt 104 is formed from a semiconductive polyimide resin material, has a length in the rotation direction 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 unit, a lifting prevention unit, and a belt cleaning unit 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 sheet holding means is for holding the sheet supplied to the transport belt unit 19Y by the guide member 17 of the sheet supply unit 12 on the endless belt 104, and may be an electrostatic force or a non-static type. Electric power may be used.
[0092]
In the present embodiment, a unit using an electrostatic force is employed, and a charging roll 106 disposed opposite to the driven roll 102 is used. Therefore, the paper conveyed from the paper supply unit 12 is charged by the charging roll 106 and pressed by a predetermined pressure to reliably electrostatically adsorb the charged paper 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 a silicone rubber and has a volume resistivity of 10%. ⁸ Ω · cm-10 ^Thirteen It is adjusted to about Ω · cm. For example, by dispersing conductive carbon, a volume resistivity of 10 ⁸ Ω · cm-10 ^Thirteen A roll is used in which the surface of a SUS core is coated with silicone rubber (about 100 μm thick) adjusted to about Ω · cm.
[0094]
When the paper is held by an electrostatic force, a voltage of 1 kv (constant voltage control) is applied while applying a pressing force of 1 kgf to the endless belt 104 and the paper by the charging roll 106, and the paper is placed on the endless belt 104. It is configured to be held. Normally, 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 is described, but a corotron or a brush may be used. In this case, the applied voltage is set under substantially the same conditions as those for the roll.
[0096]
In the present embodiment, the holding method using an electrostatic force has been described, but a holding method using a non-static force may be used. For example, there is a method in which an adhesive material (for example, a material obtained by adjusting the degree of vulcanization of urethane rubber) or the like is applied to the surface of the endless belt 104, and the paper is pressed and held by a roll or the like. Further, a method of arranging a gripper on a belt and gripping the leading edge of the sheet to convey the sheet, or a method of suctioning and conveying the sheet from below the sheet conveying path with air may be considered.
[0097]
By the way, the sheet held on the endless belt 104 by the holding unit is separated 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. Configuration. Here, in the transport belt unit 19A, a range from the charging roll 106 to the sheet peeling position is referred to as a sheet transport section.
[0098]
A paper detection sensor 107 (for example, a transmission fiber sensor) is disposed on the downstream side of the charging roll 106 in the paper transport direction so as to face the endless belt 104, and detects the leading edge of the paper so that the recording head The ink droplet ejection timing at 44Y is controlled. Note that the sheet detection sensor 107 controls the ink droplet ejection timing of the recording head 44 disposed immediately downstream in the sheet transport direction. Therefore, the transport sensor disposed downstream of the recording head 44K in the transport direction is used. It is not provided in the unit 19E.
[0099]
Further, on the downstream side of the paper detection sensor 107 in the transport direction, a lifting prevention unit is arranged to face the paper transport section of the endless belt 104. This is to prevent the paper from rising from the endless belt 104, and may be a roll, a plate, a spur, or the like. In the present embodiment, the plate 108 is a plate 108 and extends from below the charging roll 106 to an end of the recording head 44. Specifically, the plate 108 is formed of SUS, and has a thickness of 1 mm, a width of 380 mm, and a length of 100 mm.
[0100]
The belt cleaning unit is disposed at a position outside the paper conveyance section of the endless belt 104 so as to be opposed to the endless belt 104 and is capable of approaching and separating from the endless belt 104, and removes ink adhered to the surface of the endless belt 104. Cleaning is performed. Generally, there are a cleaning roll, a brush, a blade, and the like. However, since the purpose of the present invention is to remove ink, a cleaning roll 116 in which an ink absorber is wound around the roll surface is preferable.
[0101]
As a material of the ink absorber wound around the surface of the cleaning roll 116, a polyester felt fiber material or an acrylonitrile felt fiber material is preferable, and further, a polyester felt fiber material and an acrylonitrile felt fiber material are mixed. Is also preferred. 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 is finely adjusted.
[0102]
Other examples include a polyamide fiber material, a polypropylene fiber material, a polyvinyl alcohol fiber material, a polyvinylidene chloride fiber material, and a polyurethane fiber material.
[0103]
Considering the absorbency of ink and the like, a polyester fiber material is more preferable, and a material mixture of the above materials may be used.
[0104]
The ink absorber of the present embodiment is formed from polypropylene and polyethylene.
[0105]
The interval between the transport belt units 19 adjacent in the transport direction, for example, the interval between the transport belt units 19A and 19B is shorter than the minimum length of the sheet in the transport direction (A4 short length in this embodiment). This is so that the holding of the sheet can be started by the downstream conveying belt unit before the holding of the sheet by the upstream conveying belt unit is completed regardless of the sheet size.
(Configuration of recording head)
Next, the recording head units 44Y to 44K will be described in detail with reference to FIGS. FIG. 3 is a schematic diagram of the recording head unit 16 as viewed from the paper transport position.
[0106]
The recording heads 44Y to 44K eject ink droplets of cyan, magenta, yellow, and black, respectively, and as shown in FIG. 1, a paper transport direction (arrow X direction, hereinafter sometimes referred to as a transport direction). 2), the transport belt unit 19 is interposed between the recording heads.
[0107]
Since the configuration of each of the recording heads 44Y to 44K is the same, only one recording head 44 will be described below.
[0108]
Each of the recording heads 44 is configured 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 ink droplets are ejected by a well-known thermal inkjet method.
[0110]
The unit recording heads 40 are arranged in a straight line so that the nozzle arrangement direction coincides with the sheet width direction (arrow Y direction, hereinafter sometimes referred to as the width direction) perpendicular to the sheet conveyance direction. The recording head arrays 42YA and 42YB are formed by attaching six unit recording heads 40 to the respective recording heads.
[0111]
As shown in FIG. 3, the recording head arrays 42YA and 42YB each include six unit recording heads 40 arranged at regular intervals, and the arrangement of the unit recording heads 40 in the recording head arrays 42YA and 42YB. Are arranged so as to be shifted from each other in the width direction, so that a part of the nozzle rows of the unit recording head 40 is disposed so as to have an overlap area OL overlapping between the recording head arrays 42A and 42B. By providing the overlap area OL in this way, it is possible to prevent the occurrence of an area where printing cannot be performed in the print area. That is, printing of one color on a sheet is performed by discharging ink droplets from the nozzles 58 of the unit recording head 40 of the recording head array pair 42A, 42B. In this embodiment, the combination of the pair of print head arrays 42YA and 42YB is referred to as a print head 44.
[0112]
The printing area is basically the largest of the recording areas obtained by subtracting the non-printing margins from both ends of the sheet, but is generally larger than the maximum sheet width PW to be printed. Also in the present embodiment, since the paper may be conveyed while being inclined at a predetermined angle (skew) with respect to the conveyance direction, and since there is a high demand for marginless printing, the printing area may be larger than the maximum paper width PW. (See FIG. 3). The print area of the recording head 44 of this embodiment is 12 inches, and the maximum paper width PW is 297 mm, which is the short width of A3 (longitudinal width of A4).
[0113]
The recording head 44 is configured to perform printing in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side in the transport direction and to perform full-color printing. The reference numbers of the heads are assigned Y, M, C, and K (as 44Y, 44M, 44C, and 44K) to distinguish them (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 adjacent 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 in 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 holder 76 having a hole 74 formed therein, and a stainless steel wheel 78 held by the holder 76. .
[0116]
The holding member 76 is composed of a first member 76A whose diameter is reduced at the center in the axial direction to allow the wheel to be inserted, and a second member 76B which is fitted to the reduced diameter portion and clamps the wheel 78 together with the first member 76A. ing. The wheel 78 has a large number of teeth 79 formed on the outer periphery thereof at regular intervals. The tip of the tooth 79 has an obtuse angle and an R-shaped tip (see FIG. 5 (B)). , An acute angle (see FIG. 5C).
[0117]
In the present embodiment, the thickness of the wheel 78 is 0.1 mm, and the thickness of the tip (tip) is reduced to about 0.01 to 0.02 mm by tapering. The wheel 78 is formed by simultaneously processing the outer shape and the tapered end of the SUS631EH material by double-sided step etching, and has a surface coated with a fluorine resin water repellent.
(Configuration of maintenance part)
The configuration of the maintenance units 18Y to 18K opposed to 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 arranged 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 having a rectangular concave portion 82A formed thereon, a rubber portion 84 provided above the receiving portion 82 and having an opening 84A formed therein, An ink absorber 86 made of polypropylene and polyethylene is provided on the bottom surface of the concave portion 82A. Therefore, at the time of a dummy jet to be described later, ink droplets are ejected from the nozzles 58 of each unit recording head 40 into the concave portion 82A via the opening 84A of the cap member 80, and are absorbed by the ink absorber 86. .
[0119]
The rubber portion 84 covers the entire nozzle surface 40A at the time of capping described later, and is configured such that the nozzle 58 is located in the opening portion 84.
[0120]
Here, as the plastic material forming the receiving portion 82, there are 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-based rubber, butadiene-based rubber, olefin-based rubber, ether-based rubber, polysulfide-based rubber, urethane-based rubber, fluorine-based rubber, and silicone rubber. Various elastic members can be used, such as various elastomers (rubber elastic bodies), blended rubbers of these rubber-based materials, or blended rubbers of these rubber-based materials with various plastics. good.
[0122]
Among these materials, hydrogenated nitrile butadiene rubber, ethylene propylene rubber (EPDM), polydimethyl silicone rubber, methyl vinyl silicone rubber, methyl is preferred in terms of heat resistance, weather resistance, chemical resistance, abrasion resistance, and workability. Phenyl silicone rubber, fluorosilicone rubber and the like are preferred.
[0123]
Further, as a material of the ink absorber 86, a polyester felt fiber material or an acrylonitrile felt fiber material is preferable, and 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, and the like of the used fiber material, the ink holding ability of the ink absorber 86 can be finely adjusted.
[0124]
Other examples include a polyamide fiber material, a polypropylene fiber material, a polyvinyl alcohol fiber material, a polyvinylidene chloride fiber material, and a polyurethane fiber material.
[0125]
Considering the absorbency of recording liquid such as ink, polyester fiber material is more preferable, and it is also preferable to use a material system in which the above materials are mixed.
[0126]
As shown in FIG. 8, the cap members 80 are 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 a lifting mechanism The unit 302 is configured so as 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 attached to a drive shaft 306 of the drive motor 304 and abutting on a lower surface of the common substrate 300. Therefore, the drive motor 304 is driven to rotate the eccentric cam 308, and the common substrate 300 contacted by the eccentric cam 308 approaches and separates from the nozzle surface 40A of the unit recording head 40.
[0128]
A spring 87 for adjusting the pressing force when pressing 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 rises, and the rubber portion 84 presses against the nozzle surface 40A to seal the nozzle surface 40A including the nozzle 58, thereby suppressing drying of the ink and preventing dust and dirt. Prevents adhesion. Further, at the time of a wiping operation to be 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 having an arch shape when viewed in the width direction, and a wiper 92 disposed above the holding member 90 and extending in the transport direction. Things.
[0131]
The holding member 90 is made of a strong metal material 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, a length (L1) in the longitudinal (transport) direction of 10 mm, a width (W1) in the short (width) direction of 0.8 mm, and a height of 0.8 mm. 6 mm and the contact amount is 1.5 mm.
[0133]
Examples of the material of the wiper 92 include various natural rubbers such as raw rubber, isoprene-based rubber, butadiene-based rubber, olefin-based rubber, ether-based rubber, polysulfide-based rubber, urethane-based rubber, fluorine-based rubber, and silicone rubber, and various elastomers (rubber elastic). Alternatively, various elastic members such as a blended rubber of these rubber-based materials or a blended rubber of these rubber-based materials and various plastics can be used, and a combination of these materials by adhesion or the like may be used.
[0134]
Among these materials, hydrogenated nitrile butadiene rubber, ethylene propylene rubber (EPDM), polydimethyl silicone rubber, methyl vinyl silicone rubber, methyl is preferred in terms of heat resistance, weather resistance, chemical resistance, abrasion resistance, and workability. Phenyl silicone rubber, fluorosilicone rubber and the like are preferred.
[0135]
Further, thermoplastic elastomers and the like, which are excellent in terms of fatigue resistance, moldability, rubber characteristics, and the like, are also preferable.
[0136]
Further, the surface of the wiper 92 may be covered with a protective layer for use. As the protective layer, a fluorine-based resin having excellent liquid repellency and low frictional characteristics is preferable. Further, various plastic materials are also applicable.
[0137]
As a specific material, a molded product such as a polyester resin such as polyethylene terephthalate and polybutylene terephthalate, a polyvinyl chloride resin, a polyvinylidene chloride resin, an epoxy resin, a polycarbonate resin, a polyethylene resin, a polypropylene resin, and a polystyrene resin may be used. .
[0138]
Further, a film obtained by laminating film materials of these materials and bonding them may be cut with high precision. At this time, an acrylic polymer or a rubber polymer is suitable as the adhesive.
[0139]
As shown in FIG. 8, the wiping members 88 are unitized by attaching six wiping members 88 respectively corresponding to the unit recording heads 40 constituting the recording head array 42 to the common substrate 310. The unit recording head 40 is configured to be integrally movable toward and away from the nozzle surface 40A and in the width direction.
[0140]
The moving mechanism 312 basically includes a slider 314 that supports the common substrate 310 movably 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. It is composed. 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, on one side surface of the common substrate 310, a convex portion 324 on which a rack 322 is formed is formed, and is meshed with a driving gear 326 of a driving motor 316 mounted on a slider 314. Therefore, the common substrate 310 can be moved in the width direction on the slider 314 by the drive of the drive motor 316.
[0141]
Further, a protrusion 332 provided with a rack 330 extending in the up-down direction is formed below the slider 314, and the drive gear 334 of the drive motor 318 is meshed with the protrusion 332. Therefore, the slider 314 can be moved up and down by driving 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 so as to be able to approach / separate (elevate / fall) with respect to the nozzle surface 40A by the moving mechanism 312, 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 at the home position so as not to interfere with the conveyed sheet (see FIG. 10A), but rises during wiping. Then, 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 section 18, guide members 94 are provided at both ends in the width direction of each maintenance device 81 so that the sheet does not enter the concave portion 82A of the cap member 80 when the sheet is transported (see FIGS. 6 and 7). ).
[0144]
The guide member 94 is formed of a SUS material, and as shown in FIG. 7, a horizontal portion 94A extending in the transport direction, two vertical portions 94B extending vertically downward from both ends of the horizontal portion 94A, Guide portions 94C and 94D extending obliquely downward in the transport direction from both ends in the transport direction of the portion 94A.
[0145]
Note that 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 conveyed sheet is pressed against the guide member 94 (horizontal portion 94A) by the star wheel 70 at the printing position in the conveying direction, and the sheet deformed by ink adhesion or the like is kept at a fixed distance from the nozzle surface 40A. It is.
[0146]
The operation of the thus configured ink jet recording apparatus 10 will be described.
[0147]
The sheet pulled out from the tray 14 of the sheet supply unit 12 by the pull-out roller pair 16 is supplied to the transport belt unit 19A by the guide member 18.
[0148]
On the other hand, in the transport belt 19Y, the drive roller 100 is driven, and the endless belt 104 is rotated in the arrow X direction.
[0149]
Therefore, the sheet that has come into contact with the endless belt 104 is conveyed together with the endless belt 104 in the direction of arrow X, and is charged by the charging roll 106 and pressed against the endless belt 104 to be reliably electrostatically attracted to the endless belt 104. become. By transporting the electrostatically attracted paper together with the endless belt 104, the leading edge of the paper is detected by the paper detection sensor 107, and the timing of ink droplet ejection from each unit recording head 40 of the recording head 44Y is controlled. Also, the sheet electrostatically adsorbed on the endless belt 104 is prevented from rising from the endless belt 104 by the plate 108 serving as a lift prevention means, and the flatness is maintained, and the curvature increases at the position of the driven roller 102B. It is peeled off from the endless belt 104 and is transported between the recording head 44Y and the maintenance section 18Y.
[0150]
The leading edge of the sheet reaches the horizontal portion 94A by being guided by the guide portion 94C of the guide member 94 provided adjacent to the maintenance device 81 in the width direction in the maintenance portion 18Y. That is, the back surface of the sheet is supported by the guide member 94, thereby preventing the sheet from being pushed 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 elastically abutting against the horizontal portion 94A, and the lifting of the paper is prevented, so that the recording head 44Y (the nozzle surface 40A of each unit recording head 40). Is a fixed distance from
[0152]
In this state, when the sheet passes under the recording head 44Y, the ink is discharged from the nozzles 58 of each unit recording head 40 of the recording head array 42YA constituting the recording head 44Y, and subsequently from the nozzle 58 of each unit recording head 40 of the recording head array 42YB. Drops are ejected, and a yellow image is formed on the paper.
[0153]
Since the interval between the transport belt units 19A and 19B is shorter than the minimum length in the transport direction of the sheet, the transport belt unit is not removed before the trailing end of the sheet is peeled off from the endless belt 104 of the transport belt unit 19A. The 19B endless belt 104 can hold the leading edge of the sheet and can surely convey the sheet.
[0154]
Hereinafter, magenta, cyan, and black ink droplets are ejected from the unit recording heads 40 constituting the recording heads 44M, 44C, and 44K to the sheet held and conveyed on the endless belt 104, so that full color printing is performed. Is formed on the sheet.
[0155]
The sheet on which the color image has been 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 every time a predetermined number of sheets are printed during continuous printing of a plurality of sheets. That is, of all the unit recording heads 40 constituting the recording heads 44 </ b> Y to 44 </ b> K, ink droplets are ejected from any nozzle 58 toward the cap member 80 (so-called dummy jet). The dummy jet may be performed by all the nozzles of all the unit recording heads 40, by the selected unit recording head 40, or by all the nozzles 58 of the recording head array 42, or by ejecting ink droplets for a predetermined time. Only the nozzles 58 that are not provided 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 the dummy jet at the time of continuous printing of a plurality of sheets is set to 3 mm, and the leading edge of the subsequent sheet arrives after passing the preceding sheet every 30 pages (A4). At the previous timing, 1000 drops are ejected from all nozzles.
[0159]
At this time, since the ink absorbing member 86 is provided 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 manner, by discharging ink droplets (dummy jets) from all the nozzles of the unit recording head 40, it is possible to initialize the discharge performance by drying ink (particularly water-based ink and solvent ink). In addition, even if the ink is an oil-based ink or a solid ink that hardly dries, it is possible to eliminate bubbles adhering to the ink flow path inside the head by printing, or to remove dust adhering to the nozzle surface. Can be initialized.
[0161]
As in the present embodiment, the dummy jet can be performed without moving the recording head 44 or the cap member 80 during the printing of a plurality of sheets to be continuously printed (conveyed), so that the printing speed (production ) Is achieved. In addition, the printing performance of the recording head 44 is kept constant by the dummy jet, and high-quality printing can be performed.
[0162]
Next, the wiping operation will be described.
[0163]
The wiping operation is performed before starting printing. The recording head 40 (nozzle surface 40A) is wiped by the wiping member 88 of the maintenance unit 18. The 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 slider 314 and the common substrate 310 supported by the slider 314 are 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 to the nozzle surface 40A side of the recording head 40) (see FIG. 10 (A) → FIG. 10 (B)).
[0165]
In the present embodiment, the cap member 80 is lowered 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 positioned 1.5 mm higher than the nozzle surface 40A (hereinafter, referred to as the position). , 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 (the direction of the arrow Z in FIG. 10) (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. Therefore, the wiping member 88 attached to the common substrate 310 moves in the width direction, and the wiper 92 of the wiping member 88, the tip of which is higher than the nozzle surface 40A, slides on the nozzle surface 40A of the unit recording head 40. Moving. As a result, dust, dried ink, and the like attached to the nozzle surface 40A are removed (see FIG. 10C). At this time, the wiping member 88 moves so as to straddle the lowered cap member 80.
[0168]
In the present embodiment, since the wiper 92 slides on the nozzle surface 40A while maintaining the contact amount of 1.5 mm, dirt adhering 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 the drive motor 318 of the moving mechanism 312, and is moved to the height of the home position (see FIG. 10E).
[0170]
Subsequently, by driving the drive motor 318 of the moving mechanism 312 shown in FIG. 8, the common substrate 310, that is, the wiping member 88 is moved together to the opposite side in the width direction and returned 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 to return 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, by driving the drive motor 304 of the elevating mechanism 302 shown in FIG. 8, the common substrate 300 is raised, and the rubber portion 84 of the cap member 80 attached to the common substrate 300 is moved to the nozzle surface 40A of the recording head 40. (See FIG. 9 (A) → FIG. 9 (B)). As a result, the airtightness of the nozzle surface 40 (nozzle 58) is ensured, and the viscosity and drying of the ink are prevented, and the adhesion of dust is also prevented.
[0173]
As described above, in the ink jet recording apparatus 10 according to the present embodiment, by disposing the transport belt units 19A to 19E on the upstream side and the downstream side of each of the recording heads 44Y to 44K, the position facing the recording heads 44Y to 44K is achieved. , Maintenance parts 18Y to 18K are arranged. Therefore, there is no need to move the recording heads 44Y to 44K or the maintenance device 81, and the maintenance operation can be performed quickly, and a decrease in productivity can be minimized. Further, misalignment or the like due to the movement of the recording head is prevented, and high-quality printing can be performed. Further, since the moving mechanism is not required, the device configuration is simplified.
[0174]
On the other hand, since the paper is transported by holding the paper on the endless belt 104 of the transport belt units 19A to 19E, the paper is reliably held on the endless belt 104 and transported stably. In addition, since the lifting prevention means (for example, the plate 10) is provided to face the endless belt 104, the paper which may rise from the endless belt 104 due to the adhesion of ink or the like is securely held on the endless belt 104. It is transported between the recording head 44 and the maintenance unit 18.
[0175]
Further, in the present embodiment, although the conveyance unit does not exist below the recording heads 44Y to 44K, the guide member 94 prevents the sheet from being pushed into the maintenance device 81. Further, the paper is prevented from floating from the guide member 94 by the star wheel 70 elastically contacting the guide member 94, and the paper is maintained at a constant distance from the nozzle surface 40 </ b> A of the unit recording head 40. Therefore, at the printing position, the paper is printed at a fixed distance from the nozzle surface 40A and printed with high image quality.
[0176]
By the way, since the interval between the transport belt units 19 is shorter than the minimum transport direction length of the paper, even if the paper of any size is transported, the downstream transport belt unit is separated before the paper is peeled by the upstream transport belt unit. The leading edge of the sheet is held by the transport belt unit. Therefore, the sheet is reliably transported 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 42A and 42B in which a plurality of short unit recording heads 40 are arranged on both sides of a common substrate 46, respectively. It can be shared with inexpensive devices (recording heads) that are mass-produced, and the recording head 40 that can print at full width at low cost can be configured. In addition, since a space is generated between the recording heads 44 and the unit recording heads 40, there is an advantage that the star wheel 70 can be provided.
[0178]
In addition, by configuring the recording head arrays 42A and 42B on both sides of the common substrate 46, the configuration of each of the recording head arrays 42A and 42B is simplified (miniaturized), and the manufacture and high precision adjustment are simplified. In particular, there is an effect that the distance in the transport direction of the recording head 44 can be reduced. Further, there is an advantage that the configuration of the maintenance device 81 (the cap member 80 and the wiping member 88) can be shared with those used in a short recording head.
[0179]
However, the recording head 44 is not limited to such a configuration. As shown in FIG. 11, six unit recording heads 40 are attached to two common substrates 46A and 46B, respectively, and the recording head arrays 42A and 42B can also be configured.
[0180]
Further, the recording heads 44 are configured by arranging unit recording heads 110 (see FIG. 12) in which the nozzles 58 of the unit recording heads 40 are formed up to the ends in the nozzle array direction in a width direction on a common substrate (not shown). (See FIG. 13). In order to match 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 precision. However, the configuration is such that the recording head 44 can be miniaturized most.
[0181]
In addition, although the nozzle arrangement of the unit recording heads 40 and 110 is linear, it has been described, but the arrangement is not limited to this. For example, as shown in FIG. 14, the nozzles can be arranged in a staggered manner.
[0182]
In the present embodiment, the method of ejecting ink droplets from the unit recording head 40 has been described as a thermal inkjet method. However, any method may be used as long as the color material is directly transferred to the paper in a non-contact manner. . An ink jet system is typical, but any known system can be applied. Further, the ink jet system is not limited to the thermal ink jet system, but may be a piezo ink jet, a continuous flow ink jet, an electrostatic suction ink jet, or the like.
[0183]
Further, as the ink to be used, any of a water-based ink, an oil-based ink, a so-called solid ink which is solid at room temperature, a solvent ink and the like can be applied. The coloring material in the ink may be any pigment or dye.
[0184]
Further, in the present embodiment, the cap member 80 is provided corresponding to the unit recording head 40, but one cap member 80 may correspond to a plurality of unit recording heads 40.
[0185]
In the present embodiment, the recording head arrays 42A and 42B and the maintenance unit 18 and the transport belt unit 19 disposed upstream of the recording head arrays 42A and 42B are configured as one image forming unit.
[0186]
By arranging one or a plurality of image forming units, it is possible to easily configure an image forming apparatus according to each requirement including single color, full color and special color. In addition, the maintenance of the device is improved by the unitization.
[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 will be omitted. Hereinafter, description will be made focusing on different parts of the first embodiment.
[0187]
As shown in FIG. 15, the transport belt unit 19 is different from the first embodiment in that an endless belt 104 is stretched around one drive roller 100 and one driven roller 102. The endless belt 104 is configured to be tensioned by 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 the present embodiment. The roller is a hollow roller formed 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 integrally driven by a lifting mechanism and a moving mechanism, respectively.
[0190]
Further, in the present embodiment, means for sucking ink from the concave portion 82A of the receiving portion 82 of the cap member 80 is provided. More specifically, as shown in FIG. 15, a lower portion of each cap member 80 has a first waste ink recovery tank 132 (which communicates with a concave portion 82A of a rubber portion 82 of each cap member 80 via a channel 130). Capacity is 4 cc). Further, a second waste ink recovery tank 136 (having a capacity of) connected to the six first waste ink recovery tanks 130 respectively corresponding to the six cap members 80 arranged in a line in the width direction through the flow path 134. 60 cc).
[0191]
Further, a third waste ink recovery tank 140 is provided, which is communicated with all eight second waste ink recovery tanks 136 via a flow path 138.
[0192]
The third waste ink collection tank 140 is capable of discharging waste ink to the outside from the flow path 142 and is connected to a vacuum pump 146 via a filter 144.
[0193]
The third waste ink recovery tank 140 has a configuration in which the negative pressure is measured by the negative pressure measuring device 148.
[0194]
In addition, 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, and 142, respectively, and can be selectively opened and closed.
[0195]
Therefore, the drainage ink collected in the cap member 80 (the concave portion 82A) is recovered by driving the vacuum pump 146 and opening and closing the electromagnetic on-off valves 150, 152, 154, or the ink in the nozzle surface 40A or the nozzle 58 by the vacuum described later. Can be sucked.
[0196]
The operation of the thus configured ink jet recording apparatus 10 will be described. Note that 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]
Vacuum is performed at the timing of the non-printing state. Therefore, the transport 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, by driving the elevating mechanism in the same manner as in the first embodiment, the cap member 80 located at the home position rises and comes into pressure contact with the nozzle surface 40A of the unit recording head 40 (see FIG. 9B). As a result, the rubber portion 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 on-off valve 150 provided on the flow path 130 and the third electromagnetic on-off valve 154 provided on 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 of about −30 kPa to −100 kPa with respect to the atmospheric pressure (for example, −70 kPa), the drive of the vacuum pump 146 is stopped. Thus, the first to third waste ink recovery tanks 132, 136, and 140 are set to a predetermined negative pressure. Further, the second solenoid on-off 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 from which ink is to be collected with the corresponding first discharged ink collecting tank 132 is opened. As a result, the first waste ink recovery tank 132 at a predetermined negative pressure communicates with the concave portion 82A of the cap member 80, and the ink or rubber portion 84 stored in the concave portion 82A of the receiving portion 82 makes the nozzle surface airtight. The ink and dust adhering to the nozzle 40 and the thickened ink existing inside the nozzle 58 are sucked at a negative pressure and collected in the first waste ink collection tank 132.
[0202]
Subsequently, similarly to 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, which is at a negative pressure. Become.
[0203]
In this manner, by applying a negative pressure to the concave portion 82A of the recording head 80, the ink (discharged ink) accumulated 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 manner, wiping is performed in the same manner as in the first embodiment.
[0205]
Therefore, the ink jet recording apparatus of the present embodiment has the same operation and effects as those of the first embodiment, and also has the effect that the vacuum operation can be performed without moving the recording heads 44Y to 44K.
[0206]
Further, 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 releasability of the paper is improved. .
[0207]
The vacuum operation and mechanism described in the present embodiment can 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 a decrease in print image quality due to misalignment due to the recording head movement and a decrease in print productivity due to the recording head movement, and the like. High productivity 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 present invention.
FIG. 2 is a schematic side view showing a transport 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 present invention.
FIG. 4 is a plan view of a unit recording head according to the first embodiment of the present invention.
5A is a cross-sectional view of the 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 an explanatory perspective view of a main part of the maintenance device according to the first embodiment of the present invention.
FIG. 8 is an explanatory diagram of a driving mechanism of the recording apparatus according to the first embodiment of the present invention.
FIGS. 9A and 9B are diagrams illustrating a capping operation in the recording apparatus according to the first embodiment of the present invention.
FIGS. 10A to 10G are explanatory diagrams of a wiping operation in the printing apparatus according to the first embodiment of the present invention.
FIG. 11 is a diagram illustrating a variation of a recording head array.
FIG. 12 is a diagram showing variations of a unit recording head.
FIG. 13 is a diagram illustrating variations of a recording head.
FIG. 14 is a diagram illustrating variations of a unit recording head.
FIG. 15 is a schematic configuration diagram illustrating a recording apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
10 Inkjet recording device (recording device)
19 Conveyor belt unit (conveying means)
40 unit recording head
42 Recording Head Array
44 Recording Head
70 Star wheel (transportation 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 (20)

A recording apparatus that forms an image by discharging droplets onto a recording medium,
A recording head that ejects droplets from a droplet ejection surface;
A maintenance unit that is arranged to face a droplet discharge surface of each recording head and performs maintenance of the recording head;
A transport unit that is disposed before and after the recording head in the transport direction of the recording medium, and that transports the recording medium between the droplet discharge surface of the recording head and the maintenance unit,
A recording device, comprising: an endless belt; and holding means for holding the recording medium on a surface of the endless belt. 2. 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. The lifting device for preventing the recording medium from rising from the endless belt is provided at a position facing the endless belt in the recording medium holding range of the endless belt. 2. The recording device according to claim 1. The recording apparatus according to claim 1, wherein the transport unit includes a belt cleaning unit configured to clean the endless belt. 6. The printing medium according to claim 1, wherein a distance between conveying units disposed on an upstream side and a downstream side of the recording medium in the conveying direction with respect to the recording head is shorter than a minimum length of the recording medium in the conveying direction. 2. The recording device according to claim 1. The recording apparatus according to claim 1, wherein a conveyance auxiliary unit that secures the flatness of the recording medium is provided between the recording head and the maintenance unit. 8. The recording apparatus according to claim 7, wherein the transport assisting unit is provided on the recording head side. 9. The recording apparatus according to claim 8, wherein the transport assisting unit is a spur that contacts a recording surface of the recording medium. The recording apparatus according to claim 7, wherein the transport assisting unit is provided on the maintenance unit side. The recording apparatus according to claim 10, wherein the transport assisting unit is a guide member that supports a non-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. 13. The recording apparatus according to claim 1, wherein the recording head includes a plurality of unit recording heads. 14. The recording apparatus according to claim 13, wherein the recording head is configured by combining a plurality of recording head arrays each including a plurality of unit recording heads arranged in a width direction. 15. The recording apparatus according to claim 8, wherein the transport assisting unit is disposed between a plurality of the unit recording heads. The maintenance unit 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 that the droplet discharged during non-printing is A cap means for landing,
Cleaning means for wiping the droplet discharge surface,
The recording apparatus according to any one of claims 1 to 15, further comprising: 17. The recording apparatus according to claim 16, wherein the cleaning unit is configured to be able to approach and separate from a droplet discharge surface of the recording head, and to contact the droplet discharge surface during cleaning. 18. The recording apparatus according to claim 1, wherein a plurality of the recording heads are arranged along a transport direction of the recording medium. 19. The recording apparatus according to claim 18, wherein the plurality of recording heads discharge liquids of different colors. 20. The recording apparatus according to claim 1, wherein the recording head, the maintenance unit, and a conveying unit disposed upstream or downstream of the recording head are unitized. apparatus.

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