JP2006021336A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder which holds stable images by possessing a reserve discharge function wherein smudging by ink is suppressed as much as possible. <P>SOLUTION: The inkjet recorder equipped with a printing head of a full line head printing system includes a transfer belt stretched with a predetermined interval spaced from the printing head to transfer a recording medium, and an ink receptacle arranged opposite to the printing head via the transfer belt. The inkjet recorder moves a part of a plurality of belt supporting rollers which stretch the transfer belt by a timing whereby the recording medium is not transferred, retreats the transfer belt from immediately below the printing head, and carries out ink reserve discharge from the printing head towards the ink receptacle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus that performs printing on a recording medium using a printing unit.

  In the ink jet recording apparatus, the ink discharge port of the print head and the thin tube connected to the ink discharge port are used for a long time, and bubbles, small dust, and the like are formed in the discharge port and the thin tube. Alternatively, the periphery of the ejection port is soiled with ink, and this ink is solidified around the ejection port, resulting in poor ink ejection. Alternatively, the discharge ink is pulled by the surface tension of the ink around the discharge port, and troubles such as discharge of the ink in a bent direction occur. Therefore, high image quality cannot be maintained unless the discharge port and the narrow tube are cleaned in a timely manner. For this reason, the ink supply path (capillary tube) connected to the discharge port and the discharge port by cleaning the discharge port by an ink cleaning member incorporated in the ink jet recording apparatus or performing preliminary discharge as an ink discharge operation at the time of non-recording Bubbles, dust, etc. inside are poured out from the print head together with ink.

  In the serial printing method using a print head movable in the main scanning direction, it is possible to provide a preliminary ejection ink receiver at a position where the recording medium is removed, so that it is easy to perform preliminary ejection during the recording operation. is there. On the other hand, in a full line head printing method using a line type print head that ejects ink over the entire width of the recording medium, ink is ejected from the fixed print head toward the recording medium being conveyed. Therefore, it is difficult to perform preliminary ejection during the recording operation.

  As a prior art of an apparatus adopting the full line head printing method, a method of performing preliminary ejection directly on a platen member when there is no recording medium at the time of non-recording, or performing preliminary ejection on a conveyance belt that conveys the recording medium There is also a method.

In the method of performing preliminary discharge on the conveyance belt, a belt cleaning unit provided in the vicinity of the line head on the downstream side from the ink discharge port presses against the conveyance belt, and the conveyance belt moves along with the movement of the conveyance belt. The ink discharged on the surface is wiped off and cleaned. (For example, refer to Patent Document 1).
JP 2000-127362 A (column 11, lines 2 to 5)

  However, the method of performing preliminary ejection directly on the platen member in the prior art has the inconvenience of not only soiling the platen member but also soiling the recording medium itself. In addition, in the method of performing preliminary discharge on the conveyance belt of the recording medium, an operation mechanism is required in which the belt cleaning unit is brought into contact with and separated from the conveyance belt at a timing when the recording medium is not present. When performing continuous printing on a large number of recording media, the contact and separation must be repeated for a short time when no recording medium is present, and when the belt cleaning means is separated from the conveyance belt, There is a tendency for ink to remain unwiped on the conveyor belt.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording apparatus that has a preliminary ejection function that suppresses contamination due to ink as much as possible and maintains a stable image.

  In an inkjet recording apparatus provided with a full-line head printing type print head, a conveyance belt for conveying a recording medium stretched at a predetermined interval from the print head, and the print head via the conveyance belt An ink receiving container disposed opposite to each other, and at a timing when the recording medium is not conveyed, a part of a belt support roller is moved to a plurality of tensioning the conveying belt, and the conveying belt is moved from directly below the print head. An ink jet recording apparatus, wherein the ink is preliminarily ejected to perform preliminary ink ejection from the print head toward the ink receiving container.

  During a short period of time when the recording operation is not performed, the recording medium and the conveyance belt that obstruct the passage of the preliminary ejection ink are temporarily retracted, the ink receiving container moves to the print head, and the ink ejection port of the print head and the ink receiver It can collide with the ink injection port of the container and can be received directly from the ink print head to the ink receiving container, and a stable image without contamination can be maintained.

  Embodiments of the present invention will be described with reference to the drawings. The description in this column does not limit the technical scope of the claims or the meaning of terms.

  FIG. 1 is a diagram showing a main part of an ink jet recording apparatus according to the present invention.

  In FIG. 1, reference numeral 1 denotes an apparatus main body of an ink jet recording apparatus. Reference numeral 2 denotes a belt mechanism that conveys recording paper, which is a recording medium according to the present invention, and includes a conveying belt 20, a first moving roller 21, a second moving roller 22, a driving roller 23, a conveying roller pair 24, and guide rollers 25 and 26. The charger 27 is configured to electrostatically attract the recording paper P to the surface of the transport belt 20. Reference numeral 3 denotes a print head of a line head printing system that covers almost the entire area of the recording paper as a recording medium. The ink discharge port surface B and the conveying belt 20 are kept at a predetermined distance, and K (black) from the upstream side in the conveying direction. , C (cyan), M (magenta), and Y (yellow). Reference numeral 4 denotes an ink receiving portion for storing ink preliminarily ejected from the print head 3, and an ink receiving container 41 corresponding to the position of the print head for each color is arranged. The details of the belt mechanism 2 and the ink receiving container 41 will be described later. A paper feeding / conveying unit 5 includes a paper cassette 50 for storing the recording paper P, a feeding roller 51, a paper feeding roller 52, a registration roller 53, a paper feeding guide 54, and the like. Reference numeral 60 denotes a paper discharge roller, 61 a paper discharge conveyance roller, 62 a conveyance guide, and 63 a paper discharge tray.

  FIG. 2 is an enlarged view of the periphery of the belt mechanism portion and the ink receiving portion in FIG.

  FIG. 2A is a view of the inside from the front side of the apparatus main body, and FIG. 2B shows a cross section taken along arrow YY in FIG.

  2 (a) and 2 (b), A is an ink printing unit constituting the belt mechanism and the ink receiving container according to the present invention. The ink printing unit A holds the belt mechanism portion and the ink receiving portion with unit frame bodies 10A and 10B, and is installed in the apparatus main body via a support member (not shown).

  The conveying belt 20 forms a loop via a first moving roller 21, a second moving roller 22, a driving roller 23, a conveying roller pair 24, guide rollers 25, 26, and the like, which are a plurality of belt supporting rollers, and is not illustrated. The vehicle runs in the direction of arrow h by a driving roller 23 that obtains rotational force from the driving source.

  The first and second moving rollers 21 and 22 are supported by roller support plates 211 and 221, and both end portions of the roller support plates 211 and 221 are placed on the guide rails 212 and 221. Is fixed to the unit frames 10A and 10B via fixing members 213 and 223. The roller support plates 211 and 221 are fixed to the drive wires S1 and S2. The drive wires S1, S2 are stretched via guide pulleys 226, 227, 228 and a drive pulley 229, and obtain a rotational force from a drive unit (not shown), so that the drive pulley 229 rotates by a predetermined number of rotations. The roller support plates 211 and 221 can be slid in the directions of arrows f and g to reciprocate. The guide pulleys 226, 227, and 228 are supported by a support shaft (not shown) provided in the unit frame 10A. The drive wire S1 is attached to the drive pulley 229 a plurality of times.

  Next, the raising / lowering operation of the ink receiving part 4 will be described.

  The lifting platform 40 has a guide dowel 401, which engages a guide groove 402 provided in the unit frame 10A, 10B. A guide plate 403 that assists the vertical movement of the lifting platform 40 is also provided in the unit frames 10A and 10B. Furthermore, two eccentric cams 45 are provided in the vicinity of the unit frame bodies 10A and 10B at the center of the lower surface of the lifting platform 40. The spring hooks 405 provided on the guide plate 403 and the lifting platform 40 are provided. A spring 406 is hung on a spring hook (not shown), and the eccentric cam 45 and the lifting platform 40 are in contact with each other. The two eccentric cams 45 are attached to the rotating shaft 406 in the same phase. The position of the lifting platform 40 in FIG. 2A is at the lowest position, and the rotating shaft 408 obtains a rotating force from a power source (not shown) and rotates the eccentric cam 45 by 180 °. 40 lifts the lifting platform 40 to the uppermost position against the lifting platform 45 against the spring 408, and the ink receiving container 41 contacts the ink discharge port surface B.

  FIG. 3 is a diagram illustrating a state in which the pushed-up ink receiving container is in contact with the ink discharge port surface.

  FIG. 4 is a plan view of the ink receiving container as viewed from the cross section and from the top.

  FIG. 4A shows a cross section of the ink receiving container, and FIG. 4B is a plan view seen from the upper surface of the ink receiving container.

  Each color ink receiving container 41 is placed on a lift 40 and a notch m (see FIG. 2B) provided in the unit frame 10B along a guide (not shown) provided on the lift 40. And is inserted in the direction of the arrow w and fixed at a predetermined position by a pressing member (not shown). The ink receiving container 41 is provided with an air port 411, and when the ink receiving container 41 is inserted, the air port 411 is inserted into the insertion portion of the communication pipe 42 fixed at a predetermined position of the lifting platform 40. Then, it is joined to a pump 48 (see FIG. 1) which is a negative pressure generating means disposed in the apparatus main body via a flexible air supply tube 43 (see FIG. 1).

  In addition, an ink injection port 412 is provided on the upper surface of the ink receiving container 41, and a seal member 413, which is a relatively soft elastic member, is attached to the periphery of the ink receiving port 41. The lifting platform 20 is at the highest position. When pushed up, the seal member 413 comes into contact with the ink discharge surface B, and the ink injection port 412 and the ink discharge portion 31 abut each other. As a result, the ink receiving container 41 is kept secret from the outside air.

  Next, the preliminary ink ejection operation according to the present invention will be described.

  Returning to FIG. 2, when an ink preliminary discharge command is received from a control unit (not shown) at a timing when the recording paper is not conveyed, the drive pulley 229 obtains a rotational force from a power source (not shown) and rotates clockwise. Then, the roller support plate 211 at the position X1 is slid on the guide rail 212 via the drive wires S1 and S2, and the roller support plate 221 at the position X3 is slid on the guide rail 222 to the position X2. The first moving roller 21 and the second moving roller 22 are moved to a predetermined distance to X4, and the first moving roller 21 and the second moving roller 22 are moved to the positions X2 and X4 in a state where the conveying belt 20 is stretched. As a result, the conveyor belt 20 is removed between the ink receiving container 41 and the print head 3. Next, the eccentric cam 45 starts to rotate in response to a push-up command of the lift 40 from the control unit, and pushes up the lift 40. The elevator 40 rises from the initial position along the guide plate 403 and the guide groove 402 against the spring 406, and stops after the eccentric cam 45 rotates 180 °, that is, at the uppermost position. At this point, preliminary ink ejection from the print head 3 for each color is performed. Thereafter, the eccentric cam 45 rotates 180 ° to return the lifting platform 40 to the initial position. Next, the drive pulley 229 rotates counterclockwise, and the ink preliminary ejection operation is completed by returning the roller support plates 211 and 221 (first and second moving rollers 21 and 22) to the positions X1 and X3.

  As described above, the present invention moves a part of the plurality of belt support rollers that stretch the conveyance belt at a timing when the recording paper is not conveyed, and the conveyance belt does not exist below the print head. The ink is preliminarily ejected.

  Here, the image forming process will be described.

  First, in FIG. 1 and FIG. 2, a print button (not shown) is pressed, and simultaneously with the start of the image forming mode, a feed motor 51 is rotated to feed the recording paper P from the cassette 50. The recording paper P is temporarily stopped by the registration roller 53 via the paper supply roller 52, is timed with the image information, is conveyed with the rotation of the registration roller 53, and is conveyed by the driving roller 23. Of the image corresponding to the K image data by the K print head 3 while being held in a state of being electrostatically attracted to the surface of the conveyor belt 20 by the charger 27 and maintaining the flatness. Ink ejection is started, and an ink image corresponding to the K image of the original image is formed on the recording paper P.

  Thereafter, in synchronization with the K ink image, the C image printing process is started, and the C ink image is superimposed on the K ink image. In a similar printing process, the M and Y ink images are superimposed on the K and C superimposed ink images on the recording paper P, respectively, so that a four-color superimposed image of K, C, M, and Y is formed.

  Further, the recording paper P after the image processing is fed on the transport belt 20, separated in curvature by the first moving roller, transferred to the transport guide 62, and discharged from the discharge roller 60 through the discharge transport roller 61. The paper is discharged to the paper tray 63.

  Here, in the present embodiment, the preliminary ink ejection operation is always performed before image formation, and in the case of continuous image formation, it is performed at intervals of 5 seconds (the execution interval is set according to the physical properties of the ink). When the preliminary ejection is completed, control is performed so as to return to the image formable state again.

It is a figure which shows the principal part of the inkjet recording device regarding this invention. FIG. 2 is an enlarged view of the periphery of the belt mechanism and the ink receiving container in FIG. 1. It is a figure which shows the state which the ink receiving container pushed up contact | abuts to the ink discharge port surface. It is the top view seen from the section and upper surface of an ink receiving container.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 10A, 10B Unit frame 2 Belt mechanism part 20 Conveyance belt 21 1st moving roller 22 2nd moving roller 23 Drive roller 27 Charger 211, 221 Roller support plate 212, 222 Guide rail 3 Print head 31 Ink discharge part DESCRIPTION OF SYMBOLS 4 Ink receiving part 40 Lifting stand 41 Ink receiving container 43 Air supply pipe 48 Pump 401 Guide dowel 403 Guide plate 406 Spring 5 Paper feed conveyance part 50 Paper cassette 51 Feeding roller A Belt mechanism part S1, S2 Drive wire

Claims (4)

In an inkjet recording apparatus provided with a full-line head printing type print head, a conveyance belt for conveying a recording medium stretched at a predetermined interval from the print head, and the print head via the conveyance belt A plurality of belt support rollers that stretch the conveyor belt at a timing when the recording medium is not conveyed, and move the conveyor belt from directly below the print head. An ink jet recording apparatus, wherein the ink is preliminarily ejected to perform preliminary ink ejection from the print head toward the ink receiving container. The ink receiving container moves in the direction of the print head after the recording operation is completed, the ink discharge port of the print head and the ink injection port of the ink receiving container are abutted, and the ink receiving container is sealed. The inkjet recording apparatus according to claim 1. The ink jet recording apparatus according to claim 1, wherein the ink receiving container is in communication with a negative pressure generating unit. The inkjet recording apparatus according to claim 1, wherein the conveyance belt electrostatically attracts a recording medium.

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