JP2010132435A - Image recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the abrasion of a platen by a medium pressing roller for preventing the floating of a recording medium, in an image recorder mounted with a line type recording head. <P>SOLUTION: This image recorder has a bearing part for supporting the medium pressing roller constituted of a thick shaft abutting on a carrier belt and rotating driven by the movement through the rotation of the carrier belt and a thin shaft for making a clearance for passing the recording medium. The lower end of this bearing part abuts on the platen when recording an image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image recording apparatus having a conveyance mechanism for conveying a recording medium to a fixed recording head for recording an image.

  In general, inkjet printers are widely used due to low noise during recording and good quality of recorded images. This ink jet printer is roughly divided into a serial type ink jet printer that performs recording on a recording medium while moving the recording head and the recording medium together, and a recording medium in which only the recording medium is moved by fixing the recording head. There are two types: full line type ink jet printers (hereinafter referred to as line printers) that perform recording on the top. In particular, in recent years, there have been many proposals related to line printers because of the demand for faster image recording, that is, higher recording speed.

  In such a line printer, as a mechanism for transporting the recording medium, a belt transport is provided for regulating the flatness of the recording area facing the ink jet head and transporting the recording medium while adsorbing the recording medium to the endless belt. The mechanism is adopted.

Such a belt conveyance mechanism needs to reliably adsorb the recording medium to the endless belt in order to avoid a collision between the recording medium being conveyed and the recording head. Therefore, Patent Document 1 discloses a technique for preventing the recording medium from floating and for reliably adsorbing the recording medium to an endless belt. In Patent Document 1, a press roller that abuts against an endless belt is disposed on the upstream side of the recording head block so as to be driven to rotate. I have to.
Japanese Patent Laid-Open No. 7-53082

In Patent Document 1 described above, the pressing roller is brought into contact with the belt that drives the recording roller to prevent the recording medium from floating. For this reason, the flattened platen is in a state of being pressed with a predetermined force by the pressing roller with the belt interposed therebetween. Therefore, the place of the platen pressed by the pressing roller is worn with time. In other words, a dent occurs at the platen where the presser roller abuts. Due to this dent, the transport speed of the transported recording medium becomes uneven, and high-quality image recording cannot be performed.
SUMMARY An advantage of some aspects of the invention is that it provides an image recording apparatus that can prevent a recording medium from floating and can maintain conveyance performance.

  In order to achieve the above object, an image recording apparatus of the present invention comprises a line head composed of one or a plurality of recording heads, a head portion for recording an image on a recording medium, and at least a region facing the line head. A plate-shaped platen, and a transport mechanism for transporting the recording medium by a belt, and disposed upstream of the line head in the transport direction of the recording medium, and suppresses the recording medium to the belt side against the recording medium floating from the belt And a presser mechanism that includes a roller member that rotatably supports both ends of the roller, and a bearing member that includes a restricting portion that contacts the platen and restricts the position of the roller. Is in contact with the belt, and the restricting portion is in contact with the platen.

  Further, the image recording apparatus of the present invention comprises a line head composed of one or a plurality of recording heads, a head portion for recording an image on a recording medium, and a plate-shaped resin at least in a region facing the line head. A conveyance mechanism that has a formed platen and conveys the recording medium by a belt, a roller disposed upstream and in the conveyance direction of the recording medium from the line head, and an urging force that urges the roller toward the belt A holding mechanism having a member and a bearing member that rotatably supports both ends of the roller, and the bearing member has a restricting portion extending to the platen side from a portion where the roller is supported, During image recording, the roller is in contact with the belt and the restricting portion is in contact with the platen.

  According to the present invention, it is possible to provide an image recording apparatus capable of preventing the recording medium from floating and maintaining the conveyance performance.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of an image recording apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing the shape of the platen. FIG. 3 is a perspective view of the image recording unit, and FIG. 4 is a diagram of the image recording unit viewed from below. FIG. 5A shows the detailed configuration of the roller bearing in the presser mechanism, and FIG. 5B shows the shape of the roller in the presser mechanism. FIG. 6 is a diagram showing the positional relationship between the medium pressing mechanism and the transport mechanism at the image recording position. In the present embodiment, the recording medium conveyance direction is the X direction, the direction orthogonal to the X direction is the Y direction or the width direction, and the direction orthogonal to the X direction and the Y direction is referred to as the Z direction or the vertical direction. .

The image recording apparatus 10 is roughly divided into a recording medium supply system 11, an image recording unit 12, a transport mechanism 13, an elevating mechanism 14, and a recording medium storage system 15.
The recording medium supply system 11 includes a paper feed table 22 that accommodates a plurality of recording media 21, a paper feed roller 23, and a registration roller pair 24. The paper feed roller 23 is also referred to as a pickup roller. The paper feed roller 23 comes into contact with the recording medium 21 accommodated in the paper feed table 22 and sequentially takes out the recording medium 21 one by one and receives it by the registration roller pair 24. hand over.

  The registration roller pair 24 is a roller for correcting (correcting) the inclination (skew) of the recording medium 21 to be conveyed with respect to the conveyance direction (X-axis direction). The registration roller pair 24 includes a pair of upper and lower registration rollers 24 a and 24 b, and is arranged so that the upper surface of the lower registration roller 24 b is substantially flush with the conveyance path extension line of the recording medium 21. . Further, a registration roller 24a biased by a spring (not shown) is provided above the registration roller 24b so as to press the registration roller 24b downward. The support shafts of the registration roller 24a and the registration roller 24b are substantially parallel. The registration roller pair 24 abuts the front end of the recording medium 21 fed by the paper feeding roller 21 to the nip portion of the registration roller pair 24, and is inclined (inclined) with respect to the conveyance direction (X-axis direction) of the recording medium 21. After the line) is corrected (corrected), the recording medium 21 is conveyed to the conveying mechanism 13 in accordance with an image recording timing in the image recording unit 12 described later.

  The transport mechanism 13 is disposed on the downstream side of the supply system 12 in the transport direction, and is disposed to face the image recording unit 12. The transport mechanism 13 includes a suction fan 41, a transport belt 42, a platen 43, a driving roller 44, a driven roller 45, tension rollers 46 (46a, 46b), and a transport frame 47. The transport mechanism 13 can be moved between the image recording position shown in FIG. 1 and a non-image recording position retracted from the image recording position by the elevating mechanism 14.

  The conveyance belt 42 has a width equal to or larger than the width of the recording medium 21 to be conveyed and is formed in an endless belt shape, and a large number of holes are provided on the surface thereof. The conveyor belt 42 is wound in a tensioned state by a driving roller 44, a driven roller 45, and a tension roller 46 that are rotatably held by a conveying frame 47, and is driven in a predetermined direction by driving the driving roller 44. Rotate.

  A platen 43 is provided below the conveyor belt 42. The platen 43 is also held by the transport frame 47. The platen 43 is processed into a plate shape so that at least a region facing the image recording unit 12 is a flat surface, and a large number of holes 43a are opened as shown in FIG.

  As shown in FIG. 2, the platen 43 is provided with two ribs 43 b that extend in the conveying direction on both outer sides of the conveying belt 42 and abut against a bearing portion 102 of the medium pressing mechanism 100 described later. Yes. The platen 43 of the present embodiment is formed of a resin member such as ABS, for example. By making the platen 43 made of resin in this way, there are merits such as mass production, cost reduction of parts, weight reduction of the apparatus, and reduction of work load accompanying the weight reduction. On the other hand, there is a demerit in terms of durability such as abrasion due to abrasion. Therefore, in this embodiment, this disadvantage is avoided by adopting the configuration of the medium pressing mechanism 100 described later.

  Next, the image recording unit 12 will be described. In this embodiment, for example, the image recording unit 12 is a head unit 31 (31C, 31K, 31M) that ejects ink of four colors (cyan (C), black (B), magenta (M), and yellow (Y)). , 31Y), a head holding member 32 for holding the head portion 31, a gap adjusting member 33, and a medium pressing mechanism 100.

  As shown in FIG. 4, the head holding member 32 is provided with a plurality of openings 35. A short recording head is positioned and fixed in each of the openings 35. As described above, the mounting of the recording head constitutes a line-type head portion 31 that is equal to or more than the recording area in which image recording is performed in the width direction of the recording medium 21.

  In the present embodiment, six recording heads are arranged in a staggered manner in a direction orthogonal to the transport direction, and the head unit 31 that is equal to or larger than the width of the recording medium 21 is configured. Of course, the number of recording heads is not limited to this, and the head unit 31 may be configured by one long recording head. Further, the arrangement of the recording heads is not limited to the staggered arrangement, and the head unit 31 may be configured by overlapping a part of the recording heads and arranging them in a direction orthogonal to the transport direction.

In the head unit 31 (31C to 31Y), each color ink supplied from an ink supply system (not shown) is discharged onto the recording medium 21 to record an image.
The interval adjustment member 33 is provided on the facing surface of the head holding member 32 that faces the conveyance mechanism 13, and adjusts the gap amount between the image recording unit 12 and the conveyance mechanism 13. Specifically, two spacing adjusting members 33 are provided on the opposite surface on the upstream side in the transport direction (upstream in the transport direction from the head portion 31), and on the downstream side in the transport direction (upstream in the transport direction from the head portion 31). Two interval adjusting members 33 are provided.

The interval adjusting member 33 is a pin formed to protrude toward the transport mechanism 13 and has a length that slightly protrudes from the nozzle surface of the recording head 36.
In the present embodiment, the tip of the interval adjusting member 33 is protruded 1 mm from the nozzle surface of each recording head in the head portion 31. The distance adjusting member 33 can vary the amount of protrusion from the nozzle surface by a protrusion amount adjusting member (not shown).

  The medium pressing mechanism 100 is provided on the facing surface of the head holding member 32 that faces the transport mechanism 13. The medium pressing mechanism 100 includes a plate 104, a medium pressing roller 101, a roller bearing portion 102, and an ink absorber 105.

  The plate 104 has an opening at a position corresponding to the opening 35 of the head holding member 32, and is attached to a facing surface of the head holding member 32 that faces the transport mechanism 13. In the present embodiment, the plate 104 can be detached from the facing surface. The plate 104 is provided with an ink absorber 105. Thereby, the mist-like ink generated when the head unit 31 ejects the ink can be absorbed by the ink absorber 105, and the contamination in the apparatus can be reduced.

  As shown in FIGS. 3 and 4, the medium pressing roller 101 is disposed on the upstream side of each recording head. In the present embodiment, a total of eight medium pressing rollers 101 are arranged upstream of each recording head.

  As shown in FIG. 5A, both ends of the medium pressing roller 101 are held by the bearing portions 102. As shown in FIG. 4A, the bearing portion 102 is provided to be slidable in the vertical direction with respect to the plate 104. And the bearing part 102 is urged | biased downward (conveyance mechanism) by the coil spring 103 as an urging | biasing member.

  The bearing portion 102 has a shape in which a lower end 102 a extends toward the platen 43 from a portion where the medium pressing roller 101 is pivotally supported. The lower end 102a of the bearing portion 102 is flattened, and comes into contact with the rib 43b of the platen 43 described above when recording an image.

  By this contact, the distance between the medium pressing roller 101 and the platen 43 can be regulated. Thus, the lower end 102 a of the bearing portion 102 has a function as a restricting portion that restricts the distance between the medium pressing roller 101 and the platen 43. Here, the medium pressing roller 101 is driven and rotated by the rotation of the conveying belt 42, and the paper passing performance is better if a predetermined gap is provided at a location through which the recording medium 21 passes.

  In this embodiment, in order to improve the paper passing performance, the medium pressing roller 101 has a shape as shown in FIG. The thick shaft portions 101 a of the medium pressing roller 101 provided at both ends are pressed against the transport belt 42 and are rotated following the movement of the transport belt 42 due to the rotation. Inside the thick shaft portion 101a is a thin shaft portion 101b having a smaller diameter than the thick shaft portion 101a, and a gap A through which the recording medium 21 passes (the difference in diameter between the thick shaft portion 101a and the thin shaft portion 101b). To produce. Although this gap A depends on the thickness of the recording medium 21, if the thickness of the recording medium 21 is plain paper, it may be about 0.5 mm. Further, the width B needs to be longer than the width of the recording medium 21 that passes therethrough.

  With such a configuration, at the time of image recording, with the lower end 102a of the bearing portion 102 in contact with the rib 43b of the platen 43, the thick shaft portion 101a of the medium pressing roller 101 contacts the conveying belt 42 that is driven to rotate. The thin shaft portion 101b forms a space through which the recording medium 21 passes.

  The medium pressing mechanism 100 according to the present embodiment has a configuration in which a roller bearing portion 102 is provided on a plate 104 and the medium pressing roller 101 is rotatably supported. The plate 104 is fixed to the head holding member 32 by screws or locking members such as hooks. However, the medium pressing mechanism 100 is not limited to this configuration. A configuration in which the plate 104 is omitted, for example, a configuration in which a roller bearing portion 102 is provided on the side facing the conveyance belt 42 of the head holding member 32 or directly on the side surface so that the medium pressing roller 101 is rotatably supported. Also good.

Next, the elevating mechanism 14 will be described.
The lifting mechanism 14 is a moving mechanism for moving the transport mechanism 13 to an image recording position and a non-recording position of the image recording apparatus 10. The elevating mechanism 14 can elevate the transport mechanism 13 by winding a wire (not shown) with a motor.

Next, the storage system 15 that stores the recording medium 21 on which an image is recorded will be described.
The storage system 15 is disposed downstream of the transport mechanism 13 in the transport direction. The storage system 15 includes a discharge roller pair 61 and a stocker 62. The discharge roller pair 61 functions to discharge the image-recorded recording medium 21 from the transport mechanism 13 to the outside. The stocker 62 stores the recording medium 21 on which an image has been recorded. The stocker 62 may be equipped with an editing function that sorts each page when the recording medium 21 is stored.

Next, the recording operation of the image recording apparatus 10 of this embodiment will be described.
An image formation instruction is input from an operation panel (not shown) of the image recording apparatus 10 or an image formation instruction signal is input from a host device (not shown) connected by a signal line. In response to this instruction, the transport mechanism 13 is lifted from the non-recording position by the elevating mechanism 14 and moved to the recording position shown in FIG. At the recording position, when the transport mechanism is raised by the elevating mechanism 14, the interval adjusting member 33 contacts the platen 43 so that the interval between the image recording unit and the transport mechanism becomes a predetermined interval. It has been adjusted.

  At this time, as shown in FIG. 6, the thick shaft portion 101a of the medium pressing roller 101 abuts on the conveying belt 42, and at the same time, the lower end 102a of the bearing portion 102 abuts on the rib 43b. Here, it is difficult to reproduce the above phenomenon for all components due to tolerances at the time of manufacturing the components, so that the medium pressing roller 101 always comes into contact with the conveying belt 21 before the bearing portion 102. Design with tolerances in mind. With this configuration, the medium pressing roller 101 is reliably rotated by the driving of the conveyor belt 42 being propagated.

  Thereafter, the paper feed roller 23 is driven while the registration roller pair 24, the drive roller 45, and the discharge roller pair 61 are driven. As a result, the uppermost recording medium 21 is taken out from the paper feed tray 22 by the paper feed roller 23. Then, the recording medium 21 reaches the gripping portion formed by the facing portion between the registration roller 24a and the registration roller 24b of the registration roller pair 24.

  At this time, the rotation of the registration rollers 24a and 24b is temporarily stopped by a registration clutch (not shown). By this temporary stop, the leading end portion of the recording medium 21 that has been conveyed toward the registration roller pair 24 hits the gripping portion, and is temporarily stopped and curved to correct the conveyed posture. That is, if there is a skew in the recording medium 21, the skew is corrected. When a predetermined time has passed after the contact, the rotation restraint by the registration clutch is released, and the rotation of the registration roller pair 24 is started, whereby the recording medium 21 is transferred onto the conveyance belt 42 of the conveyance mechanism 13 at a predetermined speed. Is sent out.

  On the conveyor belt 42, the suction force by the suction fan 41 is applied through innumerable holes provided in the platen 43 and innumerable holes provided in the conveyor belt 42. The recording medium 21 fed from the registration roller pair 24 onto the conveyor belt 42 is adsorbed by the aforementioned suction force onto the conveyor belt 42 that circulates in the clockwise direction in FIG. It is conveyed in the direction.

  The medium pressing roller 101 presses a part of the recording medium 21 that has been lifted from the upper surface of the conveying belt 42 against the conveying belt 42, so that the recording medium 21 is reliably adsorbed to the conveying belt 42 and is recorded on each head 31. The contact of the medium 21 is avoided.

  The recording medium 21 conveyed by the conveying belt 42 of the platen 43 is mounted on the head holding unit 32 corresponding to each color of cyan (C), black (K), magenta (M), and yellow (Y). -It passes under each head part 31C, 31K, 31M, 31Y which is arranged.

  During the passage, ink droplets are ejected from the head portions 31C, 31K, 31M, and 31Y onto the recording medium 21 at the timing when the image forming position is reached, and an image is recorded on the recording medium 21. In this way, the recording medium 21 on which the images of the respective colors are overlaid and recorded is discharged out of the apparatus by the discharge roller pair 61 and stored in the stocker 62.

  When such image recording is continued without providing the bearing portion 102 of the present embodiment, the medium presser roller 101 is urged toward the platen 43 by the coil spring 103, so that the thickness of the medium presser roller 101 is increased. The portion pressed by the shaft portion 101a is rubbed by the back surface of the conveying belt 42, the wear of the platen 43 advances, and the medium pressing roller 101 itself is moved downward.

  On the other hand, in the present embodiment, at the time of image recording, the lower end 102a of the bearing portion 102 is in contact with the rib 43b formed on the platen 43, and the pressing roller 101 is not lowered below a predetermined position, that is, the conveyance. The urging force for pressing the belt 42 more than necessary is limited, and the recording medium 21 can be accurately conveyed.

As described above, according to the present embodiment, the conveyance of the recording medium 21 conveyed by the conveyance belt 42 is suppressed by the medium pressing roller while the bearing portion 102 of the medium pressing roller contacts the platen 43, thereby conveying the recording medium 21. The biasing force that presses the belt 42 against the platen more than necessary is limited.
Therefore, according to this embodiment, it is possible to prevent jamming due to the floating of the recording medium, and to suppress damage due to wear on the platen by the conveyance belt.

  In this embodiment, the rib 43b is provided on the platen 43. However, if the length of the lower end 102a of the bearing portion 102 is extended by the height of the rib 43b, the rib 43b can be omitted. In the present embodiment, the case where resin is used as the material of the platen 43 has been described. However, the present invention is not limited to this, and a metal member such as aluminum or stainless steel may be used. When a metal member is used, the amount of wear is slight compared with resin, but it is worn a little. Therefore, even when the material of the platen is a metal member, damage to the platen due to wear can be suppressed by adopting the configuration of the present embodiment.

Next, with reference to FIG. 7, a first modification of the first embodiment will be described.
In the first embodiment, the bearing portion 102 is provided on the head portion 31 side. However, in the present modification, the bearing portion 102 is provided on the transport mechanism 13 side, that is, on the platen 43 side, as shown in FIG. This is a configuration provided.

  The bearing portion 102 is provided with an abutting portion 102 a that branches and extends from a bearing portion that receives the medium pressing roller 101. The abutting portion 102 a abuts on the platen 43 and regulates the interval between the medium pressing roller 101 and the platen 43.

  The bearing portion 102 is supported by the support portion 104 of the platen 43 so as to be slidable up and down. Further, a coil spring 103 is stretched between a spring receiving portion 102b provided on the bearing portion 102 and a spring receiving portion 43c provided on the platen 43 side. The coil spring 103 urges the roller bearing portion 102, that is, the medium pressing roller 101 to abut against the platen 43.

According to this modification, it is possible to obtain the same operational effects as those of the first embodiment described above. Further, the configuration of the head unit is simplified by providing it on the transport mechanism side, that is, the platen side.
Further, in this modification, the elastic force is generated on the suction side by the coil spring, but it can be realized by generating an action of suction by the electromagnet instead.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the present invention. .

  Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be obtained as an invention.

FIG. 1 is a diagram showing a schematic configuration of an image recording apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the shape of the platen in the image recording apparatus. FIG. 3 is a perspective view of the image recording unit. FIG. 4 is a diagram of the image recording unit as viewed from below in FIG. FIG. 5A shows the detailed configuration of the roller bearing in the presser mechanism, and FIG. 5B shows the shape of the roller in the presser mechanism. FIG. 6 is a diagram showing the positional relationship between the medium pressing mechanism and the transport mechanism at the image recording position. It is a figure which shows the 1st modification of 1st Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Image recording apparatus, 11 ... Supply system, 12 ... Image recording part, 13 ... Conveyance mechanism, 14 ... Lifting mechanism, 15 ... Storage system, 21 ... Recording medium, 22 ... Paper feed stand, 23 ... Paper feed roller, 24 ... Registration roller pair, 24a, 24b ... Registration roller, 31, 31K, 31C, 31M, 31Y ... Head, 32 ... Head holding member, 33 ... Spacing adjustment member, 41 ... Suction fan, 42 ... Conveying belt, 43 ... Platen 44 ... Drive roller, 45 ... Follower roller, 46a, 46b ... Tension roller, 47 ... Conveying frame, 61 ... Discharge roller pair, 62 ... Stocker, 100 ... Media press mechanism, 101 ... Media press roller, 102 ... Media press roller Bearings 103... Coil springs 104. Medium press roller thick portions 105. Ink absorbers.

Claims (7)

A line head is constituted by one or a plurality of recording heads, and a head unit that records an image on a recording medium;
A transport mechanism that has a flat platen at least in a region facing the line head, and transports the recording medium by a belt;
A roller disposed upstream of the line head in the conveyance direction of the recording medium, and a roller for suppressing the recording medium toward the belt relative to the recording medium floating from the belt, and both ends of the roller are rotatably supported. And a presser mechanism having a bearing member provided with a restricting portion that contacts the platen and restricts the position of the roller,
In image recording, the roller is in contact with the belt, and the restricting portion is in contact with the platen. A biasing member that biases the roller toward the belt;
The image recording apparatus according to claim 1, wherein the restricting portion restricts a force that the roller presses against the belt by the biasing member.   The image recording apparatus according to claim 1, wherein the platen is made of a resin.   2. The roller according to claim 1, wherein a thick shaft portion provided at both ends is in contact with the belt, and a space for allowing the recording medium to pass through a narrow shaft portion smaller in diameter than the thick shaft portion inside the roller is generated. 4. The image recording apparatus according to any one of items 1 to 3.   The image recording apparatus according to claim 1, wherein the pressing mechanism is provided on the platen. The head portion has a head holding member for holding and fixing the recording head,
The image recording apparatus according to claim 1, wherein the pressing mechanism is provided on the head holding member. A line head is constituted by one or a plurality of recording heads, and a head unit that records an image on a recording medium;
A transport mechanism for transporting the recording medium by a belt, having a platen formed of a flat plate-shaped resin at least in a region facing the line head;
A roller disposed upstream and in the conveyance direction of the recording medium from the line head, a biasing member that biases the roller toward the belt, and both ends of the roller are rotatably supported. A presser mechanism having a bearing member,
The bearing member has a restricting portion that extends toward the platen from a portion that supports the roller, and the roller contacts the belt and the restricting portion contacts the platen during image recording. A characteristic image recording apparatus.

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