JP3244942B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus used for facsimile machines, copiers, printers and output devices of computers, and more particularly to an ink jet recording apparatus for performing printing on both sides of recording paper in an ink jet system. .

[0002]

2. Description of the Related Art Conventionally, ink jet recording apparatuses for printing on paper by discharging ink from nozzles of a recording head have been put to practical use. Recently, apparatuses capable of printing from both sides of paper have been proposed. (JP-A-5-33003
No. 7). In this ink jet recording apparatus, the recording means is disposed opposite to both sides of the recording paper, and the recording paper is conveyed between the two recording means to discharge ink, and immediately after printing, almost the entire surface of the recording paper is transferred to the belt. It is designed to be conveyed while being sucked. Also, conventionally, in such an ink jet recording apparatus, it is known that high printing quality can be obtained by setting the distance between the recording paper and the ink ejection surface of the recording means to about 1 mm or less.

[0003]

However, when a recording sheet is conveyed between two recording means, the recording sheet is 1 m in length.
When the sheet is bent by m or more, the sheet comes into contact with the ink ejection surface of one of the recording units. As a result, there is a problem that a printed image flows or nozzles are clogged and white streaks are generated in the image, and there is a possibility that print quality is degraded. However, the conventional Japanese Patent Application Laid-Open No. 5-330037
In the recording apparatus described in Japanese Patent Application Laid-Open Publication No. H11-139, a transport mechanism for transporting a recording sheet without bending between both recording means is not disclosed.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide an ink jet recording apparatus in which recording paper is conveyed without bending between recording means in an apparatus for performing printing from both sides by recording means. And

[0005]

In order to achieve the above-mentioned object, the present invention provides an ink jet apparatus which discharges ink from nozzles of recording heads disposed opposite to each other with a required gap, and feeds the ink to a transport path passing through the gap. In an ink jet recording apparatus for recording an image on both sides of a recording paper conveyed along the recording paper, the recording paper is disposed on both ends in the width direction of the recording paper, and each end is sandwiched from both sides to convey the recording paper along the conveyance path. A pair of paper conveying means movable in the width direction to convey, and a pair of deflection preventing means disposed at both sides of the recording paper at positions facing the conveyance path and preventing the recording paper from bending. A plurality of thin plate members that are movable in the width direction of the recording paper and that are rotatable around the axis in the width direction, and the bending prevention unit is adjacent to the paper conveyance unit. Between and with thin plate members Contact is made of a disposed an elastic member between the respective thin plate members (claim 1).

Further, the thin plate member has a polygonal shape.

Further, in the ink jet recording apparatus according to claim 1 or 2, the shaft is supported on both outer sides of the sheet conveying means and is arranged in the width direction and movably arranged on the axis. A regulating member that regulates contact of the elastic member with the thin plate member, wherein the thin plate member is disposed on the shaft (claim 3).

Further, the thin plate member is provided on the regulating member.

Further, the thin plate members of the pair of deflection preventing means are alternately arranged in the width direction.

The ink jet recording apparatus according to any one of claims 1 to 5, further comprising a plurality of sets of opposing recording heads along the transport path, wherein the pair of deflection preventing means includes at least one of the gaps. It is arranged on the upstream side in the sheet transport direction (claim 6).

[0011]

According to the first aspect of the present invention, the recording sheet is conveyed to the gap between the recording heads disposed opposite to each other at the same position or slightly shifted positions, with both ends in the width direction being sandwiched from both sides. At this time, when the recording paper bends, it comes into contact with the thin plate member, so that the bending is suppressed. The thin plate member is disposed so as to be rotatable around a width-direction axis, or is rotated around a width-direction axis by a driving force, so that even if the sheet comes into contact, the sheet conveyance is not hindered. In addition, when the sheet conveying means moves according to the size of the recording sheet, the elastic members hold the sheet conveying means and the adjacent thin plate members and the adjacent thin plate members at required intervals.

According to the second aspect of the present invention, when the thin plate member comes into contact with the recording paper to be conveyed, it comes into contact at each vertex of the polygon, and it is possible to prevent the conveyance of the recording paper. Absent.

According to the third aspect of the present invention, when a small-sized recording sheet is conveyed, the pair of sheet conveying means approaches each other, and the elastic member disposed therebetween is compressed. Become. In this case, since the elastic member does not come into contact with the thin plate member by the regulating member, the compressed pressure of the elastic member is not applied to the thin plate member.

According to the fourth aspect of the present invention, when the regulating member moves on the axis, the thin plate member moves with the regulating member, and rotates on the regulating member when the recording paper conveyed comes into contact. It will be.

According to the fifth aspect of the present invention, when each sheet conveying means moves in the width direction according to the sheet size, the thin plate members of the pair of deflection preventing means do not contact each other. , Move smoothly.

Further, according to the present invention, the bending of the recording paper is prevented on the upstream side in the paper transport direction of each gap between the opposing recording heads.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment of the ink jet recording apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing the appearance of the apparatus of the first embodiment. 2A and 2B are diagrams showing a schematic configuration of the inside of the apparatus, wherein FIG. 2A is a left side view and FIG. 2B is a front view.

This device is, for example, a printer for printing character data and the like input from an external device.
A paper storage unit composed of paper feed cassettes 21 to 24 is provided on the right side, and a printing unit 4 for printing on both the front and back surfaces while transporting the recording paper is provided on the left side, and the paper is moved from right to left in the meantime. A sheet transport system 13 for transporting, and a sorter 8 below the printing unit 4 are provided. The sorter 8 stores the printed recording paper by moving the bins 8a one by one in the horizontal direction by a spiral cam (not shown). An operation panel 1 is provided at an appropriate position on the surface of the apparatus.
And a paper feed bypass unit 3.

The operation panel 1 has an operation unit 1a (FIG. 1) provided with a paper size instruction key for manually instructing the size of the recording paper, an ejection recovery key for performing an ejection recovery operation, and the like.
3), and a display unit 1b (FIG. 13) composed of an LCD, an LED, etc., for displaying setting contents. The paper feed bypass unit 3 performs manual paper feed in accordance with the width of the paper with a width aligning mechanism 3a provided on the apparatus surface.

In the paper storage unit, paper feed cassettes 21 to 24 having different sizes that can store cut paper are stacked and disposed. In the paper feed cassettes 21 to 24, for example, A4 size recording paper is placed vertically in the paper feed cassette 21, A3 size is placed vertically in the paper feed cassette 22, and B4 size is vertical,
The B5 size is stored in the paper feed cassette 24 horizontally. Note that the size and orientation of the paper stored in each cassette are not limited to the above.

The paper transport system 13 includes paper feed cassettes 21 to 21.
24, paper feed rollers 31 to 34, 37 for feeding paper, a pair of transport rollers for transporting the paper, a transport guide for guiding the transport paper, and timing for image recording. A pair of registration rollers 38 and the like that convey the sheet in response thereto are provided.

The printing unit 4 has a pair of drive-side transport belts 43 and driven-side transport belts 44 sandwiching both ends in the width direction of the recording paper and transporting the recording paper along a dashed line R in FIG. A printing mechanism including four head units 5a and 5b disposed on both sides of the conveyed paper so as to face each other, and a drying device 10 for drying ink on the printed paper surface.

First, the paper transport mechanism will be described with reference to FIGS. 3A and 3B are diagrams showing the configuration of the printing unit 4, wherein FIG. 3A is a left side view, and FIG. 3B is a front view. FIG.
FIGS. 3A and 3B illustrate the head holding mechanism of the head unit in FIGS. 3A and 3B for convenience of explanation. FIGS. 5A and 5B are diagrams showing a main part of the paper transport mechanism of the printing unit 4, wherein FIG. 5A is a left side view and FIG. 5B is a front view. In FIGS. 3 to 5, a later-described deflection preventing member provided on the shafts 85a and 95a is omitted. FIG.
In FIG. 4A, FIG. 4A and FIG. 5A, pulleys 83 and 84 are omitted for convenience of explanation.

The pair of drive-side conveying belts 43, 43 are connected to pulleys 80 to 84 and idle rollers 85, 8, respectively.
5, ... have an endless shape. The drive-side transport belt 43 is made by adding chloroprene rubber to, for example, a nonwoven mesh fabric made of polyester, and has a small elongation, thereby enabling stable transport. In addition, the pair of driven-side transport belts 44, 44
4 and idle rollers 95, 95,... The driven side conveyance belt 44 is made of, for example, urethane rubber, has a large expansion and contraction,
3 is formed of a material that easily conforms to the above. The transport belts 43 and 44 have a width of, for example, 15 mm.

The pulley 80 is rotatably disposed on a transport belt moving plate 42, which will be described later, while the drive shaft 804 is fitted therein. The drive shaft 804 is rotatably supported by the side plates 11 and 12 fixed to the apparatus main body, has a D-shaped cross section, and both pulleys 80 rotate as the drive shaft 804 rotates. It is supposed to. The gear 801 fixed to the drive shaft 804 is the gear 8 of the transport belt motor 803.
02 is engaged. Conveyor belt motor 803
Consists of, for example, a stepping motor, and a gear 802,
The drive shaft 804 is rotationally driven via 801 to rotate the pulley 80 to rotate the drive-side transport belt 43.

The driven conveyor belt 44 is driven to rotate by frictional force with the drive conveyor belt 43. Further, the rotation amount and speed of the pulley 80, that is, the transport distance and transport speed of the recording paper are controlled by a drive pulse supplied to the transport belt motor 803.

The pulley 81 and the idle rollers 85,...
Are shafts 81a and 85 provided between the side plates 11 and 12.
are rotatably penetrated by a,... and are rotatably disposed on the transport belt moving plate 42. Similarly,
The pulleys 90 and 91 and the idle rollers 95 are provided with shafts 90a and 91a and a shaft 95 disposed between the side plates 11 and 12, respectively.
are rotatably penetrated by a,... and are rotatably disposed on the transport belt moving plate 42. The idle rollers 85 and 95 are disposed above and below the opposing surfaces of the opposing head units 5a and 5b, that is, at five locations.
In addition to preventing bending of the transfer belts 3 and 44, the position of the transfer belts 3 and 44 is prevented.

The drive shaft 804, the shaft 81a and the shaft 85a,.
, And the shafts 90a, 91a, and 95a,... Are arranged side by side with a required biasing force in a direction approaching each other at a required interval, and are stretched over each pulley and idle roller. The driving-side conveyance belt 43 and the driven-side conveyance belt 44 abut at a required pressure from the pulleys 81 and 91 to the pulleys 80 and 90. Also,
A roller 81b and a roller 91b (not shown) are provided at appropriate positions in the center of the shaft 81a and the shaft 91a, and are in contact with each other at a required pressure. These rollers 81b and 91b
With the rotation of each of the conveyor belts 43, 44, the shafts 81a, 91a
Or rotatably disposed so as to rotate upon contact with the transport paper.

FIGS. 6A and 6B are views showing a deflection preventing member, wherein FIG. 6A shows the shape of a thin plate member, and FIG. 6B shows the shaft 85a of FIG.
Only the vicinity is shown.

The deflection preventing member 851 comprises a thin plate member 852 and an elastic member 853, and is disposed between the idle rollers 85 on each shaft 85a. Thin plate member 852
Is a substantially polygonal thin plate having a sharp apex such as a car sword-shaped shuriken, as shown in FIG.
In addition to being disposed on the shaft 85a so as to be movable and rotatable, a plurality of them are disposed at a required interval from each other. The elastic member 853 is made of, for example, a coil spring, and expands and contracts by its elastic force. The elastic member 853 has a shaft 85 between the idle roller 85 and the thin plate member 852 and between the thin plate members 852.
a.

Similarly, as shown in FIG. 9A, the deflection preventing member 951 includes a thin plate member 952 and an elastic member 953, and is disposed between the idle rollers 95, 95 on each shaft 95a. The thin plate member 952 and the elastic member 953 have the same configuration as the thin plate member 852 and the elastic member 853. The thin plate members 952 are alternately arranged at positions not opposed to the thin plate members 852.

With the above configuration, when the drive shaft 804 rotates clockwise in FIG. 5B, the recording paper fed from the registration roller pair 38 to the printing unit 4 is moved between the pulleys 81 and 91. The central portion in the width direction is sandwiched between the rollers 81b and 91b, and the width of, for example, 5 mm at both ends in the width direction is sandwiched between the drive-side transport belt 43 and the driven-side transport belt 44, respectively. And pulleys 81 and 9
The sheet P is conveyed in the direction P (FIG. 5) while being held between the drive-side conveyance belt 43 and the driven-side conveyance belt 44 from the section 1 to the section between the pulleys 80 and 90.

At this time, the recording paper is formed by pulleys 81 and 91.
Between the pulleys 80 and 90 and the thin plate members 852 and 9
Since it is in contact with each vertex of 52, it can be conveyed without bending any more. Also, the thin plate members 852, 952
Is in contact with the recording paper at each vertex, so that the surface of the paper is not stained even immediately after printing.

Note that the pulleys 80,
Similarly, the bending prevention members 851 and 951 may be provided on the 90. In this case, the bending of the sheet can be more effectively prevented.

The thin plate members 852 and 952 are
a, 95a, and the shafts 85a, 95a may be rotationally driven such that the peripheral speeds of the pulleys 85, 95 are equal to the speed of the conveyor belt.

The thin plate members 852 and 952 may be arranged at positions facing each other. Further, the thin plate member 85
2,952 may be a thin disk whose shape does not stain the paper surface immediately after printing. Further, the thin plate member 852,
952 may have different shapes, such as one having a polygonal shape and the other having a disk shape. The shafts 85a and 95a immediately downstream of the pulleys 81 and 91, that is, the thin plate members 852 and 952 disposed immediately upstream of the head units 5a and 5b, which are the most upstream, still print on the paper. Since it is not provided, it may be cylindrical.

The pulley 82 is disposed diagonally above left of the pulley 81 in FIG. 5B, and the pulley 92 is disposed diagonally above right of the pulley 91 in FIG. Therefore, pulley 8
The recording paper fed from the registration roller pair 38 in the P direction can be reliably guided between the pulleys 81 and 91 by the conveyor belt between the pulleys 81 and 91 and between the pulleys 92 and 91.

Next, a mechanism for moving the conveyor belts 43 and 44 will be described with reference to FIGS. FIG. 7 is a front view showing the shape of the transport belt moving plate 42.

The pair of transport belt moving plates 42, 42 are supported by the apparatus main body so as to be movable toward and away from each other.
The position of the transport belt can be changed according to the size of the recording paper.

The transport belt moving plate 42 is provided with a shaft hole for rotatably holding each of the pulleys and idle rollers and a square hole for avoiding each of the head units 5a and 5b and the drying device 10. At the same time, shaft holes 418 and 419 are formed at appropriate positions at both ends of the central portion.
, Tubular bearing members 421a and 422a are fixedly mounted. A stay 422 supported by the side plates 11 and 12 is fitted to the bearing member 422a, and a conveyor belt moving shaft 421 rotatably supported by the side plates 11 and 12 is fitted to the bearing member 421a. The conveyor belt moving plates 42 are held by the stay 422 and the conveyor belt moving shaft 421.

The bearing member 422a is configured so that the stay 422 can slide smoothly. The bearing member 421a and the conveyor belt moving shaft 421 have a female screw formed on the inner surface of the bearing member 421a, and a male screw is formed over a required range of the outer surface of the conveyor belt moving shaft 421 to form a ball screw structure. I have. The screws of the conveyor belt moving shaft 421 have different directions around the center part, that is, FIG.
In the middle, for example, the left side is formed with a right-hand thread, and the right side is formed with a left-hand thread. In this case, the conveyor belt moving plates 42, 42 move closer to each other when the conveyor belt moving shaft 421 rotates clockwise in FIG. 4B, and move away from each other when the conveyor belt moving shaft 421 rotates counterclockwise.

The gear 423 fixed to the conveyor belt moving shaft 421 is meshed with the gear 424 of the belt moving plate motor 425. The belt moving plate motor 425 includes, for example, a stepping motor and rotates the conveyor belt moving shaft 421 via the gears 424 and 423. The forward and reverse rotation of the moving shaft causes the conveyor belt moving plate 42,
42 can be moved according to the sheet width of the recording sheet. The rotation amount of the transport belt moving shaft 421, that is, the moving distance of the transport belt moving plates 42, 42 is controlled by a driving pulse supplied to the belt moving plate motor 425.

With the above configuration, for example, when printing on A3 size recording paper, the transport belt moving plate 4
2 and 42 move to the position shown by the solid line in FIG.
In the case of the A4 vertical size, it moves to the position shown by the dotted line in FIG.

As described above, each pulley and each conveyor belt can be integrally moved in the sheet width direction indicated by an arrow in FIG. 4 by the conveyor belt moving plates 42, 42 according to the sheet width of the recording sheet on which printing is performed. Therefore, corresponding to various paper sizes, both ends in the width direction of the recording paper are securely held between the drive-side transport belt 43 and the driven-side transport belt 44, respectively.
Paper conveyance can be performed.

Also, for example, when moving from the position of A3 size indicated by the dotted line in FIG. 8 to the position of A4 vertical size indicated by the solid line in FIG. 8, the elastic member 853 is compressed, and each thin plate member 852 becomes a required member. Since the recording paper moves while maintaining the interval, the bending of the recording paper can be prevented regardless of the paper size.

The thin plate members 852 may be arranged at different intervals so as to be dense at the center of the shaft 85a. In this case, the deflection of the central portion of the sheet away from the transport belts 43 and 44 can be prevented well, which is effective when the recording sheet is large.

The idle roller 85 and each thin plate member 8
52 are disposed at the same interval, and each elastic member 853
May be configured with the same spring constant. In this case, since the idle roller 85 and each thin plate member 852 move while maintaining an equal interval, it is possible to prevent bending at the same interval in the width direction of the recording paper.

FIGS. 9A and 9B show examples of the arrangement of the thin plate members 852 and 952. FIG. 9A shows a state corresponding to a large-size sheet, and FIG. 9B shows a state corresponding to a small-size sheet. As shown in FIG. 9, if the thin plate members 852 and 952 are arranged at positions not opposed to each other, that is, in a staggered manner, the thin plate members 852 and 952 do not contact each other.
The transport belt moving plates 42, 42 can be moved smoothly.

The transport belt moved in the width direction according to the size of the recording paper is formed by a pair of drive-side transport belts 4.
3, 43 and one of the pair of driven conveyor belts 44, 44. Then, the other transport belts 43 and 44 which do not move according to the sheet size may be moved to the outside of the head units 5a and 5b only during a capping operation or an idle discharge operation described later. In this case, the required moving distance of the other conveyor belts 43 and 44 can be reduced.

Here, another configuration example of the deflection preventing members 851 and 951 will be described with reference to FIGS.
FIGS. 10 and 11 show the deflection preventing members 851 and 951, respectively.
FIGS. 7A and 7B are diagrams illustrating a configuration including a regulating member, FIG. 7A illustrates a configuration of a thin plate member and a regulating member, and FIG. 7B illustrates shafts 85a and 95a.
2 shows a state in which it is arranged.

In FIG. 10, the regulating member 854 is a U-shaped frame in a plan view and is movably disposed on the shaft 85a. The thin plate member 852 is disposed inside the regulating member 854.
The regulating member 954 has the same configuration. In FIG. 11, the regulating member 854 has a cylindrical shape having a groove in the center of the peripheral surface, and is movably disposed on the shaft 85a.
2 is rotatably disposed in the groove of the regulating member 854, and the regulating member 954 has the same configuration. The restricting members 854 and 954 restrict the elastic members 853 and 953 from coming into contact with the thin plate members 852 and 952.

With this configuration, even if the elastic members 853 and 953 are compressed corresponding to the small-size paper and the spring pressure increases, the spring pressure is applied only to the regulating members 854 and 954. 852 and 952 are not affected. Therefore, even when the recording paper is small in size, the thin plate members 852 and 952 can rotate smoothly and can prevent bending without hindering the conveyance of the recording paper.

Next, the printing mechanism will be described with reference to FIG. The four head units 5a have a rectangular parallelepiped shape, are disposed on one surface side of the recording paper to be conveyed at a predetermined interval along the paper conveyance path, and are provided with four head units 5b.
Has a rectangular parallelepiped shape similar to that of the head unit 5a, and is disposed on the other surface side of the sheet conveyance path at a position facing each head unit 5a.

Each head unit 5a is composed of a recording head 51a and a cap part 52a.
Each head unit 5b includes a recording head 51b and a cap 52b. Recording head 5
1a is arranged side by side on the upper side of the cap portion 52a in FIG.
On the other hand, the recording head 51b is
The recording head 51a and the cap 52b, and the recording head 51b and the cap 52a are
They are arranged at positions facing each other. The head unit 5a and the head unit 5b can be moved in the direction of contact and separation between the close contact position and the separated position by a head holding mechanism described later, and are arranged at the close contact position when printing is not performed. When printing is performed, they are arranged at a predetermined interval of, for example, 2 mm.

The recording heads 51a and 51b are provided with, for example, nozzle rows in which micro-diameter nozzles are arranged in a row at a predetermined pitch, and are provided for each nozzle. And prints an image on both sides of the recording paper. The dimension of the nozzle row is set to a value at which the short side of A3 size paper can be printed, for example.

The recording heads 51a and 51b eject yellow (Y), magenta (M), cyan (C) and black (BK) inks in order from the upstream side in the paper transport direction P. These inks are sequentially ejected to perform color printing.

The nozzle row may be composed of a plurality of nozzle rows in which each nozzle is arranged in a staggered manner. Also, a head unit 5 including recording heads 51a and 51b for discharging black (BK) ink is provided.
a and 5b may be provided so as to enable monochrome printing.

The ink is supplied to each of the head units 5a and 5b from an ink cartridge 14 (see FIG. 2) provided at an appropriate position in the apparatus main body via an ink supply tube (not shown) made of, for example, a soft synthetic resin. . The ink cartridge 14 (see FIG. 2) includes four cartridges,
Each cartridge has yellow (Y), magenta (M),
Cyan (C) and black (BK) inks are sealed, and ink is supplied from ink needles attached to the base end of the ink supply tube.

The cap portions 52a, 52b are provided with caps made of, for example, rubber or soft synthetic resin, and the recording heads 51b, 51a are in close contact with the head units 5a, 5b.
To prevent solidification of the ink at the tip of the nozzle and intrusion of foreign matter, bubbles and the like into the nozzle.

A waste ink tube (not shown) is connected to the caps of the cap portions 52a and 52b, and suction means such as a pump 103 (FIG. 13) is interposed in the waste ink tube. The pump 103 generates a suction force at the position where the head units 5a and 5b are in close contact with each other, and returns the meniscus formed at the nozzle tip of the recording heads 51a and 51b to a normal position, and removes bubbles and foreign matter in the nozzles together with ink. The ejection recovery operation, such as removing the ink ejection failure, is performed. The ink sucked by the pump 103 is absorbed by an ink absorber made of urethane foam or the like inside a waste ink tank 18 (FIG. 2) disposed close to the ink cartridge 14 (FIG. 2) via a waste ink tube. Is done.

During printing, the feeding of the recording paper to the printing unit 4 is temporarily stopped at required intervals, and the conveyance belt 4 is stopped.
As shown in FIG.
a and 51b, and the recording heads 51a and 5b are retracted.
By performing idle discharge in which ink is discharged from all nozzles from 1b toward the cap portions 52b, 52a, clogging of nozzles that are not used during printing or that are not used frequently is prevented. Note that the idle discharge may be performed at a close contact position of the head units 5a and 5b.

Next, the head holding mechanism of the head unit will be described with reference to FIGS. 12A and 12B are diagrams showing a configuration of a head holding mechanism, FIG. 12A is a left side view, and FIG.
Is a front view.

Each head unit 5a is shown in FIG.
A required area on the left, right, and middle sides is a pair of head moving plates 61.
a, 61a and are integrally held. On the other hand, in each head unit 5b, similarly, a required area on the left and right side surfaces has a pair of head moving plates 61b, 61b (not shown).
And are integrally held.

The head moving plate 61a is, as shown in FIG.
A holding portion 611a formed to protrude rightward from the side plate 11.
In addition, a through hole 62a is formed, and a through hole 63a is formed in a holding portion 612a formed to protrude leftward from the side plate 12. Similarly, the head moving plate 61b includes a holding portion 611b formed to protrude rightward (a front side in FIG. 12B) from the side plate 11 in FIG.
Through holes 62a (not shown) and 63a (not shown) are respectively formed in holding portions 612b (not shown) formed to protrude leftward from 2. A head moving shaft 62 rotatably supported by the apparatus main body is fitted into the through hole 62a.
The head support shaft 6 supported by the apparatus main body is provided in the through hole 63a.
3 are fitted. The head moving plates 61a and 61b are held by these shafts 62 and 63.

The through hole 63a allows the head support shaft 63 to slide smoothly. The through hole 62a and the head moving shaft 62 have a ball screw structure in which a female screw is formed on the inner surface of the through hole 62a and a male screw is formed on the outer surface of the head moving shaft 62. Head moving axis 62
12 are differently oriented around the center, i.e., FIG.
In (b), for example, the left side is formed with a right-hand thread, and the right side is formed with a left-hand thread. In this case, the head moving plates 61a, 61b
12A, when the head moving shaft 62 rotates clockwise in FIG. 12A, the head moving shafts 62 separate from each other, and when the head moving shaft 62 rotates counterclockwise in FIG.

Gear 65 fixed to head moving shaft 62
Are engaged with the gear 66 of the head moving motor 64. The head moving motor 64 is formed of, for example, a stepping motor, and the head moving shaft 6 is driven by gears 66 and 65.
2 is rotated. The amount of rotation of the head moving shaft 62, that is, the moving distance of the head moving plates 61a and 61b is controlled by a driving pulse supplied to the head moving motor 64.

The operation of moving the head units 5a and 5b in the above configuration will be described with reference to FIGS.

When the printing operation is completed, first, the conveying belt moving shaft 421 is rotated in the counterclockwise direction in FIG. 3B, so that the conveying belt moving plates 42, 42 are respectively in FIG. 3A. Move in the direction of the arrow, and
3 moves outward from between the opposing head units 5a and 5b. Next, the head moving shaft 62 is shown in FIG.
By rotating in the counterclockwise direction, the head moving plate 6 is rotated.
The head units 1a and 61b move in the direction of the arrow in FIG. 12B, and the head units 5a and 5b are brought into close contact with each other to perform capping.

On the other hand, when starting the printing operation, first,
When the head moving shaft 62 rotates clockwise in FIG. 12A, the head moving plates 61a and 61b move in directions opposite to the arrows in FIG. 12B, respectively, and the head units 5a and 5b are moved. Are released and the capping is released. Next, the transport belt moving shaft 421 is
By rotating clockwise by the required amount, the conveyor belt moving plates 42, 42 move in the directions opposite to the arrows in FIG. 3A, respectively, and the conveyor belts 43, 43 of the head units 5a, 5b facing each other move. Move to a position corresponding to the paper size in between.

As described above, by rotating the head moving shaft 62 to move the head moving plates 61a, 61b, the recording heads 51a, 5b of the head units 5a, 5b are moved.
1b can be capped and released.

It is also possible to move only one of the head moving plates 61a and 61b and move one of the head units 5a and 5b in the contact / separation direction to perform capping and release. In this case, the other head units 5a and 5b need not be movably disposed.

Next, the configuration of the drying apparatus 10 will be described with reference to FIG. The drying device 10 includes the head unit 5
A fan 101 and a heater 102 are arranged on both sides of the sheets a and 5b on the downstream side in the sheet conveying direction. For example, as shown in FIG. 3, three fans 101 are arranged on both sides of the paper transport path, respectively, and blow air toward the recording paper. The heater 102 has a heat source such as a halogen lamp or a nichrome wire,
Between them, they are arranged over the print width of the head units 5a and 5b. With the drying device 10 having such a configuration,
Hot air is blown onto both sides of the recording paper to dry the ink on the surface of the paper.

Next, the control configuration of this device will be described with reference to FIG.
This will be described with reference to the block diagram of FIG. In this device, the operation of each unit is performed based on an operation signal and an image signal input from an external device such as a personal computer.

The control unit 110 includes the CPU 120 and the storage unit 1
11 and the like to control the operation of the entire apparatus in synchronization with the internal clock of the CPU 120. CPU1
Reference numeral 20 includes a recording control unit 121, a mechanism control unit 122, a display control unit 123, and the like. The recording control unit 121 and the mechanism control unit 122 perform control operations in synchronization with each other. The storage unit 111 includes a ROM in which a control program is stored, a RAM for temporarily storing data, and the like. The interface (I / F) unit 112
It receives a signal input from an external device, and outputs an image signal to the recording control unit 121 and an operation signal such as a paper size to the mechanism control unit 122.

The mechanism control unit 122 drives the paper transport system 13 such as a paper feed roller via a drive circuit 114 based on the input operation signal to feed paper from a required paper feed cassette and to perform recording. The drive of the sorter 8 is controlled every time printing on paper is completed, and the paper is stored in each bin or the same bin. Further, a driving pulse is supplied to each motor such as the conveyance belt motor 803 via the driving circuit 114 to drive the motors. The drive circuit 114 includes a power supply unit, a transistor, and the like, and supplies a drive current to a drive system such as a motor based on a control signal from the mechanism control unit 122.

The mechanism control unit 122 determines the separation of the recording sheet from the transport belts 43 and 44 based on the number of drive pulses supplied to the transport belt motor 803 and the elapsed time from the start of driving of the registration roller pair 38. I do. Also,
The mechanism control unit 122 operates the fan 101 and the heater 102 from the start of printing on the recording paper until the last recording paper to be printed is separated from the transport belts 43 and 44. The detachment of the recording sheet from the transport belts 43 and 44 may be detected by disposing a sheet sensor such as a reflection type optical sensor immediately below the pulley 80. The mechanism control unit 122 also operates the pump 10 at a required interval during power-on, when a discharge recovery key of the operation unit 1a is pressed, or when power is turned on.
3 is operated to perform the ejection recovery operation.

When the size manually input with the paper size instruction key of the operation unit 1a is larger than the size input from the external device, the mechanism control unit 122 prints on the recording paper of the size input by the key. It may be.

The recording control unit 121 converts the input image signals into the driving circuits 113a, 113a of the head units 5a, 5b.
3b for serial transmission. Drive circuit 113
Reference numerals a and 113b are provided at appropriate places in the head units 5a and 5b, respectively, and have a latch unit. The latch unit temporarily latches a transmitted binary or multi-valued image signal for one line of a recording sheet, for example. The signal is converted into a parallel signal.

Further, the recording control unit 121
The parallel signals converted by 3a and 113b are output as pulse drive signals to the corresponding piezoelectric elements of the recording heads 51a and 51b in synchronization with the mechanism control unit 122 to control the ejection of ink. For example, "0", "1"
In the case of a value signal, a fixed amount of ink is ejected from a nozzle by applying a voltage to the piezoelectric element during the pulse width of the signal of “1” and rapidly increasing the liquid pressure. . The image signals for one line are sequentially transmitted at a predetermined cycle, whereby two-dimensional image recording is performed.

The cycle of the ink ejection, that is, the cycle of the signal output to the piezoelectric element is set within the range of the capability of the head units 5a and 5b, and the transport speed of the recording paper during printing, that is, the transport belt motor 803 The rotation speed of
It is set corresponding to the ink ejection cycle.

The display control unit 123 detects the presence or absence of paper in each paper cassette, the shortage of the remaining amount of ink, and the like, and displays the detection result on the display unit 1b. The ink remaining amount detection unit 115 detects the remaining amount of ink in the ink cartridge 14, and is displayed on the display unit 1b when the remaining amount becomes equal to or less than a predetermined level.

Next, the procedure of the printing operation will be described with reference to the flowchart of FIG. First, the head moving plate 6
1a and 61b move, the capping is released, and the head units 5a and 5b are arranged at predetermined intervals (step S1).
2 is moved, and the conveyor belts 43 and 44 are arranged at predetermined positions corresponding to the size of the recording paper to be printed (step S2).

Next, when the paper feed rollers and the like of the paper transport system 13 are operated to feed paper from a required paper feed cassette, the leading edge of the paper reaches the registration roller pair 38 and the paper is bent and the leading edge of the paper is aligned. Then, the paper transport system 13 is temporarily stopped, and then the pair of registration rollers 38 is operated to feed the paper to the printing unit 4, and the driving of the transport belt 43 is started (step S3), and the drying device 10 is turned on. (Step S4).

Next, ink is ejected from each of the recording heads 51a and 51b to start printing (step S5).
Unless printing of this page is completed (N in step S6)
O), repeated. Then, when the printing is completed (YES in step S6), it is determined whether or not the paper has been separated from the transport belts 43 and 44 (step S7). When it is determined that the paper has been separated (YES in step S7), the next page is determined. It is determined whether or not the image signal data to be printed remains (step S8).

If the next data remains (YES in step S8), the control of the sorter 8 is performed (step S9), and the process returns to step S3. On the other hand, if the next data does not remain (NO in step S8), the transport belt 43 is stopped and the drying device 10 is turned off (step S10).

Next, the transport belt moving plates 42, 42 are moved, and the transport belts 43, 44 are moved by the head units 5a,
5b (step S11). Subsequently, the head moving plates 61a and 61b move, and the recording heads 51a and 61b move.
51b is capped (step S12).

As described above, the recording paper is conveyed while being held between both ends in the width direction by the conveyance belts 43 and 44 which can be moved in the width direction. It can be conveyed between 5a and 5b to perform double-sided printing.

[0088]

As described above, according to the first aspect of the present invention, since the rotatable thin plate member is provided, it is possible to prevent the recording paper from being bent without disturbing the conveyance thereof. Thus, an image with high print quality can be obtained. In addition, since the elastic member is disposed between the sheet conveying means and the adjacent thin plate member and between the adjacent thin plate members and is held at a required interval, the bending is prevented regardless of the size of the recording sheet. can do.

According to the second aspect of the present invention, since the thin plate member has a polygonal shape, it comes into contact with the conveyed recording paper at each vertex, and the contact area becomes very small. Can be prevented from being bent without soiling.

According to the third and fourth aspects of the present invention, even if the pressure of the elastic member increases when the recording paper is of a small size,
Since the thin plate member rotates smoothly, it does not hinder sheet conveyance.

According to the fifth aspect of the present invention, since the thin plate members of the pair of deflection preventing means are arranged alternately, when each sheet conveying means moves in the width direction according to the sheet size,
Since the thin plate members of the pair of deflection preventing means do not contact each other, they can be moved smoothly.

According to the sixth aspect of the present invention, a pair of deflection preventing means is provided upstream of each gap between the opposing recording heads in the sheet transport direction, so that the deflection of the recording sheet can be reduced before printing. Thus, an image with high print quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of an apparatus according to an embodiment of an ink jet recording apparatus according to the present invention.

FIGS. 2A and 2B are diagrams showing a schematic configuration of the inside of the apparatus, wherein FIG. 2A is a left side view and FIG. 2B is a front view.

3A and 3B are diagrams showing a configuration of a printing unit 4, wherein FIG. 3A is a left side view, and FIG. 3B is a front view.

FIGS. 4 (a) and (b) show a head holding mechanism of a recording head in FIGS. 3 (a) and (b) for convenience of explanation.

FIGS. 5A and 5B are diagrams showing a main part of a paper transport mechanism of the printing unit 4, wherein FIG. 5A is a left side view and FIG.

6A and 6B are views showing a deflection preventing member, wherein FIG. 6A shows the shape of a thin plate member, and FIG. 6B shows only the vicinity of a shaft 85a in FIG. 5A.

FIG. 7 is a front view showing a shape of a transport belt moving plate 42;

FIG. 8 is a diagram showing a state in which the transport belts 43 have moved in FIG. 6B corresponding to small-size paper.

FIG. 9 is a view showing an arrangement example of thin plate members 852 and 952;
(A) shows a state corresponding to large size paper, and (b) shows a state corresponding to small size paper.

FIGS. 10A and 10B are diagrams showing a configuration in which the deflection preventing members 851 and 951 have a buffering member, wherein FIG. 10A shows a configuration of a thin plate member and a buffering member, and FIG. 10B shows a state where they are disposed on shafts 85a and 95a. Is shown.

11A and 11B are diagrams illustrating a configuration in which the deflection preventing members 851 and 951 include a buffer member, wherein FIG. 11A illustrates a configuration of a thin plate member and a buffer member, and FIG. 11B illustrates a state where the deflection prevention members are disposed on shafts 85a and 95a. Is shown.

12A and 12B are diagrams illustrating a configuration of a head holding mechanism, wherein FIG. 12A is a left side view, and FIG. 12B is a front view.

FIG. 13 is a block diagram showing a control configuration.

FIG. 14 is a flowchart illustrating a procedure of a printing operation.

[Explanation of symbols]

 1a Operation unit 1b Display unit 4 Printing unit 5a, 5b Head unit 10 Drying device 11, 12 Side plate 13 Paper transport system 38 Registration roller pair 42 Transport belt moving plate 43 Driving transport belt 44 Follower transport belt 51a, 51b Recording head 52a , 52b Cap unit 62 Head moving shaft 64 Head moving motor 80-84, 90-94 Pulley 85, 95 Idle roller 85a, 95a Shaft 101 Fan 102 Heater 103 Pump 110 Control unit 111 Storage unit 113a, 113b, 114 Drive circuit 115 Ink Remaining amount detection unit 120 CPU 121 Recording control unit 122 Mechanism control unit 123 Display control unit 421 Conveying belt moving shaft 425 Belt moving plate motor 803 Conveying belt motor 804 Drive shaft 851,951 Deflection preventing member 852, 52 thin members 853,953 elastic members 854,954 restricting member

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Baba 1-2-2, Tamazuki, Chuo-ku, Osaka-shi Inside Mita Kogyo Co., Ltd. (72) Inventor Yoshiko Kawachi 1-2-28, Tamazuki, Chuo-ku, Osaka-shi Mita Kogyo Incorporated company (72) Inventor Setsuo Hori 1-2-2 Tamazo, Chuo-ku, Osaka Mita Kogyo Co., Ltd. (56) References JP-A-5-112001 (JP, A) JP-A-59-188467 (JP) , A) JP-A-5-112000 (JP, A) JP-A-57-144867 (JP, A) JP-A-5-185661 (JP, A) JP-A-6-35241 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 13/00-13/32

Claims (6)

(57) [Claims] 1. An ink jet recording apparatus, comprising: ejecting ink from nozzles of a recording head disposed opposite to each other with a predetermined gap to record images on both sides of a recording sheet conveyed along a conveyance path passing through the gap. In the apparatus, a pair of paper transport means disposed at both ends in the width direction of the recording paper, and capable of moving the recording paper along the transport path while nipping each end from both sides, A pair of deflection preventing means disposed at both sides of the recording sheet at a position facing the conveyance path and for preventing bending of the recording sheet, wherein the deflection preventing means extends in a width direction of the recording sheet. A plurality of thin plate members that are movable and rotatable around the axis in the width direction are disposed between the thin plate members adjacent to the sheet conveying means and between the thin plate members adjacent to each other. With the elastic member An ink jet recording apparatus characterized in that: 2. The ink jet recording apparatus according to claim 1, wherein said thin plate member has a polygonal shape. 3. An ink jet recording apparatus according to claim 1, wherein said shaft is supported on both outer sides of said sheet conveying means and is arranged in said width direction, and is movably arranged on said axis. An ink jet recording apparatus, comprising: a regulating member that regulates contact of the elastic member with the thin plate member, wherein the thin plate member is disposed on the shaft. 4. The ink jet recording apparatus according to claim 3, wherein said thin plate member is disposed on said regulating member. 5. The ink jet recording apparatus according to claim 1, wherein the thin plate members of the pair of deflection preventing means are arranged alternately in the width direction. 6. The ink jet recording apparatus according to claim 1, further comprising a plurality of pairs of opposed recording heads along the transport path, wherein the pair of deflection preventing means includes:
An ink jet recording apparatus, which is disposed at least upstream of each of the gaps in the paper transport direction.