JPH07314825A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To convey a recording sheet without deflection. CONSTITUTION:Pulleys 80, 81 each has a truncated conical shape in such a manner that the pulley 80 has a large-diameter large-end face side disposed at the lateral outside of a conveying recording sheet, while the pulley 81 has a large-diameter large-end face side disposed at the lateral inside of the sheet. Similarly, pulleys of a driven side conveying belt each has a truncated conical shape in such a manner that the pulley of an upstream side of the sheet conveying direction has a large end face disposed at the lateral outside of the sheet, while the pulley of a downstream side of the sheet conveying direction has a large end face disposed at the lateral inside of the sheet. With this shape, the sheet P1 held at the lateral both ends by the drive side conveying belt 43 and the driven side conveying belt is conveyed in a direction P by a conveying force of a direction F, i.e., in a direction P while being printed in a direction extending toward a downstream, and hence the sheet can be conveyed by eliminating the deflection of the sheet.

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 as an output device of a facsimile, a copying machine, a printer or a computer, and more particularly to an ink jet recording apparatus for printing on both sides of a recording sheet by an ink jet method. .

[0002]

2. Description of the Related Art Conventionally, an ink jet recording apparatus for ejecting ink from a nozzle of a recording means to print on a sheet has been put into practical use, and recently, an apparatus capable of printing on both sides of the sheet has been proposed. (JP-A-5-330037)
Issue). In this ink jet recording apparatus, the recording means is disposed so as to face both sides of the recording paper, the recording paper is conveyed between both recording means to eject ink, and immediately after printing, almost the entire surface of the recording paper is on the belt. It is designed to be sucked and transported. Further, conventionally, in such an ink jet recording apparatus, it is known that a high print quality can be obtained when the distance between the recording paper and the ink ejection surface of the recording means is set to about 1 mm or less.

[0003]

However, when the recording paper is conveyed between the two recording means, the recording paper is 1 m long.
If 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, the printed image may flow, or the nozzle may be clogged to cause white streaks in the image, which may deteriorate the print quality. However, the above-mentioned conventional Japanese Patent Laid-Open No. 5-330037.
The recording apparatus described in the publication does not disclose a conveyance mechanism for conveying the recording sheet without bending between both recording means.

The present invention solves the above problems, and an object of the present invention is to provide an ink jet recording apparatus for printing on both sides of a recording sheet, in which the recording sheet is conveyed without bending between the recording means. And

[0005]

In order to achieve the above object, the present invention discharges ink from nozzles of recording heads which are arranged opposite to each other with a required gap, to a conveying path passing through the gap. In an ink jet recording apparatus for recording images on both sides of a recording sheet conveyed along the two sides of the recording sheet conveyed along the conveyance path, the two recording sheets being sandwiched from both sides. Endless conveyor belts, upstream pulleys and downstream pulleys that stretch these conveyor belts at upstream and downstream positions in the conveying direction, and one of the pulleys on one end in the width direction and the above Among the pulleys on the other side in the width direction, there is provided a sheet conveying means for conveying the recording sheet, which comprises a rotational force supplying means connected to one pulley, and the upstream pulley is at least one end side in the width direction. The downstream pulley is formed in a conical shape that is tapered outward in the width direction, and the downstream pulley has a conical shape in which the side corresponding to the upstream pulley that is formed in a conical shape is tapered inward in the width direction. Is formed (claim 1).

Further, the rotational force supplying means is one of the downstream pulleys on the one end side in the width direction, one of the downstream pulleys and the other pulley on the other end side in the width direction, and the one downstream side. Is connected to the pulley (claim 2).

In the ink jet recording apparatus according to the first or second aspect, the side corresponding to the upstream pulley formed in a conical shape and stretched around a pulley to which the rotational force supply means is connected. Speed detecting means for detecting the rotation speed of the conveyor belt, belt position moving means for moving the tension position of the conveyor belt with respect to the pulley, and the tension means when the detected rotation speed is higher than a predetermined level. And a movement control means for moving the position toward the tapered side of the pulley and moving the tensioned position to the opposite side to the tapered side of the pulley when the position is lower than a predetermined level. 3).

[0008]

According to the first aspect of the present invention, the recording paper is sandwiched from both sides by two endless conveyor belts at both ends in the width direction, and the recording heads are arranged at the same position or slightly opposite to each other. Is transported to the gap. At this time, since the respective conveyor belts stretched around the respective pulleys deviate to the side of the larger diameter of the respective pulleys, at least one end side upstream and downstream pulleys in the width direction are formed in a conical shape. Each pair of conveyor belts is stretched around the downstream pulley side more apart from the upstream pulley side. Therefore, the recording sheet is conveyed while being pulled outward at least at one end side in the width direction, and the bending of the sheet is prevented.

According to the second aspect of the invention, the pulleys on the downstream side of one of the two endless conveyor belts that sandwich the recording sheet from both sides rotate at both ends in the width direction of the recording sheet. As a result, the conveyor belt rotates in the direction in which it is pulled.

According to the third aspect of the invention, the rotational speed of the rotating conveyor belt on the side where the upstream and downstream pulleys are formed in a conical shape is detected. Then, when the detected rotation speed is higher than a predetermined level, the tension position of the conveyor belt moves to the side where the pulley is narrowed, while when the rotation speed is lower than the predetermined level, the tension position is narrowed by the pulley. Move to the opposite side of the ball. Therefore, the rotation speed of the conveyor belt is maintained at a predetermined level.

[0011]

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 external appearance of the device of the first embodiment. FIG. 2 is a diagram showing a schematic configuration of the inside of the device, (a) is a left side view, and (b) is a front view.

This device is, for example, a printer that prints character data or the like input from an external device. In FIG. 2 (b),
The right side is provided with a sheet storage unit including the sheet feeding cassettes 21 to 24, the left side is provided with a printing unit 4 for performing printing on both the front surface and the back side while conveying the recording sheet, and the sheets are transferred from the right side to the left side. A paper transport system 13 for transporting and a sorter 8 are disposed below the printing unit 4, respectively. 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). In addition, the operation panel 1 is provided at a proper place on the surface of the device.
Also, a paper feed bypass unit 3 is provided.

The operation panel 1 is provided with an operation section 1a (FIG. 1) provided with a paper size instruction key for manually instructing the size of the recording paper, a discharge recovery key for performing a discharge recovery operation, and the like.
1) and a display unit 1b (FIG. 11) configured of an LCD, an LED, etc., for displaying setting contents. The paper feed bypass section 3 is for manually feeding paper by adjusting the width alignment mechanism 3a arranged on the surface of the apparatus to the paper width.

Sheet feed cassettes 21 to 24 having different sizes capable of storing cut sheets are stacked and arranged in the sheet storage section. 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 in the paper feed cassette 23 in the paper feed direction. The B4 size is oriented vertically,
The B5 size is horizontally stored in the paper feed cassette 24. The size and orientation of the paper stored in each cassette is not limited to the above.

The paper transport system 13 includes paper feed cassettes 21 to 21.
24 and the paper feed bypass unit 3, which are provided for feeding paper, feed rollers 31 to 34, 37, a pair of conveyance rollers for conveying the paper, a conveyance guide for guiding the conveyance paper, and an image recording timing. Correspondingly, a pair of registration rollers 38 for carrying the sheet are provided.

In the printing unit 4, a pair of drive side conveyor belt 43 and driven side conveyor belt 44 sandwich the recording paper at both ends in the width direction and convey the recording paper along a chain line R in FIG. 2B. The printing mechanism is composed of four head units 5a and 5b, which are arranged on both sides of the conveyed paper so as to face each other, and a drying device 10 for drying ink on the surface of the printed paper.

First, the paper transport mechanism will be described with reference to FIGS. 3A and 3B are views showing the configuration of the printing unit 4, where FIG. 3A is a left side view and FIG. 3B is a front view. Figure 4
3A and 3B are schematic illustrations of the head holding mechanism of the head unit in FIGS. 3A and 3B for convenience of description. 5A and 5B are views showing the main part of the paper transport mechanism of the printing unit 4, where FIG. 5A is a left side view and FIG. 5B is a front view. In addition, in FIG. 3 (a), FIG. 4 (a) and FIG. 5 (a),
For convenience of explanation, the pulleys 83 and 84 are not shown.

The pair of drive-side conveyor belts 43, 43 includes pulleys 80-84 and idle rollers 85, 8 respectively.
It has an endless shape stretched over 5, ... The drive-side transport belt 43 is made of, for example, polyester mesh-free woven fabric to which chloroprene rubber is added, and the stretch is small and stable transport is possible. Further, the pair of driven-side transport belts 44, 44 respectively include pulleys 90-9.
4 and the idle rollers 95, 95, ... The driven-side transport belt 44 is made of urethane rubber, for example, and has a large expansion / contraction, and the driven-side transport belt 4
3 is formed of a material that easily fits. The conveyor belts 43 and 44 have a width of 15 mm, for example.

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

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

The pulley 81 and the idle roller 85, ...
Is a shaft 81a and a shaft 85 arranged between the side plates 11 and 12.
.. is rotatably penetrated, and is rotatably disposed on the conveyor belt moving plate 42. Also, similarly,
The pulleys 90, 91 and the idle rollers 95, ... Include shafts 90a, 91a and shafts 95 arranged between the side plates 11, 12.
.. is rotatably penetrated, and is rotatably disposed on the conveyor belt moving plate 42. The idle rollers 85 and 95 are arranged above and below the facing surfaces of the head units 5a and 5b facing each other, that is, at five positions.
The flexure of the belts 3,44 is prevented and the tension position is regulated. The belts are rotated by being driven by the frictional force with the conveyor belts 43,44.

Drive shaft 804, shaft 81a and shaft 85a, ...
, And the shaft 90a, the shaft 91a, and the shaft 95a are arranged side by side with a required urging force in a direction in which they are close to each other at a required interval, and are stretched around each pulley and idle roller. The drive-side transport belt 43 and the driven-side transport belt 44 contact each other 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 fixedly installed at appropriate places in the central portions of the shaft 81a and the shaft 91a, and abut each other with a required pressure. The rollers 81b and 91b are
The shafts 81a and 91a are rotatably arranged and are rotated by the contact of the conveyed paper.

6A and 6B are views showing the shapes of the pulleys 80 and 81. FIG. 6A is an enlarged view of a main part of FIG. 4A, and FIG.
8 is a right side view of the right side pulleys 80, 81 in FIG.

The pulleys 80, 81 are frusto-conical in shape, and the pulley 80 has a large-diameter large end face side that is conveyed outward in the width direction of the recording sheet, while the pulley 81 has a large-end face side that conveys the recording sheet. Are respectively arranged on the inner side in the width direction of. Similarly, the pulleys 90 and 91 also have a truncated cone shape,
The pulley 90 is arranged on the outer side in the width direction of the recording paper whose large end face is conveyed, while the pulley 91 is arranged on the inner side in the width direction of the recording paper whose large end face is conveyed.

The pulleys 82 to 84, 92 to 94 and the idle rollers 85 and 95 have a columnar shape as shown in FIG. Further, the pulleys 82 to 84 and 92 to 94 may have a crown shape in which the central portion of the cylinder is formed somewhat higher as shown in FIG. In the case of the shape as shown in FIG.
The conveyor belts 43 and 44 are less likely to come off.

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 transferred between the pulleys 81 and 91. Then, the center portion in the width direction is sandwiched by the rollers 81b and 91b, and, for example, a width of 5 mm at both ends in the width direction is sandwiched by the drive side conveyor belt 43 and the driven side conveyor belt 44, respectively. And the pulleys 81, 9
It is conveyed in the P direction (FIG. 5) while being sandwiched and held by the drive side conveyor belt 43 and the driven side conveyor belt 44 from between 1 to between the pulleys 80 and 90.

Generally, when a belt is stretched around a truncated cone-shaped pulley, the tension position of the belt approaches the large end face side as the belt rotates, so the pair of drive-side transport belts 4
3 and the pair of driven-side transport belts 44 are stretched in a state where the downstream side in the sheet transport direction spreads outward in the width direction of the recording sheet in a V shape. Therefore, the conveyor belt 43,
The recording paper P1 whose widthwise ends are sandwiched by 44 is conveyed in the P direction, and the conveyance force is applied in the F direction, that is, in the direction in which it spreads toward the downstream side. You can

The conical generatrix angle θ of the truncated cone of the pulleys 80, 81, 90, 91 is θ = 0.5 to 6 °, preferably
It is 1.5 to 4.5 °. When θ <0.5 °, the bending of the conveyed sheet cannot be sufficiently eliminated. On the other hand, θ
When> 6 °, the space between the pulleys 80 and 80 is too wide, and the width of the paper sandwiched between the transport belts 43 and 44 is reduced, and the paper gripping force is reduced, and the paper cannot be held. Will fall into.

The pulleys 80, 81, 90 and 91 are
Only one end side in the paper width direction has a truncated cone shape, and the other end side is shown in FIG.
It may have a cylindrical shape as shown in FIG. Even in this case, since the conveying force is applied to the recording sheet in the direction in which the recording sheet spreads downstream, it is possible to prevent the sheet from bending.

Further, instead of the pulley 81, the pulley 82 may be shaped as shown in FIG. 6 to prevent the bending of the sheet in the same manner. In this case, the pulley 81 may be shaped as shown in FIG. 7 or 8.

Further, the pulley 82 is arranged diagonally above and to the left of the pulley 81 in FIG. 5 (b), and the pulley 92 is arranged diagonally above and right of the pulley 91 in FIG. Therefore, the pulley 8
The recording sheet fed in the P direction from the registration roller pair 38 can be reliably guided between the pulleys 81 and 91 by the conveyor belt between the rollers 81 and 91 and the pulleys 92 and 91.

Next, the moving mechanism of the conveyor belts 43 and 44 will be described with reference to FIGS. 4 and 9. FIG. 9 is a front view showing the shape of the transport belt moving plate 42.

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

The transport belt moving plate 42 is provided with shaft holes for rotatably holding the above pulleys and idle rollers and square holes for avoiding 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.
The tubular bearing members 421a and 422a are fixedly installed. 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, 42 are held by the stay 422 and the conveyor belt moving shaft 421.

The stay 422 of the bearing member 422a can be slid 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 formed over the required range on the outer surface of the conveyor belt moving shaft 421 to form a ball screw structure. There is. The screw of the conveyor belt moving shaft 421 is oriented in different directions with the central portion as a boundary, that is, FIG.
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 come close to each other when the conveyor belt moving shaft 421 rotates clockwise in FIG. 4B, and separate 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 is composed of, for example, a stepping motor, and rotates the conveyor belt moving shaft 421 via gears 424 and 423. The conveyor belt moving plate 42,
42 can be moved according to the width of the recording paper. The rotation amount of the conveyor belt moving shaft 421, that is, the moving distance of the conveyor belt moving plates 42, 42 is controlled by the drive pulse supplied to the belt moving plate motor 425.

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

As described above, the pulleys and the conveyor belts can be integrally moved in the sheet width direction indicated by the arrow in FIG. 4 by the conveyor belt moving plates 42, 42 according to the sheet width of the recording sheet to be printed. Therefore, in correspondence with various paper sizes, both ends of the recording paper in the width direction are securely held by the drive side conveyor belt 43 and the driven side conveyor belt 44, respectively.
Paper can be conveyed.

A pair of drive side conveyor belts 4 are used as conveyor belts which are moved in the width direction according to the size of the recording paper.
It is also possible to use only one of the conveyor belts 3, 43 and the pair of driven side conveyor belts 44, 44. The other conveyor 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 other conveyor belts 43 and 44 can shorten the required moving distance.

Next, the printing mechanism will be described with reference to FIG. The four head units 5a are in the shape of a rectangular parallelepiped, and are arranged on one surface side of the recording paper to be conveyed with a predetermined interval along the paper conveyance path, and the four head units 5b are arranged.
Has a rectangular parallelepiped shape similar to that of the head unit 5a, and is disposed on the other surface side across 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 portion 52a, and
Each head unit 5b is composed of a recording head 51b and a cap portion 52b. Recording head 5
1a is arranged in parallel on the upper side of the cap portion 52a in FIG.
On the other hand, the recording head 51b has a cap portion 52b shown in FIG.
The recording head 51a and the cap portion 52b, and the recording head 51b and the cap portion 52a are arranged side by side on the middle and lower sides.
They are arranged at positions facing each other. The head unit 5a and the head unit 5b are movable between the contact position and the separation position in the contact and separation directions by a head holding mechanism described later, and are arranged in the contact position when printing is not performed. When printing is performed, they are arranged at a predetermined interval of 2 mm, for example.

The recording heads 51a and 51b are each provided with a nozzle row in which minute nozzles are arranged in a row at a predetermined pitch. Then, for example, it is composed of a piezoelectric element, and ink is ejected from the nozzles toward the recording paper by an ink ejection mechanism provided in each nozzle to print an image on both sides of the recording paper. The size 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) ink in this order from the upstream side in the paper transport direction P. These inks are sequentially ejected to perform color printing.

The nozzle array may be composed of a plurality of nozzle arrays in which the nozzles are arranged in a staggered manner. In addition, a head unit 5 including recording heads 51a and 51b for ejecting black (BK) ink
Only one of a and 5b may be provided so that black-and-white printing is possible.

Ink is supplied to each head unit 5a, 5b from an ink cartridge 14 (see FIG. 2) arranged at a proper position in the apparatus main body through an ink supply tube (not shown) made of, for example, a soft synthetic resin. . The ink cartridge 14 (see FIG. 2) is composed of four cartridges,
Each cartridge has yellow (Y), magenta (M),
Cyan (C) and black (BK) inks are enclosed, and ink is supplied from an ink needle attached to the base end of the ink supply tube.

The cap portions 52a and 52b are provided with caps made of, for example, rubber or soft synthetic resin, and the recording heads 51b and 51a are located at the close contact positions of the head units 5a and 5b.
Is performed to prevent solidification of the ink at the tip of the nozzle and invasion of foreign matter, bubbles, etc. 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. 11) is provided in the waste ink tube. The pump 103 generates a suction force at the close contact position of the head units 5a and 5b, restores the meniscus formed at the nozzle tips of the recording heads 51a and 51b to a normal position, and causes air bubbles and foreign matters in the nozzles with ink. After the removal, the ejection recovery operation such as eliminating the defective ejection of the ink is performed. The ink sucked by the pump 103 is absorbed by the ink absorber made of urethane foam or the like inside the waste ink tank 18 (FIG. 2) disposed in the vicinity of the ink cartridge 14 (FIG. 2) via the waste ink tube. To be done.

During printing, the feeding of the recording paper to the printing unit 4 is temporarily stopped at a required interval, and the transport belt 4 is stopped.
As shown in FIG.
The recording heads 51a, 5 are retracted from between a and 51b.
By performing the idle discharge in which ink is discharged from all the nozzles from 1b toward the cap portions 52b and 52a, it is possible to prevent clogging of nozzles that are not used during printing or that are rarely used during printing. The blank discharge may be performed in the capping state.

Next, the head holding mechanism of the head unit will be described with reference to FIGS. 10A and 10B are views showing the configuration of the head holding mechanism. FIG. 10A is a left side view, and FIG.
Is a front view.

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

The head moving plate 61a is the same as that shown in FIG.
A holding portion 611a formed by protruding rightward from the side plate 11.
A through hole 62a is formed in the through hole 63a, and a through hole 63a is formed in a holding portion 612a formed so as to project leftward from the side plate 12. Similarly, the head moving plate 61b has a holding portion 611b formed to project rightward from the side plate 11 in FIG. 10A (front side in FIG. 10B) and the side plate 1.
Through-holes 62a (not shown) and 63a (not shown) are formed in holding portions 612b (not shown) formed by projecting to the left from 2. A head moving shaft 62, which is rotatably supported by the apparatus 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 is fitted. The head moving plates 61a and 61b are held by the shafts 62 and 63.

The head support shaft 63 can smoothly slide in the through hole 63a. 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 movement axis 62
The screws of FIG.
In (b), for example, the left side has a right-hand thread and the right side has a left-hand thread. In this case, the head moving plates 61a and 61b
When the head moving shaft 62 rotates in the clockwise direction in FIG. 10A, they are separated from each other, and when they are rotated in the counterclockwise direction, they approach each other.

Gear 65 fixed to head moving shaft 62
Are meshed with the gear 66 of the head moving motor 64. The head moving motor 64 is composed of, for example, a stepping motor, and through the gears 66 and 65, the head moving shaft 6
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 the drive pulse supplied to the head moving motor 64.

The movement operation of the head units 5a and 5b having the above-described structure will be described with reference to FIGS.

Upon completion of the printing operation, first, the conveyor belt moving shaft 421 rotates counterclockwise in FIG. 3 (b), whereby the conveyor belt moving plates 42, 42 respectively move in FIG. 3 (a). Move in the direction of the arrow, and convey belts 43, 4
3 moves outward from between the head units 5a and 5b facing each other. Next, when the head moving shaft 62 is shown in FIG.
By rotating in the counterclockwise direction, the head moving plate 6
1a and 61b respectively move in the direction of the arrow in FIG. 10 (b), and the head units 5a and 5b come into close contact with each other for capping.

On the other hand, when starting the printing operation, first,
By rotating the head moving shaft 62 in the clockwise direction in FIG. 10 (a), the head moving plates 61a, 61b move in the directions opposite to the arrows in FIG. 10 (b), and the head units 5a, 5b are moved. Are separated and capping is released. Next, in FIG. 3B, the conveyor belt moving shaft 421 is
By rotating the conveyor belt moving plates 42, 42 in the direction opposite to the arrow in FIG. 3 (a) by rotating the conveyor belts 43, 43 by the required amount in the clockwise direction, the conveyor belts 43, 43 of the head units 5a, 5b facing each other are moved. Move to the position corresponding to the paper size in between.

In this way, by rotating the head moving shaft 62 to move the head moving plates 61a and 61b, the recording heads 51a and 5b of the head units 5a and 5b are moved.
Capping of 1b and its cancellation can be performed.

Note that capping and its release may be performed by moving only one of the head moving plates 61a and 61b and moving one of the head units 5a and 5b in the contacting / separating direction. In this case, the other head unit 5a, 5b need not be movably arranged.

Next, the structure of the drying device 10 will be described with reference to FIG. The drying device 10 includes the head unit 5
It is composed of a fan 101 and a heater 102, which are arranged on both sides of a and 5b on the downstream side in the sheet conveying direction. For example, three fans 101 are arranged in parallel on both sides of the paper transport path as shown in FIG. 3, and blow the air toward the recording paper. The heater 102 has a heat source composed of a halogen lamp, a nichrome wire, etc., and has a sheet conveying path and a fan 10.
1 is disposed across the print width of the head units 5a and 5b. With the drying device 10 having such a configuration,
Warm 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 apparatus is shown in FIG.
This will be described with reference to the block diagram of FIG. In this device, each part operates 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, and controls 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, and 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 that stores a control program, a RAM that temporarily stores data, and the like. The interface (I / F) unit 112 is
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.

Based on the input operation signal, the mechanism control section 122 drives the sheet conveying system 13 such as the sheet feeding roller via the drive circuit 114 to cause the sheet feeding system to feed the sheet from the required sheet feeding cassette and to perform the recording. The drive of the sorter 8 is controlled every time printing on the paper is completed, and the paper is stored in the same bin or each bin. Further, a drive pulse is supplied to each motor such as the conveyor belt motor 803 via the drive circuit 114 to drive the motor. 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.

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

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

The recording control section 121 outputs the input image signal to the drive circuits 113a, 11 of the head units 5a, 5b.
3b is serially transmitted. Drive circuit 113
Reference characters a and 113b are provided at appropriate positions in the head units 5a and 5b, respectively, and have a latch portion. The serial binary or multi-valued image signals for one line of the recording paper, for example, are temporarily latched, It is converted into a parallel signal.

Further, the recording control section 121 includes the drive circuit 11
The parallel signals converted by 3a and 113b are output to the corresponding piezoelectric elements of the recording heads 51a and 51b as pulse drive signals in synchronization with the mechanism control unit 122 to control ink ejection. For example, 2 of “0” and “1”
In the case of the value signal, for the signal of "1", a voltage is applied to the piezoelectric element during the pulse width thereof, and the hydraulic pressure rapidly increases, so that a fixed amount of ink is ejected from the nozzle. . The image signal for one line is sequentially transmitted at a predetermined cycle, whereby two-dimensional image recording is performed.

The cycle of ink ejection, that is, the cycle of signal output to the piezoelectric element is set within the range of the capabilities of the head units 5a and 5b, and the conveying speed of the recording paper during printing, that is, the conveyor 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 feed cassette, the shortage of ink remaining, and the like, and displays the detection result on the display unit 1b. The remaining ink 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 falls below 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, capping is released, head units 5a and 5b are arranged at positions with a predetermined interval (step S1), and then the conveyor belt moving plates 42 and 4 are moved.
2 is moved, and the conveyor belts 43 and 44 are arranged at a predetermined position corresponding to the size of the recording paper on which printing is performed (step S2).

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

Then, ink is ejected from each of the recording heads 51a and 51b to start printing (step S5),
While printing of this page is not completed (N in step S6
O), repeated. Then, when printing is completed (YES in step S6), it is determined whether or not the paper is separated from the conveyor belts 43 and 44 (step S7), and when it is determined that the paper is separated (YES in step S7), the next page 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 sorter 8 is controlled (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 conveyor belt 43 is stopped and the drying device 10 is turned off (step S10).

Next, the transport belt moving plates 42, 42 move, and the transport belts 43, 44 move the head units 5a,
5b is retracted to the outside (step S11), and subsequently the head moving plates 61a and 61b move to move the recording heads 51a and 61a.
51b is capped (step S12).

As described above, since the widthwise movable conveyor belts 43 and 44 sandwich and hold both ends of the recording sheet in the width direction to convey the recording sheet, recording sheets of various sizes can be reliably carried out by the head unit. It is possible to carry out double-sided printing by conveying between 5a and 5b.

Next, a second embodiment of the ink jet recording apparatus according to the present invention will be described with reference to the drawings.
The same reference numerals are given to those having the same functions as those in the first embodiment, and the description of the members having the same configuration will be omitted.

The sheet conveying speed by the driving side conveying belt 43 is determined by the outer diameter of the pulley 80 when the rotating speed of the conveying belt motor 803 is constant. When the paper conveyance speed changes with respect to the ink ejection cycle, the image printed on the paper expands or contracts in the paper conveyance direction, and when it deteriorates further, a horizontal striped pattern occurs in the printed image. Further, in FIG. 6A, when the outer diameters of the left and right pulleys 80 are different due to dimensional errors in manufacturing, surface wear due to long-term use, and the like, a difference in conveyance speed occurs at both ends in the width direction of the sheet. As a result, the paper is conveyed obliquely, and the print quality is degraded.

Therefore, in the second embodiment, the bending of the recording sheet is prevented, and the pair of drive-side conveying belts 43, 43 is used.
The object of the present invention is to keep the paper conveyance speed constant and prevent skewed conveyance by keeping the rotation speed constant to obtain an image of high print quality.

That is, in the second embodiment, by providing the belt position adjusting mechanism for adjusting the tension position of the drive side conveyor belt 43 on the truncated cone-shaped pulley 80,
The rotation speeds of both conveyor belts 43 are kept constant.

13A and 13B are views showing the structure of the belt position adjusting mechanism. FIG. 13A is a partially enlarged view of FIG. 6A viewed from the back side of the paper, and FIG. 13B is a sectional view taken along line BB in FIG. (C) is a C arrow line view in (b).

The belt position adjusting mechanism comprises a conveyor belt speed sensor 131, a conveyor belt speed adjusting plate 132, an adjusting plate moving motor 133 and the like. It should be noted that the belt position adjusting mechanism has the same structure for the left and right pulleys 80 in FIG. 6A.

The pulley 80 is different from that of the first embodiment in that
The length of the cone is lengthened. Drive side conveyor belt 43
Has a striped pattern of white and black with a required width formed on the surface at equal intervals in the longitudinal direction. The transport belt moving plate 42 is provided with a square hole 134, and the transport belt speed adjusting plate 132 is slidably arranged in the square hole 134.

The conveyor belt speed adjusting plate 132 has a rectangular parallelepiped shape and is rotated by finely adjusting the tension position of the conveyor belt 43 on the pulley 80 to change the outer diameter of the pulley 80 at the tension position. It adjusts the speed. The transport belt speed adjusting plate 132 is provided with a through hole 132a that is slightly wider than the transport belt 43, and the transport belt 43 is provided inside.
Has been passed through. Further, a rack 132c is formed on the upper end portion 132b of the conveyor belt speed adjusting plate 132 at the left end portion in FIG.

Through-hole 13 of the conveyor belt speed adjusting plate 132
A conveyor belt speed sensor 131 is arranged on the bottom surface of 2a. The conveyor belt speed sensor 131 is, for example, a reflective optical sensor including a light emitting portion and a light receiving portion, and the through hole 13
Light is emitted toward the rotating conveyor belt 43 passed through 2a and the reflected light is received.
When the light is reflected by the white part of No. 3, the light receiving part is turned on, and when it is reflected by the black part, it is turned off.

The adjusting plate moving motor 133 is composed of, for example, a stepping motor, is arranged on the conveying belt moving plate 42, and the pinion gear 133a fixed to the motor shaft is meshed with the rack 132b of the conveying belt speed adjusting plate 132. There is. Then, the adjustment plate moving motor 133 rotates in the normal direction,
When inverted, the pinion gear 133a and the rack 132b
The transfer belt speed adjusting plate 132 is shown in FIG.
By moving in the left and right directions, the tension position of the conveyor belt 43 on the pulley 80 can be finely adjusted.

Next, the control configuration will be described with reference to the block diagram of FIG. In addition to the function of the first embodiment, the storage unit 111 stores a predetermined rotation speed of the drive side conveyor belt 43. In addition to the function of the first embodiment, the mechanism control unit 122 counts the number of times the light receiving unit is turned on and off within a predetermined time, which is input from the conveyor belt speed sensor 131, and determines the rotation speed of the drive-side conveyor belt 43. It is something to detect. Further, based on the detected rotation speed of the conveyor belt 43, the adjustment plate moving motor 13 is driven via the drive circuit 114.
3 is supplied with a drive pulse to convey belt speed adjusting plate 132.
Is to move.

Next, the operation of adjusting the rotation speed of the conveyor belt 43 will be described. In step S3 of FIG.
In the state where the sheet is fed to the registration roller pair 38, first, the conveyor belt 43 is rotationally driven, and the conveyor belt speed sensor 131 detects the rotational speed.

When the rotation speed of the conveyor belt 43 is faster than a predetermined value, the adjusting plate moving motor 133 is rotated so that the conveyor belt speed adjusting plate 132 moves to the left in FIG. 13C, that is, the conveyor belt 43. 13A moves in the direction in which the outer diameter of the pulley 80 on the right side is reduced in FIG.

On the other hand, when the rotation speed of the conveyor belt 43 is lower than the predetermined value, the conveyor belt speed adjusting plate 132 is set to the position shown in FIG.
In FIG. 13C, the conveyor belt 43 moves to the right in FIG.
In (a), the pulley 80 on the left side moves in a direction in which the outer diameter of the pulley 80 increases. Then, when the rotation speed of the conveyor belt 43 reaches a predetermined value, the registration roller pair 38 is operated to start feeding the paper.

Thus, by the belt position adjusting mechanism,
Since the rotation speed of the drive side conveyor belt 43 is detected and the belt tension position on the frustoconical pulley 80 is moved according to the detected rotation speed, the conveyor belt 4 is always
The rotation speed of 3 can be kept constant. Further, since the belt position adjusting mechanism is provided for both of the pulleys 80, the rotation speeds of the pair of drive-side transport belts 43 can be kept the same, and the oblique transport of the recording paper can be prevented.

The belt position adjusting mechanism may be provided only on one of the conveyor belts 43, and only the conveyor belt speed sensor 131 may be provided on the other conveyor belt 43. Then, by adjusting the belt position of the one conveyor belt 43 according to the rotation speed of the other conveyor belt 43, the rotation speeds of both conveyor belts 43, 43 are kept the same, and the rotation speed of the conveyor belt motor 803. May be adjusted to maintain the rotation speed of the conveyor belts 43, 43 at a value set according to the ink ejection cycle.
This makes it possible to obtain high-quality printing quality and reduce the number of parts.

Further, one of the pair of pulleys 81, 81 and the pair of pulleys 80, 80 has a columnar shape as shown in FIG. 7, and a belt position adjusting mechanism is provided only on the side of the truncated cone-shaped pulleys 81, 80 for conveyance. The rotation speed of the belt 43 may be adjusted. In this case, the number of parts can be reduced while maintaining the same rotation speed of the conveyor belts 43 at both ends in the width direction.

Each of the above embodiments may be applied to an ink jet recording apparatus having a printing unit as shown in FIG. FIG. 15 is a perspective view showing a schematic configuration of the printing unit 4. In addition, the same reference numerals are given to those having the same functions as those of the above-mentioned respective embodiments.

The apparatus shown in FIG. 15 performs serial printing by ejecting ink while moving the head units 5a and 5b while the recording paper P1 is stopped, and alternately carries out paper conveyance for the print width and serial printing. The image is recorded on a recording sheet.

The structure of the printing unit 4 will be described. The pair of drive-side transport belts 43, 43 includes a drive pulley 431 and drive pulleys 432, 433, 434, respectively.
It has an endless shape stretched over (the front side in FIG. 15 is not shown). The pair of driven-side transport belts 44, 44 includes pulleys 441, 442, 443, 444 (in FIG. 15,
The front side has an endless shape stretched over (not shown). Each of the pulleys 432 to 434 and 441 to 444 is rotatably arranged on a pair of conveyor belt moving plates 42, 42 described later.

The pulley 431 is fitted on the drive shaft 804 and is rotatably arranged on the conveyor belt moving plate 42. The drive shaft 804 is rotatably supported by the main body of the apparatus, has a D-shaped cross section, and both pulleys 431 rotate with the rotation of the drive shaft 804. The gear 801 fixed to the drive shaft 804 is meshed with the gear 802 of the conveyor belt motor 803. The conveyor belt motor 803 is composed of, for example, a stepping motor, and rotates the drive shaft 804 through the gears 802 and 801 to rotate the pulley 431 and drive the drive-side conveyor belt 43.

Then, the recording paper P1 fed to the printing unit 4 is conveyed in the P direction by sandwiching both ends of the recording paper P1 in the width direction by the drive side conveyor belt 43 and the driven side conveyor belt 44. The amount of rotation of the pulley 431, that is, the recording paper conveyance distance is controlled by the drive pulse supplied to the conveyance belt motor 803.

Next, the moving mechanism of the conveyor belts 43 and 44 will be described. A pair of conveyor belt moving plates 42, 42
Are supported by the apparatus main body so as to be movable toward and away from each other, and holes are bored at opposing positions, and bearing members 421a and 421a are arranged in the holes. Bearing member 421
A conveyor belt moving shaft 421, which is rotatably held by the apparatus main body, is fitted in a and 421a. Bearing member 421
a and the conveyor belt moving shaft 421 are formed with a female screw on the inner surface of the bearing member 421a and a male screw over the required range on the outer surface of the conveyor belt moving shaft 421.
It has a ball screw structure. Conveyor belt moving shaft 421
The screws of FIG.
For example, the back side is formed with a right-hand thread and the front side is formed with a left-hand thread. In this case, the transport belt moving plates 42, 42 are
When the conveyor belt moving shafts 421 rotate clockwise as viewed from the front right side in FIG. 15, they approach each other, and when they rotate counterclockwise, they move away from each other.

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 is composed of, for example, a stepping motor, and rotates the conveyor belt moving shaft 421 via gears 424 and 423.

As a result, the conveyor belt moving plates 42, 4
2 can be moved according to the width of the recording paper on which printing is performed. It should be noted that this apparatus is capable of printing on recording paper of A3 (vertical) size at the maximum, and the home position of the transport belt moving plates 42, 42 is A3 (vertical).
It is set to the position corresponding to the size. Also, gear 4
The rotation amount of 23, that is, the moving distance of the conveyor belt moving plates 42, 42 is controlled by the drive pulse supplied to the belt moving plate motor 425.

As described above, since the conveyor belt moving plates 42, 42 can be moved according to the width of the recording paper to be printed, even if the different paper sizes are used, the both ends in the width direction are surely conveyed on the drive side. The belt 43 and the driven side conveyor belt 44 can sandwich and convey.

Next, the moving mechanism of the head units 5a and 5b will be described. In FIG. 15, the same members as those of the moving mechanism of the head unit 5a, which are members of the moving mechanism of the head unit 5b, are designated by the same reference numerals and suffixes b, and the description thereof is omitted.

The carriage 53a, which constitutes the head body of the head unit 5a, has a through hole 5 formed in an appropriate place on the upper portion thereof.
31a and a fitting groove 532a formed at the lower end thereof are arranged in the contact and separation directions of the transport belt moving plates 42, 42, respectively, and a carriage moving shaft 601a and a carriage supporting shaft 605 are provided.
It is fitted in a and is supported by both shafts so as to be able to reciprocate.

The carriage support shaft 605a is fixed to the apparatus main body, and the fitting groove 532a slides on this support shaft. The carriage moving shaft 601a is
It is rotatably supported by the apparatus body. Through hole 531a
A female screw is formed on the inner surface of the through hole 531a, and the carriage moving shaft 601a and the carriage moving shaft 601a.
A male screw is formed on the outer surface of 01a to form a ball screw structure.

The gear 603a fixed to the carriage moving shaft 601a is the gear 6 of the carriage drive motor 602a.
It is meshed with 04a. Carriage drive motor 6
02a is, for example, a stepping motor, and includes a gear 6
The carriage moving shaft 601a is rotated via 04a and 603a, and the carriage 53a, that is, the head unit 5a reciprocates by forward and reverse rotations of the moving shaft. The amount of rotation of the carriage moving shaft 601a, that is, the moving distance of the head unit 5a is controlled by the driving pulse supplied to the carriage driving motor 602a.

In FIG. 15, the carriage drive motor 6
02a, 602b is composed of one motor, gear 603
The head units 5a and 5b may be moved by providing a transmission mechanism for transmitting the rotational driving force to a and 603b.

In the apparatus having the printing unit 4 having the above-described structure, the pulleys 431 and 432 are frustoconical like the pulleys 80 and 81 shown in FIG. 6, and the pulleys 441 and 442 are also the pulleys 90 and Similar to 91, FIG.
With the truncated cone shape as shown in FIG. 3, it is possible to prevent the conveyed recording paper from being bent.

Further, by providing a belt position adjusting mechanism in the vicinity of the pulley 431 of the conveyor belt 43, the rotation speed of the conveyor belt 43 is kept constant, so that the sheet conveying speed is kept constant, and high quality printing quality is obtained. Obtainable.

[0108]

As described above, according to the first aspect of the invention, the pulleys on the upstream side in the sheet conveying direction are each formed in a conical shape that is tapered outward in the sheet width direction, and the pulleys on the downstream side are formed. Since the pulleys are each formed in a conical shape that is tapered inward in the width direction, the recording sheet is conveyed while being pulled outward at both ends in the width direction, whereby the recording sheet is bent into the gap between the recording heads. It is possible to convey the image without any trouble and obtain an image with high print quality.

According to the second aspect of the present invention, the pulleys on the downstream side of one of the two endless conveyor belts for sandwiching the recording sheet from both sides are rotated at both widthwise ends of the recording sheet. Therefore, the paper can be more reliably conveyed by rotating the conveyance belt in the pulling direction.

According to the third aspect of the present invention, the rotational speeds of the rotating conveyor belts that are opposed to each other are detected, and when the detected rotational speed is higher than a predetermined level, the tension position of the conveyor belt is set to the pulley. When the rotation speed is lower than a predetermined level, the tension position is moved to the opposite side of the pulley from the tapered side. Can be kept in
Images with high print quality can be obtained. Further, since the rotation speeds of the transport drive belts at both ends in the width direction can be kept the same, it is possible to prevent the skewed transport of the recording paper.

[Brief description of drawings]

FIG. 1 is a perspective view showing the outer appearance of an inkjet recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of the inside of the apparatus, (a) is a left side view, and (b) 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.

4A and 4B are schematic views of the head holding mechanism of the head unit shown in FIGS. 3A and 3B, for convenience of description.

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

6A and 6B are diagrams showing the shapes of pulleys 80 and 81, FIG. 6A is an enlarged view of a main part of FIG. 4A, and FIG. 6B is a right side view of the right pulleys 80 and 81 in FIG. .

FIG. 7 is a diagram showing a cylindrical shape which is an example of the shapes of a pulley and an idle roller, (a) is a front view, and (b) is (a).
FIG.

8A and 8B are diagrams showing another example of the shapes of a pulley and an idle roller, showing a crown shape in which a central portion of a cylinder is formed to be slightly higher, where FIG. 8A is a front view and FIG. 8B is a right side surface of FIG. 8A. It is a figure.

9 is a front view showing the shape of a transport belt moving plate 42. FIG.

FIG. 10 is a diagram showing a head holding mechanism, in which (a) is a left side view and (b) is a front view.

FIG. 11 is a block diagram showing a control configuration of the first embodiment.

FIG. 12 is a flowchart illustrating a procedure of a printing operation according to the first embodiment.

FIG. 13 is a diagram showing a configuration of a belt position adjusting mechanism,
6A is a partially enlarged view of FIG. 6A viewed from the back side of the paper,
(B) is a BB sectional view of (a), (c) is a C arrow view of (b).

FIG. 14 is a block diagram showing a control configuration of a second embodiment.

FIG. 15 is a perspective view showing a schematic configuration of a printing unit 4 in another device example.

[Explanation of symbols]

 1a Operation part 1b Display part 4 Printing unit 5a, 5b Head unit 10 Drying device 11, 12 Side plate 13 Paper conveying system 38 Registration roller pair 42 Conveying belt moving plate 43 Driving side conveying belt 44 Driven side conveying belt 51a, 51b Recording head 52a , 52b Cap section 53a, 53b Carriage 62 Head moving shaft 64 Head moving motor 80-84, 90-94 Pulley 85, 95 Idle roller 101 Fan 102 Heater 103 Pump 110 Control section 111 Storage section 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 131 Conveyor belt speed sensor 132 Conveyor belt speed adjusting plate 132a Through hole 132b Top surface part 132c Rack 133 Adjusting plate Dynamic motor 133a pinion gear 421 conveyor belt moving shaft 425 belt moving plate motor 803 transport belt motor 804 drives shaft

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shizushi Kado 1-2-2 Tamatsukuri, Chuo-ku, Osaka City Mita Engineering Co., Ltd. (72) Kenichi Sabu 1-2-2 Tamatsukuri, Chuo-ku, Osaka No. Mita Engineering Co., Ltd. (72) Inventor Hiromi Kosaka 1-228 Tamazuzo, Chuo-ku, Osaka Mita Engineering Co., Ltd. (72) Koichi Baba 1-22 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd. (72) Inventor Masayuki Ishii 1-228 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd. (72) Yoshiko Kawachi 1-228 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Within the corporation

Claims (3)

[Claims] 1. Ink jet recording in which ink is ejected from nozzles of recording heads which are arranged facing each other with a required gap, and images are recorded on both sides of a recording sheet conveyed along a conveying path passing through the gap. In the apparatus, two endless conveyor belts, which are respectively disposed at both ends in the width direction of the recording sheet conveyed along the conveying path and hold the recording sheet from both sides, and these conveying belts in the conveying direction. An upstream pulley and a downstream pulley that are stretched at upstream and downstream positions and one pulley of the one end in the width direction and one pulley of the pulleys on the other end in the width direction are connected to each other. And a sheet conveying unit configured to convey the recording sheet, the upstream pulley having at least one end side in the width direction formed in a conical shape tapered outward in the width direction, the above The inkjet recording device is characterized in that the downstream pulley has a conical shape in which the side corresponding to the upstream pulley formed in a conical shape is tapered inward in the width direction. 2. The rotational force supply means is one downstream side of the downstream pulleys on one end side in the width direction and one downstream side pulley and the downstream pulleys on the other end side in the width direction of the downstream side pulley. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is connected to the pulley. 3. The ink jet recording apparatus according to claim 1 or 2, wherein the ink jet recording apparatus is stretched over a pulley which is formed in a conical shape and which corresponds to the upstream pulley and to which the rotational force supply means is connected. Speed detecting means for detecting the rotation speed of the conveyor belt, belt position moving means for moving the tension position of the conveyor belt with respect to the pulley, and the tension means when the detected rotation speed is higher than a predetermined level. Move the position to the tapered side of the pulley,
An inkjet recording apparatus comprising: a movement control unit that moves the tensioned position to a side opposite to the tapered side of the pulley when the tension is lower than a predetermined level.