JPH08217305A - Ink jet printer - Google Patents

Abstract

PURPOSE: To provide an ink jet printer by which the entering of the tip of a paper sheet toward a space staying between a head and a paper discharge roller couple, even when the paper sheet is curved, is prevented and the contact to the head and the block of the paper sheet are eliminated. CONSTITUTION: Between a printing part A for discharging an ink on the surface of a paper sheet to be carried and printing and the paper discharge roller couple 71, 72 for discharging the paper sheet printed by the printing part A, a guide roller 75 for guiding the paper sheet toward the discharge roller couple after contacting to this, when the paper sheet is curved, is provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to ink jet printers. In particular, it relates to the improvement of the paper discharge mechanism.

[0002]

2. Description of the Related Art As a conventional inkjet printer, one shown in FIG. 16 is known (Japanese Patent Laid-Open No. 4-3).
41848).

In FIG. 1, reference numeral 1 is a printing portion, which is formed by an ink jet head 2 and a paper guide member 6.

A paper feed roller 4 supplies the paper P to the printing section 1 by the paper feed roller 4.

An ink jet head (hereinafter also simply referred to as a head) 2 ejects ink while reciprocating in a direction orthogonal to the paper surface of FIG. 16, and prints on the surface of the paper P sent out from the paper feed roller 4. In addition, A is a printing area by the head 2.

The paper guide member 6 has a guide surface 6a that contacts the back surface of the paper P and guides the paper P.

The printed paper is ejected by the paper ejection roller pair 5.

[0008]

In the conventional ink jet printer described above, when the paper P warps in a concave shape in FIG. 16 for some reason, the front end of the paper P is located between the head 2 and the discharge roller pair 5. There is a risk of approaching a certain space S.

When the front end of the paper P enters into the space S, the printed surface of the paper P comes into contact with the head 2 and is rubbed. Further, when the leading edge of the sheet P is not finally guided to the paper discharge roller pair 5, the leading edge of the sheet P is clogged in the space S, which causes a paper jam condition.

The object of the present invention is to solve the above problems in advance, and even when the paper is warped, the leading edge of the paper can enter toward the space between the head and the paper discharge roller pair. Another object of the present invention is to provide an ink jet printer which is prevented and prevents paper from coming into contact with the head or jamming.

[0011]

In order to achieve the above-mentioned object, an ink jet printer according to a first aspect of the present invention is a printer for ejecting ink on the surface of a sheet to be conveyed for printing, and a sheet conveyer than the printing section. In an inkjet printer provided with a paper discharge roller pair for discharging the paper printed by the printing unit, which is arranged on the downstream side in the direction, when the paper is warped between the printing unit and the paper discharge roller pair, A guide roller is provided which is in contact with and guides the sheet toward the pair of discharge rollers.

An ink jet printer according to a second aspect is the ink jet printer according to the first aspect,
The paper is supplied to the printing unit via a curved paper path.

[0013]

According to the ink jet printer of the first aspect, the paper printed on the surface by the printing unit is ejected by the paper ejection roller pair.

At this time, even if the paper is warped, a guide is provided between the printing section and the paper discharge roller pair to guide the paper toward the paper discharge roller pair by coming into contact with the paper when the paper is warped. Since the rollers are provided, the guide roller surely guides the paper to the paper discharge roller pair.

That is, according to the ink jet printer of the first aspect, even if the paper is warped, the leading edge of the paper is prevented from entering toward the space between the head and the paper discharge roller pair, and the paper is thus prevented. Does not come into contact with the head or become clogged.

According to the ink jet printer of the second aspect, since the paper is configured to be supplied to the printing unit through the curved paper path, the size of the printer is smaller than that when the paper path is straight. Can be realized.

Since the paper path is curved, the front end of the paper tends to easily enter between the printing unit and the discharge roller pair. A guide roller is provided between the paper ejection roller pair to guide the paper toward the paper ejection roller pair when the paper is warped. Therefore, the guide roller surely ejects the paper. Guided by a pair of paper rollers.

That is, according to the ink jet printer of the second aspect, the size of the printer can be reduced, and at the same time, even when the paper is warped, the leading end of the paper is between the head and the pair of paper discharge rollers. It is possible to realize a printer in which the paper is prevented from entering toward the space and the paper does not come into contact with the head or jam.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view showing an internal structure of an embodiment of an ink jet printer according to the present invention, FIG. 2 is a partially omitted plan view showing the same internal structure, and FIG. 3 is a partially enlarged view of FIG.

First, an outline of this printer will be described.

In FIG. 1, reference numeral 10 denotes a printer main body, and 1
Reference numeral 1 is a case of the main body, and 20 is an automatic paper feeder incorporated in the main body 10.

The main body 10 is driven by the paper feed roller 30 and the paper feed roller 30 in pressure contact with each other along the paper path PP through which the paper P (see FIG. 3) fed by the automatic paper feeder 20 passes. The pinch roller 40, the regulation member 50 that guides the back surface of the paper P, the carriage 61 on which the inkjet head 60 that ejects ink droplets toward the paper and prints are mounted, and the characteristic parts of this embodiment. Guide roller 7
5, a pair of paper discharge rollers 71 and 72, and a discharge unit 80. Further, on the front surface of the main body 10, a paper discharge tray 90 for stacking the discharged paper is provided.

Paper P fed by the automatic paper feeder 20
(See FIG. 3) reaches the paper feed roller 30 through the paper path PP curved in a concave shape as a whole in FIG. 1, and the feed angle is defined by the pinch roller 40, and the paper feed roller 30 is fed out. First, the leading edge of the fed paper P also serves as a guide member.
0, and then as shown in FIG.
b is guided while abutting on the uppermost surface 51a of the rib 51 formed on the upper surface of the defining member 50, the distance from the inkjet head 60 is defined, and the surface P thereof is defined.
Ink is ejected from the head 60 onto a and printed. A
Is a print area and forms a print portion. The printed paper P has a pair of discharge rollers 71, 72 and a discharge section 80.
And is discharged onto the discharge tray 90.

Next, details of each unit will be described.

As shown in FIGS. 1 and 2, a main body 10 has a case 11 in which a bottom frame 12 made of a metal plate also serving as a shield plate, and left and right plastic stands erected on the bottom frame 12. Side frames 13, 14
And an intermediate frame 15 made of a metal plate, which is erected on the side frames 13 and 14, and a plastic sub-frame 16 fixed in place on each of the above frames.

The sub-frame 16 includes a bottom plate 16a forming a lower portion of the paper path PP, a back plate 16b, and side plates 16c and 16c 'integrally formed on the left and right sides of the bottom plate 16a and the back plate 16b. Is equipped with. That is, the bottom plate 16a, the back plate 16b, and the side plates 16c and 16c 'are integrally formed. A rib-shaped paper guide 16e is formed on the upper surface of the bottom plate 16a.

The automatic paper feeding device 20 includes two paper feeding rollers 2.
1, a hopper 22, an edge guide 23, and a paper feed tray 24.

The paper feed roller 21 is composed of a D-shaped roller having a rubber layer on the surface thereof, and is fixed to a grooved paper feed roller shaft 21a. The paper feed roller shaft 21a is rotatably supported by the side plates 16c and 16c 'of the sub-frame 16, and is rotationally driven at the time of paper feed by a transmission mechanism (not shown) that is interlocked with the drive mechanism 100.

The hopper 22 has a bottom plate 22a for supporting the lower surface of the sheet and side plates 22b, 22b integrally formed on the left and right above the bottom portion 22a (only one of which is shown in FIG. 1).
Similarly, triangular side plates 22c and 22c (only one of which is shown in FIG. 1) integrally formed on the lower left and right sides of the bottom portion 22a, and side plates 22b and 22c integrally projecting laterally. It is provided with pins 22d and 22d. The pins 22d, 22d are engaged with the long holes 16d, 16d formed in the side plate 16c of the sub-frame 16, so that the hopper 22 can move up and down in an oblique direction with respect to the sub-frame 16. It is possible to install. Hopper 22 and bottom plate 16a of sub-frame 16
A hopper spring 25 is provided between and, and the hopper 22 is biased obliquely upward by the hopper spring 25. The hopper spring 25 is used for the paper feed roller 2
Two are provided at positions corresponding to 1. The side plates 16c and 16c 'of the sub-frame 16 are provided with a cam mechanism (not shown) interlocking with the drive mechanism 100 for pushing down the hopper 22 against the spring force of the hopper spring 25.
Then, the hopper 22 is released from the pressing by the cam mechanism at the time of paper feeding, and is pushed up by the hopper spring 25 so as to push the paper toward the paper feeding roller 21, and is pushed down by the cam mechanism after the paper feeding is completed. Laura 2
The contact of the sheet with 1 is released.

The edge guide 23 has a bottom plate 23a, a bent portion 23b provided at the tip of the bottom plate 23a, a clip portion 23c provided at the rear end of the bottom surface, and a side plate 23d. The bent portion 23b is the groove 22 of the hopper 22.
It is slidably attached to the hopper 22 by engaging with e and elastically sandwiching the clip portion 23c so as to wrap the rear portion (upper end portion) of the hopper 22.

The edge guide 23 is for guiding the left side of a sheet (not shown) set on the hopper 22 in FIG. Subframe 1 is on the right side of the paper
6 is guided by the upper inner surface of the side plate 16c 'on the right side of 6.

As shown in FIG. 1, the paper feed tray 24 is attachable / detachable to / from the main body 10 by inserting an insert piece 24a formed in the lower portion thereof into an insert hole 11a provided in the case 11 of the main body 10. The bottom surface of the sheet is supported in cooperation with the hopper 22 in the attached state.

In the above-described work of setting the sheets in the automatic paper feeder 20, when the automatic paper feeder is not in operation, the hopper 22 is pushed down by the cam mechanism described above, so that a plurality of sheets are set. All you have to do is insert the paper from above.

Automatic paper feeder 2 with paper set
When 0 is operated, the hopper 22 is pushed up due to the release of the pressure by the cam mechanism, and only the uppermost sheet on the hopper comes into contact with the sheet feeding roller 21 and the sheet feeding path PP.
Is sent to.

The paper feed roller 30, as shown in FIG.
It is composed of two relatively long rubber rods fixed to the paper feed roller shaft 31 in the form of round rods. The paper feed roller shaft 31 is supported by the side frames 13 and 14, and is rotationally driven by the drive mechanism 100. When printing by the head 60, the paper P is printed between the lines every time the head 60 prints one line. Transport by minute.

The pinch rollers 40 are metal round bar rollers, and four rollers are provided for the paper feed roller 30. As shown in FIG. 3, the pinch roller 40 is
The shafts 40a at the both ends of the arm 40 of the holder 41
It is rotatably supported by a rectangular hole 42a formed in the same and is movable in the arrow X direction. Holder 4
1 also serves as a paper guide and forms the upper part of the paper path PP. As shown in FIGS. 1 and 2, a pair of hooks 44 is provided on the upper portion of the holder 41, and the holder 41 is swingably suspended by the hooks 44 with respect to the intermediate frame 15. A spring 45 is provided between the holder 41 and the intermediate frame 15, and the urging force of the spring 45 causes the pinch roller 40 to move.
Is a top portion 30a of the paper feed roller 30 as shown in FIG.
The sheet abuts on the sheet feeding roller 30 at a position a which is slightly deviated to the downstream side in the sheet conveying direction.

Therefore, in the pinch roller 40, the shafts 40a at both ends are movably supported in the arrow X direction by the rectangular holes 42a formed in the arm portion 42, and the top of the paper feed roller 30. The sheet feeding roller 30 is in contact with the sheet feeding roller 30 at a position a which is slightly deviated to the downstream side of the sheet conveying direction with respect to 30a.

The regulating member 50 is arranged on the back surface side of the paper P (see FIG. 3) conveyed by the paper feed roller 30, and as shown in FIG. It has a horizontal portion 51f that forms a rib and a rib 51 that integrally projects upward from the horizontal portion 51f. A plurality of ribs 51 are formed in a direction orthogonal to the conveyance direction of the paper P.

As shown in FIG. 3, the rib 51 has a slope 5
1b, an uppermost surface 51a connected to the inclined surface 51b, and a descending inclined surface 51d connected to the uppermost surface 51a are substantially trapezoidal in side view and extend in the sheet conveying direction.
The inclined surface 51b guides the leading end of the paper P fed by the paper feed roller 30, and the uppermost surface 51a contacts the back surface Pb of the paper to define the distance between the inkjet head 60 and the paper P.

Further, on the upstream side of the paper discharge roller pair 71, 72 in the paper carrying direction, it is located on the downstream side of the rib 51 in the paper carrying direction, and the leading end of the paper P is located at the paper discharge roller pair 71, 72.
A guide portion 51e that guides the vehicle toward is provided. The guide portion 51e is provided only in the vicinity of the upstream side of the paper discharge roller pair 71, 72, and is not provided in other parts.

The regulating member 50 is fixed to the bottom frame 12.

The ink jet head 60 is a head capable of performing color printing by ejecting a plurality of colors of ink, and is attached to the carriage 61 as shown in FIG. The carriage 61 has a guide shaft 62.
1 is guided by the guide shaft 62 and the upper edge 15a of the intermediate frame, and is driven by a carriage motor (not shown).
It reciprocates in the direction orthogonal to the paper surface of. On the carriage 61, a monochrome ink tank 63 and a color ink tank 64 are simultaneously mounted in a state of being arranged in a direction orthogonal to the paper surface of FIG.

As shown in FIG. 2, a plurality of paper discharge roller pairs 71 and 72 are arranged in the paper width direction (7 pairs shown). One roller 71 of the pair of discharge rollers 71, 72 is a rubber roller that is rotationally driven by the drive mechanism 100 via a transmission mechanism (not shown), and the other roller 72 is a serrated roller that is pressed against the roller 71 and is driven to rotate. Has been done. The shaft 71 a of the rubber roller 71 is rotatably supported by the side plate 52 of the regulation member 50. The knurled roller 72 is provided on the support plate 53 formed integrally with the regulation member,
It is rotatably supported around a round bar-shaped coil spring 73. As shown in FIG. 13, the serrated roller 72
Is pressed against the rubber roller 71 by the spring force of the coil spring 73. Therefore, the Giza roller 7
No. 2 is designed so that, when the paper P is a thick paper such as an envelope, it does not extremely press the paper and does not escape upward as shown in FIG.
The peripheral speed of the paper discharge roller pair 71, 72, that is, the paper conveyance speed is slightly increased as compared with the feed speed of the paper feed roller 30. Therefore, after the leading edge of the paper P reaches the paper discharge roller pair, the paper feed roller 30 and the transport roller pair 7
It is conveyed in such a state that it is stretched between 1, 72.

Then, the rib 51 of the regulating member 50 described above is used.
The uppermost surface 51a of the sheet P is slightly displaced toward the inkjet head 60 side from the position where the sheet passes if the ribs 51 are not provided.
It comes in contact with the back surface of the paper sheet by urging it to the side. In other words, the sheet P is pushed down with respect to the regulation member 51 by the paper feed roller 30, the pinch roller 40, and the pair of paper ejection rollers 71 and 72 through the regulation member 50. Are transported by
b is surely brought into contact with the uppermost surface 51a of the rib 51.

As shown in FIGS. 2 and 3, the guide roller 75 is rotatably attached to the tip of an arm portion 54 which is integrally formed on the lower rear portion of the support plate 53.
The guide roller 75 includes a printing section A and a pair of discharge rollers 71, 7
2 and is positioned between the sheet P and the sheet P as shown in FIG.
It is designed to lead toward 72. Further, the guide roller 75 moves the head 6 within a range in which the warped paper P can be guided.
The roller has a small diameter so that it is provided near 0. Further, as shown in FIG. 2, the guide roller 75 is provided at a substantially central portion in a plan view so as to correspond to the thickened portion of the envelope when folded. The guide roller 75 is made of water-repellent plastic.

The discharge section 80, as shown in FIGS.
Supporting pieces 81 and 82 for supporting both side portions of the sheet discharged by the pair of discharging rollers 71 and 72 from below are provided, and a pushing down portion 83 for pushing down the middle of the sheet downward.

One support piece 81 is composed of a fixed rib integrally formed with the regulating member 50.

As shown in FIGS. 5 to 7, the other support piece 82 has a shaft 82a integrally formed at its base.
The shaft 82a is attached to the slider 84 so as to be rotatable and movable back and forth (movable in the directions of arrows X1 and X2 in FIG. 5). The slider 84 will be described later in detail.

A hook 82b is integrally provided on the lower portion of the shaft 82a, and the hook 82b and the slider 8 are provided.
The tension spring 84 is provided between the hook 84b and the hook 84b.
a is provided. The tension spring 84a is provided on the support piece 8
2 is always biased in the direction of arrow X1. A locking portion 84c is formed on the front portion of the slider 84, and the locking portion 8c is formed.
The lower portion 82c of the support piece 82 is engaged and disengaged with a click operation with respect to 4c. The support piece 82 is
When the lower portion 82c is engaged with the locking portion 84c, it stands up like one of the support pieces 81, and when a certain amount of force on the upper portion thereof is applied from the left side or the right side, the lower portion 82c.
At the same time, the shaft 8
While 2a is moving in the direction of arrow X2, it is tilted to the left or right. The state where the support piece 82 is tilted to the left is shown by phantom lines in FIGS. 6 and 2.
2 can also fall to the right (see FIG. 7). Further, when the support piece 82 in the fallen state is lightly pinched and raised by the finger or the like, the support piece 82 is erected by the spring force of the tension spring 84a, and the lower portion 82c thereof is engaged with the locking portion 84c and erected. Is retained.

The slider 84 is slidably attached to the bottom frame 12, and its sliding operation is interlocked with the above-mentioned edge guide 23 of the automatic paper feeder 20 by an interlocking mechanism (described later). ing.

As shown mainly in FIG. 5, the slider 84 has a base portion 84d at its rear portion, and the base portion 84d is slidable with respect to the bent portion 12a at the front portion of the bottom frame 12. And a leg portion 84f guided by the upper surface 12b of the bottom frame 12 are formed. Slider 84
Are slidably supported with respect to the bottom frame 12 by these fitting portions 84e and legs 84f.
The upper surface 84g of the base portion 84d is slidably supported by the lower surface of the front plate 55 of the regulating member 50.

The interlocking mechanism includes the interlocking rod 110 shown in FIG.
A first pinion 111 integrally formed at the front portion of the interlocking rod 110, second pinion 112 and 112 integrally formed at the rear portion of the interlocking rod 110, and a first rack 56 that meshes with the first pinion 111. And a second rack 16f that meshes with the second pinion 112. The first rack 56 is formed on the lower surface of the hanging piece 57 of the regulating member 50, and the second rack 16 f is the bottom plate 1 of the sub-frame 16.
6a is formed on the lower surface of the rear portion.

As shown in FIGS. 5 and 8, the front portion of the first pinion 111, that is, the tip 113 of the interlocking rod is rotatably supported in the bearing hole 84h formed in the base portion 84d of the slider 84, and 1 near the rear of the pinion 111
14 is a rear upper surface 84 of the base portion 84d of the slider 84.
i and the lower surface 58a of the hanging piece 58 of the regulating member 50 are rotatably supported. The rear portion 114 of the first pinion 111 is also slidable in the direction orthogonal to the paper surface of FIG. 5 with respect to the lower surface 58a of the hanging piece 58 of the regulating member 50.

On the other hand, as shown in FIG. 1, the rear end 115 of the interlocking rod 110 is rollable by the lower bent portion 16g of the back plate 16b of the sub-frame 16 and the second pinion 1 is provided.
12 and the second rack 16f are supported so that a meshing force can be obtained. Then, as shown in FIG. 9, the rear portion 116 of the second pinion 112 is rotatably engaged with the recess 26 a formed in the lower portion of the connecting plate 26.

The upper part 26b of the connecting plate 26 is fixed to the edge guide 23 and moves together with the edge guide 23.

Therefore, when the edge guide 23 is slid on the hopper 22 when the paper is set in the automatic paper feeder 20, the second rack 16f and the second rod of the interlocking rod 110 are moved.
At the same time as the interlocking rod 110 rolls in a direction orthogonal to the paper surface of FIG. 1 by meshing with the pinion 112, the first pinion 1
11 and the first rack 56 mesh with each other, the tip 113 of the interlocking rod 110 is reliably moved by the same distance as the rear end 115 without being affected by the bending of the interlocking rod 110, and the slider 84, that is, the support piece 82. Is edge guide 2
It will move the same distance as 3.

As described above, the support piece 82 is the edge guide 2
It surely moves in the same distance as the edge guide 23 in conjunction with 3 (see the phantom line in FIG. 2).

The support piece 82 is formed in a substantially triangular shape, and in the state of standing upright as shown in FIGS. 1 and 5, the guide surface 82 inclined upward in the paper discharge direction.
d. The support piece 81 is also formed in a substantially triangular shape, and has a guide surface 81d (see FIG. 2) that is inclined upward in the paper discharge direction.

The push-down portion 83 is composed of a serrated roller, and is rotatably supported by a holder 83a rotatably attached to the support plate 53, as shown in FIG. The holder 83a has a guide side 83 with which the leading end of the paper P ejected by the paper ejection roller pair 71, 72 abuts.
b. When the leading edge of the sheet comes into contact with the guide side 83b, the holder 83a is lifted by the sheet and rotates in the direction of the arrow Y in FIG. To guide you.

According to the ink jet printer as described above, the following operational effects can be obtained.

(I) When setting the paper, the hopper 2
2 can be set simply by inserting paper along the paper feed tray 24 and the paper feed tray 24.

At this time, the size of the paper to be set is changed (for example, A4 size is changed to B5 size), and the edge guide 23 is slid so that the side plate 23d of the edge guide 23 is brought into contact with the left edge of the changed paper. Then, by the above-mentioned operation of the interlocking mechanism, the support piece 8 of the discharge portion 80 is
2 will also slide.

(Ii) By the operation of the printer, the automatic paper feeder 20 operates to feed the paper to the paper feed path PP,
When reaching the paper feed roller 30, the feed angle is regulated by the pinch roller 40, and the paper is fed out from the paper feed roller 30.

At this time, as described above, the pinch roller 40 is used.
Is pressed against the paper feed roller 30 with the self-centering function, so that skewing of the paper is prevented.

(Iii) As shown in FIG. 3, the leading edge of the paper P fed by the paper feed roller 30 is the regulating member 5.
The inclined surface 51b of 0 is guided so as to be scooped, and the back surface Pb of the rib 51 abuts the uppermost surface 51a of the rib 51 to define the distance from the inkjet head 60, and the head 60 ejects ink onto the surface Pa. After being printed and printed, the leading edge of the paper is ejected by a roller pair 7
It will be heading to 1,72.

Here, as shown in FIG. 4, even if the paper P is warped relatively largely, the guide roller 75 is provided between the head 60 and the paper discharge roller pair 71, 72. The guide roller 75 ensures that the paper P is guided to the paper discharge roller pair 71, 72.

That is, even when the paper P is warped, the leading edge Pf of the paper is prevented from entering toward the space S between the head 60 and the pair of discharge rollers 71 and 72, and the paper P is head 60. It will not come into contact with or become clogged.

In FIG. 4, the phantom line indicates the head 6 located above when printing on thick paper such as an envelope.
In this case, the head 60 is shown.
Since the distance between the lower surface (nozzle opening surface, that is, the ink ejection surface) 60a of the sheet and the regulating member 50 becomes large, the leading edge Pf of the sheet is directed toward the space S between the head 60 and the pair of discharge rollers 71 and 72. Although it tends to enter easily, even in such a case, the space S where the leading edge Pf of the sheet is between the head 60 and the pair of discharge rollers 71 and 72.
Is surely prevented from approaching toward.

Further, in the printer of this embodiment, since the paper P is supplied to the printing section A through the curved paper path PP, the printer is more straight than the case where the paper path is straight. Can be miniaturized.

Although the paper path PP is curved, the leading edge Pf of the paper tends to easily enter the space S between the head 60 and the pair of paper discharge rollers 71 and 72, but As described above, the paper P is reliably guided to the paper discharge roller pair 71, 72 by the guide roller.

(Iv) The conveyed paper P has its back surface P
When b comes into contact with the rib 51 of the regulating member 50, the distance from the head 60 is regulated and printing is performed.

Since the rib 51 extends in the paper P conveyance direction, the rib 51 does not hinder the paper conveyance.

Since a plurality of ribs 51 are formed in the direction orthogonal to the paper transport direction, ink dots are formed at a high density on the paper P, and even when the paper P is wavy due to the water content of the ink. The bulge of the sheet acts so as to enter the space 51s (see FIG. 10C) between the ribs 51.

Therefore, even if the paper P is wavy, the paper P does not come into contact with the head 60 and rub against it.

Regarding this point, FIGS. 10 (a), (b) and (c)
Will be described in detail with reference to. 10 (a) (b) (c)
[Fig. 3] is a schematic front view for explaining the operation in an easy-to-understand manner.

In FIG. 7A, L is the ideal distance between the head 60 and the sheet when the sheet P is not wavy. As shown in FIG. 10A, if the rib is not formed on the defining member and the flat portion 51f defines the distance between the paper P and the head 60 to be the ideal distance L, the paper will be wetted by the water content of the ink. When P is wavy, the ridge Pc of the wavy paper P and the ink ejection surface 60a of the head 60 may be rubbed.

In order to solve such a problem, FIG.
As shown in 0 (b), it is conceivable to set the distance between the head 60 and the flat surface portion 51f to be a large distance L1.

However, if the distance is increased, and if the paper is flat without waviness, the distance between the paper and the head guided by the flat portion 51f (that is, substantially the same distance as L1) becomes too large. Another problem arises in that the ideal print state cannot be obtained. This is because the distance between the ink droplets ejected from the head 60 and the landing on the paper becomes large, so that the error between the ideal landing point and the actual landing point becomes large.

On the other hand, according to this embodiment, as shown in FIG.
As shown in (c), since the paper is guided by the ribs 51, in the normal case where the printing density is relatively low, that is, when the paper is not wavy, the flat paper P ′ is provided with the ribs 51. In the case where the distance between the paper and the head 60 can be set to an ideal distance L by guiding on the upper surface of the paper, ink dots are formed on the paper P at a high density, and the water of the ink causes the paper P to wavy. In addition, since the bulge (valley Pd) of the paper acts so as to enter the space 51s between the ribs 51 by its own weight, even if the paper P corrugates, its peak Pc contacts the head 60. No more rubbing.

Further, among the roller pair single units 71 and 72 constituting the conveying roller, the rubber rollers 71 arranged below the paper are arranged in plural in the paper width direction, not by one long round bar roller. It is composed of short rollers. Therefore, the swelling (valley portion Pd) of the corrugated sheet containing the water content of the ink hangs more effectively. It is desirable that the width of the rubber roller 71 be set as small as possible within a range in which the sheet conveying force is not significantly reduced. As shown in FIG. 11A, if the rubber roller is a long roller 71 ′, the valley portion Pd of the corrugated paper P rides on the roller 71 ′, and the serrated roller 7 ′ is formed.
This is because even if the paper is pressed by 2, the mountain portion Pc will be in a floating state.

Therefore, as shown in FIG. 11B, the width W of the rubber roller 71 in this embodiment is set smaller than the corrugated pitch P1 of the corrugated paper. As a result, the valley portion Pd of the corrugated paper hangs more effectively.

(V) When the paper P reaches the paper discharge roller pair 71, 72, the paper P is fed by the paper feed roller 30 and the paper discharge roller pair 7.
Since it is in a state of being stretched between 1 and 72, even if the ink dots are formed at high density on the paper P and the paper P is wavy by the water content of the ink, the bulge of the paper P is It is reduced by the tension acting on the paper P. Furthermore, since the regulating member 50 contacts the back surface Pb of the paper P by urging the paper P toward the inkjet head, the bulge of the paper P should be positioned relatively away from the head 60. Will be done.

Therefore, even if the paper is wavy, the paper does not come into contact with the head and rub against it.

Moreover, as described above, since the bulge of the sheet acts so as to enter the space 51s between the ribs 51, it is more reliable that the corrugated sheet P comes into contact with the head 60 and rubs against it. To be prevented.

(Vi) Since the rib 51 is substantially trapezoidal in side view, the following operational effects (a) and (b) are further provided.
Is obtained.

(A) The type of printer, for example, in a serial printer which receives print data in units of one line from the host computer and prints every line,
It may be necessary to transport the paper in the reverse direction (ie, reverse feed).

For example, when a certain standard character is printed and then an enlarged character is printed on the next line, and the top of the enlarged character is located above the top of the standard character printed on the preceding line, the paper After being conveyed in the opposite direction, division printing is performed by repeating the printing by scanning the head and the paper feeding for the length of the printing area A shown in FIG. 3 a plurality of times to form enlarged characters. In such a case, it is necessary to send the paper back.

If the rib is not trapezoidal in side view but is rectangular in side view (see 51 ″ in FIG. 12 (a)), a portion (eg, an envelope of an envelope) that inhibits backward feeding is provided on the back surface of the sheet. If there is a flap or the like), that portion may be caught by the rib during the backward feeding, which may cause a pitch defect, that is, a misalignment in the distance between the rows to be fed backward and the feeding amount in the forward direction immediately after that.

On the other hand, according to the ink jet printer of the present embodiment, the ribs 51 are substantially trapezoidal in side view, so that even if the envelope or the like is sent backward, the flap or the like does not get caught, and therefore, It also eliminates pitch defects.

(B) As shown in FIG.
When printing is performed in the vicinity of the leading end of the paper, the vicinity of the leading end of the paper may be curved as shown in FIG.

In such a case, assuming that the rib 51 ″ has a shape as shown in FIG. 12A, the sheet is not fed until the front end Pf of the sheet reaches the pair of discharge rollers 71, 72. Since the front end Pf of P is supported by the upper surface of the rib 51 ″, the paper is easily floated and the head is easily rubbed.

On the other hand, since the rib 51 of this embodiment has a substantially trapezoidal shape in side view, the leading edge Pf of the sheet comes off immediately from the uppermost surface 51a of the rib as shown in FIG. 12 (b). Therefore, the floating of the paper P is reduced and the head is less likely to rub.

(Vii) The upstream side of the paper discharge roller pair 71, 72 in the paper transport direction is located downstream of the rib 51 in the paper transport direction, and the front end of the paper P is discharged by the paper discharge roller pair 71, 72.
Since the guide portion 51e for guiding toward the 72 is provided, the leading end of the paper P is surely ejected by the pair of paper ejection rollers 71, 7 even though the rib 51 is formed in a substantially trapezoidal shape in a side view.
You will be guided toward 2.

Since the guide portion 51e is provided only in the vicinity of the upstream side of the paper discharge roller pair 71, 72 and is not provided in other parts, the leading end of the paper P is surely discharged. , 72, and at the same time, the sheet P is reliably prevented from abutting and rubbing against the head 60.

(Ix) When color printing is performed by ejecting a plurality of colors of ink from the head 60, since ink dots are further formed on the ink dots, the wavy state of the paper becomes particularly large. Did (iv) ~
Due to the action of (vii), the corrugated paper P is fed to the head 60.
It is surely prevented from abutting against and rubbing.

(Ix) As shown in FIG. 5, when the leading edge Pf of the sheet P discharged by the pair of sheet discharging rollers 71 and 72 comes into contact with the guide side 83b of the holder 83a, the center of the sheet leading edge Pf in the width direction is measured. In the meantime, while rotating the holder 83a in the direction of the arrow Y in FIG.
On the contrary, it is guided by the serrated roller 83 so as to be pushed down by the guide side 83b.

At the same time, both side portions of the leading edge Pf of the sheet are gradually guided upward by the inclined surfaces 81d and 82d of the support pieces 81 and 82.

Therefore, the paper P is gradually discharged from the leading end portion thereof while being forcibly biased into a concave shape in which the printing surface is dented when viewed from the discharge direction.

FIG. 13 shows a schematic view of the state where the paper P is being discharged.

As shown in this figure, when the paper P is forcibly biased in a concave shape when viewed from the discharge direction, the paper P becomes stiff and is conveyed in a floating state. Therefore, as shown in FIG. 13, the ejected paper P is printed on the printing surface P1 of the paper P1 which has been previously printed, ejected, and stacked.
The time until sliding contact with a is delayed, and the printed paper P1
The time for the ink to dry is secured.

When the sheet P is further conveyed and the rear end of the sheet passes the pair of discharge rollers 71 and 72, the conveying force is lost, and the rear end of the sheet is held by the discharge section 80 in the concave shape.

Then, as shown in FIG. 14, the succeeding paper P2 is printed, and the leading end P2f of the paper P2 is the discharge roller pair 71,
By passing the sheet 72 and hitting the trailing edge Pr of the preceding sheet P, the holding of the preceding sheet P by the discharge unit 80 is released. When the preceding paper P is pushed by the succeeding paper P2, its holding is released and it is stacked on the preceding printed paper (P1 in FIG. 13). Time is further delayed.

After the leading edge P2f of the succeeding sheet P2 is applied to the trailing edge Pr of the preceding sheet P to release the holding of the preceding sheet P, the conveyance of the succeeding sheet P2 is temporarily stopped. This stopping operation can be performed by counting the number of pulses of the motor that drives the pair of discharge rollers 71 and 72, and stopping the driving of the motor when the number of pulses reaches a predetermined number. As described above, the leading edge P2f of the succeeding sheet P2 is the trailing edge Pr of the preceding sheet P.
When the method of pushing out the preceding paper P by hitting it against the paper is adopted, the leading edge P2f of the succeeding paper P2 and the trailing edge Pr of the preceding paper P are engaged with each other, and the printed paper ahead of the preceding paper P is printed. The stacking operation (dropping operation) on P1 (see FIG. 13) may become uncertain, but by temporarily stopping the conveyance of the succeeding paper P2, the inertia of the preceding paper P is utilized. , The leading edge P2 of the following paper
The engagement between f and the trailing edge Pr of the preceding sheet can be reliably released.

Since the operation of the discharge section 80 is as described above, when the size of the paper to be printed is changed (for example, when the A4 size is changed to the B5 size), both sides of the paper are surely supported. In order to be guided by the pieces 81 and 82, it is necessary to move one support piece 82 in accordance with the size of the paper.

In this regard, according to the present embodiment, when the paper to be printed is set in the automatic paper feeder 20, the size of the paper to be set is changed (for example, A4 size is changed to B5 size) and the edge guide is set. When the edge guide 23 is slid to bring the side plate 23d of 23 into contact with the left side edge of the changed sheet, the support piece 82 of the discharge section 80 also slides due to the above-described operation of the interlocking mechanism.

Therefore, it is possible to save the labor of sliding the support piece 82 separately from the operation of the edge guide 23, and at the same time, it is possible to always obtain an appropriate paper discharge operation.

(X) When printing on a paper having a small width such as a postcard, the edge guide 23 is a side plate of the sub-frame forming the other edge guide as shown by the phantom line in FIG. 16c 'is approached. When the edge guide 23 is slid from the position shown by the solid line in FIG. 2 to the position shown by the virtual line, the support piece 82 passes through the push-down portion 83, but the support piece 82 is rotatable as described above. Therefore, when the support piece 82 passes through the push-down portion 83, it comes into contact with the push-down portion 83 and falls down as shown by the solid line in FIG. 7.

Therefore, the support piece 82 is not damaged.

Further, in the paper discharging operation of the paper Ph having a small width such as a postcard, as shown in FIG. 15, the paper Ph is supported and discharged by only one supporting piece 81. If the paper having a small width, particularly a relatively thick paper such as a postcard, is ejected by supporting both sides thereof with supporting pieces 81 and 82 as shown in FIG. This is because it is difficult to obtain the curved state of the sheet shown, and the pushing action of the preceding sheet by the succeeding sheet cannot be reliably obtained.

For this reason, in the present embodiment, as shown in FIG. 15, for paper such as postcards, only one supporting piece 81 is supported to put the paper Ph in a cantilever state, and the trailing edge of the preceding paper is set. The edge Phr and the leading edge Ph2f of the succeeding sheet are surely brought into contact with each other.

According to this embodiment, when the edge guide 23 is slid from the position shown by the solid line in FIG. 2 to the position shown by the phantom line, when the support piece 82 passes through the push-down portion 83, the solid line shown in FIG. Since it automatically falls as shown, the above-mentioned cantilever state is automatically obtained.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be appropriately made within the scope of the gist of the present invention.

For example, in the above embodiment, the guide roller 7
Although only one 5 is provided at a position corresponding to the folded back portion (thick portion) of the envelope, a plurality of sheets may be provided because the entire sheet may swell.

Further, in the above embodiment, the guide roller 75
Was made of water-repellent plastic, but it is also possible to use a serrated roller. The use of the knurled roller is more effective in that the printed surface does not become dirty.

[0116]

According to the present invention, even if the paper is warped, the leading end of the paper is prevented from entering toward the space between the head and the pair of paper discharge rollers, and the paper comes into contact with the head. It is possible to obtain an effect that it does not get stuck or jammed.

[0117]

[Brief description of drawings]

FIG. 1 is a side sectional view showing an internal structure of an embodiment of an inkjet printer according to the present invention.

FIG. 2 is a partially omitted plan view showing the internal structure of the same.

FIG. 3 is a partially enlarged view of FIG.

FIG. 4 is a partially enlarged view of FIG.

5 is a partially enlarged view of FIG.

6 is a plan view mainly showing a support piece, and a plan view with parts omitted in FIG. 5;

FIG. 7 is an enlarged front view mainly showing a support piece.

FIG. 8 is a view on arrow VIII in FIG.

FIG. 9 is a rear view of the connecting plate.

10 (a), (b) and (c) are schematic front views for easily explaining the operation.

11A and 11B are schematic front views for easily explaining the operation of the discharge roller portion.

12A and 12B are schematic side views for explaining the action of the ribs in an easy-to-understand manner.

FIG. 13 is an explanatory perspective view of a paper discharge operation.

FIG. 14 is an explanatory perspective view of a paper discharge operation.

FIG. 15 is an explanatory perspective view of the paper discharge operation.

FIG. 16 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 A printing unit P paper 71, 72 paper discharge roller pair 75 guide roller

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 9, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art As a conventional ink jet printer, one shown in FIG. 17 is known (Japanese Patent Laid-Open No. 4-3).
41848).

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

An ink jet head (hereinafter also simply referred to as a head) 2 ejects ink while reciprocating in a direction orthogonal to the paper surface of FIG. 17 , and prints on the surface of the paper P sent out from the paper feed roller 4. In addition, A is a printing area by the head 2.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

In the conventional ink jet printer described above, when the paper P warps concavely in FIG. 17 for some reason, the leading edge of the paper P is between the head 2 and the paper discharge roller pair 5. There is a risk of approaching the space S at.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0100

[Correction method] Change

[Correction content]

[0100] shows a schematic view of a state where the sheet P is being discharged in Figure 1 4.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0101

[Correction method] Change

[Correction content]

As shown in this figure, when the paper P is forcibly biased in a concave shape when viewed from the discharge direction, the paper P becomes stiff and is conveyed in a floating state. Therefore, as shown in FIG. 1 4, the sheet P to be discharged, the printing surface of the paper P1 are stacked is discharged printed previously P1
The time until sliding contact with a is delayed, and the printed paper P1
The time for the ink to dry is secured.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0103

[Correction method] Change

[Correction content]

[0103] Then, the succeeding sheet P2 is printed as shown in FIG. 1 5, the tip P2f sheet discharge roller pair 71,
By passing the sheet 72 and hitting the trailing edge Pr of the preceding sheet P, the holding of the preceding sheet P by the discharge unit 80 is released. Preceding paper P, the the holding is to be stacked on the printing paper sheet in the released earlier (P1 in FIG. 1. 4), sliding contact with the print paper sheet when pressed in the succeeding sheet P2 Until the time is further delayed.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0104

[Correction method] Change

[Correction content]

After the leading edge P2f of the succeeding sheet P2 is applied to the trailing edge Pr of the preceding sheet P to release the holding of the preceding sheet P, the conveyance of the succeeding sheet P2 is temporarily stopped. This stopping operation can be performed by counting the number of pulses of the motor that drives the pair of discharge rollers 71 and 72, and stopping the driving of the motor when the number of pulses reaches a predetermined number. As described above, the leading edge P2f of the succeeding sheet P2 is the trailing edge Pr of the preceding sheet P.
When the method of pushing out the preceding paper P by hitting it against the paper is adopted, the leading edge P2f of the succeeding paper P2 and the trailing edge Pr of the preceding paper P are engaged, and the printed paper ahead of the preceding paper P P1 it is possible (Fig. 1 4 reference) laminating operation onto (darken operation) becomes uncertain, by temporarily Tomaue the conveyance of the succeeding sheet P2, utilizing the inertia of the preceding sheet P Then, the leading edge P2 of the succeeding sheet
The engagement between f and the trailing edge Pr of the preceding sheet can be reliably released.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0110

[Correction method] Change

[Correction content]

Further, in the paper discharge operation of the paper Ph having a small width such as a postcard, as shown in FIG. 16 , the paper Ph is supported and discharged by only one supporting piece 81. . Small paper width, in particular a relatively heavy paper as such postcards, if as shown in FIG. 1 5, Then was adapted to discharge the paper to support the both sides of the support pieces 81 and 82, FIG. This is because it is difficult to obtain the curved state of the sheet shown in (3), and the pushing action of the preceding sheet by the succeeding sheet cannot be surely obtained.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0111

[Correction method] Change

[Correction content]

For this reason, in this embodiment, as shown in FIG. 16 , for paper such as postcards, only one supporting piece 81 is supported to put the paper Ph in a cantilevered state, and the paper Ph The edge Phr and the leading edge Ph2f of the succeeding sheet are surely brought into contact with each other.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a side sectional view showing an internal structure of an embodiment of an inkjet printer according to the present invention.

FIG. 2 is a partially omitted plan view showing the internal structure of the same.

FIG. 3 is a partially enlarged view of FIG.

FIG. 4 is a partially enlarged view of FIG.

5 is a partially enlarged view of FIG.

6 is a plan view mainly showing a support piece, and a plan view with parts omitted in FIG. 5;

FIG. 7 is an enlarged front view mainly showing a support piece.

FIG. 8 is a view on arrow VIII in FIG.

FIG. 9 is a rear view of the connecting plate.

10 (a), (b) and (c) are schematic front views for easily explaining the operation.

11A and 11B are schematic front views for easily explaining the operation of the discharge roller portion.

12A and 12B are schematic side views for explaining the action of the ribs in an easy-to-understand manner.

13 (a) and 13 (b) are explanatory views of the knurled roller.
View.

FIG. 14 is an explanatory perspective view of a paper discharge operation.

FIG. 15 is an explanatory perspective view of the paper discharge operation.

FIG. 16 is an explanatory perspective view of the paper discharge operation.

FIG. 17 is an explanatory diagram of a conventional technique.

[Explanation of Codes] A printing unit P paper 71, 72 paper discharge roller pair 75 guide roller

Claims (2)

[Claims] 1. A printing unit for ejecting ink onto the surface of a conveyed sheet for printing, and a discharge roller arranged downstream of the printing unit in the sheet conveying direction for discharging the sheet printed by the printing section. In an inkjet printer having a pair, a guide roller is provided between the printing unit and the pair of discharge rollers to guide the sheet toward the pair of discharge rollers when the sheet is warped. Inkjet printer characterized by. 2. The ink jet printer according to claim 1, wherein the paper is supplied to the printing unit via a curved paper path.