JPH08318620A - Ink-jet printer - Google Patents

Abstract

PURPOSE: To smoothly discharge a sheet of paper even if it is stiff one and prevent jagged marks on the surface of the paper from being conspicuous by a method wherein both sides of the printed paper are supported from below by driven rollers that rotate as they touch the paper. CONSTITUTION: A paper outlet H is equipped with a pair of supporting devices to support both sides of a sheet of paper P from below and a press-down part. The respective supporting devices have a driven roller 80 that rotates as it touches the paper P. The driven rollers 80 are provided in a pair so as to support both sides of the paper P from below when the paper P is discharged. Supporting members 52c are erected on a base 52b that is formed as an integral part of a restricting member 50, and a spindle 81 of the driven rollers 80 is supported on the supporting members 52c so that the driven rollers 80 can be freely rotated even by a very small power. A guide plates 82 integrally erected from the base 52b is lead the front end of the paper P to the driven rollers 80.

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 unit.

[0002]

2. Description of the Related Art In general, an ink jet printer is designed to eject ink onto a sheet for printing.
When printing on multiple sheets of paper continuously, if the next paper is ejected before the ink on the printed paper dries and comes into sliding contact with the printed surface of the printed paper, the printed surface of the printed paper becomes dirty. There is a problem that it will end up.

As an attempt to solve such a problem, an ink jet printer described in JP-A-6-91861 is known.

FIG. 3 is a perspective view showing the paper discharge section of this printer.

The ejecting section 1 has an ink jet head 60 '.
Both side supporting portions 2 and 2 for guiding and guiding both side portions of the paper P printed and discharged on the upper surface by the above from below.
And a push-down portion 3 for pushing down the central portion of the paper.

The both-sides supporting portion 2 is composed of a fixed rib integrally formed with the frame 4, and an upper surface 2a thereof is inclined upward in the paper discharge direction.

The depressing portion 3 is composed of a serrated roller, and is rotatably supported by an arm 3a rotatably attached to a frame (not shown).

Reference numeral 6 denotes a paper discharge roller, which is a roller that comes into contact with the printing surface of the paper after printing, and is therefore a serrated roller. Below the serrated roller 6, a rubber roller (driving roller) 7 for contacting the back surface of the sheet and applying a conveying force to the sheet is provided. The notched roller 6 presses the paper against the rubber roller 7 by an urging member (not shown).

The discharge operation of the printer as described above is as follows.

(I) When printing is performed on the paper P and the paper P enters the discharge section 1, both side portions thereof are gradually guided upward by the upper surfaces 2a of the both-side support portions 2 and supported. At the same time, the central portion of the paper gradually pushes up the push-down portion 3 while rotating the arm 3a upward, but conversely, the central portion of the paper gradually enters below the push-down portion 3 to push down the push-down portion 3 and the arm 3a. It will be pushed down compared to both sides due to the weight of.

In this way, the paper P is gradually discharged from the leading end thereof while being forcibly bent into a concave shape in which the printing surface is depressed when viewed from the discharge direction. It should be noted that such a concave shape of the sheet may occur due to the weight of the sheet even if the pressing portion 3 is not necessarily provided.

(Ii) When the paper P is forcibly bent into a concave shape when viewed from the discharge direction, the rigidity of the paper P becomes strong and the paper P is conveyed in a floating state. Therefore, as shown in FIG. 4, the ejected paper P is printed and ejected first, and the printing surface P1 of the paper P1 that is ejected and stacked on the ejection tray 5 is printed.
The time until sliding contact with f is delayed, and the printed paper P1
The time for the ink to dry is secured.

(Iii) The paper P is further conveyed, and as shown in FIG.
As shown in FIG. 3, when the trailing edge Pb passes the sheet discharge roller 6, the carrying force is lost, and the trailing edge portion Pc of the sheet is held by the discharging section 1 in a concave shape.

(Iv) The succeeding paper P2 is printed, and as shown in FIG. 5, the leading end P2a of the preceding paper P passes through the paper discharge roller 6 and hits the trailing end Pb of the preceding paper P. The holding by the discharging unit 1 is released (the released state is shown in FIG. 6). The preceding sheet P is released from its holding when it is pushed by the succeeding sheet P2 and is stacked on the preceding printed sheet (P1 in FIG. 4). Time is further delayed.

[0015]

In the printer having the above-described paper discharge structure, when printing is attempted on a relatively strong paper such as an envelope or a postcard and the paper is to be discharged, the supporting surface of the supporting portion 2 is used. Since 2a is located at a relatively high position with respect to the discharged paper, it has a great resistance to the discharged paper in a state that it is stiff and therefore difficult to bend, and the feeding accuracy of the paper is reduced, and the print quality may be deteriorated. was there. Further, in some cases, it may be impossible to eject the paper itself.

In order to solve such a problem, the biasing force of the biasing member for biasing the serrated roller 6 is increased,
It is conceivable that the pressure contact force with respect to the rubber roller 7 is increased to increase the conveying force. However, if the biasing force by the notch roller 6 is increased, the notch marks are formed on the surface of the paper (printing surface) in a dotted line shape, and the print quality deteriorates. Is not desirable. For paper with a glossy surface (glossy paper),
This is especially undesirable because the marks are noticeable.

The object of the present invention is to solve the above-mentioned problems, and even in the case of discharging a strong sheet, the sheet can be smoothly discharged, the feeding accuracy of the sheet does not deteriorate, and the sheet is not discharged. An object of the present invention is to provide an ink jet printer having no noticeable dent marks on the surface.

[0018]

In order to achieve the above object, an ink jet printer according to a first aspect of the present invention comprises a pair of supporting means for supporting both side portions of a sheet printed and discharged on the upper surface by an ink jet head from below. The pair of supporting means are constituted by driven rollers that rotate in contact with the sheet.

[0019]

According to the ink jet printer of the first aspect, the paper printed on the upper surface by the ink jet head and ejected is ejected while the both side portions thereof are supported by the pair of supporting means.

Since the pair of supporting means are composed of driven rollers which rotate in contact with the paper, the resistance against the discharged paper is significantly reduced.

Therefore, even if the pair of supporting means is located at a relatively high position with respect to the sheet to be ejected and the ejected sheet is a relatively strong sheet, the sheet is ejected smoothly. The feed accuracy does not decrease.

Therefore, since it is not necessary to increase the pressure contact force of the paper discharge roller, crease marks are not conspicuously left on the paper, and the print quality is not deteriorated.

[0023]

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 diagram showing a main part of an embodiment of an ink jet printer according to the present invention. FIG. 1 (a) is a partially cut side view, and FIG. 1 (b) is a partially omitted b arrow view in FIG. 1 (a). is there.

In FIG. 1, reference numeral 30 denotes a paper feed roller, which is composed of a rubber roller or the like, and is rotationally driven by a drive mechanism (not shown).

Reference numeral 40 denotes a pinch roller, which is composed of a metal roller or the like, and is brought into pressure contact with the paper feed roller 30 and is driven to rotate.

The paper P is fed toward the pressure contact portion between the paper feed roller 30 and the pinch roller 40 by a paper feed means such as an automatic paper feed device (not shown). The sheet 30 and the pinch roller 40 are pressed against each other and conveyed.

Reference numeral 50 is a regulating member which guides the back surface of the paper P and at the same time regulates the distance between the ink jet head 60 and the paper P. The regulating member 50 has a horizontal portion 51f and a rib 51 integrally projecting upward from the horizontal portion 51f on the upper surface thereof. A plurality of ribs 51 are formed in a direction orthogonal to the transport direction of the paper P (direction orthogonal to the paper surface of FIG. 1).

Paper P sent out from paper feed roller 30
First, the tip is guided by the defining member 50,
Next, the back surface is guided while abutting against the uppermost surface 51a of the rib 51 formed on the upper surface of the regulation member 50, thereby defining the distance from the inkjet head 60, and the ink from the head 60 on the front surface (upper surface). Are ejected and printed.

The head 60 is mounted on a carriage (not shown) and prints while reciprocating in a direction orthogonal to the paper surface of FIG.

When the head 60 prints, the paper feed roller 30 conveys the paper P by a space between lines every time the head 60 prints one line.

71 and 72 are a pair of paper discharge rollers, and a plurality of pairs are arranged in the paper width direction (direction orthogonal to the paper surface of FIG. 1). One roller 71 of the pair of discharge rollers 71 and 72 is a rubber roller that is rotationally driven by a drive mechanism (not shown), and the other roller 72 is a serrated roller that is pressed against the roller 71 and is driven to rotate. Rubber roller 71
The shaft 71a is rotatably supported by the side plate 52 of the regulating member 50. The serrated roller 72 is rotatably supported by a support member (not shown) about a round bar-shaped coil spring 73. As shown in FIG. 2, the serrated roller 72 is pressed against the rubber roller 71 by the spring force of the coil spring 73. Therefore, when the paper P is a thick paper such as an envelope, the serrated roller 72 does not extremely press the paper and does not escape upward as shown in FIG. 2B to reduce the paper feeding accuracy. . 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, the paper P is conveyed in a state in which it is stretched between the paper feed roller 30 and the paper discharge roller pair 71, 72 after the leading edge of the paper P reaches the paper discharge roller pair.

In FIG. 1, H is a paper discharge unit,
It has a pair of supporting means 80 for supporting both side portions of the discharged paper P from below, and a push-down portion (not shown in FIG. 1) similar to the push-down portion 3 shown in FIG.

The supporting means 80 is a driven roller which rotates in contact with the paper P. The driven roller 80
Are provided so as to support both side portions of the discharged sheet from below, but only one is shown in FIG.

The driven roller 80 is supported such that its shaft 81 can freely rotate even with a slight force with respect to a support portion 52c which is erected on a base portion 52b formed integrally with the regulating member 50. ing.

Reference numeral 82 is a guide plate, which is integrally erected from the base portion 52b.

The guide plate 82 has a different role from that of the conventional two-sided supporting portion 2 shown in FIG. 3, and is for guiding the leading end of the sheet to the driven roller 81.

Therefore, the height of the guide plate 82 is formed to be relatively low, and at least, it is formed to be lower than the line t connecting the upper part of the paper discharge rubber roller 71 and the upper part of the driven roller 80. . Therefore, the guide plate 82 hardly acts as a resistance against the discharged paper.

The driven roller 81 is located on the inner side in the paper width direction than the furthest edged serrated roller 72 'of the serrated rollers 72 arranged in a direction orthogonal to the paper surface of FIG. In the conventional printer shown in FIG. 3, the supporting surface 2a is at the same position in the paper width direction (on an extension line in the paper transport direction) as the serrated roller 6'contacting the upper side portion of the paper P as shown in FIG. Was configured to be. For this reason, the side edge Pe of the sheet is raised, and it may come into contact with the head 60 'and become dirty.

On the other hand, according to the present embodiment, since the driven roller 80 for supporting the sheet from below is located inward of the serrated roller 72 'in the sheet width direction, the side portion of the sheet is serrated. Pressed down by. Therefore, the side edge Pe does not come into contact with the head 60 and become dirty.

According to the discharging section H as described above, basically, the same sheet discharging operation as that of the discharging section 1 in the above-mentioned prior art can be obtained, but instead of the conventional both side supporting section 2, a pair of pair of supporting sections 2 is provided. Since the driven roller 80 is provided, the resistance to the discharged paper P is significantly reduced by the rotation of the driven roller 80.

Therefore, even if the pair of driven rollers 80 is at a relatively high position with respect to the discharged paper and the discharged paper P is a relatively strong paper, the paper is smoothly discharged. As a result, the feed accuracy does not decrease.

Therefore, since it is not necessary to increase the pressure contact force of the paper discharge serrated roller 72, the serrated marks on the paper P are not conspicuously left and the print quality is not deteriorated.

[0044]

According to the first aspect of the invention, the sheet is smoothly discharged, and the feeding accuracy is not deteriorated.

[0045]

[Brief description of drawings]

1A and 1B are views showing a main part of an embodiment of an inkjet printer according to the present invention, in which FIG. 1A is a partially cut side view, and FIG. 1B is a partially omitted b arrow view in FIG.

2A and 2B are explanatory perspective views of a serrated roller.

FIG. 3 is an explanatory diagram of a conventional technique.

FIG. 4 is an explanatory diagram of a conventional technique.

FIG. 5 is an explanatory diagram of a conventional technique.

FIG. 6 is an explanatory diagram of a conventional technique.

FIG. 7 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 P paper 60 Inkjet head 80 Driven roller

Claims (1)

[Claims] 1. A pair of supporting means for supporting, from below, both side portions of a sheet printed on an upper surface by an ink jet head and discharged, the pair of supporting means being driven rollers to rotate in contact with the sheet. An inkjet printer characterized by being configured with.