JPH09300758A - Sheet-feeding device and printer equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize highly accurate printing by certainly guiding paper to a platen surface to accurately position the same thereon. SOLUTION: A press roller 54 is supported by a shakable arm 39 so that the contact plane passing the contact position of a feed roller 53 and the press roller 54 crosses a platen surface 38a at an angle of 1-20 deg. from above. The inclined surface 38b rising toward the platen surface in a feed direction is formed to the end part of the platen surface 38a and the platen surface 38a is arranged on the plane almost same to the contact plane connecting the rear surface of the press roller 54 and the contact position of discharge rollers 55, 56. The paper fed by the rollers 53, 54 is received by the inclined surface 38b to rise toward the platen surface 38a. The paper is pressed to the platen surface 38a on the basis of the angle formed with respect to the contact plane to form an almost straight plane along the platen surface from the rear surface of the press roller 54. The position of paper is kept even if the leading end thereof reaches the discharge rollers 55, 56.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet body conveying apparatus which sandwiches a sheet body with a pair of conveying rollers, conveys the sheet body along a reference surface, and nips and ejects the sheet body from the reference surface with a pair of discharge rollers. The present invention also relates to a printing device including the sheet conveying device.

[0002]

2. Description of the Related Art It is known that in a sheet conveying apparatus, a sheet such as a sheet is sent to a predetermined work position by a conveying roller, and then the sheet is discharged by a discharging roller.

In an ink jet type printing apparatus, in order to perform printing with high accuracy by the print head at the above-mentioned working position, the sheet is kept in close contact with the platen surface facing the print head so that the sheet does not float up. I have to send it out. Further, even in a copying machine, an image reading machine, etc., it is necessary to bring a sheet body into close contact with a predetermined work surface for exposure and the like.

Therefore, the direction of the sheet body to be sent out is
Some of them are not parallel to the platen surface or work surface (hereinafter referred to as a reference surface) but intersect at a predetermined angle. That is, as shown in FIG. 5, the conveying roller is composed of the feed roller 1 and the pressing roller 2, and the contact position S of both rollers is such that a tangential plane SH passing through the contact position forms a predetermined angle θ with the reference plane P. Position it so that it intersects. The sheet body is this tangent plane S
Since it is sent out in the H direction, if the contact position S is adjusted,
The sheet body can be sent out in a desired direction so that it does not rise above the reference surface.

[0005]

However, since a gap is required between the conveying roller and the end of the reference surface, the tangent plane S
If H and the reference plane P are on the same plane, even if the contact position S and the reference plane P are separated from each other in the feeding direction, the sheet body is naturally fed out from both rollers 1 and 2 on the reference plane. When the tangential plane SH and the reference plane P intersect with each other at an angle θ as shown in FIG. 5, the sheet body is received on the reference plane P unless the reference plane P is separated from the contact position S downward as shown in FIG. I can't.

When the sheet thus sent out reaches the discharge rollers 3 and 4, it is stretched between the transport rollers 1 and 2 and the discharge rollers 3 and 4, and floats from the reference plane P. It becomes impossible to perform accurate printing and reading operations.

An object of the present invention is to realize a sheet body transporting device which can reliably guide a sheet body to a reference plane and accurately position the sheet body on the reference plane, and thereby to perform highly accurate printing. It is an object of the present invention to realize a printing device that can perform printing.

[0008]

According to a first aspect of the present invention, a sheet body is sandwiched by a pair of conveying rollers and conveyed along a reference surface, and a pair of discharge rollers is provided from the reference surface. In the sheet body transporting apparatus for nipping and discharging the sheet, the pair of transporting rollers includes a feed roller and a pressing roller biased toward the feed roller, and passes through a contact position between the feeding roller and the pressing roller. The feed roller and the pressing roller are arranged so that the tangential plane intersects the reference plane at a predetermined angle from above,
An inclined surface that rises toward the reference surface in the conveyance direction is provided at an end portion of the reference surface on the conveyance roller side, and the reference surface is provided at a position substantially in contact with the sheet body extending between the conveyance roller and the discharge roller. Are arranged.

As described above, an inclined surface that rises toward the reference surface in the conveying direction is provided at the end portion of the reference surface on the conveying roller side, and the sheet body conveyed by the conveying roller is received by the inclined surface, By ascending toward the reference surface, the sheet body can be received by the reference surface even if the reference surface is arranged close to the pressing roller of the transport roller. Further, by this, the reference surface is arranged at a position almost in contact with the sheet member extending between the conveying roller and the discharging roller, and the sheet is conveyed from before the leading end of the sheet member reaches the discharging roller to when the trailing end thereof passes through the conveying roller. The body is accurately positioned without lifting from the reference plane.

Further, in the above-mentioned structure, preferably, the first member which descends toward the contact position between the feed roller and the pressing roller and is substantially continuous with the outer periphery of the pressing roller on the sheet body supply side to the conveying roller. Further includes a second guide surface that faces the first guide surface and has a tip that is close to the first guide surface and that feeds the sheet body fed along the first guide surface. The sheet body guided toward the contact position between the roller and the press roller and fed along the second guide surface once comes into contact with the first guide toward the contact position between the feed roller and the press roller. Be guided. Then, the sheet body is surely conveyed along the contact plane between the feed roller and the pressing roller and positioned on the reference plane.

Further, in each of the above constitutions, preferably,
Since the feed roller has a larger diameter than the pressing roller and is connected to the drive source, the sheet body is conveyed with high precision by the large-diameter feed roller connected to the drive source. Further, when the feed roller has such a large diameter, the reference surface cannot be arranged close to the pressing roller. However, the inclined surface allows the reference surface to be arranged close to the pressing roller, so that the sheet body can be accurately arranged. Not only is it positioned, but it is also transported with high precision.

Since the sheet body is accurately positioned on the reference plane as described above, the sheet body conveying apparatus uses the platen plane as the reference plane, and the print head is opposed to the platen plane to provide a highly accurate printing apparatus. Printing becomes possible. Especially,
In a printing apparatus using an inkjet head, the leading end of the sheet body is pushed toward the reference surface side by a conveying roller when the sheet body is inserted, so that the sheet body can be inserted without coming into contact with the printing head.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows a schematic structure of a printing apparatus.
The printing device generally includes a sheet device, that is, a printing paper conveyance device 50, a printing unit 40 that performs a printing operation on the printing paper, and a cover frame 31 that houses them.
Consists of

The printing unit 40 includes a carriage support plate 4
The carriage 4 is attached to the guide bars 43 and 44 supported on the carriage 2.
5 is slidably supported, and the print head 41 is mounted on the carriage 45 thereof. The carriage 45 reciprocates along the paper with the print head 41 facing a platen surface 38a described later. The print head 41 is an inkjet head that ejects ink droplets onto a sheet to print in a dot matrix form.

The transport device 50 transports the paper stored in the paper feed cassette 51 or the paper inserted from the manual insertion slot 58 to a position facing the print head 41, and scans the print head 41 every scanning. It conveys while feeding at a right angle to the direction. Specifically, the paper feed cassette 5
A paper feed roller 52 for taking out the paper one by one, a pair of carrying rollers 53, 54 for carrying the taken-out paper or a manually fed paper to a position facing the print head 41, and a pair of discharge rollers for discharging the printed paper. 55, 56,
First and second guides and supports for paper between rollers
Wall 36, 38 and arm 39.

The transport rollers 53, 54 are composed of a feed roller 53 having a surface made of high friction rubber, and a metal pressing roller 54 that abuts so as to follow the feed roller 53. The feeding roller 53 is a pressing roller 54. It has a larger diameter and is connected to a drive source such as a motor, and the pressing roller 54 is supported by the tip of the arm 39. The arm 39 is supported by a shaft 37 so as to be swingable around an axis parallel to the feed roller 53, and a pressing roller 54 is caused by a spring 35 to move the press roller 54.
It is urged in the direction of coming into contact with 3. Further, the shaft 37 is arranged on the supply side of the contact position of both rollers and on the side opposite to the feed roller 53 from the surface passing through the contact position.

The discharge rollers 55 and 56 are composed of a roller 55 made of high-friction rubber for supporting the paper from the back side, and a spur roller 56 having a sharp projection on the outer periphery that abuts so as to follow the roller 56.

The first wall 36 and the arm 39 are arranged so as to face each other so as to form a passage on the supply side to the conveying rollers 53 and 54. The arm 39 has transport rollers 53, 5
4, a first guide surface 39a that descends toward the contact position of 4 and is substantially continuous with the outer peripheral surface of the pressing roller 54 is formed.
A second guide surface 36a is formed on the upper surface of the wall 36 so as to face the first guide surface 39a. As shown in detail in FIG. 2, the tip end of the second guide surface 36a on the feed roller side is close to the first guide surface 39a. As a result, the sheet taken out from the sheet feeding cassette 51 by the sheet feeding roller 52 along the separation inclined surface 34 is sent out while curving upward, abuts on the first guide surface 39a, and is conveyed along the same surface. The rollers 53 and 54 are guided to the contact position. Further, the sheet inserted through the manual insertion slot 58 contacts the second guide surface 36a and is guided to the contact position of the transport rollers 53 and 54 along the same surface.

The second wall 38 is provided between the transport rollers 53 and 54 and the discharge rollers 55 and 56 to print the print sheet on the print head 4.
1 is arranged so as to be supported from the back side at a position opposite to 1. That is, the upper surface of the wall 38 is a reference surface for printing,
That is, it is formed as the platen surface 38.

The contact position S between the feed roller 53 and the pressing roller 54 is, as shown in detail in FIG.
It is shifted to the a side. That is, the line connecting the feed roller 53 and the press roller 54 is not perpendicular to the platen surface 38a, but the press roller 54 is attached to the feed roller 53 so that the platen surface 38a is inclined to the same side by an angle θ, for example, 1 to 20 °. It is placed against. As a result, the tangential plane SH passing through the contact position S of both rollers intersects with the platen surface 38a at an angle θ from above, for example, 1 to 20 °. At least a portion of the first guide surface 39a adjacent to the contact position is
It is formed along this angle.

An inclined surface 38b that rises toward the platen surface 38a in the transport direction is formed at the end of the second wall 38 on the feed roller 53 side. The inclined surface 38b is formed at an acute angle with the tangential plane SH when viewed from the roller side, and the platen surface 38a is a tangential plane SK that connects the contact position of the discharge rollers 55 and 56 and the lower surface of the pressing roller 54. They are formed on almost the same plane. That is, the platen surface 38a is arranged at a position where it is substantially in contact with the sheet of paper that has passed between the transport rollers 53 and 54 and the discharge rollers 55 and 56. The inclined surface 38
In order to dispose the platen surface 38a at the same position as described above without providing a, the second wall 38 must be formed extremely sharply at a position close to the feed roller 53, as can be inferred from FIG. In reality, this is almost impossible, and the platen surface is arranged below the paper as in the conventional one shown in FIG.
This becomes more remarkable as the diameter of the feed roller increases. As described above, by providing the inclined surface 38b, it becomes possible to arrange the platen surface at the same position as the sheet conveyance path.

As a result, the sheet is conveyed by the conveying rollers 53 and 54 along the tangential plane SH, and the inclined surface 38b.
And is raised toward the platen surface 38a. On the platen surface 38a, the sheet is pressed against the platen surface based on the angle θ with the tangent plane SH, and forms a substantially straight plane from the lower surface of the pressing roller 54 along the platen surface. Even if the leading edge of the paper reaches the discharge rollers 55 and 56, the position of the paper is maintained. Since the distance between the print head 41 and the sheet does not change even before and after the leading edge of the sheet reaches the discharge rollers 55 and 56, and after the trailing edge of the sheet is removed from the transport rollers 53 and 54, the leading edge of the sheet is discharged from the discharge roller. Even if printing is started before reaching 55 and 56, and printing is continued until the trailing edge is removed from the conveyance rollers 53 and 54,
The printing operation is performed with the same accuracy.

Further, in the printing apparatus using the ink jet type head, when the paper is inserted, the leading end thereof is the platen surface 38a.
By being pushed to the side, it does not come into contact with the print head 41 and become contaminated with the ink of the nozzles of the print head.

The paper discharged by the discharge rollers 55 and 56 is stored in the paper discharge stacker 57. In addition, the pressing roller 54 is provided on the supply side with respect to the contact position S.
Since it is supported by 9, the arm 39 itself can be arranged in an appropriate space away from the printing position, and the print head 41 and its related components can be arranged at a high density in the printing position. Can be converted.

Further, the shaft 37 which is the swing center of the arm 39
Exists on the supply side of the contact position S and on the side opposite to the feed roller 53 from the tangential plane passing through the contact position S. As a result, when the paper becomes thicker as shown in FIG. 4, the contact position S between the feed roller 53 and the pressing roller 54 (that is, the paper nipping position) S through the paper is S
0, S1, S2, ..., Gradually move to the transport side. As a result, the contact positions S0, S1, S2, ...
Of the tangent planes SH0, SH1, SH2, ..., The angle of intersection with the platen surface 38a increases to θ0, θ1, θ2 ,. Therefore, the thicker the paper, the greater the tendency of the paper to be pressed against the platen surface 38a. On the other hand, the thicker the repulsive force of the paper is, the harder it is to follow the concave guide surface of the first guide surface 39a, and the tendency that the paper is displaced from the feeding direction of the feed roller 10 and the pressing roller 8, that is, the tendency to float from the platen surface 38a is strong. Become. That is, as the paper becomes thicker, the tendency of sticking on the platen surface 38a and the tendency of floating on the platen surface 38a are offset, and the paper can be stably conveyed.

As shown in FIG. 2, the first guide surface 39a is formed as a concave guide surface that is curved and concave at a portion immediately before the contact position S at a right angle to the sheet conveying direction. There is. That is, the concave guide surface is formed so as to have a substantially arc shape centered on the sheet side when viewed in a cross section in the sheet feeding direction.

Since the concave guide surface is formed at the tip portion of the first guide surface 39a, the leading end of the sheet is guided by the concave guide surface, and the paper is fed to the feed roller 53 and the pressing roller 54. When sandwiched, the shape is along the concave guide surface, the angle when entering the contact position S is stable, and the tendency to adhere to the platen surface 38a is strengthened. Therefore, highly accurate printing is possible.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a schematic configuration of a printing device to which a sheet conveying device of the present invention is applied.

FIG. 2 is an enlarged cross-sectional view around a transport roller.

FIG. 3 is an operation explanatory diagram in which a part of FIG. 2 is extracted.

FIG. 4 is an operation explanatory diagram in which a part of FIG. 2 is extracted.

FIG. 5 is a side view showing a schematic configuration of a conventional transfer device.

[Explanation of symbols]

 53 feeding roller 54 pressing roller 55, 56 discharging roller 38a platen surface (reference surface) 38b inclined surface 36a second guide surface 39a first guide surface 41 print head

Claims (5)

[Claims] 1. A sheet body transporting device in which a sheet body is sandwiched by a pair of transport rollers, transported along a reference plane, and sandwiched by a pair of discharge rollers from the reference plane to discharge the sheet body. Is a feed roller and a pressing roller biased toward the feed roller, and a tangent plane passing through a contact position between the feed roller and the pressing roller intersects with the reference plane at a predetermined angle from above. like,
The feed roller and the pressing roller are arranged, and an inclined surface that rises toward the reference surface in the conveyance direction is provided at an end portion of the reference surface on the conveyance roller side, and extends between the conveyance roller and the discharge roller. Also, the sheet body transporting device, wherein the reference surface is arranged at a position substantially in contact with the sheet body. 2. The first feeding device according to claim 1, wherein the first feeding member descends toward a contact position between the feeding roller and the pressing roller and is substantially continuous to an outer circumference of the pressing roller on a sheet body supplying side to the conveying roller. The sheet body transporting device further comprising a guide surface and a second guide surface facing the first guide surface and having a leading end approaching the first guide surface. 3. The sheet conveying device according to claim 1, wherein the feed roller has a larger diameter than the pressing roller and is connected to a drive source. 4. A printing apparatus comprising the sheet conveying device according to claim 1, wherein the reference surface is a platen surface, and a print head is opposed to the platen surface. 5. The print head according to claim 4,
A printing apparatus, which is an inkjet head that ejects ink droplets toward the sheet body.