JP2556245Y2 - Recording paper transport mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a recording paper transport mechanism for selectively guiding recording paper from a plurality of paper cassettes to registration rollers, or a paper feeding unit and a paper reversing unit on a lower surface side of an image forming apparatus main body. The present invention relates to a recording paper transport device applied to an image forming system in which units such as are stacked and arranged, and more specifically, merges another transport path with one recording paper transport path and selects from any one of the transport paths. The present invention relates to a recording paper transport mechanism for guiding recording paper to a target position.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus for forming a copying machine, a printer or the like, a plurality of cassettes having different storage sizes or a cassette and a manual feed mechanism are used in order to avoid complicated replacement of the cassette storing the recording paper. There is known an image forming apparatus in which recording papers having different sizes are selectively fed to upper and lower sides of one side of the apparatus.
FIG. 3 schematically illustrates a main part of a recording paper feeding section of this type of apparatus. Reference numeral 22 denotes an upper paper feeding cassette, and 27 denotes a lower paper feeding cassette. 21, 2
8 are provided. 23 is the upper paper cassette 22
A main feed path 24 for guiding the recording paper fed from the lower feed cassette 27 to the entrance end of the registration roller 20, and a branch feeding path 24 for guiding the recording paper fed from the lower sheet cassette 27 to the entrance end of the registration roller 20. The outlet end of the branch feed path 24 is connected to the main feed path 23
An opening 25 is provided in the middle of the position.

In such a configuration, in particular, the main feeding path 2
When the outlet end of the branch feed path 24 is opened 25 in the curved portion of the register roller 3, when the upper cassette 22 feeds the registration roller 20 through the main feed path 23 to the inlet end of the registration roller 20, the outlet opening 2 is used.
5 has a step-like shape between the upstream wall and the downstream wall, the leading end of the recording paper along the shape of the main feeding path 23 has the outlet opening 2.
(5) The recording paper 29 itself is curved and fed following the transport path 23 as shown in FIG. When the end passes through the outlet opening 25, the end is dropped with an elastic force due to bending, and a problem arises in that the end comes into contact with the end of the downstream wall to generate abnormal noise.

In recent years, for example, as shown in FIG. 4, the function of the apparatus main body 50 itself has been minimized as much as possible, and a paper feed unit 5 in which a paper feed cassette 55 has been stored for the purpose of use by the user.
1. A paper reversing unit that reverses the recording paper 29 after printing to return to the apparatus main body 50 for performing double-sided printing, a sorter that sorts the recording paper 29 after printing, and the like are unitized. There is a configuration in which an image forming system suitable for a purpose of use can be formed by selecting and mounting it on the apparatus main body 50 side. (Act No. 2-29063)

[0005] Such a unit system generally allows each unit 50, 50 as shown in FIG.
51 is configured to be able to be stacked one above the other, and a slit opening 52 for carrying out or carrying in the recording paper 29 and a transport path 24 communicating with the slit opening 52 are provided at the same position on either of the upper and lower surfaces facing each other, Each is configured to achieve a predetermined function via the transport path 24.
Also in such a device, especially in the case of the sheet feeding cassette 55 which is detachably housed in the sheet feeding unit 51 or the device main body 50, the sheet feeding unit 30 is directed toward the other upper unit or the entrance end of the transport roller 30 leading to the registration roller 20. A first feeding path 23 for guiding the recording sheet from the recording sheet stacking section 55a of the sheet feeding cassette 55 via the sheet feeding roller 54 and a vertical feeding path 24 for inserting the recording sheet 29 from the lower unit toward the upper unit; When these two feeding paths 23 and 24 are merged at the entrance side of the transport roller 30, the same problem as in the related art occurs.

[0006]

SUMMARY OF THE INVENTION In view of the drawbacks of the prior art, when the present invention merges one transport path with another transport path, a jam or recording paper trailing edge generated at an outlet opening of the other transport path may cause a problem. An object of the present invention is to provide a recording paper transport mechanism capable of preventing generation of abnormal noise when passing through an outlet opening with a simple configuration.

[0007]

According to the present invention, not only the apparatus shown in FIGS. 3 and 4 but also a second recording path is joined to a first recording paper recording path so that the recording paper is fed from one of the recording paths. The present invention is applied to a recording paper transport mechanism for selectively guiding recording paper to a target position. First, the recording paper is moved along an exit opening surface of a second transport path located on the first recording paper transport path. The first feature is that the sheet-like elastic thin layer body extends from the upstream shore portion to the downstream shore portion of the transport path. The second feature is that
The point is that the free end side of the thin layer body is formed in a symmetrical shape such that the central portion is concave or convex with respect to a direction perpendicular to the recording paper conveyance direction.

[0008]

According to this technical means, when passing through the outlet opening 25 through the first transport path, a sheet-like elastic thin layer is mounted along the outlet opening surface and the step of the outlet opening is formed. Is concealed, so that the leading edge of the recording paper does not contact the downstream wall of the outlet opening, so that the jam can be eliminated, and also on the trailing end side, the trailing edge may be dropped by the outlet opening. In addition, there is no occurrence of abnormal noise due to collision with the downstream wall edge at the time of dropping. Further, since the thin elastic body is formed in a sheet shape, the leading end of the recording paper presses the thin elastic body when the recording paper passes through the outlet opening from the second conveyance path, and The outlet opening is opened while the free end side of the is bent so that it can be easily inserted. In this case, if the urging force applied to the leading end of the recording paper is strong, the leading end of the recording paper may be bent and a jam may occur. For this reason, the elastic thin body may not be provided over the entire area in the width direction of the outlet opening, but may be provided in a central predetermined width area. When the free end side is formed in a straight line along a direction perpendicular to the recording paper conveyance direction, when the sheet forming the thin layer body is formed by press molding, burrs are generated on the free end side, and the outlet is formed. Even when the leading edge of the recording paper passes through the opening 25, even if the width is restricted to some extent, if the leading edge abuts on the thin layer member at once, the insertion of the recording paper is prevented by the burrs, and a jam is likely to occur. . For this reason, it has been considered that the free end is cut obliquely. However, since the biasing force of the thin-layer body configured as described above is biased, skew is likely to occur.

Therefore, in the present invention, the free end side of the thin layer body is formed symmetrically with respect to the direction perpendicular to the recording paper conveyance direction such that the central portion becomes concave or convex. As a result,
Since the free end has a symmetrical inclination line, when the recording paper leading end passes through the outlet opening from the second conveyance path, the leading end does not contact the thin layer body at once, and the symmetrical inclination is obtained. Since the contact is made by point contact along the line, the contact can be easily escaped from the burr, and since the contact is symmetrical, no skewing occurs.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; However, unless otherwise specified, dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Not just.

FIG. 1 is a schematic diagram showing a main portion of the present invention applied to the recording paper feeding section shown in FIG. 3. The recording paper 29 fed from the upper paper cassette 22 as described above is registered with a registration roller (not shown). A main feed path 23 leading to the entrance end of the registration roller 20; a branch feed path 24 leading the recording paper 29 fed from the lower sheet cassette 27 (not shown) to the entrance end of the registration roller 20;
Has an outlet opening 25 which opens the outlet end of the main feeding path 23 at an intermediate position thereof, and (A) is provided on the surface of the outlet opening 25.
As shown in FIG. 7, a sheet-shaped mylar (trade name: DuPont Co., Ltd.) 26 functioning as a thin layer elastic body having a base end adhered to the upstream shore portion 231 of the main feeding path 23 is connected to the outlet opening 2.
5 extends to the downstream shore 232 along the surface. The mylar 26 is formed by press-molding a polyester sheet as shown in FIG.
A mylar shown on the upper side of (C) with the base end side 26a adhered to the base 31 linearly along the direction orthogonal to the recording paper transport direction and the free end side 26b located on the opposite side in the orthogonal direction. It is formed in a symmetrical curve shape (substantially half-drum shape) such that the central portion becomes concave like 26A, or in a flat arc shape such that the central portion becomes convex like mylar 26B shown below. The length of the mylar 26 in the width direction (the direction orthogonal to the recording paper transport direction) does not need to be set to be the same as the maximum width of the recording paper 29 passing through the transport path, and may be set to a smaller width. .

According to this embodiment, as described in detail in the above invention, when passing through the outlet opening 25 through the main feed path 23, the outlet opening 25 is
Since the step is concealed, it can be inserted smoothly without generating a jam or an abnormal noise. Also, when the recording paper 29 passes through the outlet opening 25 from the branch feed path 24, the outlet opening 25 is opened while the leading end of the recording paper 29 presses the mylar 26, so that the recording paper 29 can be easily inserted. (See (B))

At this time, since the free end side 26b of the mylar 26 is formed in a symmetrical shape so that the central portion is concave or convex with respect to the direction perpendicular to the recording paper conveying direction, the branch feed path 24 When the leading end of the recording paper 29 passes, when the mylar 26 is formed in a concave shape at the center, it is directed toward both sides from the center. To be in contact
The burrs can be easily escaped, and since the contact is symmetrical, no skew occurs.

FIG. 2 shows a sectional configuration of a sheet feeding unit 55 used in the image forming system shown in FIG. 4 which is detachably accommodated in the apparatus main body 50. The first feed path 23 and the first feed path 23, which are guided from the recording paper stacking portion 55a of the paper feed cassette 55 through the paper feed roller 54 toward the entrance end of the transport roller 30 that guides the other unit or the registration roller 20 Recording paper 2 on the front side from lower unit to higher unit
9, and the outlet end of the vertical transport path 24 is formed by cutting one end of a shore 231 that forms the lower surface of the first feed path 23 into a slit shape, and the outlet opening 25.
To form In such a device as well, the free end of the mylar 26 joined to the upper surface of the shore portion 231 forming the lower surface of the first feed path 23, which is located on the upstream side of the outlet opening 25, is located on the opposite bank across the outlet opening 25. It extends toward the upper end of the vertical wall. This embodiment has the same effect as the above embodiment.

[0015]

As described above, according to the present invention, when one conveyance path is merged with another conveyance path, a jam generated at the exit opening of the other conveyance path or the rear end side of the recording paper when passing through the exit opening. Generation of abnormal noise can be prevented with a simple configuration. And so on.

[Brief description of the drawings]

FIGS. 1A and 1B are main configuration diagrams of the present invention applied to the recording paper feeding unit of FIG. 3, wherein FIG. 1A is a layout diagram thereof, and FIG. 1B is a diagram in which recording paper is inserted from a second conveyance path. (C) shows the shape of the thin film body.

FIG. 2 is a sectional view of a sheet feeding unit used in the image forming system shown in FIG. 4 or a sheet feeding cassette detachably housed in an apparatus main body.

FIG. 3A is a schematic diagram of a paper feeding device configured to be able to selectively feed recording paper from a plurality of cassettes, and FIG.

FIG. 4 is a schematic diagram of an image forming system in which units such as a paper feed unit are stacked and arranged on a lower surface side of an image forming apparatus main body;

[Explanation of symbols]

 Reference Signs List 23 First recording paper transport path 24 Second transport path 25 Exit opening 231 Upstream shore 232 Downstream shore 26 Thin layer

Claims (1)

(57) [Scope of request for utility model registration] 1. A recording paper transport mechanism in which a second transport path merges with a first recording paper transport path and selectively guides the recording paper from one of the transport paths to a target position. Along the exit opening surface of the second transport path located on the recording paper transport path, the sheet-like elastic thin layer body extends from one end toward the downstream shore part of the first recording paper transport path from the upstream shore part. And a free end side of the thin layer body is formed symmetrically with respect to a direction orthogonal to the recording paper conveyance direction such that a central portion is concave or convex.