JP2000292991A - Automatic document feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic manuscript feeder where the carrying clearance of a manuscript can be freely adjusted. SOLUTION: In the automatic manuscript feeder where an image is read while the manuscript is being carried, a carrying guide 2 guiding the above- mentioned manuscript to be turned over to a reading position C by being in contact with it is constituted to be installed by a bracket 2b with a variable position of attachment. For example, the bracket 2b can be adjusted to form a carrying clearance B' that is most appropriate to suppress variation in speed of the document by being freely slid by slots 2c and 2d on both edges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder which reads an image of a document sent one by one while reversing the document.

[0002]

2. Description of the Related Art An original image is read while changing the transport direction so that the original sent out for each sheet is reversed.
2. Description of the Related Art A so-called sheet-through type automatic document feeder is used, for example, mounted on an image reading device such as a copying machine. FIG. 5 shows a schematic configuration of such a conventional automatic document feeder. Documents separated one by one from the document table 12 enter in the direction of arrow A, and are guided by the pull-out roller 1 to the first transport path B constituted by the transport guide 2 and the paper feed guide 3. In this way, the document is reversed to the reading position C while changing the transport direction so that the original surface faces the contact glass 4.

Conventionally, a guide means such as a conveyance guide 2 which comes into contact with a document for guiding to a reading position C has a fixed mounting position at the time of assembling the apparatus, and its position and dimensions are determined in advance by a mold or the like. ing. Therefore, the clearance space of the transport path B (hereinafter, referred to as “transport gap”)
Is a configuration that is always determined to have a constant width. The document is conveyed to the reading position 10 of the reading unit through the first conveyance path B, and the image information is read on the contact glass 4 by exposing the optical unit (not shown) to the point of the reading position C. Then, the document from which the image information has been read is discharged to the discharge tray 13 through the second transport path D and the third transport path E by the auxiliary roller 9 and the discharge roller 10.

[0004]

By the way, in the above-mentioned sheet-through type document feeder, in order to read the same image as the document image, it is ideal that the speed at which the document is conveyed completely matches the reading speed. The reading state is set. Generally, when the transport gap is narrowed, the transport speed is stabilized.

However, in the case of thick paper or the like, the transport speed may not be stable due to the narrow transport gap, and the transport speed may actually change slightly depending on the strength of the waist of the document. That is, when the transport paths B, C, and D are configured to feed the document while being inverted, the document is bent in the transport gap, so that the transport speed at the time of reading is not completely constant, and the read image is not read. Problems such as expansion and contraction occur.

FIG. 6 shows a document feeding state in the above-mentioned conventional document feeding device. In particular, when the leading edge of the document comes into contact with the rake face of the scale 6 as shown in FIG.
When the trailing edge of the document comes out of the pull-out roller 1 as shown in FIG. 6B, or when the trailing edge of the document comes off the transport guide 2 as shown in FIG. The conveyance speed viewed from the reading position C greatly changes depending on the strength of the waist of the document. Also, due to variations in dimensional tolerances of the components constituting the transfer path such as the transfer guide 1 and the like, the transfer gap is not always constant depending on the apparatus, which also causes a reduction in transfer accuracy.

Accordingly, it is an object of the present invention to set a transport gap for minimizing the influence on the transport speed of a document so that reading is faithfully performed on a document image, and there is variation in dimensional tolerances of parts and the like. An object of the present invention is to provide an automatic document feeder that does not cause an error in a transfer gap.

[0008]

According to the present invention, there is provided an automatic document feeder for guiding an original to a reading position while reversing the original and reading the original image while transporting the original. At least a part of the guide member for guiding the document is installed so that its mounting position can be changed so that the conveyance gap through which the document passes can be adjusted.

[0009] It is possible to adopt a configuration in which the mounting position of the transport guide that is installed upstream of the reading position and contacts and guides the original can be changed. Further, the transport guide may be configured such that the mounting position can be changed by one or more elongated holes provided for fixing the transport guide.

Alternatively, the transport guide may be rotatably supported and rotatable by a slot at the other end, so that the mounting position can be changed.

Further, a stopper is provided to secure a constant interval between the transport guide and an inner guide which is arranged to face the transport guide plate and constitutes a transport path. It is possible to adopt a configuration in which a means for urging is provided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic document feeder according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a main configuration of an automatic document feeder according to the present invention.
FIG. 2 shows a detailed configuration near the upstream of the reading unit in FIG. When the document is nipped and sent by the pull-out roller 1a and the pull-out driven roller 1b from the entry direction A,
The sheet is guided to the first transport path B, and is transported to the reading position C through the first transport path B.

The first transport path B includes a transport guide 2 and a paper feed guide 3, and a reading section for reading a document image includes a contact glass 4, a reading background plate 5, a scale 6, and the like. I have. Further, the reading background plate 5 is disposed so as to secure a certain gap between the reading background plate 5 and the contact glass 4, and the document guided in the reading position C direction by the transport guide 2 and the scale 6 is in contact with the contact glass 4. , And the reading background plate 5.

The document is read at the reading position C, and the image information is read therefrom. Then, the document is guided by the scale 6 to the second transport path D composed of the lower discharge guide 7 and the upper discharge guide 8. Upon entering the second transport path D, the sheet is nipped and sent by the auxiliary roller 9a and the auxiliary driven roller 9b, passes through the third transport path E, and further to the sheet discharge section by the sheet discharge roller 10a and the sheet discharge driven roller 10b. Is discharged.

In the automatic document feeder configured as described above, the transfer guide 2 serving as a guide member for abutting the document and guiding the document in the reverse direction is a guide portion 2a made of resin.
And a bracket 2b for holding the guide portion 2a
It is composed of That is, the first transport path B
So that the transfer gap B ′ can be adjusted.
Is mounted by two fixing long holes 2c and 2d provided in the bracket 2b, and the mounting position is changeable.

The bracket 2b is inserted into two long holes 2c and 2d provided on both sides in the longitudinal direction of the bracket 2b, and is fixedly inserted therein. (In the direction of arrow X in the figure). Thus, the transport gap can be freely adjusted and then fixed. As described above, with the movement of the bracket 2b, the transport gap B 'of the first transport path B including the guide portion 2a of the transport guide 2 and the paper feed guide 3 can be freely set to be expanded or narrowed. It is possible to set an appropriate transport gap B ′ for minimizing the speed change in any of the states of FIGS. 6A to 6C described in the related art. Incidentally, the mounting position of the transport guide 2 constituting such an appropriate first transport gap B 'can be confirmed in advance by experiments or the like, and a serviceman appropriately adjusts the position according to the use state. There are various setting methods.

FIGS. 3 and 4 show other examples of the structure of the transport guide. FIG. 3 shows a second embodiment of the transport guide 2. The means for installing the transport guide 2 so that the mounting position of the transport guide 2 can be changed so as to freely adjust the first transport gap B 'is not limited to the configuration in which the bracket 2b is slid along its long hole. It can also be realized as a configuration supported rotatably.

In this case, for example, as shown in FIG. 3, the transport guide is rotatably supported at a fulcrum 2e and is rotatable at the other end in the direction of arrow X 'about the fulcrum 2e. May be provided. With such a configuration, the long hole 2f for position adjustment becomes one place,
It is possible to simplify the operation of adjusting the mounting position and adjust the first transport gap B ′.

FIG. 4 shows a third embodiment of the transport guide 2. According to the third embodiment, a constant first conveyance gap B 'can be secured regardless of the dimensional tolerance of each member. That is, the transport guide is provided with a convex portion 2g as a stopper for securing a constant interval between the transport guide 2 and the paper feed guide 3, which is an inner guide facing the transport guide. Further, the transport guide 2 is provided with a tension spring 11 as an elastic member for urging the transport guide 2 toward the paper feed guide 3.

According to this configuration, in the assembled state, the first transport gap B 'is determined only by the height of the convex portion 2g because the convex portion 2g of the transport guide 2 always contacts the paper feed guide 3 side. . The means for urging the transport guide 2 with the tension spring 11 is necessary because the transport guide 2 cannot be fixed to the paper feed guide 3 side in order to open the first transport path B.

[0021]

As described above, the automatic document feeder according to the present invention guides the original in the automatic document feeder that guides the original to the reading position while inverting the original and reads the original image while transporting the original. Since at least part of the guide member is installed so that its mounting position can be changed,
It is possible to adjust the transport gap to minimize the change in the transport speed of the original, and to improve the transport accuracy of the original with a simple configuration that only adjusts the position of the guide member, thereby improving the faithfulness of the original image. Reading can be performed.

In addition to the above, a stopper is provided to secure a constant distance between the transport guide and an inner guide which is disposed opposite to the transport guide plate and forms a transport path.
According to the configuration in which the means for biasing the transport guide toward the inner guide is provided, an optimal transport gap can always be secured without causing an error due to a variation in accuracy of the components in a predetermined transport gap, As a result, the conveyance guide is always secured at a position where the change in the conveyance speed of the document can be minimized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main configuration of an automatic document feeder according to the present invention.

FIG. 2 is a sectional view showing a detailed configuration near an upstream of a reading unit in FIG. 1;

FIG. 3 is a view showing the configuration of a second embodiment of the transport guide according to the present invention.

FIG. 4 is a view showing a configuration of a third embodiment of the transport guide according to the present invention.

FIG. 5 is a diagram showing a schematic configuration of a conventional automatic document feeder.

6A and 6B are diagrams for explaining a state of feeding a document in a conventional document feeder. FIG. 6A shows a state in which the leading end of the document is in contact with a rake face, and FIG. FIG. 6C illustrates a state in which the roller pair has been removed, and FIG.

[Explanation of symbols]

2 Conveyance Guide 2c, 2d, 2f Slot 2g Stopper (Protrusion) 3 Inner Guide (Sheet Guide) 11 Means for Energizing Conveyance Guide (Tension Spring) B Transport Path B 'Transport Gap C Reading Position

Claims (5)

[Claims] A guide member for guiding an original so as to be able to adjust a conveyance gap through which the original passes in an automatic document feeder that guides the original to a reading position while reversing the original and reads the original image while conveying the original. An automatic document feeder, wherein at least a part of the automatic document feeder is installed so that its mounting position can be changed. 2. The automatic document feeder according to claim 1, wherein a mounting position of a transfer guide that is installed upstream of said reading position and contacts and guides the document can be changed. 3. The automatic document feeder according to claim 1, wherein the position of the feed guide can be changed by one or more slots provided for fixing the feed guide. 4. The transport guide according to claim 1, wherein the transport guide is rotatably supported and rotatable by a slot at the other end, so that the mounting position can be changed. The automatic document feeder according to any of the above. 5. A stopper provided for securing a constant interval between the transport guide and an inner guide which is arranged to face the transport guide plate and constitutes a transport path, and wherein the transport guide is moved toward the inner guide. 5. The automatic document feeder according to claim 2, further comprising means for urging the document.