JP4248775B2 - Document reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a document reading device provided in an image forming apparatus such as a copying machine, a printer, a facsimile machine, a scanner, or the like, and more particularly to an improvement of a document pressure plate for pressing a document set on a contact glass.
[0002]
[Prior art]
An image forming apparatus or a scanner includes a contact glass for setting a document, a reading optical system disposed immediately below the contact glass, and a document pressure plate pivotally supported by the apparatus main body so as to open and close the upper surface of the contact glass. A document reading device is provided.
FIG. 4 is a cross-sectional view showing a configuration of a document pressure plate of a conventional document reading apparatus.
This document reading apparatus includes a contact glass 101 on the upper surface of a reading apparatus main body (or image forming apparatus main body) 100, and a reading optical system (not shown) is disposed immediately below the contact glass 101. A document scale 102 serving as a reference for positioning the document edge when the document D is set is disposed at a position along at least one edge of the contact glass 101. A hinge 103 is attached to the upper surface of the apparatus main body along one edge of the contact glass 101, and a document pressure plate 105 is pivotally supported by the hinge 103 so as to be opened and closed in the direction of the arrow.
The original pressure plate 105 is fixed to the pressure plate main body 106 pivotally supported by the hinge 103 so as to be openable and closable with respect to the apparatus main body 100, a sponge-like pad 107 disposed on the lower surface of the pressure plate main body 106, and the pressure plate main body 106. And a white sheet 108 made of a soft resin attached to the lower surface of the flat pad 107.
The white sheet 108 is fixed by, for example, bending two opposing edges into a V shape, and inserting and locking the V-shaped portion into a locking groove 109 provided in the pressure plate main body 106.
[0003]
When placing the document D on the contact glass 101, the document scale 102 protrudes above the upper surface of the contact glass 101, and after positioning the edge of the document D against the document set end surface of the document scale 102, The document pressure plate 105 is closed and brought into close contact with the upper surface of the contact glass 101.
At this time, if one end of the white sheet 108 is on the upper surface of the original scale 102 as shown in the figure, a gap is formed between the upper surface of the contact glass near the original scale and the white sheet 108, so that the edge of the original is corrugated. When there is a wrinkle or a curled wrinkle, the original is read while it is floating in the gap, causing a reading failure.
[0004]
More specifically, in the conventional document pressure plate, the surface (lower surface) of the white sheet 108 is used as the back surface (upper surface) of the document D in order to read the wavy and document-curled document on the contact glass 101. The surface of the document to be read must be brought into close contact with the upper surface of the contact glass. At this time, if the white sheet 108 is placed on the original scale 102, the original scale is thick, so that the lower surface of the white sheet 108 cannot be brought into close contact with the upper surface of the contact glass end, and a gap is generated. Occurs, causing problems such as straight line bending. In order to solve such a problem, the edge of the white sheet 108 is shortened so as not to overlap the document scale, and a gap is set between the edge of the white sheet and the document scale. However, since there is no surface on which the light from the light source of the reading optical system is reflected in the gap portion, there is a problem that a black belt image is generated in the portion corresponding to the gap. Such a problem that occurs when the lower surface of the document pressure plate overlaps the document scale also occurs in an automatic document feeder that has both a sheet-through type reading unit and a reading unit that uses a pressure plate. To do. This problem also occurs when an original is fed onto the contact glass by the lower surface of the conveyance belt in an automatic document feeder of the type that conveys the document onto the contact glass by the document conveyance belt.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems of the prior art, and when the lower surface of the original pressure plate or the conveying belt of the automatic original feeding device presses the original onto the contact glass, these are over the original scale. To provide a document reading device that eliminates a problem that a gap is formed between the contact glass edge and the document scale by wrapping, and as a result, the pressing force at the document edge decreases to cause a reading failure. Objective.
In particular, even if the positional relationship between the edge of the white sheet constituting the original pressure plate and the original scale is deviated, an original reading apparatus that can prevent the original from being lifted by easily bringing the white sheet surface into close contact with the contact glass. The purpose is to provide.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the invention of claim 1 includes an apparatus main body provided with a contact glass for placing a document, and a document setting end surface that is disposed along the edge of the contact glass and protrudes from the upper surface of the contact glass. An original reading plate comprising: an original scale provided; and an original pressure plate that pivotally supports one end edge of the apparatus main body so as to be pivotable in the vertical direction by a hinge and opens and closes the upper surface of the contact glass. The pressure plate main body pivotally supported by the hinge so as to be openable and closable with respect to the apparatus main body, a pad attached to the lower surface of the pressure plate main body, and the pad on the lower surface of the pad attached to the original scale side removes the pad on the upper surface. and a flexible pressing sheet has a movable end portions, the movable end of the flexible pressing sheet by vertically movable supported by a part of the piezoelectric plate body Comprising a pressing member for urging downward, and when closing of the document pressing plate, the tip of the movable end portion is configured to move it in contact with the copy edge on the contact glass to the document scale side It is characterized by. A second aspect of the present invention, prior Symbol flexible pressing sheet that is bonded by an adhesive surface, except for the non-adhesive surface of a predetermined width from the document scale side edge of the lower surface of the plate-like pad Features. The invention of claim 3 is characterized in that the document pressure plate according to claim 1 or 2 is applied to a document pressure plate portion of a sheet-through type automatic document feeder. According to each of the above inventions, a part of the flexible presser sheet or the like is pressed by the presser member that can swing within a certain range, so that the document floating due to the step of the document scale can be reduced.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
FIGS. 1A and 1B are a sectional view showing an open state of a document pressure plate used in a document reading apparatus according to an embodiment of the present invention, and a sectional view showing a closed state. FIG. 2 is an exploded perspective view of the main part of the original platen.
This document reading apparatus includes a contact glass 2 on the upper surface of a reading apparatus main body (or image forming apparatus main body) 1, and a reading optical system (not shown) is disposed immediately below the contact glass 2. A document scale 3 serving as a reference for positioning the document edge when the document D is set is disposed at a position along at least one edge of the contact glass 2. A hinge 4 is attached to the upper surface of the apparatus main body along one edge of the contact glass 2, and a document pressure plate 5 is pivotally supported by the hinge 4 so as to be opened and closed in the direction of the arrow.
The hinge 4 is normally provided on the rear side (back side) of the upper surface of the apparatus main body so that an operator located in front of the apparatus main body can grasp the front side of the document pressure plate 5 and open and close it in the vertical direction. Although it is configured, in this example, it is not limited to the case where there is a hinge on the rear side, but also applies to a type configured to open and close to the left or right by providing a hinge on either the left or right can do.
[0008]
The document pressure plate 5 protrudes from a pressure plate body 10 that is pivotally supported with respect to the device body 1 by a hinge 4 provided on a document scale 3 provided on the rear side of the upper surface of the device body, and a lower surface of the pressure plate body 10. A flat plate pad 11 made of sponge disposed and fixed in the supporting portion 10a provided, and a part of the upper surface is bonded to the lower surface of the flat pad 11 by a fixing method such as double-sided tape or Velcro (registered trademark). A white sheet (flexible presser sheet) 12 made of a fixed soft resin and a presser member 13 are provided. The white sheet 12 is attached to the lower surface of the flat pad by the bonding surface 11a of the flat pad 11 shown in FIG. 2, and the end portion on the original scale side is a free end portion 12a. Since the free end portion 12a has a length that overlaps the original scale 3, when the original pressure plate 5 is closed as shown in FIG. 1 (b), it is between the contact glass 2 and the original scale. In addition to forming a gap that causes black streak images, the pressing member 13 has a shaft support portion 13a that is supported by the pressure plate body 10 so as to be movable up and down and a free end portion 12a of the white sheet. The free end 12a can be pressed onto the upper surface of the contact glass and brought into close contact with the original D when the original pressure plate is closed, and between the contact glass and the original scale. Do not form voids that cause image defects.
[0009]
As shown in FIG. 1A, when the document pressure plate 5 is opened, the pressing member 13 is moved by the pressing piece 13b by its own weight or the urging force of an elastic member (not shown). ) Is pushed down and bent, so that in the process of closing the document pressure plate on the contact glass, the leading end of the free end portion 12a comes into contact with the upper surface of the document on the contact glass first. When the closing operation of the document pressure plate 5 further proceeds, the leading end of the free end portion 12a moves while pressing the document toward the document setting end surface 3a of the document scale 3, and finally the free end portion. Only 12a rides on the original scale 3, and the state shown in FIG. 1B is obtained. In this state, the free end portion 12a is stopped in a state of being in close contact with the upper surface of the document and the document setting end surface 3a, so that a gap that causes black stripes and a gap that causes reading failure are formed. There's no room for it.
Even when the edge of the document is deformed by wavy or curled wrinkles, the leading end of the free end 12a comes into contact with the raised portion of the document first in the process of closing the document pressure plate as described above. Since the edge of the document can be brought into contact with the document scale while gradually flattening the presser, it is possible to finally press down without lifting. Depending on the shape of the raised portion and the manner of contact of the free end 12a, the end of the document may be once pressed to the side opposite to the document scale. Since the portion 12a is urged toward the original scale side, the original end portion can finally come into contact with the set end surface 3a of the original scale.
[0010]
In this example, the presser member 13 is a U-shaped body composed of a presser piece 13b and an extended piece 13c that is bent and extended from both ends of the presser piece 13b. The presser member 13 is rocked by a seesaw-type balance around the shaft support part 13a. Although power is obtained, the free end 12a may be forcibly pressed by a pressing means (elastic member) such as a spring (not shown).
In the state where the original pressure plate 5 is opened, the presser member 13 presses the free end portion 12a by the presser piece 13b of the presser member 13 so that the tip thereof faces the upper surface of the contact glass. The presser piece 13b is allowed to contact the upper surface of the contact glass (the upper surface of the original document) via the free end portion 12a and receive a reaction force to rotate counterclockwise to allow the free end portion 12a to move upward. To do. By this continuous operation, the document end is pressed by the free end 12a, and even the document end having undulations, curls, etc. is surely pressed into the contact glass surface, and there are gaps and gaps. Reading in a non-formed state is possible. Further, the positional relationship between the edge 11 b (document scale side edge) of the flat pad 11 and the pressing piece 13 b of the pressing member 13 is set at a position where the pad edge 11 b is further away from the document scale 3. . For this reason, the edge of the white sheet 12 can be made free.
Further, the adhesion range 11a between the white sheet 12 and the pad 11 is not necessarily adhered entirely as shown in FIG. 2, but is adhered from a position separated from the document scale side edge 11b of the pad 1 by a predetermined width. This increases the degree of freedom in bending of the free end portion 12a that is not bonded.
[0011]
Next, in the illustrated embodiment, the pressing member 13 is provided at a position close to the hinge 4 of the document pressure plate 5, but this is only because the document scale 3 happens to be on the hinge side. If the document scale 3 is on the side opposite to the hinge 4, the presser member 13 and the free end portion 12 a may be provided on the side opposite to the hinge 4. The operation can be performed in the same manner as the form, and the action of pushing the leading edge of the document into the document scale side is created.
Also, the reason why the white sheet 12 is made into one sheet and the free end portion is not divided from the other part (the part bonded to the pad) is that the part that is divided when the original is read becomes a black line. Because there is a risk of becoming. However, in order to increase the downward opening state of the pressing member 13 and the free end portion 12a when the document pressure plate 5 is opened, the pad for supporting the white sheet is divided at an appropriate position and rotated downward. It is also effective to make it possible.
The present invention is not limited to a pure document pressure plate that does not have an automatic document feeding function (ADF function), but is a sheet-through type automatic document as shown in the front view of FIG. The present invention can also be applied to a paper feeder (ADF).
[0012]
That is, the automatic document feeder 30 shown in FIG. 3 is arranged on contact glasses 32 and 33 provided on an apparatus main body 31 such as an image forming apparatus, and the hinge 4 (rotation) located on the left side of the apparatus 30 is arranged. The shaft can be opened and closed in the direction of the arrow. The automatic document feeder 30 includes a sheet-through sheet feeding unit 35 and a document pressure plate unit 36. Further, a reading means 50 that can move between a fixed position indicated by a solid line and a position indicated by a dotted line is disposed on the apparatus main body 31 side, and the reading means 50 is stopped at a solid line position during sheet-through reading. The image of the original document passing over the contact glass 32 is read. On the other hand, at the time of reading by the document pressure plate, the reading unit 50 reads the document fixed on the contact glass 33 by moving the scanning range indicated by the arrow.
The sheet-through sheet feeding unit 35 feeds the document D set on the document table 37 toward the contact glass 32 through the sheet feeding path 38 and stops when the document D passes through the contact glass 32. 50 reads the original surface. Thereafter, the document is discharged to the paper discharge unit 39.
In the document pressure plate portion 36, as shown in the figure, the flat pad 11, the white sheet 12, and the pressing member 13 are disposed on the lower surface of the pressure plate main body 40. Therefore, when the automatic document feeder 30 is opened and closed, As in the embodiment, the lifted document can be reliably pressed and brought into contact with the document scale 3.
[0013]
That is, the flat pad 11 disposed on the lower surface of the pressure plate main body 10 extends to the vicinity of the left end portion of the contact glass 33. The document scale 3 is arranged at the left end portion of the contact glass 33 so as to protrude upward from the contact glass surface. The free end portion 12a located at the front end of the white sheet 12 is extended so as to overlap the document scale 3 when the pressure plate is closed. The presser piece 13b of the presser member 13 is appropriately set in size and shape so that the appropriate position of the free end portion 12a can be pressed down. Since the presser piece 13b presses the free end 12a as shown in the figure when the pressure plate is closed, the edge of the document is positioned on the surface of the contact glass 33 in the state where the edge of the document is positioned on the set end surface 3a of the document scale 3 as in the above embodiment. The document can be read while the document surface is closely attached.
In the automatic document feeder 30 shown in FIG. 3, the hinge 4 is disposed on the left side when viewed from the front, but the hinge 4 is disposed rearward so that the front side of the apparatus 30 is opened and closed vertically. In other words, the pressing member 13 is disposed on the rear side of the flat pad 11. When the hinge is disposed on the right side, the pressing member 13 is disposed on the right side of the flat pad 11.
[0014]
【The invention's effect】
As described above, according to the present invention, when the lower surface of the document pressure plate or the conveyance belt of the automatic document feeder presses the document onto the contact glass, these overlap with the document scale, thereby A gap is formed between the document portion and the document scale, and as a result, the pressing force at the document edge portion is reduced, and the problem that reading failure occurs can be solved.
In particular, even if the positional relationship between the edge of the white sheet constituting the document pressure plate and the document scale is deviated, the white sheet surface can be easily brought into close contact with the contact glass to prevent the document from being lifted.
That is, according to the first aspect of the present invention, when the original platen is closed, the end of the original is surely pressed by the pressing force of the pressing member, so that the original floating can be suppressed, the straight bend, the black belt image Etc. can be eliminated.
In the invention of claim 2, the length of the pad corresponding to the portion where the pressing member abuts on the white sheet is shortened so that the white sheet is not pressed by the pad, and the degree of freedom of bending of the white sheet is increased. Since it can be pressed to just before the end, it is possible to hold the document floating.
In the invention of claim 3, since the adhesive surface between the white sheet on the side where the pressing member abuts and the pad is located on the inner side of the pad edge, it is not subjected to a rigid load by the pad, so the white sheet can be flexed freely. Since the degree can be increased, the document floating can be suppressed.
In the invention of claim 4, since the document pressure plate according to claim 1, 2 or 3 is applied to the document pressure plate portion of the sheet-through type automatic document feeder, the sheet-through type automatic equipped with the document pressure plate portion. In the document feeder, it is possible to improve the document setting performance by the document pressure plate and reduce the reading failure.
[Brief description of the drawings]
FIGS. 1A and 1B are a cross-sectional view showing an open state of a document pressure plate used in a document reading apparatus according to an embodiment of the present invention, and a cross-sectional view showing a closed state.
FIG. 2 is an exploded perspective view of a main part of an original platen according to the present invention.
FIG. 3 is a configuration diagram of an original reading apparatus according to another embodiment of the present invention.
FIG. 4 is an explanatory diagram of a conventional example.
[Explanation of symbols]
1. Reading device main body (image forming apparatus main body), 2 contact glass, 3 original scale, 3a set end face, 4 hinge, 5 original pressure plate, 10 pressure plate main body, 11 flat pad, 12 white sheet (flexible presser sheet), 12a Free end portion, 13 Presser member, 13a Shaft support portion, 13b Presser piece, 30 Automatic document feeder, 31 Main body, 32, 33 Contact glass, 35 Sheet-through feeder, 36 Original pressure plate portion.

Claims (3)

An apparatus main body provided with a contact glass for placing an original, an original scale provided with an original setting end face which is disposed along the edge of the contact glass and protrudes from the upper surface of the contact glass, and one end edge is hinged by the apparatus main body An original platen that is pivotally supported by the upper and lower sides to open and close the upper surface of the contact glass. The original platen is pivotally supported by the hinge so as to be opened and closed. A pressure plate main body, a pad attached to the lower surface of the pressure plate main body, and a flexible presser sheet attached to the lower surface of the pad and having an end portion on the side of the original scale as a movable end portion from which the pad on the upper surface is removed. , and a pressing member for urging downward the movable end of the flexible retaining sheet by a part thereof is supported to be vertically movable by piezoelectric plate body, said original During closure of the pressure plate, the document reading apparatus characterized by the tip of the movable end portion is configured to move it in contact with the copy edge on the contact glass to the document scale side. Before hear FLEXIBLE presser sheet to claim 1, characterized in that it is bonded by an adhesive surface, except for the non-adhesive surface of a predetermined width from the document scale side edge of the lower surface of the plate-like pad The document reading device described. The document pressing plate according to claim 1 or 2, characterized and to RuHara draft reading apparatus that has been applied to the document pressing plate portion of the automatic document feeder of the sheet-through type.

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