JP2012063491A - Image reader and image forming apparatus equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader with low cost and compact size which can easily and safely prevent the occurrence of abnormal images when a document image is read using a pressure plate.SOLUTION: In an image reader 1, a configuration is adopted where document abutting surfaces 101a and 101b of document abutting members 10a and 10b are made slanted with an obtuse angle with respect to the surface of a contact glass 3, and contact surfaces of a pressure plate 2 with the document abutting members 10a and 10b are made slanted in an opposite direction with the same or approximately the same slope. When the pressure plate 2 is being set, edges thereof are securely placed on the upper side of the document abutting members 10a and 10b, and the upper portion of the pressure plate 2 is placed in a protruding manner in an upward direction with respect to the document abutting members 10a and 10b. With the above configuration, upon setting down the pressure plate 2 on a document 20 on the contact glass 3, gaps are not likely to occur between the document abutting members 10a and 10b and edges of the document 20. Even if the gaps occur, a rear surface 5b of an ADF 5 is not read by the image reader 1, thereby preventing the occurrence of abnormal images.

Description

  The present invention relates to an image reading apparatus used for a facsimile, a scanner, a copier, and a multifunction machine of these, an image reading apparatus with an automatic document feeding function, and an image forming apparatus using these.

  FIG. 1 is a perspective view showing a conventional image forming apparatus such as a copying machine or a multifunction machine that uses an automatic document feeding function. In the figure, 1 is an image reading device, 2 is a pressure plate, 3 is contact glass, 4 is a paper discharge unit for stacking paper on which images have been recorded, 5 is an automatic document feeder (hereinafter referred to as ADF), and 6 is paper feed. Reference numeral 7 denotes an ADF 5 original platen. The ADF 5 can be opened and closed by turning up and down using a handle 30 on the front side of the apparatus, using a hinge on the back side (indicated by reference numeral 31 in FIG. 2). The paper feed unit 6 includes a plurality of paper feed stages 25 to 28. Further, it has a document discharge tray 29 for stacking documents sent from the ADF 5. In the figure, reference numeral 9 denotes a contact glass for reading a sheet-through document.

  The fixing member for the ADF 5 and the pressure plate 2 is made of an elastic member 21 such as a sponge (hereinafter referred to as a sponge 21 unless otherwise required) (see FIG. 5). That is, the sponge 21 is affixed to the back surface (lower surface) 5b of the component member 5a of the ADF 5 with a double-sided tape or the like, and the pressure plate 2 and the sponge 21 are connected via the hook-and-loop fastener 22 so that the pressure plate 2 can be detached from the ADF 5. As a configuration. When positioning the pressure plate 2 with respect to the ADF 5, the pressure plate 2 is once removed from the ADF 5, and two adjacent edges of the pressure plate 2 are brought into contact with the document abutting members 10a and 10b (shown in FIG. 3), respectively. The pressure plate 2 is attached to the ADF 5 by closing the ADF 5 in this state. By this mounting operation, the pressure plate 2 can be positioned.

  In such an image forming apparatus, when an original image is to be read without using the automatic document feed function of the ADF 5, the ADF 5 is lifted and opened by using a handle 30 as shown in FIG. The document 20 is placed on the contact glass 3 by abutting the document abutting members 10a and 10b provided on the edges of the document 20 along the edges of the document 20 (FIG. 4), and then the ADF 5 is closed, as shown in FIG. Then, the original plate 20 is held by the pressure plate 2 and the start button on the operation panel 11 is pressed to perform the image reading operation.

  However, the document abutting surfaces of the document abutting members 10a and 10b (for example, the surface denoted by reference numeral 101b in FIG. 3B) and the pressing surface of the pressure plate 2 are often not completely flat. Even if the document abutting members 10a and 10b intersect at right angles and the document abutting surfaces are perfectly flat, the edges of the document 20 itself may not be linear. In some cases, a minute gap (for example, symbol X in FIG. 6) may be formed between the edge of the document 20 and the document abutting surfaces of the document abutting members 10a and 10b. If there is such a gap, the image reading device 1 reads a part of the back surface (lower surface) 5b of the component member 5a of the ADF 5 as an image, so that part appears as a black image, which is a so-called abnormal image. .

  Further, even if the edges of the document 20 are properly abutted against the document abutting members 10a and 10b, due to the contact between the pressure plate 2 and the document 20 when the ADF 5 is closed, and the wind pressure associated with the operation of closing the ADF 5, The original 20 may be misaligned or the original 20 may be bent obliquely, resulting in an abnormal image.

  In the technique described in Patent Document 1, with respect to the above-described problem, the document setting reference surface includes a holding unit that holds an end portion of the document between the contact glass and the document setting reference surface. It has an inclined surface formed to protrude from the lower end to the upper end of the contact glass to improve the document holding property.

  However, the invention of Patent Document 1 has problems such as poor visibility because the document is hidden by the holding means, and the document is easily caught by the holding means.

  Therefore, in the present invention, an image reading apparatus and an automatic document feeder capable of preventing the occurrence of abnormal images as described above when reading a document image using a pressure plate easily, safely, and at low cost and compactly are provided. It is an object of the present invention to provide an image reading apparatus and an image forming apparatus using them.

  According to a first aspect of the image reading apparatus of the present invention, the document is placed on the contact glass by abutting the edge of the document against a document abutting portion serving as a reference for setting the document on the contact glass. In the image reading apparatus for fixing the original document placed on the contact glass using a pressure plate and closely contacting the contact glass to read an image on the original surface of the original document, the pressure plate is a configuration of the image reading apparatus. Among the plurality of pressure plate fixing members provided for fixing to the body, the stroke of the pressure plate fixing member provided corresponding to the reference position for setting the original is longer than the other pressure plate fixing members. .

  According to the second aspect of the present invention, in the image reading apparatus of the first aspect, an elastic member is used for the pressure plate fixing member, and an elastic member having a long stroke provided corresponding to a reference position for setting the document. The material is characterized in that the pressing force when the pressure plate is closed is weaker than other elastic members, and the pressing force of the plurality of elastic members when the pressure plate is closed is uniform.

  According to a third aspect of the present invention, in the image reading apparatus according to the first aspect, an elastic member having a long stroke is provided corresponding to a reference position for setting the original using an elastic member for the pressure plate fixing member. It is characterized in that the pressing force is weakened by making the area smaller than other elastic members, and the pressing force of the plurality of elastic members is uniform when the pressure plate is closed.

  According to a fourth aspect of the present invention, in the image reading apparatus of the second or third aspect, the elastic member is a sponge.

  According to the fifth aspect of the present invention, an edge of the original is abutted against an original abutting portion serving as a reference for setting the original on the contact glass, and the original is placed on the contact glass. In the image reading apparatus that reads the image of the document surface of the document by fixing the document placed on the contact glass and closely contacting the contact glass, the document abutting surface of the document abutting member has an upper edge side The contact glass has a slope inclined to the outer peripheral edge side, and has a slope inclined to the opposite side of the original plate abutting member of the pressure plate.

  According to a sixth aspect of the present invention, in the image reading apparatus according to the fifth aspect, the upper portion of the pressure plate is abutted against the original while the pressure plate is closed and the inclined surface of the document abutting member is in contact with the inclined surface of the pressure plate. It is characterized in that it is positioned above the upper edge of the slope of the member.

  According to the seventh aspect of the present invention, in the image reading apparatus according to the fifth or sixth aspect, the pressure plate includes a plurality of pressure plate fixing members for fixing the pressure plate to a constituent body of the image reading device, and the original among the pressure plate fixing members. The stroke of the pressure plate fixing member provided corresponding to the reference position for setting the is longer than the other pressure plate fixing members.

  According to the eighth aspect of the present invention, in the image reading apparatus according to the seventh aspect, an elastic member having a long stroke provided corresponding to a reference position for setting the original is used for the pressure plate fixing member. The material is characterized in that the pressing force when the pressure plate is closed is weaker than other elastic members, and the pressing force of the plurality of elastic members when the pressure plate is closed is uniform.

  According to a ninth aspect of the present invention, in the image reading apparatus according to the seventh aspect, an elastic member having a long stroke is provided corresponding to a reference position for setting the original using an elastic member for the pressure plate fixing member. It is characterized in that the pressing force is weakened by making the area smaller than other elastic members, and the pressing force of the plurality of elastic members is uniform when the pressure plate is closed.

According to a tenth aspect of the present invention, in the image reading apparatus according to the eighth or ninth aspect, the elastic member is a sponge.

  According to the eleventh aspect of the present invention, in the image reading apparatus according to any one of the first to tenth aspects, an automatic document feeder is provided.

  An image forming apparatus according to a twelfth aspect includes the image reading apparatus according to any one of the first to eleventh aspects.

  ADVANTAGE OF THE INVENTION According to this invention, the automatic document feeder which can prevent generation | occurrence | production of the abnormal image at the time of image formation using a pressure plate, an image reading apparatus using the same, and an image forming apparatus can be provided.

A perspective view showing an example of using an automatic document feeding function in a conventional image forming apparatus such as a copying machine or a multifunction machine 1 is a perspective view showing an open / close operation state of an ADF for trying to read a document image without using the automatic document feed function of the ADF in the image forming apparatus of FIG. Plan view (A) and BB cross-sectional view (B) showing arrangement of contact glass and document abutting member in apparatus of FIG. A plan view (A) and a BB cross-sectional view (B) showing a state where a document is set on a contact glass using a document abutting member in the apparatus of FIG. 1 is a cross-sectional view showing a state where an original is held on a contact glass by a pressure plate in the apparatus of FIG. FIG. 5 is an enlarged cross-sectional view showing a state where a minute gap is formed between the edge of the document and the document abutting surface of the document abutting member in the state of FIG. Front sectional view (A) and right side sectional view (B) showing Example 1 of the present invention Front sectional view (A) and right side sectional view (B) showing a state in which a document is set on a contact glass using a document abutting member in Embodiment 1 of the present invention A plan view (A) showing an example of the arrangement of sponges as pressure plate fixing members and a plan view (B) showing a document setting reference position FIG. 9A is a perspective view of the pressure plate and sponge shown in FIG. 9A, and a plan view showing a document setting state using the pressure plate and sponge.

  As an embodiment of the present invention, the platen contacts the contact glass from the document setting reference position side by increasing the stroke of the document setting reference position. As another embodiment of the present invention, an abnormal black image due to a gap is eliminated by providing a slope on the abutting surface of the document. In the first embodiment, the abutting surface is not provided with an inclined surface, but when the inclined surface is provided on the abutting surface as in the second embodiment, the gap between the pressure plate and the abutting member is eliminated to prevent abnormal images. In addition, since the stroke of the pressure plate fixing member on the document setting reference position side is longer than the other pressure plate fixing members, the pressure plate and the abutting member are pressed against each other when closing the pressure plate. It is easy to prevent the occurrence of an abnormal image due to the position of the document being displaced or the document being inclined by the wind pressure when closed.

  In other words, if the end portions of the pressure plate and the abutting member are inclined, even if a gap is formed, the pressure plate always exists above the edge portion of the document, so that the image reading apparatus does not read the back surface portion of the ADF. . In addition, if the end of the pressure plate and the abutting member is an inclined surface, the collision is mitigated when the pressure plate and the abutting member are in contact with each other, so that it is possible to reduce the impact noise and prevent the end of the pressure plate and the abutting member from being damaged. become.

Embodiments of the present invention will be described below with reference to the drawings.
7 is a front sectional view (A: a view seen from the same direction as FIG. 5) and a right side sectional view (B: a document abutting member 10a as seen from the right side of FIG. 3). FIG. The document abutting surfaces 101 a and 101 b of the document abutting members 10 a and 10 b are not perpendicular to the surface of the contact glass 3, and the document abutting surfaces 101 a and 101 b are inclined surfaces (inclinations) that form an obtuse angle with respect to the surface of the contact glass 3. Is inclined toward the outer peripheral edge of the contact glass 3, and the contact surface side of the pressure plate 2 with respect to the document abutting members 10a and 10b is also inclined in the same or substantially the same manner. For this reason, if the setting method of the pressure plate 2 as described above is used, the edge of the pressure plate 2 definitely gets on the upper side of the document abutting members 10a and 10b, and the upper portion of the pressure plate 2 is the position of the document abutting members 10a and 10b. As a result, the position can be adjusted so that a gap as described above cannot be formed even when the pressure plate 2 is lowered onto the contact glass 3, and the back surface 5 b of the component member 5 a of the ADF 5 is positioned on the document reading device 1. It is possible to reduce the occurrence of an abnormal image that is caused by being read by.

  If the angle α of the abutting surface 101b, that is, the inclination of the abutting surface 101b is too acute, the original 20 is brought into contact with the abutting surface 101b when the original 20 is set (see FIGS. 8A and 8B). The inner angle α formed by the slope is preferably about 60 to 80 degrees. However, this inclination angle may be determined as appropriate, and is not limited to this description or the illustrated example.

  As shown in FIG. 8, when the document 20 is set on the contact glass 3, the pressure plate 2 is abutted against the document 10a and pressed against the members 10a and 10b. Can be eliminated.

  For fixing the ADF 5 and the pressure plate 2, the sponge 21 may be used as a pressure plate fixing member as in the above-described conventional example. However, the original setting reference position (a position indicated by Z in FIG. 9A): In the example, it is preferable to use the sponge 21a (see FIG. 9B) provided on the side near the intersection position of the document abutting surfaces 101a and 101b, which has a longer stroke than the sponge 21 at other positions. When the thickness of the sponge 21 at another position (in other words, the height from the upper surface of the pressure plate 2 or from the rear surface 5b of the component member 5a of the ADF 5) is set to 10 mm, for example, it is made to correspond to the document setting reference position Z. The stroke of the sponge provided is preferably about 15 mm, for example. With this configuration, when the ADF 5 is opened, the pressure plate 2 on the document setting reference position Z side is in a state of hanging below other portions.

  That is, when the ADF 5 is closed, the pressure plate 2 comes into contact with the contact glass 3 side from the document setting reference position Z side and presses against the document abutting member 10 (see FIG. 10). When the document 20 is placed on the contact glass 3, the stroke of the sponge 21a that is a fixing member of the pressure plate 2 on the document setting reference position Z side is longer than that of the sponge 21 that is another pressure plate fixing member. Since the members 10a and 10b are pressed against the pressure plate 2 at the first position at the document setting reference position Z, the members 10a and 10b are pressed. Is less likely to shift or the document 20 is not inclined, thereby reducing the occurrence of abnormal images and reducing the cost.

  In addition, since this structure is the structure which lengthens the stroke of sponge 20a, an additional component is unnecessary and it can implement | achieve, without raising a cost.

  Further, since the end portions of the pressure plate 2 and the abutting members 10a and 10b are inclined, the collision is mitigated when the pressure plate 2 and the abutting members 10a and 10b come into contact with each other. It is also possible to prevent breakage of the ends of 10a and 10b. This is because the slope has a larger area, and the larger the area, the less the force at the time of collision.

  It should be noted that not only the stroke of the sponge 20a provided at the document setting reference position Z can be lengthened, but also the stroke corresponding to the slope of the abutting members 10a and 10b can be lengthened.

  In addition, it is considered that the pressing force is stronger in the portion of the pressure plate 2 corresponding to the sponge 20a having a long stroke as described above than in other portions. That is, the pressing force by the pressure plate 2 may vary between the portion corresponding to the sponge 20a having a long stroke and the other portions. As described in Patent Document 2, there is a possibility that the influence of such a variation in the pressing force may appear such as a shadow portion in the image. Regarding this point, for example, the material of the sponge with a long stroke is changed to a sponge having a weak pressing force when the sponge is closed, and the pressing force of the four sponges is made uniform when the pressure plate 2 is closed. This can be solved by reducing the pressing force by reducing the area of the sponge having a long stroke and making the pressing forces of the four sponges 21 uniform in the illustrated example when the pressure plate 2 is closed. With such a configuration, the original can be automatically abutted against the original abutting member 10 when the pressure plate is closed in accordance with the prevention of the abnormal image, so that the setting property of the original is improved.

1: Image reading device 2: Pressure plate 3: Contact glass 4: Paper discharge unit 5: Automatic document feeder (ADF)
5a: ADF component 5b: Back surface (lower surface) of ADF component
6: Paper feed unit 7: Document placement plate 9: Contact glass 10, 10a, 10b for reading sheet through document: Document abutting member 11: Operation panel 20: Document 21: Elastic member 21a: Sponge 22: Surface fastener 25 to 28: Paper feed stage 29: Document discharge tray 30: Handle 31: Hinge 101a, 101b: Document abutting surface α: Interior angle X of the abutting surface X: Clearance Z: Document setting reference position

JP 2004-163835 A Japanese Patent No. 3576746 JP 2009-045586 A JP 2007-309968 A

Claims (12)

The document is placed on the contact glass by abutting the edge of the document against a document abutting portion serving as a reference for setting the document on the contact glass, and placed on the contact glass using a pressure plate In an image reading apparatus that fixes an original and closely contacts the contact glass to read an image on the original surface of the original,
Among the plurality of pressure plate fixing members provided to fix the pressure plate to the component of the image reading apparatus, the stroke of the pressure plate fixing member provided corresponding to the reference position for setting the document is different from other pressure plate fixing members. Longer than,
An image reading apparatus. The image reading apparatus according to claim 1.
An elastic member is used for the pressure plate fixing member, and the material of the elastic member having a long stroke provided corresponding to a reference position for setting the original is set so that the pressing force when the pressure plate is closed is higher than that of other elastic members. An image reading apparatus that is weak and configured so that the pressing force of the plurality of elastic members is uniform when the pressure plate is closed. The image reading apparatus according to claim 1.
An elastic member is used for the pressure plate fixing member, and the area of the elastic member having a long stroke provided corresponding to a reference position for setting the original is made smaller than other elastic members to weaken the pressing force. An image reading apparatus characterized in that the pressing force of the plurality of elastic members when closed is uniform.   4. The image reading apparatus according to claim 2, wherein the elastic member is a sponge. The document is placed on the contact glass by abutting the edge of the document against a document abutting portion serving as a reference for setting the document on the contact glass, and placed on the contact glass using a pressure plate In an image reading apparatus that fixes an original and closely contacts the contact glass to read an image on the original surface of the original,
The document abutting surface of the document abutting member has a slope whose upper edge side is inclined toward the outer peripheral edge side of the contact glass,
Having a slope inclined to the opposite side of the slope of the document abutting member of the pressure plate,
An image reading apparatus. The image reading apparatus according to claim 5.
The upper portion of the pressure plate is positioned above the upper edge of the slope of the document abutting member in a state where the pressure plate is closed and the slope of the document abutting member is in contact with the slope of the pressure plate. An image reading apparatus. The image reading apparatus according to claim 5 or 6,
A plurality of pressure plate fixing members are provided to fix the pressure plate to the component of the image reading apparatus, and a stroke of the pressure plate fixing member provided corresponding to a reference position for setting the original is set among these pressure plate fixing members. An image reading apparatus characterized by being longer than other pressure plate fixing members. The image reading apparatus according to claim 7.
An elastic member is used for the pressure plate fixing member, and the material of the elastic member having a long stroke provided corresponding to a reference position for setting the original is set so that the pressing force when the pressure plate is closed is higher than that of other elastic members. An image reading apparatus that is weak and configured so that the pressing force of the plurality of elastic members is uniform when the pressure plate is closed. The image reading apparatus according to claim 7.
An elastic member is used for the pressure plate fixing member, and the area of the elastic member having a long stroke provided corresponding to a reference position for setting the original is made smaller than other elastic members to weaken the pressing force. An image reading apparatus characterized in that the pressing force of the plurality of elastic members when closed is uniform.   10. The image reading apparatus according to claim 8, wherein the elastic member is a sponge.   11. The image reading apparatus according to claim 1, further comprising an automatic document feeder. An image forming apparatus comprising the image reading apparatus according to claim 1.