JP6284843B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus that reads an original and an image forming apparatus including the image reading apparatus.

In a conventional image reading apparatus, a line-shaped reading sensor is disposed in a direction orthogonal to the document conveyance direction, and the conveyed document is scanned while being scanned for each column.
However, there are variations in sensitivity among the reading sensors, and when used as they are, there is a problem that the read image data is affected by the variation and the image cannot be accurately reproduced. In order to solve this problem, individual sensitivity variations of the reading sensor are corrected by shading correction.

  A white reference plate is used as a white reference when performing shading correction. The white reference plate is disposed at a position facing the reading sensor. However, a gap through which the document passes is required between the white reference plate and the document table. In this type of apparatus, if the original is wrinkled, there is a problem that a gap is formed between the original and the original table, and the reading accuracy is lowered. Some use a white roller instead of a white reference plate. This is a configuration in which a white roller is arranged at a position facing the reading sensor, this white roller is used in place of the white reference plate, and the original is brought into contact with the original table by urging the original in the direction of the original plate. . According to this, since the document is pressed against the document table at the reading position, the reading accuracy is improved. However, since the white roller is in contact with the document, there is a problem that dirt and scratches occur, and the white color of the roller changes and the white reference changes.

  In order to solve these problems, the conventional technique described in Japanese Patent Laid-Open No. 10-98580 discloses a technique in which a white reference plate supported so as to be movable up and down is provided at a position facing the reading sensor. In this prior art, there is further a first protrusion that makes the distance between the white reference plate and the document table constant, and the distance between the white reference plate and the document table is constant. Further, in order to prevent flapping of the original, a second protrusion lower than the first protrusion is provided so as not to block the reading portion between the pair of conveying rollers, and the sent original is pressed.

Japanese Patent Laid-Open No. 10-98580

  However, in the prior art, when dirt is attached to the white reference plate, it can be solved by wiping it off. However, if the white reference plate is damaged, it is necessary to replace parts. However, in order to replace the parts, it is necessary to open the casing of the document reading unit, remove the parts fixed to the casing, mount new parts, and finely adjust the position. There are problems such as complicated processes and time-consuming fine adjustment.

  In view of such a problem, the present invention provides an image reading apparatus and an image forming apparatus in which the white reference plate can be easily replaced and the mounting accuracy is good.

An image reading apparatus according to the present invention includes a conveyance roller that conveys a document, a pinch roller that is provided opposite to the conveyance roller and sandwiches and presses the document with the conveyance roller, and a document table that supports the document to be conveyed. A white flat plate portion that is arranged facing the document table and reads the document, and a white flat plate portion that is arranged at a position facing the reading sensor with the document table in between and serving as a reference for the reading sensor to read A white reference plate unit, a support portion that supports the flat plate portion so as to be movable toward and away from the document table, a lid portion that supports the pinch roller and on which the support portion is disposed, and In the image reading apparatus that supports the transport roller and supports the lid portion so as to be openable and closable, and further includes the document table and a base portion that accommodates the reading sensor. White reference plate unit, two to the axis of which is arranged along a longitudinal direction of said plate, the longitudinal direction of the outer and was in rotation to each of the longitudinal ends of the axis of said plate A presser roller that is freely arranged and presses the original, and a reinforcing part that is arranged along the longitudinal direction of the flat plate portion and prevents the flat plate portion from bending, and is opposed to the original platen of the lid portion. An opening through which the flat plate portion of the white reference plate unit is exposed, and the flat plate portion is bent in a direction in which a longitudinal end portion of the flat plate portion is separated from a surface serving as the white reference. A first fixing portion detachably connected to the white reference plate unit is formed at the bent portion, and the white reference plate unit has a second fixing portion detachably connected to the first fixing portion. is disposed at a position sandwiched between the two axes, the lid is the In opened relative to the base portion, it is possible to attach and detach the said plate to the white reference plate unit by detaching the second fixing portion and the first fixing portion through the opening, the lid When the section is closed, the transport roller and the pinch roller are disposed on the upstream side and the downstream side in the transport direction of the document on the document table, and the press roller is the longitudinal direction of the corresponding reading sensor. The document conveyed to the document table is pressed on both outer sides of the document .

  An image forming apparatus according to the present invention includes the above-described image reading apparatus, a conveying unit that conveys a recording medium, and a recording that records an image on the conveyed recording medium based on image data read by the document reading apparatus. And means.

  According to the present invention, the white reference plate can be easily replaced and the mounting accuracy can be improved. Thereby, the accuracy of shading correction of the reading sensor is also improved, and the document reading accuracy can be improved.

FIG. 1 is a diagram illustrating the arrangement of white reference plate units. FIG. 2 is a perspective view of the image reading apparatus. FIG. 3 is a diagram for explaining attachment and detachment of the white reference plate. FIG. 4 is a diagram illustrating the structure of the white reference plate unit. FIG. 5 is a schematic diagram of the image forming apparatus. FIG. 6 is a diagram for explaining another example of the white reference plate unit.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating the arrangement of white reference plate units. FIG. 2 is a perspective view of the image reading apparatus. The image reading apparatus will be described with reference to FIGS.

  The image reading device 10 is a device that reads a document. The image reading apparatus 10 is divided into a lid portion 1 and a base portion 5. The lid portion 1 is supported by the base portion 5 so that it can be opened and closed. The lid portion 1 is rotatably supported on the upstream side in the document transport direction of the base portion 5 and can be opened and closed.

  A white reference plate unit 2 is disposed on the lid 1 of the image reading apparatus 10. In the base unit 5, reading sensors 14 including line-type photoelectric conversion elements are arranged in a staggered manner. The white reference plate unit 2 is arranged on the back plate 4 constituting the opposed surface of the document table 15 of the lid 1, and more specifically, is arranged at a position facing the reading sensor 14.

  The base unit 5 is provided with a motor 19 for rotating a belt 17 wound around two pulleys 18. There is a shaft at the center of the pulley 18, and a plurality of transport rollers 12 are attached to the shaft. When the pulley 18 rotates, the shaft rotates, and the transport roller 12 further rotates.

  The document is transported on the document table 15 in a transport direction 16 indicated by an arrow. FIG. 2 shows a state in which the lid portion 1 is open with respect to the base portion 5. When reading a document, the lid 1 is closed. A plurality of pinch rollers 3 are arranged on the lid portion 1 at a position facing the conveying roller 12. The conveyance roller 12 rotates in conjunction with it, and conveys the original document with the pinch roller 3 provided in the lid 1. A plurality of conveyance rollers 12 are arranged in parallel along the longitudinal direction of the document table 15 so that documents of various widths can be conveyed.

  On the base unit 5, a plurality of first document position detection sensors 13 are arranged along the longitudinal direction of the document table 15, and a plurality of second document position detection sensors 6 are arranged so as to sandwich the document table 15. This is to detect whether or not the conveyed document reaches the front of the document table 15 and whether or not it reaches the downstream of the document table 15. The plurality of first document position detection sensors 13 detect the document width. The second document position detection sensor 6 is arranged on the document insertion side and the document discharge side at the center in the width direction, thereby detecting the position of the document with respect to the document table 15. By conveying along the center, it is possible to handle documents of various widths.

The periphery of the transport roller 12 is set lower than the document table 15 and the top of the outer periphery of the transport roller 12 is exposed. This is so that the transport roller 12 can sufficiently hold the document.
The reading sensors 14 are arranged in a staggered pattern on the document table 15. The white reference plate unit 2 is disposed on the lid 1 so that the respective white reference plate units 2 face each other for each reading sensor 14.

  Since the reading sensors 14 are arranged in a plurality of rows, in this example, in two rows, the distance between the transport rollers 12 provided on the two shafts becomes longer. The white reference plate unit 2 is provided with a plurality of press rollers for transporting the document without floating from the document table 15, and particularly for transporting the document without floating on the reading sensor 14. Hold down. Here, the pressing roller is pressed by the weight of the white reference plate unit 2. Preferably, a plurality of press rollers are arranged along the entire length of the reading sensor 14 in the longitudinal direction. By doing so, the document can be further prevented from floating.

  Next, the attachment / detachment of the white reference plate will be described with reference to FIGS. 3 and 4. FIG. 3 is a view of the lid 1 as viewed from the side facing the document table 15 and shows a part of the lid 1. An opening 23 is provided in the back plate 4, which is the side facing the document table 15 of the lid 1 and is the back surface of the lid. The white reference plate unit 2 is disposed in the opening 23 at a position facing the reading sensor 14. The white reference plate 20 of the white reference plate unit 2 is provided with a detachable mechanism. The white reference plate 20 is inserted into the opening 23 and fixed. A portion of the white reference plate 20 facing the reading sensor 14 is configured by a flat plate portion 21. Attachment portions 22 are disposed on both sides of the flat plate portion 21 in the longitudinal direction. The attachment portion 22 is formed by bending an end portion of the white reference plate 20 and providing an attachment hole 27 that is a through hole at that portion. Two shafts 11 are arranged in parallel behind the opening 23, and a presser roller 24 is provided at the end thereof. The presser roller 24 is a roller that presses the document, and presses it with its own weight of the white reference plate unit 2. The attachment portion 22 may be a separate body, but preferably has an integral configuration.

  FIG. 4 is a diagram illustrating the structure of the white reference plate unit. The white reference plate 20 forms a bent portion 25 in which an edge along the longitudinal direction of the flat plate portion 21 is bent. This increases the strength. A rectangular parallelepiped weight 26 is fixed to the surface of the flat plate portion 21 opposite to the surface facing the reading sensor 14. The weight 26 functions as a reinforcing material that increases the pressing force on the original by increasing the weight of the white reference plate unit 2 and prevents the flat plate portion 21 from being bent, and is preferably made of metal. . The attachment portion 22 and the attachment hole 27 are used when the white reference plate 20 is attached to and detached from the white reference plate unit 2. In order to increase the strength, it is preferable that the weight 26 is longer in the height direction than in the width direction. Further, it is preferable to fix the weight 26 so that the center of gravity of the weight 26 is located at the center in the longitudinal direction of the flat plate portion 21.

  At the end of the shaft 11, there are provided roller fixing portions 31 and 32 that rotatably support the presser roller 24. The presser roller 24 is disposed outside the reading range of the reading sensor 14. The shaft 11 is supported by a shaft support portion 28. The shaft support portion 28 is provided with an elastic portion 29 and a convex portion 30 between the roller fixing portions 31 and 32. The white reference plate 20 is fixed to the white reference plate unit 2 by fitting the convex portion 30 into the mounting hole 27. The elastic part 29 bends, so that the taper of the convex part 30 is overcome and the convex part 30 fits into the mounting hole 27. Moreover, the convex part 30 can also be removed from the attachment hole 27 because the attachment part 22 and the elastic part 29 bend. The white reference plate 20 provided with the weight 26 can be attached and detached with the lid portion 1 opened. The mechanism that can be attached and detached in this way is provided by providing the mechanism on the white reference plate 20 side as the first fixing portion and the mechanism on the white reference plate unit 2 side as the second fixing portion, and contacting and separating the respective fixing portions. The white reference plate 20 can be attached to and detached from the white reference plate unit 2.

FIG. 5 is a schematic diagram of the image forming apparatus. The image forming apparatus 40 includes an image reading unit 41 and a recording unit 42.
The image reading portion 41 is divided into a base portion 5 and a lid portion 1, and the lid portion 1 is supported on the base portion 5 so as to be opened and closed. The base unit 5 includes a transport roller 12 that transports the document 43. The conveyance roller 12 is disposed in the vicinity of inserting the document 43 and in the vicinity of discharging. A pinch roller 3 that is paired with the transport roller 12 is supported by the lid 1.

  When the lid portion 1 is closed, the pinch roller 3 presses the document 43 in the direction of the document table 15 to bring it into close contact. A white reference plate 20 is disposed at a position facing the reading sensor 14. Above the reading sensor 14, the document 43 is conveyed while being pressed by the pressing roller 24. The conveyance roller 12 is rotationally driven, and the pinch roller 3 is rotated in accordance with the rotation, and the press roller 24 is rotated while being pressed in conjunction with the conveyance of the document 43.

  The base unit 5 includes a document table 15 that supports the document 43. The surface of the document table 15 is disposed at the same height as the apex of the outer periphery of the transport roller 12. The document table 15 is a transparent and flat glass plate. A document 43 passes over the document table 15. The reading sensor 14 is disposed so as to be in contact with the surface of the document table 15 that is not the conveyance surface of the document 43. The reading sensors 14 are arranged in a zigzag pattern with two in the document insertion direction and three in the discharge direction. Each reading sensor 14 is arranged so that a part of the reading portion overlaps when reading the document 43. A white reference plate unit 2 is disposed on the lid 1. The white reference plate unit 2 includes a white reference plate 20, a shaft 11, and a pressing roller 24.

  The recording unit 42 stores a recording medium 44 to be used. The recording medium 44 is a roll of paper or plastic film. The recording medium 44 is conveyed by a conveying means having a recording medium conveying roller 45. An image is recorded on the recording medium 44 conveyed by the recording means 46. Recording on the recording medium 44 can also be performed based on image data read by the image reading device 10. It is also possible to receive image data from an external computer and record the image on a recording medium based on the image data.

  FIG. 6 is a diagram for explaining another example of the white reference plate unit. This is an example of a white reference plate unit 48 in which a plurality of press rollers 24 are provided on two shafts 11. Both ends of the white reference plate 20 are bent, a convex portion 47 is provided at the bent portion 25, and the presser roller 24 is disposed between the convex portions 47. The presser roller 24 is rotatably supported on the two shafts 11. The projection 47 and the presser roller 24 prevent the document from entering the gap. Further, by providing a plurality of presser rollers 24, it is possible to suitably press and stretch the wrinkles of the document. Furthermore, by providing protrusions at positions corresponding to the protrusions so that the openings 23 are staggered, even if the leading edge of the document is curled, the openings 23 can be prevented from entering the gaps.

  The present invention can be applied to a reading apparatus that conveys a document and reads the document.

DESCRIPTION OF SYMBOLS 1 Cover part 2 White reference board unit 3 Pinch roller 4 Back board 5 Base part 6 2nd original position detection sensor 10 Image reading apparatus 12 Conveyance roller 13 1st original position detection sensor 14 Reading sensor 15 Original stand 17 Belt 18 Pulley 19 Motor 20 White reference plate 21 Flat plate portion 23 Opening portion 24 Presser roller 25 Bending portion 26 Weight 27 Mounting hole 29 Elastic portion 30 Protruding portion 40 Image forming apparatus 41 Image reading portion 42 Recording portion 43 Document 44 Recording medium 45 Recording medium conveyance roller 46 Recording means

Claims (5)

A transport roller for transporting the document;
A pinch roller that is provided opposite to the transport roller and that presses the document against the transport roller;
A document table for supporting the document to be conveyed;
A reading sensor disposed opposite to the document table and reading the document;
A white reference plate unit having a white flat plate portion which is disposed at a position facing the reading sensor with the document table in between and serving as a reference for reading by the reading sensor;
A support portion that supports the flat plate portion so as to be movable toward and away from the document table;
A lid that supports the pinch roller and on which the support is disposed;
In the image reading apparatus that supports the transport roller and supports the lid portion so as to be openable and closable, and further includes the document table and a base portion in which the reading sensor is accommodated.
The white reference plate unit is rotated around each of two shafts arranged along the longitudinal direction of the flat plate portion and the end portion of the shaft in the longitudinal direction outside the longitudinal direction of the flat plate portion. A presser roller that is movably disposed and presses the document; and a reinforcing portion that is disposed along a longitudinal direction of the flat plate portion and prevents the flat plate portion from being bent,
The side of the lid facing the document table is provided with an opening through which the flat plate portion of the white reference plate unit is exposed.
The flat plate portion is bent in a direction in which an end portion in the longitudinal direction of the flat plate portion is separated from the surface serving as the white reference, and the first fixing is detachably connected to the white reference plate unit at the bent portion. Part is formed,
The white reference plate unit is disposed at a position where a second fixing portion detachably connected to the first fixing portion is sandwiched between the two shafts ,
The flat plate portion is attached to and detached from the white reference plate unit by attaching and detaching the first fixing portion and the second fixing portion through the opening in a state where the lid portion is open with respect to the base portion. Can
When the lid portion is closed, the transport roller and the pinch roller are disposed on the upstream side and the downstream side in the transport direction of the document on the document table, and the press roller is the corresponding sensor of the reading sensor. An image reading apparatus that presses the original conveyed to the original table on both outer sides in the longitudinal direction . Said first fixing portion has a through hole provided in the bent portion, the second fixing portion is provided on said white reference plate unit, have a convex portion which fits into the through hole in a state where the flat plate portion to the white reference plate unit is mounted, the image reading apparatus according to claim 1 the weight is characterized Rukoto disposed between the two axes. Said plate, said surface facing the platen of said plate along the front Symbol shaft and weight is fixed on the opposite side, the weight is made of metal, the longitudinal direction of said plate the image reading apparatus according to claim 1 or claim 2 centroid in the central portion is characterized that you have been arranged to be positioned in.   The said reinforcement part contains the said weight fixed to the said flat plate part that the part parallel to the said longitudinal direction of the said flat plate part is bend | folded over the full length. 4. The image reading apparatus according to any one of items 3. An image reading apparatus according to any one of claims 1 to 4,
Conveying means for conveying the recording medium;
An image forming apparatus comprising: a recording unit configured to record an image on the transported recording medium based on image data read by the document reading device.

Images