JPH11289430A - Image reader and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader and image forming device where a read image is not deteriorated, an original platen is damaged or a read means itself is not defective even when the original platen is bent due to the load of a read original. SOLUTION: A projections 3 is placed to parts of a scanning body 2 provided with a sensor unit 1 opposite to an original platen glass 10 at the outside of reading area at both ends of the sensor unit 1 respectively and a projection 4 is placed nearly in the middle between both the projections 3. The projection 4 is in existence in the read area in the main scanning direction and at the outside of the read line in the subscanning direction, and the projection 4 is less projected than the projections 3 are and projected more than a front side of the sensor unit 1. Guide rails 11 that guide the scanning body 11 along the original platen glass 1o are energized in a direction X by an energizing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to an image reading apparatus that reads an image on a document by forming an image of reflected light or transmitted light on an image sensor (photoelectric conversion element) and an image forming apparatus that forms an image.

[0002]

2. Description of the Related Art An image reading unit such as a copying machine or an image scanner irradiates a document placed on a platen glass with light,
An image is read by forming an image of the obtained reflected light or transmitted light on an image sensor using an imaging lens.

With reference to FIG. 6, a method of reading a document by a document reading device (hereinafter, referred to as an image scanner) will be described. FIG. 6 is a schematic diagram of the image scanner.

A document P is placed on a platen glass 110 of an image scanner 120 with the document reading surface facing the platen glass 110 side. By the light source of the optical unit U1,
The original P is irradiated, and the reflected light is imaged on the image sensor of the optical unit U1 through the imaging lens of the optical unit U1, and an image of one line of the original P is read. Then, by driving the optical unit U1 on the guide rail 111 along the platen glass 110 (U1 → U1 ′), the entire image of the document P is read.

FIG. 7 shows a configuration near an optical unit of an exposure / imaging optical system (hereinafter, referred to as an integrated optical system) in which a light source, an imaging lens, and an image sensor are integrally driven along an original.

A scanning unit 102 holds a sensor unit 101 including a light source, an imaging lens, and an image sensor.
02 moves on the guide rail 111 in the direction of the arrow W and along the platen glass 110, so that the platen glass 11
Scan the original on 0. Further, the scanning body 102 is configured to be urged against the platen glass 110, and the scanning body 102
Has a projection 103. Then, this protrusion 103
Thus, the platen glass 110 and the sensor unit 101 do not come into contact with each other, and the distance is kept constant.

That is, the projection 103 is placed on the platen glass 11
The scanning body 102 is driven while sliding with respect to 0.

[0008]

However, when a large book or the like is placed on the platen glass, a large load is applied to the platen glass, and when the platen glass is bent, the read image may be degraded. . FIG. 8 is a view in the direction of the arrow T in FIG. As shown in FIG. 8A, the platen glass 11
When 0 is not bent, the scanning body 102 is the guide rail 1
11 is driven without any problem. However, as shown in FIG. 8B, when a load is applied in the direction of the arrow Y and the platen glass 110 is bent by the load, the platen glass 110 is bent.
And the sensor unit 101 come into contact with each other, and as a result, the slidability deteriorates (such as an increase in driving load) or the sensor unit 10
In some cases, the optical component 1 may be damaged due to damage, or the back surface of the platen glass 110 (hereinafter, the surface facing the sensor unit is referred to as the back surface) may be damaged. In addition, the original placed on the original platen glass 110 also slightly moves in the arrow Y direction due to the bending of the original platen glass 110. As a result, the original may be outside the depth of field of the image sensor (the area indicated by the two-dot chain line in the figure), and the read image may be extremely deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to improve the quality of a read image even when the document table is bent due to the load of the read document. It is an object of the present invention to provide an image reading apparatus and an image forming apparatus which do not damage the document placing table or damage the reading means itself.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a light-transmissive original table, and a reflected or transmitted light of light illuminating the original placed on the original table. Scanning means for reading the image of the document by supporting the reading means and moving along the document mounting table; and Urging means for urging the scanning body toward the stage, wherein the scanning body is in contact with the document stage outside the reading area to maintain a constant interval between the document stage and the reading means. Wherein the scanning body has contact preventing means for preventing contact between the document placing table and the reading means when the document placing table is deformed. The distance between the document table and the reading means is constant Wherein the contact with the document table in the region outside the reading when shorter than the interval.

In this case, the distance between the reading means and the document placing table is normally held by the distance holding means, so that the read image is deteriorated even in the case of a reading means having a small depth of field such as a contact sensor. Even if the original placing table is bent by the load of the original to be read, the read image may deteriorate, the original placing table may be damaged, or the reading means itself may be damaged by contacting the original placing table. I will not do it. In addition, since such a contact prevention unit comes into contact with the document table outside the reading area, there is no obstruction to reading.

[0012] At least two or more of the space holding means are provided outside the reading area in the main scanning direction with the reading area therebetween, and the contact preventing means is provided in the reading area in the main scanning direction and in the sub-scanning direction. It may be provided outside the reading area.

With this arrangement, even if the scanning member is driven in the sub-scanning direction, the interval holding means always comes into contact with the document table outside the reading area, so that the reading area of the document table is not damaged. . In addition, even when the document table that is in contact with the interval holding means provided with the reading area in the main scanning direction bends and curves in the main scanning direction, the contact prevention means is provided in the reading area in the main scanning direction. Therefore, contact with the reading means can be effectively prevented. Even when the contact preventing means contacts the document table, the contact preventing means contacts the outside of the reading area in the sub-scanning direction, and does not hinder image reading.

The interval holding means is a first projection which protrudes toward the document placing table from the reading means, and the contact preventing means is configured such that the amount of projection from the reading means toward the document placing table is the first. The number of the second protrusions may be smaller than the number of the one protrusion.

[0015] In this case, the interval maintaining means and the contact preventing means can be provided with a simple configuration.

[0016] A guide member for guiding the scanning body along the document table may be provided, and the urging means may urge the guide member toward the document table.

Further, the scanning body comprises a base portion and a contact portion including at least the space holding means, and the urging means moves the corresponding contact portion to the base portion toward the document table. It can also be energized.

According to the present invention, there is provided an image forming apparatus comprising: an image reading section for reading an image of a document; and an image forming section for forming an image read by the image reading section on a recording material. Such an image reading device may be provided.

With this arrangement, the read image does not normally deteriorate even in the case of a reading means having a small depth of field such as a contact sensor, and even if the original placing table is bent due to the load of the original to be read, the contact is prevented. An image forming apparatus capable of forming a good image without deteriorating a read image due to the prevention means abutting on the document table can be provided. Further, even when the document table is bent by the load of the read document, the document table is not damaged and the reading means itself is not damaged, so that it is possible to provide an image forming apparatus having excellent durability. it can.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

(First Embodiment) FIG. 1 is a schematic view of an image scanner. The sensor unit 1 (including a light source, an imaging lens, and an image sensor) is connected to the scanning body 2, and is driven along a document table glass (document table) 10 on a guide rail 11 to read a document. It is composed of a system.

The sensor unit 1 uses a contact sensor and a SELFOC lens (trademark, hereinafter referred to as SLA). The structure of the contact sensor and the SLA makes it possible to make an integrated optical system compact and to use an image scanner. Although it is possible to reduce the size, on the other hand, since the distance between the read original and the image sensor, that is, the optical path length is short, the depth of field (the area that satisfies a certain resolution standard in the optical path direction, In the figure, there is a drawback that the area indicated by the two-dot chain line is narrow. For this purpose, a platen glass 10 on which a document is placed is placed.
It is necessary to always keep the surface of the platen glass 10 within the depth of field of the image sensor during the image reading of the positional relationship between the image sensor and the sensor unit 1. In the present embodiment, the reading means includes a contact sensor and an SLA.

In the portion of the scanning body 2 facing the platen glass 10, projections (first projections) 3 as spacing means are provided outside the reading areas at both ends of the sensor unit 1. A projection (second projection) 4 as a contact preventing means is provided near the approximate center between the portions 3. And the projection 4
Is located within the reading area in the main scanning direction (the sensor element direction of the image sensor) and outside the reading line in the sub-scanning direction (the driving direction of the scanning body 2). The projection 4 has a smaller projection amount than the projection 3. And it protrudes from the SLA surface.

Further, as shown in FIG. 2 (FIG. 1, view in the direction of arrow V), a guide rail (guide member) 11 is biased in the X direction by known biasing means (compression spring, torsion spring, etc.). , 21 in the drawing is supported by the apparatus 12 by a compression spring). Then, the platen glass 10 and the guide rail 11
The relationship between the dimension up to butting (dimension B in FIG. 2) and the dimension in the height direction of the scanning body 2 (dimension A in FIG. 2) is set slightly larger in dimension A than in dimension B (FIG. 2). Dimension A> Dimension B). As a result, the scanning body 2 is driven along the platen glass 10 by the urging force of the compression spring 21 while the protrusion 3 is in contact with the platen glass 10.

That is, with the above configuration, the positional relationship between the original platen glass 10 and the sensor unit 1 during image reading can be kept constant, and a good image can be obtained even with a contact sensor having a small depth of field. Obtainable.

In the case of reading an original in which the original platen glass 10 does not bend, that is, in the case of normal reading, the projections 3 at both ends are in contact with the raw material stage glass 10 and the projections 4 are in the original stage glass 10.
Scans a document without touching it.

Further, a load is applied to the platen glass 10,
When the platen glass 10 is bent (FIG. 3A), the protruding portion 4 is moved earlier than the sensor unit 1.
Since it comes into contact with 0, the load is not directly applied to the sensor unit 1. As a result, it is possible to prevent the optical components and the like of the sensor unit 1 from being damaged, and to prevent the sensor unit 1 from scratching the back surface of the platen glass 10.

Further, when a load is applied to the platen glass 10 and the platen glass 10 is largely bent (FIG. 3).
(FIG. 2B), the scanning body 2 is driven by the urging force of the compression spring 21 urging the guide rail 11 upward, and
(See FIG. 2), the sensor unit 1 moves the arrow Z until the biasing force of the compression spring 21 acting on the guide rail 11 and the load from the platen glass 10 are balanced.
Move in the direction. In this case, along with the movement of the sensor unit 1, the depth of field (the area indicated by the two-dot chain line in the figure) also moves in the direction of the arrow Z, so that extreme deterioration of the image can be prevented. The distance (dimension C in FIG. 2) between the guide rail 11 and the lower abutting portion 20 of the apparatus 12 is determined by the document table glass 1.
The value 0 is equal to or less than the amount of flexure that does not break even when flexed (dimension C <the amount of flexure to break).

According to the present invention having the above-described structure and operation, the original platen glass is prevented from flexing and directly contacting the image sensor due to the load caused by the original load. Even if the base glass is largely bent, the sensor unit moves up and down in accordance with the original base glass, so that extreme image deterioration can be prevented.

In FIG. 2, both ends of the guide rail 11 are biased by the compression springs 21. One end is rotatably supported in the up-down direction, and only the other end is attached upward by the compression spring 21. The same effect can be obtained even if the force is increased.

(Second Embodiment) In the first embodiment,
By urging the guide rail upward, the sensor unit was urged to the platen glass. However, as shown in FIG.
The guide rail 11 is fixedly supported on the apparatus, and the scanning body 2 is composed of a base portion 23 guided by the guide rail 11 and a contact portion 22 urged against the base portion 23. The same effect can be obtained by contacting the document table glass 10 with a known urging means (compression spring, torsion spring, etc.).

(Third Embodiment) As shown in FIG. 5, even if the length of the projection 4 in the main scanning direction (the direction of the sensor element of the image sensor) is substantially equal to the length of the scanning body, a load is applied to the platen glass. , And even if the platen glass is bent, the read image is not extremely deteriorated.

In the first, second, and third embodiments, the protrusion 4 having a smaller protrusion amount than the protrusions at both ends outside the reading area is located behind the reading line in the sub-scanning direction. However, even if it is arranged forward with respect to the reading line (see FIGS. 1A, 4A and 5A),
Similar effects can be obtained.

Although the above embodiment has been described with reference to an image scanner as an image reading device, a general image forming unit having an image forming unit for forming a read image on a recording material by using a contact sensor as an image sensor of the image reading unit is described. The same effect can be expected when applied to an image forming apparatus such as a copying machine or a facsimile.

[0035]

As described above, according to the present invention,
Normally, the distance between the reading means and the document table is held by the distance holding means, so that even in the case of a reading means having a small depth of field such as a contact sensor, the read image is not degraded, and the load of the read document is reduced. Even if the document placing table is bent, the read image does not deteriorate, the document placing table is not damaged, and the reading means itself is not damaged by contacting the document placing table. In addition, since such a contact prevention unit comes into contact with the document table outside the reading area, there is no obstruction to reading.

Since at least two spacing means are provided outside the reading area in the main scanning direction with the reading area therebetween, even if the scanning body is driven in the sub-scanning direction, the spacing means is always read. It does not touch the document table outside the area and does not damage the reading area of the document table. The contact preventing means is provided in the reading area in the main scanning direction even when the original placing table in contact with the interval holding means provided with the reading area in the main scanning direction warps and curves in the main scanning direction. Therefore, contact with the reading means can be effectively prevented. Even when the contact preventing means contacts the document table, the contact preventing means contacts the outside of the reading area in the sub-scanning direction, and does not hinder image reading.

Further, the spacing means is a first projection projecting more toward the document table than the reading means, and the contact preventing means projects less from the reading means toward the document table than the first projection. Since it is the second projection, the spacing means and the contact prevention means can be provided with a simple configuration.

An image forming apparatus comprising: an image reading section for reading an image of a document; and an image forming section for forming an image read by the image reading section on a recording material.
Since the image reading unit is provided with the image reading device according to the present invention, the read image is not deteriorated even in the case of a reading unit having a narrow depth of field such as a contact sensor, and the document table is not affected by the load of the read document. Even if it is bent, the contact prevention means abuts on the document table and the read image does not deteriorate,
An image forming apparatus capable of forming an excellent image can be provided. Further, even when the document table is bent by the load of the read document, the document table is not damaged and the reading means itself is not damaged, so that it is possible to provide an image forming apparatus having excellent durability. it can.

[Brief description of the drawings]

FIG. 1A is a schematic top view of an image scanner according to a first embodiment of the present invention. FIG. 1B is a schematic side view of the image scanner according to the first embodiment of the present invention viewed from the sub-scanning direction.

FIG. 2 is a view in the direction of arrow V in FIG. 1;

FIG. 3A is a schematic top view of the image scanner according to the first embodiment of the present invention when the original platen glass is bent, as viewed from the sub-scanning direction. FIG. 3B is a schematic top view in the sub-scanning direction of the image scanner according to the first embodiment of the present invention when the original platen glass is greatly bent.

FIG. 4A is a schematic top view of an image scanner according to a second embodiment of the present invention. FIG. 4B is a schematic side view of the image scanner according to the second embodiment of the present invention viewed from the sub-scanning direction.

FIG. 5A is a schematic top view of an image scanner according to a third embodiment of the present invention. FIG. 5B is a schematic side view of the image scanner according to the third embodiment of the present invention viewed from the sub-scanning direction.

FIG. 6 is a schematic diagram of an image scanner according to a conventional example.

FIGS. 7A and 7B are diagrams showing an image scanner according to a conventional example.

FIG. 8 is an image scanner according to a conventional example.
FIG. 4B is a view in the direction of arrow T in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,101 Sensor unit 2,102 Scanning body 3,4,103 Projection part 10,110 Document table glass 11,111 Guide rail 21 Compression spring 120 Image scanner U1 Optical unit P Document

Claims (6)

[Claims] A light-transmissive document table, reading means for reading, via the document table, reflected light or transmitted light of light illuminating a document placed on the document table; A scanning member that scans the image of the document by supporting the means and moves along the document table, and a biasing unit that biases the scanning member toward the document table. An image reading apparatus, comprising: a scanning body, wherein the scanning body is in contact with the document mounting table outside a reading area to maintain a constant distance between the document mounting table and the reading means. A contact preventing unit configured to prevent contact between the document placing table and the reading unit when the placing table is deformed, wherein the contact preventing unit is configured such that a distance between the document placing table and the reading unit is the predetermined distance; Outside the reading area if it becomes shorter Image reading apparatus characterized by serial and document table abuts. 2. The image forming apparatus according to claim 1, wherein at least two of the space holding units are provided outside the reading region in the main scanning direction with the reading region therebetween. 2. The image reading apparatus according to claim 1, wherein the image reading apparatus is provided outside the reading area in the direction. 3. The distance maintaining means is a first protrusion protruding from the reading means toward the document placing table, and the contact preventing means is configured such that an amount of projection from the reading means toward the document placing table is reduced. The image reading device according to claim 1, wherein the number of the second protrusions is smaller than the number of the first protrusions. 4. The apparatus according to claim 1, further comprising a guide member for guiding the scanning member along the document table, and wherein the urging means urges the guide member toward the document table. 4. The image reading device according to any one of claims 1 to 3. 5. The scanning body comprises a base portion and a contact portion including at least the interval holding means, and the urging means moves the corresponding contact portion to the base portion toward the document table. The image reading device according to claim 1, wherein the image reading device is energized. 6. An image forming apparatus comprising: an image reading unit that reads an image of a document; and an image forming unit that forms an image read by the image reading unit on a recording material. Item 6. An image forming apparatus comprising the image reading device according to any one of Items 1 to 5.