JP2001255601A - Image reading carriage and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a very reliable image reading carriage and a very reliable image reader by eliminating influence of the thermal expansion of a unit by generated heat from a lamp. SOLUTION: This image reading carriage is equipped with a lamp holder 20 holding the lamp 3, an image sensor 2, a lens unit 11, and a carriage 1 main body holding 1st mirror 6 to a 5th mirror 10, and the lamp holder 20 thermally expanded by the generated heat from the lamp 3 is provided to be displaced to the outside of an interference range with the carriage 1 main body, the image sensor 2, the lens unit 11 and the 1st mirror 6 to the 5th mirror 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading an image of an original, such as a scanner, a copying machine, or a facsimile apparatus, and more particularly, to an image reading carriage provided in these apparatuses. .

[0002]

2. Description of the Related Art Conventionally, various image reading apparatuses such as image scanners for reading digital image information and forming digital image information have been put to practical use.

In recent years, in such an image reading apparatus, although the image reading unit (carriage) itself becomes large, the structure of the entire apparatus can be simplified, and the optical adjustment can be completed only in the unit. Optical units have begun to be widely used.

An example of an image reading apparatus that reads an original using the image reading unit (carriage), which is an integrated optical system unit, will be described with reference to FIGS.

FIG. 6 is a schematic sectional view showing the image reading apparatus.

In order to read the image information, the original P is set on the original platen glass 91 toward the inside of the apparatus case, that is, the original P is set downward at a specified position.
The original P is pressed from the upper rear side of the original P by the original pressure plate 92 so as not to shift the upper side.

The image reading unit (carriage) 101 having the photoelectric conversion means (image sensor) 2 facing the original P by the original platen glass 91 is used to read one straight line of image information (one line of main scanning image information). In order to read the image information of the document P, the document P is moved in parallel in the sub-scanning direction (the direction of the arrow in the figure) from the leading end to the trailing end by a drive motor (not shown). .
As a result, a two-dimensional planar image of the original image can be read.

FIG. 7 shows an image reading unit (carriage).
1 shows a sectional view of the main body 101.

The lamp 3 as a light source is fixed directly at both ends in the longitudinal direction to the upper surface of the carriage 101, and the reflection shade 4 on the back side of the lamp 3 and the reflection shade 5 near the lamp 3 respectively have the carriage on the back side of the reflection surface. The first mirror 6 to the fifth mirror 10 are fixed to the positioning portion of the carriage 101 by a spring clip.

FIG. 4 shows a basic configuration diagram of the image reading unit (carriage) (lamp and the like are omitted).

A required portion of the document P is linearly illuminated in the main scanning direction by a lamp 3 as a light source, a reflector 4 on the back side of the lamp 3, and a reflector 5 near the lamp 3.

Here, the illustration of the platen glass 91 on which the document P is set is omitted.

A lens unit that forms an optical image on the light reflected on the image surface of the original P by an optical first mirror 6, a second mirror 7, a third mirror 8, a fourth mirror 9, and a fifth mirror 10. 11 and forms an image of the original on the image sensor 2 as a photoelectric conversion unit. Image sensor 2
Is to generate image information by performing photoelectric conversion.

After processing one line data,
The carriage as an image reading unit is moved by one line in the sub-scanning direction to create image information in the same manner, and this is repeated.

Normally, the carriage 101 has an opening for incorporating its internal optical components.

To obtain a good image during the image reading operation,
This opening is firmly fixed and sealed by a member serving as a lid such as a lamp holder so that external light and irregularly reflected light do not enter the inside of the carriage 101.

[0017]

However, in the case of the above-described prior art, the following problems have occurred.

As can be seen from the above, the optical adjustment of the image reading unit (carriage) 101 is completed only within the unit, so that a higher resolution image sensor can be used.

Therefore, unless the technical accuracy of the optical adjustment is extremely high, the capability of the high-resolution image sensor cannot be utilized. Further, even if a slight shift occurs after the optical adjustment, the performance is deteriorated.

As described in the conventional example, the required portion of the document P is linearly scanned in the main scanning direction by the lamp 3 as a light source, the reflector 4 on the back side of the lamp 3, and the reflector 5 near the lamp 3. Therefore, the image reading unit (carriage) 101 is not affected by the heat generated by the lamp 3.

That is, an image reading unit (carriage)
Regardless of whether the material of the lamp 101 is a resin material or a metal material, the heat generation of the lamp 3 causes thermal expansion and heat transfer. Due to this thermal expansion and heat transfer, the fixed positions of the optical first mirror 6, the second mirror 7, the third mirror 8, the fourth mirror 9, and the fifth mirror 10 are slightly shifted.

In the case of a mirror, this slight displacement affects both the incident angle and the reflection angle, so that the influence is doubled, and the respective displacements from the first to fifth mirrors are added. Results in a large deviation and deteriorates the performance.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to eliminate the influence of thermal expansion of a unit due to heat generation of a lamp, and to provide a highly reliable image reading apparatus. An object of the present invention is to provide a carriage and an image reading device.

[0024]

According to the present invention, there is provided a light source unit, an optical path forming unit for forming an optical path of reflected light of a document illuminated by the light source unit, and an optical path forming unit. A first frame body for holding the light source means, and an optical path forming means, in an image reading carriage provided as a unit with photoelectric conversion means for reading image information of the original by causing reflected light of the original to be incident by the forming means; And a second frame that holds the photoelectric conversion unit, wherein the first frame that thermally expands due to heat generated by the light source unit is connected to the second frame, the optical path forming unit, or the photoelectric conversion unit. It is characterized by being provided so as to be displaced out of the interference range.

[0025] Positioning and holding means for slidably positioning and holding the first frame with respect to the second frame are provided, and the first and second frames opposing each other except for a region slidably positioned and held by the positioning and holding means are provided. It is also preferable that the end face regions of the first and second frames have a predetermined gap.

It is also preferable that the predetermined gap is equal to or larger than the displacement of the first frame which thermally expands due to the heat generated by the light source means.

The positioning and holding means includes a mounting member for holding the first frame to the second frame via a hole provided in the first frame, and the mounting member comprises: It is also preferable that the screw is a stepped screw having a neck longer than the thickness of the hole and smaller than the diameter of the hole.

It is also preferable that at least one of the end face areas of the first and second frames having a predetermined gap is provided with a shielding space capable of blocking external light.

It is also preferable to provide a stepped portion having a predetermined gap in an end face region of the first and second frames, having a step from the outside to the inside of the first and second frames. It is.

The light source illuminates the document linearly in the main scanning direction, the shielding space is provided at both ends in the main scanning direction, and the stepped portion is at both ends in a direction orthogonal to the main scanning direction. It is also suitable to be provided for

In the step region of the step-like portion, the first
It is also preferable that the frame body is provided so as to be located outside the second frame body.

The image reading apparatus includes the above-described image reading carriage, and reads an original image by the image reading carriage to form an image based on image information.

[0033]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, the shape, and the relative arrangement thereof should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, and are not intended to limit the scope of the invention to the following embodiments. Note that the same components as those described in the section of the related art are denoted by the same reference numerals, and description thereof will be omitted.

First, the problem to be solved by the present invention will be described in more detail.

FIG. 4 showing the basic configuration inside the carriage (the lamps and the like are omitted) shows a state in which the carriage 3 has no thermal expansion and is not affected by the heat generated by the lamp 3 as the light source means.

The image sensor (photoelectric conversion means) 2, the lens unit (optical path forming means) 11, the first mirror 6 to the fifth mirror 10 (optical path forming means) each perform high-precision optical adjustment at an appropriate position on the carriage. And fixed
The reading position (part A) and the position of the image sensor 2 are optimal.

FIG. 5 shows a basic configuration (lamp and the like are omitted) of the inside of the carriage, which is affected by the heat generated by the lamp 3 as the light source means, and has a thermal expansion of the carriage.

Normally, the carriage and the lamp holder are integrated, and the heat generated by the lamp 3 causes a slight thermal expansion.

In the expansion of the carriage, the expansion direction and the amount of expansion are complicated depending on the configuration depending on the internal configuration of the carriage. Therefore, the position of the optical imaging component fixed to the appropriate position after the high-precision optical adjustment slightly shifts.

In FIGS. 5 and 4, the image sensor 2, the lens unit 11, and the first to sixth mirrors 10 seem to be fixed at exactly the same position because there is only a slight displacement.

However, when the optical path is checked with reference to the image sensor 2, the influence of both the incident angle and the reflection angle of the mirror is doubled, and the first mirror 6 to the fifth mirror 1 are changed.
Since the respective deviations are added up to 0, the normal reading position (part A) and the actual reading position are shifted by the X dimension.

The fact that the position is not the optimum reading position means that the position is not illuminated by the lamp 3, the reflection shade 4 and the reflection shade 5, so that the image of the document P cannot be read correctly.

In order to avoid such a problem, the influence of the heat generated by the lamp 3 is limited only to the thermal expansion of the lamp holder 20, and the carriage 1 for holding and fixing the optical imaging component is provided.
Must be unaffected.

Next, the present embodiment will be described. FIG. 3 is a top view of the main body (second frame) of the image reading unit (carriage) 1 of FIG.

Image reading carriage 1 according to this embodiment
Has a lamp holder (first frame) 20 so as to cover the upper surface of the carriage 1 body. Lamp holder 2
0 includes a lamp 3 as light source means, a reflector 4 on the back side of the lamp 3, and a reflector 5 near the lamp 3.

Thus, a slit window 24 for illuminating a desired portion of the original in a linear manner in the main scanning direction and guiding the linear original image to the optical image forming means of the carriage 1 main body is provided at the center of the lamp holder 20. It is formed in the part.

The lamp holder 20 is positioned on the carriage 1 body by the positioning holes 25 and the positioning long holes 26,
In the vicinity of the position of the positioning, the carriage is held on the carriage body by a step screw (positioning holding means, mounting means, stepped screw) 30. The longitudinal direction of the positioning elongated hole 26 is defined as a direction in which the extension of the center line faces the center of the positioning hole 25.

Here, the positioning hole 25 and the positioning long hole 2
The configuration relationship between 6 and the step screw 30 will be described in more detail.

FIG. 1 is a sectional view of the carriage 1 shown in FIG.
FIG. 2 shows a cross-sectional view as viewed from the part A.

The positioning hole 25 and the positioning long hole 26 of the lamp holder 20 are respectively fitted by positioning bosses 19 provided on the carriage 1 main body 1, and the lamp holder 20 is positioned on the carriage 1.

The positioning hole 25 and the positioning boss 19 are fitted over the entire circumferential surface. The positioning long hole 26 and the positioning boss 19 are fitted in the short circular direction. With a gap. Thus, the lamp holder 20 is mounted on the carriage 1 even if there is a slight dimensional tolerance between the distance between the positioning holes 25 and the long positioning holes 26 and the distance between the positioning bosses 19.

In the carriage 1, screw screw holes for the step screws 30 are provided immediately beside these positioning portions.
When the step screw 30 is a self-tapping screw (a female screw portion is formed on a mating member by the rotational force of the screw), the screw screw hole is provided as a lower hole thereof.

The neck of the step screw 30 is connected to the lamp holder 2.
0, there is a gap with the step screw hole 27 on the circumferential surface through the step screw hole (hole portion) 27, that is, the hole diameter of the step screw hole 27 is larger than that of the neck of the step screw 30. Is provided larger.

The length of the neck of the step screw 30 is slightly longer than the thickness of the lamp holder 20, so that the lamp holder 20 is not completely tightened. It is fixed so that it does not come off.

The contact between the lamp holder 20 and the carriage 1 comes into sliding contact only around these positioning portions and the vicinity of the step screw 30 portion. Other portions of the lamp holder 20 slightly float from the carriage 1 to form a (predetermined) gap.

Thus, the lamp holder 20 and the carriage 1 are independent from each other. Even if the lamp holder 20 is displaced due to the thermal expansion due to the heat generated by the lamp 3, the carriage 1 is pulled by the thermal expansion and the like. I do not receive.

Since the contact portion between the lamp holder 20 and the carriage 1 is also held down to a minimum, heat transfer is unlikely to occur and is not affected.

The thermal expansion of the lamp holder 20 in the thickness direction is as follows.
The amount is small compared to the planar direction, does not exceed the length of the neck of the step screw 30, and does not adversely affect the sliding movement of the lamp holder 20 and the carriage 1 at the step screw 30 portion.

Both ends of the carriage 1 in the main scanning direction are arranged so that external light and irregularly reflected light do not enter the inside of the carriage 1 from a portion where the lamp holder 20 and the carriage 1 slightly float to form a gap. Is provided with a portion serving as a shielding space 28.

Due to the shielding space 28, the performance of the high-resolution image sensor can be sufficiently exhibited without deteriorating the optical performance.

FIG. 2 shows the carriage body of FIG.
FIG. 3 is a cross-sectional view as viewed from a portion B. FIG. 2 is a cross-sectional view of a narrow space in a sub-scanning direction orthogonal to the main scanning direction, for example, at both ends in a sub-scanning direction. The case where the portion 28 is not provided will be described.

In this case, the same effect as in the case where the shielding space 28 is provided is obtained by forming the wall portion of the slightly floating gap between the lamp holder 20 and the carriage 1 into a stepped shape (forming a stepped portion). obtain.

At the front end of the wall of the carriage 1, the lower edge portion 16 is located closer to the outside of the wall, the upper edge portion 18 is located closer to the lamp holder 20 than the lower edge portion 16 and is located closer to the inside of the wall. An edge inclined portion (step) 17 connecting the two steps is provided between the portion 16 and the upper edge portion 18.

At the tip of the wall portion of the lamp holder 20, a lower cap portion 21 closer to the outside of the wall, an upper cap portion 23 and a lower cap portion closer to the carriage 1 than the lower cap portion 21 and closer to the inside of the wall. A cap portion inclined portion (step) 22 connecting the two steps is provided between the portion 21 and the cap portion upper step portion 23.

The lower edge portion 16 and the lower cap portion 21, the upper edge portion 18 and the upper cap portion 23, the edge inclined portion 17 and the inclined edge portion 22 face each other and slightly float. Creating gaps. As a result, the external light and the irregularly reflected light are shielded at the inclined portion and do not enter the carriage 1.

Similarly, the lamp holder 20 and the carriage 1 are independent, and even if the lamp holder 20 is thermally expanded due to the heat generated by the lamp 3, a gap is opened because the expansion direction is directed toward the outside of the carriage 1. Direction, and the carriage 1 is not affected by the thermal expansion of the lamp holder 20 and the carriage 1 is pulled.

Further, since there is no contact portion between the lamp holder 20 and the carriage 1, heat is hardly transmitted, and there is no influence.

[0068]

As described above, according to the present invention,
A first frame for holding the light source means, and a second frame for holding the optical path forming means and the photoelectric conversion means, wherein the first frame thermally expanded by the heat generated by the light source means; The second frame is provided so as to be displaced out of an interference range with the optical path forming means or the photoelectric conversion means, so that the second frame is formed by the heat generated by the light source means. Without being affected by the thermal expansion of the first frame, and without being affected by the heat transmitted to the first frame, the state of the optical adjustment performed with high accuracy can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a section AA of the image reading carriage of FIG. 3;

FIG. 2 is a schematic view of a section BB of the image reading carriage of FIG. 3;

3 is a top view of the image reading carriage of FIG. 6 as viewed from above.

FIG. 4 is a basic configuration diagram of an image reading carriage.

FIG. 5 is a diagram showing a basic configuration inside the carriage, showing a state where there is an influence of heat generation of a lamp and there is a thermal expansion of the carriage.

FIG. 6 is a schematic sectional view of the image reading apparatus.

FIG. 7 is a schematic sectional view of a conventional image reading carriage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 2 Image sensor 3 Illumination lamp 4,5 Reflection shade 6 First mirror 7 Second mirror 8 Third mirror 9 Fourth mirror 10 Fifth mirror 11 Lens unit 16 Lower edge portion 17 Edge inclined portion 18 Upper edge portion Part 19 Boss for positioning 20 Lamp holder 21 Lower part of cap part 22 Slope part of cap part 23 Upper part of cap part 24 Slit window 25 Positioning hole 26 Positioning long hole 27 Step screw hole 28 Shielding space 30 Step screw P Document

Claims (9)

[Claims] 1. A light source means, an optical path forming means for forming an optical path of reflected light of a document illuminated by the light source means, and a photoelectric device for causing the reflected light of the document to be incident on the light path forming means to read image information of the document. An image reading carriage provided as a unit with a conversion unit, comprising: a first frame holding the light source unit; and a second frame holding the optical path forming unit and the photoelectric conversion unit. The image reading carriage, wherein the first frame body, which thermally expands due to heat generated by the light source means, is provided so as to be displaced out of an interference range with the second frame body, the optical path forming means or the photoelectric conversion means. . 2. A positioning and holding means for slidably positioning and holding the first frame body on the second frame body, and opposing a region other than an area slidably positioned and held by the positioning and holding means. The end surface area of the first and second frames has a predetermined gap.
4. The image reading carriage according to claim 1. 3. The image reading carriage according to claim 2, wherein the predetermined gap is equal to or larger than a displacement amount of the first frame that thermally expands due to heat generation of the light source unit. 4. The positioning and holding means includes a mounting member for holding the first frame to the second frame via a hole provided in the first frame, and the mounting member includes: Is a stepped screw having a neck longer than the thickness of the hole and smaller than the diameter of the hole.
4. The image reading carriage according to claim 1. 5. The first and the second having a predetermined gap.
5. The image reading carriage according to claim 1, further comprising a shielding space in at least one part of an end surface region of the frame body, the shielding space being capable of blocking external light. 6. The first and the second, having a predetermined gap.
The stepped portion having a step from the outside to the inside of the first and second frames is provided in an end surface region of the frame of any one of claims 1, 2, 3, 4 and 5. Image reading carriage. 7. The light source unit illuminates a document linearly in the main scanning direction, the shielding space is provided at both ends in the main scanning direction, and the stepped portion is provided in a direction orthogonal to the main scanning direction. The image reading carriage according to claim 6, wherein the image reading carriage is provided at both ends. 8. The method according to claim 6, wherein the first frame is provided outside the second frame in a step region of the stepped portion. An image reading carriage according to any of the preceding claims. 9. An image reading apparatus comprising: the image reading carriage according to claim 1; and reading an original image by the image reading carriage to form an image based on image information. apparatus.