JP2005260660A - Image reading unit and image reader provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that there is a disadvantage in assembling time efficiency because a rod lens array is fixed to a frame by an adhesive, etc., in a conventional image sensor to therefore require an adhesive applying process, increasing assembling cost and require adhesive solidifying time for fixing each component, or the like for assembling. <P>SOLUTION: In an image reading unit with a structure, wherein a first member 1 and a second member 2 sandwich and fix the rod lens array 3, elastic materials 51 and 52 are provided at end parts of the rod lens array 3 in a longitudinal direction to thereby press and fix the rod lens array 3 on a positioning part 1b in the direction of a lens optical axis and a positioning part 1c in a lens longitudinal direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus such as an image scanner, a facsimile, or a copying machine, and more particularly to an image reading unit provided in an image reading unit.

  FIG. 4 shows a general configuration of a conventional image reading unit.

A plurality of image sensor chips 13 are attached to the substrate 12 arranged on the bottom surface of the case 11 made of resin or the like in a length range corresponding to the reading width. A transparent cover glass 14 is attached to the upper surface of the case 11, and a bright and dark image along the read line L is erected between the read line L set on the cover glass 14 and the image sensor chip 13. A rod lens array 15 for focusing twice on the image sensor chip 13 row is arranged. A plurality of LEDs 16 serving as a light source for illuminating the document D from the back side of the cover glass 14 are also arranged on the substrate 17 in the interior space of the case 11. The rod lens array 15 is fitted and held in a groove-shaped holder portion 18 set inside the case 11. The contact image sensor 10 is configured by combining various parts as described above. However, in the state where the rod lens array 15 is fitted and held in the groove-shaped holder portion 18 with respect to the case 11, It was glued and fixed. For example, in the conventional image sensor disclosed in Patent Document 1 below, the rod lens array is fixed to the frame with an adhesive.
JP 09-307696 A (page 4, FIG. 7)

  However, assembling the contact image sensor 10 requires many processes such as application of adhesive and solidification time of the adhesive, which is disadvantageous in production efficiency, for example. In addition, since the rod lens array is bonded and fixed to the frame, it is not possible to replace only the rod lens array. In addition, due to the difference in the linear expansion coefficient between the rod lens array and the frame due to the adhesive fixing, there is a problem that the reading performance is deteriorated due to distortion occurring in the rod lens array itself or the entire sensor unit due to temperature change.

  The present invention has been conceived under such circumstances, reduces the number of assembly steps with a simple structure, does not degrade the reading performance due to temperature changes, and easily replaces the rod lens array. An object of the present invention is to provide an image reading unit that can be used and an image reading apparatus including the image reading unit.

  In order to solve the above-described problems, in the present invention, the image reading unit is configured as the following (1) to (3), and the image reading apparatus is configured as the following (4).

(1) A first member having a surface for guiding an original, a second member for holding a substrate having an image sensor array, and a rod lens array sandwiched between the first member and the second member. An image reading unit,
The first member is provided with a positioning reference surface in the rod lens optical axis direction of the rod lens array and a positioning reference surface in the longitudinal direction of the rod lens array,
The second member holds the rod lens array movably in the rod lens optical axis direction and the rod lens array longitudinal direction between the rod lens array end portion and the first member and the second member. An image reading unit provided with an elastic member that urges the rod lens array to a positioning reference plane in the optical axis direction of the rod lens and a positioning reference plane in the longitudinal direction of the rod lens.

(2) In the image reading unit according to (1),
The elastic member is an image reading unit in which an urging portion for urging the rod lens array in the rod lens optical axis direction and the rod lens array longitudinal direction is integrally formed.

(3) In the image reading unit according to (1),
An image reading unit in which the rod member array and the elastic member are not fixed completely when the second member is inserted into the second member, but a protrusion that holds the rod member array so as not to drop off is formed on the second member.

  (4) The image reading unit according to any one of (1) to (3), and a moving mechanism that performs a predetermined relative movement between the image reading unit and a document to be read. An image reading device that reads an image of the original by relative movement between the image reading unit and the original.

  According to the present invention, by providing an elastic member, the rod lens array can be urged and positioned in the optical axis direction of the rod lens and the longitudinal direction of the rod lens array with a simple configuration, so that it is possible to reduce assembly man-hours and costs. In addition, it is possible to prevent deterioration in reading performance due to temperature changes. Further, since the position of the rod lens array is determined in the assembled state, the rod lens array can be fixed without using an adhesive, so that it is possible to replace only the rod lens array.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  FIG. 1 is a cross-sectional view illustrating a configuration of an “image reading apparatus” according to the first embodiment. In the drawing, 100 is an image reading apparatus, 100a is a sheet stacking unit for stacking and storing sheets S, 100b is a sheet stacking unit for stacking and storing sheets S after image reading, and 110 is a plurality of stacked sheets S. A sheet feeding and conveying apparatus that feeds the sheet into the apparatus, 121 to 124 are conveying rollers that convey the sheet S at a predetermined speed, 131 to 134 are driven rollers that are pressed against the conveying rollers 121 to 124, 140 , 150 is a front and back image reading unit that reads the image of the sheet S that has been sent.

  The front image reading unit 140 is supported so as to be movable substantially vertically while maintaining a parallel posture to the sheet S surface, and the back image reading unit 150 is fixedly supported on the conveyance path.

  Next, an image reading operation in the image reading apparatus 100 configured as described above will be described. When the image reading operation is started, the plurality of sheets S placed on the sheet stacking unit 100 a are fed into the image reading apparatus 100 by the sheet feeding / conveying device 110. The sheet S that has been rolled up is conveyed by the conveying roller 121 and the driven roller 131 and passes in close contact with the front and back image reading units 140 and 150.

  Then, the image formed on the front surface or the back surface of the sheet S passes through the front and back image reading units 140 and 150 while being scanned, and is output to the outside as an electric signal. After the image is read in this way, the sheet S is discharged to the paper discharge stacking unit 100b.

  Next, the image reading unit, which is a main part of the image reading apparatus of this embodiment, will be described in detail with reference to FIG. 1 is a first member, a reading guide that holds the transparent member 20, G is a sheet passing surface, 2 is a reading base that is a second member, and 3 is a rod lens that forms an image of reflected light from the sheet S on a light receiving element. Arrays, 3a and 3b are reference surfaces in the lens optical axis direction of the rod lens array 3, 3c is a reference surface in the longitudinal direction of the rod lens array 3, and 1a and 1b are lens lights of the rod lens array 3 formed on the reading guide 1. The reference surfaces 3a and 3b of the rod lens array are in contact with the reference surfaces for positioning in the axial direction. Reference numeral 1c is a reference surface for positioning the rod lens array 3 in the longitudinal direction formed on the reading guide 1, and the reference surface 3c in the longitudinal direction of the rod lens array 3 contacts. Reference numeral 1d is a reference hole serving as an assembly reference for the reading base 2 formed on the reading guide 1, 1e is an insertion guide surface when the rod lens array 3 is inserted into the reading guide 1, and 2d is formed on the reading base 2. The boss 4 which is assembled with the assembly reference hole 1d provided in the reading guide 1 is an image sensor which converts light into an electric signal and has an image sensor array. Reference numerals 51 and 52 denote elastic members having a cross-sectional shape shown in the figure, which press the rod lens array 3 against the reference surfaces 1a, 1b, and 1c. One end of the elastic member 51 is fitted to the end of the rod lens array 3. It is formed in a crotch shape.

  FIG. 3 is a cross-sectional view showing a state where the rod lens array 3 is inserted into the reading base 2 and the members 1 and 2 are not assembled. N is the distance from the center of the boss 2d in the lens optical axis direction to the reference plane 3c, and M is the distance from the center of the reference hole 1d in the lens optical axis direction to the reference plane 1c. In this state, the distance N is shorter than the distance M.

  Next, the order of assembly of the reading unit configured as described above will be described. The elastic members 51 and 52 are fitted into the end portions of the rod lens array 3 and then inserted into the reading base 2. The reading base 2 is provided with protrusions 2a and 2b, and the rod lens array 3 and the elastic members 51 and 52 are not completely fixed once inserted into the reading base 2 by these protrusions, but do not drop off. It becomes a state. Next, the reading base 2 is incorporated into the reading guide 1. At this time, since the distance N is shorter than the distance M, the rod lens array 3 is moved in the arrow P direction by the guide 1e. Thereafter, the rod lens array 3 moves to a position where the reference surface 1 c formed on the reading guide 1 presses the reference surface 3 c of the rod lens array 3. When further pushed, the reference surfaces 3a and 3b of the rod lens array 3 come into contact with the reference surfaces 1a and 1b of the reading guide 1. When the rod lens array 3 is pushed in as it is, the reference surfaces 3a, 3b and 3c of the rod lens array 3 are pressed against the reference surfaces 1a, 1b and 1c of the reading guide by the elastic members 51 and 52, respectively. Since the rod lens array 3 is moved in the direction of the arrow P by the reference surfaces 1c and 3c, the elastic member 52 has a pressing force in the longitudinal direction of the rod lens array 3 that is smaller than that of the elastic member 51, and as a result, the elastic member 51 on the opposite side. Therefore, the rod lens array 3 is always pressed against the reference surface 1c. The reading guide 1 and the reading base 2 are fastened and fixed by screws 300 and the assembly is completed.

  As described above, according to this embodiment, by providing the elastic member, the rod lens array can be biased and positioned in the rod lens optical axis direction and the rod lens array longitudinal direction with a simple configuration. The cost can be reduced, and the reading performance can be prevented from being deteriorated due to a temperature change. Further, since the position of the rod lens array is determined in the assembled state, the rod lens array can be fixed without using an adhesive, so that it is possible to replace only the rod lens array.

Sectional drawing which shows the structure of the image reading apparatus which is Example 1. FIG. Sectional drawing which shows the main structures of the image reading unit in Example 1. Sectional drawing which shows the state in which the member 1 in Example 1 and the member 2 are not assembled Sectional drawing which shows schematic structure of the image reading unit which is a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st member 2 2nd member 3 Rod lens array 51,52 Elastic member

Claims (4)

An image reading unit comprising: a first member having a surface for guiding a document; a second member for holding a substrate having an image sensor array; and a rod lens array sandwiched between the first member and the second member. Because
The first member is provided with a positioning reference surface in the rod lens optical axis direction of the rod lens array and a positioning reference surface in the longitudinal direction of the rod lens array,
The second member holds the rod lens array movably in the rod lens optical axis direction and the rod lens array longitudinal direction between the rod lens array end portion and the first member and the second member. And an elastic member that urges the rod lens array toward the positioning reference surface in the rod lens optical axis direction and the positioning reference surface in the longitudinal direction of the rod lens. The image reading unit according to claim 1,
2. The image reading unit according to claim 1, wherein the elastic member is integrally formed with an urging portion that urges the rod lens array in the rod lens optical axis direction and the rod lens array longitudinal direction. The image reading unit according to claim 1,
The second member is formed with a protrusion that holds the rod lens array and the elastic member in a state in which the rod lens array and the elastic member are not completely fixed when inserted into the second member, but are not dropped off. unit.   4. An image reading unit according to claim 1, and a moving mechanism for performing a predetermined relative movement between the image reading unit and an original to be read, and the image reading unit and the original An image reading apparatus for reading an image of the original by relative movement between the two.

Images