JPH0633118U - Image reader - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the reading error that occurs when a document floats from the document surface. [Structure] A document 6 is supported on a document placement surface S and conveyed in a predetermined direction. The light source on the lower surface of the original 6 is incident on the converging rod lens arrays 14 and 16 and is focused on the image sensors 18, 20 and 22 as a one-to-one erect real image. The focusing rod lens arrays 14 and 16 are arranged in an inverted V shape so that the plurality of image sensors 18, 20 and 22 can be arranged in a staggered pattern. In order to reduce the angle Q1 of the optical paths L2, L3 of the converging rod lens arrays 14, 16 with respect to the vertical axis L1 perpendicular to the document mounting surface S, the length of the converging rod lens arrays 14, 16 is The meandering period of the light traveling through is set to a value of N + 3/4 (N is a natural number).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an image reading apparatus in which an image of a reading line of an original is formed on an image sensor as a one-to-one erect real image by a converging rod lens array (trade name: Selfoc lens array).

[0002]

[Prior art]

 In Japanese Patent Publication No. 59-42511, as shown in FIG. 4, a pair of optical systems 2 and 3 consisting of self-occ lens array (SLA) under the reverse V shape of the manuscript are arranged on the manuscript reading line below the manuscript. The plurality of 1C image sensors 4 and 5 are arranged in a staggered manner so as to cover the document width without a gap, and the document reading line RL is arranged on the plurality of 1C image sensors 4 and 5. An image reading apparatus is disclosed in which the reflected light from is formed as a one-to-one erect real image.

[0003]

[Problems to be solved by the device]

 In order to form the incident light source A of the self-occ lens array as a one-to-one erect real image B, the meandering period of light traveling in the self-occ lens array is set to 3/4 as shown in FIG. There is a need. Further, the distance LO from the end surface of the self-occ lens array to the object or the image plane is set to a predetermined value. The length Z of the self-occ lens array in which the meandering period of light is 3/4 is usually 15.5 mm, and the LO is 11.25 mm. The width of the 1C image sensors 4 and 5 is also set to a predetermined value. When assembling the image reading device, the image sensors 4 and 5 are arranged as close to each other as possible, and the angle formed with respect to the vertical axis 11 with respect to the reading document placement surface S of the self-occ lens arrays 2 and 3. Q2 is reduced.

If the angle Q2 is large, a reading error becomes large when the document floats with respect to the document mounting surface S. That is, as shown in FIG. 6A, when the document 6 floats a distance d from the mounting surface S and the angle Q2 is large, the deviation E of the optical paths L2 and L3 of the SELFOC lens arrays 2 and 3 with respect to the reading line RL. Becomes larger, resulting in a larger reading error. On the other hand, when the angle Q1 of the optical paths L2 and L3 with respect to the vertical axis L1 is small as shown in FIGS. The shift E of the optical paths of 2, 3 with respect to the read line RL can be small. However, if a self-occ lens array with a meandering period of light of 3/4 is used and an image of a one-to-one upright real image is absent on the image sensor, the total length of the self-occ lens array becomes shorter. There was a defect that the angles Q1 and Q2 became large and the reading error became large. The present invention aims to eliminate the above defects.

[0005]

[Means for solving problems]

 In order to achieve the above-mentioned object, the present invention has a light source 12 and a property that the light travels in a zigzag manner with a constant period, and reads the original document facing the original document irradiated with the light from the light source 12. At least a pair of converging rod lens arrays 14 and 16 arranged at an angle to each other to guide the reflected light over the entire area of the line in two directions, and an erecting of the converging rod lens arrays 14 and 16. An image sensor 18, 20, 22 arranged at an image position, and the meandering period of light traveling in the length Z of the converging rod lens arrays 14, 16 is N + 3/4 period (N is a natural number). It is set to a value such that

[0006]

[Action]

 When N is 1 and the meandering period of light of the converging rod lens arrays 14 and 16 is 7/4, the length Z of the converging rod lens array is 42.51 mm and the converging rod lens of 3/4 period. This is more than double the size of the array, and the angle of the converging rod lens arrays 14 and 16 facing each other in an inverted V shape can be made small, and the reading error when the original is floated can be made small. In the image reading apparatus which employs the converging rod lens arrays 14 and 16 in which N is 1, 2, 3, ..., The image on the reading line of the original is the converging rod lens arrays 14 and 16. And is imaged on the image sensors 18, 20, 22 as a one-to-one erect real image.

[0007]

【Example】

 Hereinafter, the configuration of the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings. In FIG. 1, reference numeral 8 denotes a paper guide supported by a machine body 9 of the image reading apparatus, which is composed of a transparent glass plate, and an upper surface thereof constitutes a document mounting surface S.

On the upper surface side of the paper guide 8, a paper carrying roller 10 linked to a drive system is arranged, and by the rotation of the roller 10, the original paper 6 is carried on the paper guide 6 in the arrow direction. Is configured. A light source 12 composed of a light emitting diode is supported by the machine body toward the reading line RL on the paper guide 8.

Below the reading line RL, a pair of optical systems composed of converging rod lens arrays 14 and 16 (trade name: self-occ lens array; made by Nippon Sheet Glass) are arranged, and these optical systems are supported by the machine body 9. ing. The converging rod lens arrays 14 and 16 are capable of forming a document-sized image by arranging a large number of converging rod lens elements.

The converging rod lens elements of the converging rod lens arrays 14 and 16 have a radial refractive index distribution from the center to the periphery, and the light travels in a zigzag manner with a certain period. have. Normally, in order to form a one-to-one erect real image in the converging rod lens arrays 14 and 16, the meandering period of light is set to 3/4, as shown in FIG.

In the present embodiment, the converging rod lens arrays 14 and 16 have a light meandering period set to 7/4 as shown in FIG. 3, and a pair of light images A on the reading line RL of the original document. The erecting real image B of the image 1 is formed on the image sensors 18, 20, 22 arranged in a staggered manner below the converging rod lens arrays 14, 16.

In the above configuration, when the document 6 moves on the paper guide 8 in the direction of the arrow, the light image along the reading line RL of the document 6 enters the converging rod lens arrays 14 and 16, and the image sensor Images are formed on 18, 20, and 22 as a one-to-one erect light image. The image of one line along the reading line RL is divided into three in the present embodiment, and imaged on the corresponding image sensors 18, 20, 22 respectively.

The converging rod lens arrays 14 and 16 are not limited to the meandering period of light being 7/4, and may be N + 3/4 periods (N is a natural number).

[0014]

【effect】

 As described above, the present invention can secure a certain distance from the document surface to the image sensor. Therefore, the optical path of the converging rod lens array should be close to the direction parallel to the axis vertical to the document mounting surface. Therefore, there is an effect that it is possible to reduce the reading error that occurs when the document floats from the document mounting surface.

[Brief description of drawings]

FIG. 1 is an explanatory diagram.

FIG. 2 is an external view explanatory diagram.

FIG. 3 is an explanatory diagram.

FIG. 4 is an explanatory diagram of a conventional technique.

FIG. 5 is an explanatory diagram.

FIG. 6 is an explanatory diagram.

[Explanation of symbols]

 2 Optical system 3 Optical system 4 Image sensor 5 Image sensor 6 Original document 8 Paper guide 10 Paper transport roller 12 Light source 14 Focusing rod lens array 16 Focusing rod lens array 18 Image sensor 20 Image sensor 22 Image sensor

Claims (1)

[Scope of utility model registration request] 1. A light source 12 and a light having a property of advancing while meandering at a constant cycle, and a reflection over the entire reading line of the original document facing the original document irradiated with the light from the light source 12. At least a pair of converging rod lens arrays 14, which are arranged at an angle to each other, for guiding light in two directions,
16 and image sensors 18, 20, 2 arranged at the erect image forming positions of the converging rod lens arrays 14, 16.
2 and the focusing rod lens arrays 14, 16
The image reading apparatus is characterized in that the length Z is set to a value such that the meandering cycle of light traveling therein is N + 3/4 cycle (N is a natural number).