JPS62143557A - Image reader - Google Patents

Abstract

PURPOSE:To read a bit of image information exactly by providing a distance sensor which detects a distance between a reading part and an original surface on an original platen, and changing a reading pitch at the reading part in a subscanning direction corresponding to the distance between the reading part and the original surface. CONSTITUTION:In the titled device, the reading pitch in the subscanning direction at a reading part 1 in an original scan can be changed freely with a reading width control part 3. The distance between the reading part 1 and the original surface of an original 14 can be detected with a distance sensor 2 on the upper part of the reading part 1, and the reading speed control part 3 controls the reading pitch in the subscanning direction at the reading part 1 so that the original 14 and a bit of read image information are always coincided. In this way, even when a part of the original is apart from the original platen, the accurate reading of the bit of image information can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image reading device, such as a facsimile or OCR, which has a function of reading image information such as text and graphics.

BACKGROUND OF THE INVENTION In recent years, with the development of office automation, there has been a movement to shift document creation systems that have hitherto been based on human power to document creation systems that rely on image input.

In developing such document creation systems, image reading devices are being developed as a means for inputting image information such as documents and graphics.

An example of a conventional image reading device will be described below with reference to the drawings.

2 and 3 show the configuration of a conventional image reading device, FIG. 2 is a sectional view of the conventional image reading device, and FIG. 3 shows the configuration of a reading section in the image reading device. It is.

In FIG. 2, reference numeral 4 denotes a transparent document table made of glass or the like that brings the surface of the document into close contact; 1 denotes a reading section that reads image information on the surface of the document to be read and converts it into an electrical signal; 5. 6. 7
．． 8. Reference numeral 9 denotes a drive system for causing the reading section to run in a sub-scanning direction perpendicular to the main scanning direction of the one-dimensional image sensor; 5 is a drive section consisting of a motor, etc.; 9 is a guide for making the reading section run in a fixed direction; 8 is a wire, 7 is a pulley, and 6 is a spring that absorbs the slack of the wire.
11 is an outer frame of the image reading device.

In FIG. 3, 12 is a light source such as a fluorescent lamp that illuminates the document surface, 15 is a lens system that collects reflected light from the illuminated document surface, and 12 is a lens system that converts optical information collected by the lens system into an electrical signal. An image sensor is composed of a plurality of photoelectric conversion elements, and 10 is an original.

A case will be described in which the image reading apparatus configured as described above reads image information on the surface of a document that is brought into close contact with the document table 4.

As shown in FIG. 3, the reading section includes a light source 12, a lens system 15, and an image sensor I3.

In FIG. 2, the original placed in close contact with the original platen 4 is exposed to the light source 12.
The reflected light from the document surface is focused by the lens system 15.

This focused reflected light is photoelectrically converted by an image sensor 13 made up of a plurality of photoelectric conversion elements, and image information in the main scanning direction of the document read on the document table is read.

In addition, in FIG. 2, the reading section 1 is a driving section 5 such as a motor.
The image information of the document on the document table 4 is read by scanning the document table 4 in the sub-scanning direction along the guide 9 which is in a horizontal positional relationship with the document table 4.

(For example, Kenzo Ishibashi, Tsutomu Okabe et al., “Image Scanner J, whose demand is rising for simple image editing and processing applications (1)
9B4.9.10 issue) Nikkei Electronics, P161
~) Problems to be Solved by the Invention However, in conventional image reading apparatuses, when scanning a document, the reading pinch in the sub-scanning direction of the reading section relative to the document table is the same, so that the problem as shown in FIG. Originals for which the entire document cannot be brought into close contact with the document table (
For example, in the case of (wood, Qft, magazine, etc.), image information in a portion away from the document table is compressed in the sub-scanning direction and read, resulting in a problem that the result of the read image information differs from that of the document.

Figure 4 (81, (bl, tel) is a diagram showing the above-mentioned problem, (al is the original, (bl is the reading result when the original is completely brought into contact with the original platen, (C1 is a part of the original) This shows the reading results obtained when the image is read away from the document table.

In FIG. 4(a), 16 is the original, and in FIG. 4(b), 1
Reference numeral 7 indicates the reading result when the original is brought into close contact with the original rest, and 19 in tel is the reading result when a part of the original is removed from the original rest.

Means for Solving the Problems In order to solve the above-mentioned problems, the image reading device of the present invention is provided with a distance sensor for detecting the distance between the reading section and the document surface on the document table in the reading section. The present invention has a function of changing the reading pinch in the sub-scanning direction during document scanning in accordance with the distance between the reading section and the document surface, thereby making it possible to accurately read the image information of the document.

Function The present invention provides a distance sensor for detecting the distance between the reading section and the document surface on the document table in the reading section of the above-mentioned image reading device, and further determines the reading pitch of the reading section in the sub-scanning direction between the reading section and the document surface. This makes it possible to change the image information of the document while scanning the document in accordance with the distance from the document, thereby making it possible to accurately read the image information of the document.

Embodiment Hereinafter, an image reading apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an image reading device according to the present invention.

In FIG. 1, reference numeral 1 denotes a reading section that reads image information of a document on a document table.

Reference numeral 2 denotes a distance sensor that measures the distance from the reading section to the document surface on the document table, and 3 a reading width control section that changes the reading pitch of the reading section in the sub-scanning direction. 4
1 is a document table, 5 is a drive unit, 9 is a guide, 8 is a wire, 7 is a pulley, 6 is a spring, 14 is a document, and 11 is an outer frame.

The operation of the image reading device configured as described above will be explained below with reference to the drawings.

In FIG. 1, an original (
For example, a case of reading a tree (for example, a tree, a magazine, etc.) 14 will be explained.

As described in the conventional example, the reading section 1 has the function of illuminating the surface of the document on the document table 4 and reading the reflected light containing image information reflected therefrom.

In conventional image reading devices, the reading pinch in the sub-scanning direction of the reading unit during document scanning is limited, and if a part of the document is away from the document table, there is a problem that accurate image information cannot be read. Ta.

However, as shown in FIG. 1, the image reading device of the present invention allows the reading pitch of the reading section 1 in the sub-scanning direction to be freely changed by the reading width control section 3 during document scanning. ing.

A distance sensor 2 located above the reading section 1 detects the distance between the reading section 1 and the document surface of the document 14, and a reading speed control section 3 controls the reading section so that the read image information is always the same as the document 14. Even if the reading pinch in the sub-scanning direction of 1 is controlled and the document is read as shown in FIG. 4, frontal image information as shown in FIG. 4 (BL) can be read.

Effects of the Invention As described above, the present invention provides a reading unit of an image reading device with a distance sensor that detects the distance between the reading unit and the document surface on the document table, and furthermore, the reading pitch of the reading unit in the sub-scanning direction. This makes it possible to change the distance during document scanning in accordance with the distance between the reading unit and the document surface, thereby making it possible to accurately read the image information of the document.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an image reading device according to an embodiment of the present invention, FIG. 2 is a side sectional view of a conventional image reading device, and FIG. 3 is a side view of the reading section of a conventional image reading device. FIG. 4 is a schematic diagram showing the reading operation of a conventional image reading device. 1... Reading unit, 2... Distance sensor, 3... Old reading width control unit, 4... Original table, 5... Drive unit, 6... Spring, 7...
...Pulley, 8.Old...Wire, 9...
Guide, 11...Outer frame, 14.Old...Manuscript. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 1 Atsunari Figure 2

Claims (1)

[Claims] a reading section having a function of reading image information in the main scanning direction of a document placed on a transparent document table; a drive system having a function of scanning the reading section in the sub-scanning direction horizontally with the document table; and the reading section; It is characterized by comprising a distance sensor that detects the distance to the document surface on the document table, and a means for changing the reading pitch in the sub-scanning direction in response to the distance between the document surface on the document table and the reading section. Image reading device.