JPH01157668A - Original reader - Google Patents

Abstract

PURPOSE:To shorten an original reading time by executing a subreading in moving a mobile means from a second position to a first position, and executing a main reading in moving the means from the first position to the second position, at the time of reading the original. CONSTITUTION:At the time of a standby, a carriage 3 is stopped at an end position 9, and when a reading starting button is pushed, first, a shading board B11 is read by an image sensor 6, and the shading correction and white balance of the image sensor 6 are executed by a signal processing circuit. Thereafter, the carriage 3 is moved from the end position 9 to a start position 8, and meanwhile, the density information of an original 1 is read by the image sensor 6. When the carriage 3 reaches the start position, next, the shading board A10 is read in the same way, and ordinary image information is read thereafter. When the reading is completed, the carriage 3 is stopped at the end position. Thus, a detecting time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an original reading device that uses an image sensor to convert image information into a digital electrical signal, and more specifically, to an original reading device that uses an image sensor to convert image information into a digital electrical signal, and more specifically, to an original reading device that uses an image sensor to convert image information into a digital electrical signal. It is related to the device.

BACKGROUND OF THE INVENTION In recent years, the digitalization of copying machines has progressed, and the reading devices (hereinafter referred to as image scanners) installed in these machines have functions that are not so necessary for conventional computer terminals, such as document density detection and document size detection. becomes indispensable. Conventionally, various methods have been proposed in which a dedicated sensor or an image sensor for image reading is used for these detections. However, especially in the latter case, it is impossible to perform the original image reading and the above-mentioned detection at the same time, so a general configuration is such that the carriage carrying the light source etc. moves back and forth (so-called pre-scanning) before image reading. It is true.

Problems to be Solved by the Invention However, the above-described method has the disadvantage that it takes a long time to read the document, making it extremely difficult to use, especially when used as a copying machine.

In view of the above problems, the present invention provides an image scanner that can shorten the detection time.

Means for Solving the Problems In order to solve the above problems, the image scanner of the present invention includes a document table on which a document is placed, a light source that irradiates the document with light, and a light source that emits light reflected from the document. A light source for irradiation, an image sensor for converting the condensed reflected light into an electrical signal, a movable means in which at least the light source is disposed, and the document table and the movable means are placed in a first position and a second position. a drive means for relatively reciprocating between the positions of the movable means, and the movable means is in the second position during standby;
When reading a document, the movable means moves from the second position to the first position to perform sub-reading, and then moves from the first position to the second position to perform main reading, and at least The main reading apparatus is configured to read character image information of the original document.

Function: With the above-described configuration, the document reading device of the present invention eliminates the need for the movable means (carriage) to reciprocate when detecting document density or document size, thereby shortening the reading time.

Embodiment Hereinafter, a document reading device according to an embodiment of the present invention will be described with reference to the drawings. The figure shows a plan view of an image scanner in an embodiment.

In the figure, 1 is a document, and 2 is a platen glass on which the document 1 is placed. The carriage 3 includes a fluorescent lamp 4 that illuminates the original 1, a fiber lens array 5 that collects reflected light from the original, and an image sensor (contact type with built-in RGB filter) that converts the collected reflected light into an electrical signal. 6
It is equipped with a motor 7 (in this embodiment, a direct drive type linear motor) for reciprocating drive. A shading plate A is provided at the starting position 8 and the ending position 9 of the carriage 3, respectively.
IO and shading board Bll are provided. This shading board AIO and shading board Bll
consists of a white plate with a reflectance of 80% or more, and is used for document reading (
The shading board A and the BIO 111 are read by the image sensor 6 immediately before reading (including reading for document density detection and document size detection), and the sensitivity variations of each pixel of the image sensor 6 and correction of RGB output levels are not shown. This is done using a signal processing circuit.

The operation of the image scanner configured as above will be explained with reference to the drawings. This image scanner has a document density detection function. During normal standby, the carriage 3 is stopped at the end point position 9. When you press the reading start button (not shown), the shading board Bll
is read by the image sensor 6 and a signal processing circuit (not shown) performs shading correction and white balance of the image sensor 6. Thereafter, the carriage 3 moves from the end point position 9 to the start point position 8, and during this time, the image sensor 6 reads the density information of the original document 1. When the carriage 3 reaches the starting position, the shading plate AIO is subsequently read in the same manner, and thereafter normal image information is read. However, the difference from the conventional method is that the carriage 3 stops at the end point position at the end of reading.

Since document density detection has been conventionally used in analog and digital copying machines, a detailed signal processing method and the like will be omitted.

Although this embodiment is an image scanner having an original density detection function, the present invention can also be applied to the case where original size detection is performed instead of original density detection, or both of these are performed.

Effects of the Invention As described above, in the present invention, the movable means (carriage) is at the second position (end point position) during standby, and when reading a document, the movable means moves from the second position to the first position (starting point). position) for sub-reading (document density detection, etc.)
is then moved from the first position to the second position to perform main reading (reading of the original image information), thereby shortening the reading time when detecting the original density, for example. This is particularly effective when the image scanner of the present invention is installed in a digital copying machine.

Needless to say, the present invention is also effective in cases where document density detection is performed using a dedicated sensor instead of an image sensor.

Further, although the image scanner according to the embodiment of the present invention is of the so-called fixed type with an original table, the present invention is also effective for image scanners with a movable original table.

[Brief explanation of the drawing]

The figure is a plan view of a document reading device according to an embodiment of the present invention.

Claims (4)

[Claims] (1) a document table on which a document is placed; a light source that irradiates the document; and a light source that irradiates light reflected from the document;
an image sensor that converts the focused reflected light into an electrical signal; a movable means in which at least the light source is disposed;
a drive means for relatively reciprocating the document table and the movable means between a first position and a second position; the movable means is in the second position during standby; During reading, the movable means moves from the second position to the first position to perform sub-reading, and then moves from the first position to the second position to perform main reading, and at least A document reading device characterized in that it is configured to read character image information of a document during main reading. (2) The document reading device according to claim (1), wherein at least document density information is read during sub-reading. (3) The document reading device according to claim (1), wherein at least document size information is read during sub-reading. (4) Claims (1) and 2) further include a first shading means and a second shading means for correcting the sensitivity of the image sensor during main reading and sub-reading, respectively. The document reading device according to either (2) or (3).