JPS6399667A - Picture reader - Google Patents

Abstract

PURPOSE:To speedily and accurately adjust the focus of an imageforming element by providing a position adjusting means which regulates the image-forming element to shift in one direction against an energization means and which can adjust the position of the image-forming element. CONSTITUTION:Position adjusting means 6a and 6b are provided around both ends of a scanner base 2, and said means are provided with spring holders 12a and 12b, adjusting coils 13a and 13b and brackets 14a and 14b. Coil springs 7a and 7b are abutted on both end parts of SLA ('Selfoc(R)' lens array) (image- forming element) 5. With energizing and abutting the SLA5 in the direction of the adjusting coils 13a and 13b (original direction), the precision of the position of the SLA5 by the adjusting coils 13a and 13b is improved. On the other hand, a flat spring 8 is provided on the SLA5 and said spring 8 is formed in a doglegged shape which lies on both sides of a scan direction from a center part. Thus, the focal position of the optical path of the SLA can accurately and speedily be adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image reading device, and more particularly to an image reading device in which the focal position of an imaging element can be adjusted.

(Prior Art) In recent years, in the field of OA equipment such as copying machines and facsimile machines, there has been a demand for smaller and more personalized equipment, and SLA (Selfoc Lens Array) and other devices have been developed to meet these demands. An integrated image reading device has been developed in which an image forming element, a line image sensor, and a light source are integrally assembled and the image can be read in the same width as the document.

(Problems to be Solved by the Invention) However, in such conventional integrated image reading devices, the depth of focus (in-focus range) of the SLA (Selfoc lens array) that is the imaging element is limited. Since it is extremely shallow, if there is even a slight deviation from the center position of the conjugate length of the optical path, M T F (Mode-1ation T
transfer function (aberration balance) may deteriorate rapidly. Here, the allowable range of the depth of focus is determined by the required resolution performance (MTF relative to resolution), so in order to maintain the MTF at an optimal value, the positional accuracy of the SLA assembly must be 2jl!, for example! It is necessary to keep it within P/+u. However, the positional accuracy of SLA assembly depends on the processing accuracy of related parts, that is, the accumulation of processing tolerances. Further, since the SLA itself has variations during manufacturing, it is necessary to strictly control the machining accuracy and assembly accuracy of parts, which poses a problem of deteriorating the productivity of the device.

(Object of the Invention) Therefore, the present invention provides an image reading device with a position adjustment means that can adjust the position of the imaging element with a simple and inexpensive structure, thereby quickly and accurately adjusting the focus of the imaging element. The purpose of this invention is to improve the resolution capability of an integrated image reading device and improve productivity.

(Structure of the Invention) In order to achieve the above object, the present invention includes a light source that projects light onto a document, an image receiving element that photoelectrically converts light reflected from the document,
an image forming element located between the image receiving element and the document and forming an image of reflected light from the document on the image receiving element; and an urging means for urging the image forming element in one direction toward the image receiving element or the document. The image forming apparatus is characterized by comprising a position adjusting means that restricts movement of the image forming element in one direction against the urging means and is capable of adjusting the position of the image forming element.

(Embodiment) FIGS. 1 to 3 are diagrams showing an embodiment of the reading device of the present invention.

In FIG. 1, 1 is an image reading device, which includes a scanner base 2, an LED array 3, a line image sensor 4.5LA (selfoc lens array) 5
, position adjusting means 6a, 6b.

It includes coil springs 7a and 7b, a leaf spring 8, a glass plate 9, and a document guide 10.

The scanner base 2 is formed to extend in the width direction (row direction) of the document to be read. At the lower right side of the scanner base 2 in the figure is a light emitting diode (LED).
ode) array (light source) 3 is fixed and LED
The array 3 irradiates light over the entire width direction (row direction) of the original 11 . 5LA (imaging element) 5 is an erect, equal-magnification type lens array; An image is formed on a light receiving element (not shown).

The line image sensor 4 photoelectrically converts one line of image formed on the light receiving element according to the amount of light, and outputs it as an image signal via a driver board (not shown).

On the other hand, near both ends of the scanner base 2, there is a 1m adjustment means 6.
a, 6b are provided, and the position adjustment means 6a, 6b are provided with spring retainers 12a, 12b, adjustment screws 13a, 1
3b, and brackets 14a, 14b (
Due to the structure of the drawing, only one side is shown). One side of the spring retainers 12a and 12b is formed in a step shape and is fixed to the scanner base 2, and the other side is a coil spring (biasing means). Hold a and 7b. coil spring 7a,
7b is in contact with both ends of the 5LA5, and the SLA5
S L A by the adjusting screws 13a, 13b by forcing them in the direction of the adjusting screws 13a, 13b (in the direction of the document) and bringing them into contact with each other.
Improve the position accuracy of 5. The adjustment screws 13a and 13b are screwed into screw holes (not shown) formed in the approximately U-shaped platens 14a and 14b,
48° 14b is fixed to the scanner base 2.

The adjustment screws 13a and 13b are, for example, hexagonal socket set screws, and can be moved in the direction of arrow F in the figure by turning them from the outside with a tool such as a hexagonal wrench. Therefore, the coil springs 1a and 1b are biased, and the adjustment screw 1
The position (focal position) of 5LA5 in contact with 3a and 13b can be finely adjusted.

On the other hand, a leaf spring 8 is provided on the upper surface of 5LA5 in the figure, and the leaf spring 8 has a substantially doglegged shape extending from the center of 5LA5 to the left and right in the main running force direction, as shown in FIG. is formed. Therefore, the leaf spring 8 biases 5LA5 toward the reference plane (the portion in which the lower surface of 5LA5 contacts in the figure) to tighten the adjustment screw 13a.

Regardless of the sliding movement caused by 13b, the positional accuracy of 5LA5 is always maintained and wobbling is prevented.

Next, in FIG. 1 again, a transparent glass plate 9 is fixedly installed on the right side of the scanner base 2 in the figure.
Holes 9a and 9b (one of which is not shown) for position adjustment are formed at both ends.

Further, a document guide 10 and a platen roller 15 are in contact with the glass plate 9 1 , and the document guide 10 is formed of, for example, sheet metal, and the document 11 is smoothly fed between the glass plate 9 and the platen roller 15 . At the same time, when adjusting the focus of S L and A5, which will be described later,
Pinch and hold. The platen roller 15 is rotated by a control section and a driving section (not shown), and conveys the document 11 that is supplied between the platen roller 15 and the glass plate 9 in synchronization with the timing of main scanning by the line image sensor 4. In addition, the first
The figure shows a state in which the image reading device 1 is attached to a scanner device or the like (not shown).

Next, the effect will be explained.

First, when adjusting the focus of the 5LA (Selfoc Lens Array) 5 of the assembled image reading device 1, the output of the driver board provided in the line image sensor 4 is transmitted to the synchroscope through the simulator of the control unit (not shown). Connect to other measuring instruments. Next, the image reading device 1
A test chart is inserted between the glass plate 9 and the document guide 10. For example, a predetermined pattern is drawn on the test chart. On the other hand, when a control signal is output from the simulator to the image reading device 1, L E
The D array 3 is turned on, and light is irradiated over the entire width direction (main scanning direction) of the test chart.

The image of the portion irradiated with light is formed on the light receiving element of the line image sensor 4 via 5LA5, is read by main scanning at a predetermined timing, and is photoelectrically converted. The photoelectrically converted image is processed as both signals by the driver board and then output to the synchroscope via the simulator. While monitoring the image signal input to the synchroscope, the operator drills holes 9a and 9b (one not shown) formed in the glass plate 9 as shown in FIG.
From there, use a tool such as a hex wrench 16 to tighten the adjustment screw 13a.

While turning 13b, set 5L to the position where the output waveform becomes the optimum value.
Adjust the position of A5. Note that the position where the output waveform becomes the optimum value is the position where the line image sensor 4 performs the most photoelectric conversion of the image on the adjustment chart (the position where the output level ratio is high).
, that is, the position where 5LA5 is in focus.

Here, 5LA5 is the leaf spring 8 of the position adjusting means 5a, 5b.
The coil springs 7a,
Since the adjustment screws 13a and 13b are always biased by the adjustment screws 7b, there is a sufficient adjustment range even when the processing tolerances of the parts are large. 13b can accurately adjust the focal position. In this way, the focal position of the optical path of the SLA (Selfoc lens array) can be adjusted accurately and quickly using the position adjusting means 6a, 6b and the coil springs 7a, 7b, which are simple and inexpensive.

Therefore, it is possible to provide an image reading device with higher resolution ability without sacrificing the advantage of miniaturization of the device by using the same-magnification reading type line image sensor 4.

(Effects) According to the present invention, the focus of the imaging element integrated with the light source and the reading means can be quickly and accurately adjusted, and the resolving power of the integrated image reading device is improved and the productivity is improved. can improve sex.

[Brief explanation of the drawing]

1 to 3 are views showing one embodiment of the image reading device of the present invention, and FIG. 1 is a cross-sectional view of the main part of the image reading device, and
The figure is a diagram showing the relationship between the scanner base, SLA (Selfoc lens array), and position adjustment means of the image reading device, and FIG. 3 is a perspective view showing the relationship between the position adjustment means and the coil spring (biasing means). It is. 1... Image reading device, 3... LED array (light source), 4...
・Line image sensor (image receiving element), 5...
5LA (Selfoc lens array) (imaging element), 6a, 6b...Position adjustment means, 7a, 7b...
...Coil spring (biasing means).

Claims (1)

[Claims] A light source that projects light onto the original, an image receiving element that photoelectrically converts the light reflected from the original, and an imaging element that is located between the image receiving element and the original and forms an image of the light reflected from the original onto the image receiving element. a biasing means for biasing the imaging element in one direction toward the image receiving element or the document; and a biasing means for regulating the movement of the imaging element in one direction against the biasing means and controlling the position of the imaging element. An image reading device comprising: adjustable position adjustment means.