JPH0756242A - Image reading unit - Google Patents

Abstract

PURPOSE:To adjust magnification in a short time and to reduce the deviation of the magnification by executing focusing by moving an image forming lens with respect to a solid image pickup element, integrating the solid image pickup element and the image forming lens and moving them along an optical axis. CONSTITUTION:The lens unit 64 of a reading unit 50 is provided with the image forming lens 32 movably held by a lens barrel 30. The lens 32 is moved along the optical axis when the magnification is adjusted. Besides, the unit 64 is movably fitted along the optical axis with respect to a reading unit main body 52. Moreover, a driver substrate 66 coupled to the solid image pickup element 28 is fixed to the unit 64 so that the element 28 can be moved together with the unit 64. In the case that the magnification is adjusted by the unit 50, the lens 32 is moved with respect to the element 28 and the focusing is executed on the element 28 first. Next, the element 28 and the lens 32 are integrated and moved along the optical axis. Then, the length of an optical path is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading unit such as a copying machine, and more particularly to an image reading unit in which a plurality of reflecting mirrors, a solid-state image pickup device and the like are housed in the reading unit.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, an image reading unit of this type has a light source 12, 12 and reflecting mirrors 14, 16, 18, in a reading unit main body (case) 10 formed of a light shielding member. 20, 22, 24, a lens unit 26, and a solid-state image sensor (CCD) 28 are housed and configured.

The lens unit 26 is provided with an image forming lens 32 movably held by a lens barrel 30. The image forming lens 32 is shown by a dotted line along the optical axis during magnification adjustment. You can move in the direction of the arrow. The reading unit configured as described above is used for the light source 1 when reading the document 36 placed on the platen glass 34.
While irradiating light from the documents 2 and 12 toward the document 36, the document 36 is scanned by moving in the direction of the arrow A along the guide shaft 38, and the scanned light is reflected by the reflection mirrors 14 to 24 a plurality of times. The optical path length is extended and condensed by the imaging lens 32, and the condensed light beam 40 is imaged on the solid-state image sensor 26.

By the way, the magnification of the reading unit is adjusted after assembly. As for the method of adjusting the magnification, the image forming lens 32 is moved along the optical axis to perform focusing on the solid-state image sensor 28, and then the reflecting mirror 14 is used.
24 to 24 are moved along the optical axis to adjust the optical path length.
This focusing and optical path length adjustment are repeated a plurality of times to adjust the magnification.

[0005]

However, in the conventional image reading unit, the imaging lens 3 is used when adjusting the magnification.
Since the focusing by 2 and the optical path length adjustment by the reflecting mirrors 14 to 24 have to be repeated a plurality of times, there is a drawback that it takes time and the deviation of the magnification becomes large.

The present invention has been made in view of the above circumstances, and the magnification can be adjusted in a short time.
It is an object of the present invention to provide an image reading unit capable of reducing the deviation of magnification.

[0007]

In order to achieve the above object, the present invention comprises a platen glass of an image reading apparatus on which a document is placed and a reading unit which moves below the platen glass when reading the document. The reading unit includes a light source that irradiates a document with light, a plurality of reflection mirrors that reflect the light reflected by the document a plurality of times to extend the optical path length, and a reflection mirror at the final stage of the plurality of reflection mirrors. In an image reading unit in which an imaging lens that collects the light reflected by the lens and moves on the optical axis when adjusting the magnification and an imaging unit that forms an image of the light condensed by the imaging lens are housed. And
After the imaging lens is moved with respect to the image pickup unit to perform focusing, the imaging lens and the image pickup unit are integrally moved along the optical axis to adjust the optical path length. It is characterized by adjusting.

[0008]

According to the present invention, after the imaging lens is moved with respect to the image pickup section to perform focusing, the image pickup section and the image pickup lens are integrally moved along the optical axis to move the optical path length. The magnification was adjusted by performing the adjustment. This allows
As compared with the conventional reading unit which has to repeat the focusing and the optical path length adjustment a plurality of times, the magnification adjustment can be performed in a short time and the deviation of the magnification can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of an image reading unit according to the present invention will be described below in detail with reference to the accompanying drawings. In Figure 1,
An embodiment of the image reading unit 50 according to the present invention is shown, and the same or similar members as those in the conventional example shown in FIG.

The reading unit 50 shown in FIG. 1 has a pair of illumination lamps 12, 12 and reflecting mirrors 54, 56, 5 inside a reading unit main body 52 formed of a light shielding member.
8, 60, 62, the lens unit 64, the solid-state image sensor 28, etc. are accommodated and comprised. The lens unit 64 is provided with an image forming lens 32 movably held by the lens barrel 30, and the image forming lens 32 is along the optical axis in the direction of the arrow indicated by the dotted line in the figure when the magnification is adjusted. You can move.

The lens unit 64 is attached to the reading unit main body 52 so as to be movable in the directions of arrows B and C along the optical axis. Further, the driver board 66 of the solid-state image pickup device 28 connected to the solid-state image pickup device 28 is fixed to the lens unit 64, and the solid-state image pickup device 28 and the lens unit 64 can be moved integrally.

The reading unit 50 irradiates the original 36 with light from the illumination lamps 12 and 12 while reading the original 36 placed on the platen glass 34, and along the guide shaft 38 in the direction of arrow A. Then, the original 36 is scanned. Then, the scanned light is reflected six times in the order of the reflection mirror 54, the reflection mirror 56, the reflection mirror 58, the reflection mirror 60, the reflection mirror 62, and the reflection mirror 60, so that the optical path length is extended and the imaging lens 26 is used. The solid-state image pickup device 28
Image on top.

Next, a method of adjusting the magnification with the reading unit 50 having the above-described structure will be described. First, only the imaging lens 32 is appropriately moved in the direction of the arrow shown by the dotted line in the figure to focus on the solid-state image sensor 28. Next, the lens unit 64 is appropriately moved along the optical axis, that is, the solid-state imaging device 28 and the imaging lens 32 are integrally moved to adjust the optical path length and adjust the magnification.

Therefore, according to the present embodiment, the magnification adjustment can be performed in a short time and the magnification adjustment can be performed in comparison with the conventional reading unit in which the focusing and the magnification adjustment must be repeated a plurality of times. The gap can be reduced.

[0015]

As described above, according to the image reading unit of the present invention, after the magnification adjusting lens is moved with respect to the image pickup section to perform focusing, the image pickup section and the imaging lens are integrated. Since the magnification is adjusted by moving along the optical axis and adjusting the optical path length, it is necessary to repeat focusing and magnification adjustment multiple times, compared with a conventional reading unit. Thus, the magnification adjustment can be performed in a short time and the deviation of the magnification can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an image reading unit according to the present invention.

FIG. 2 is a sectional view showing an example of a conventional image reading unit.

[Explanation of symbols]

 12 ... Illumination lamp 28 ... Solid-state image sensor 30 ... Lens barrel 32 ... Imaging lens 34 ... Platen glass 36 ... Original document 54, 56, 58, 60, 62 ... Reflecting mirror 64 ... Lens unit 66 ... Driver board

Claims (1)

[Claims] 1. A platen glass of an image reading device on which a document is placed, and a reading unit that moves below the platen glass when reading the document, wherein the reading unit illuminates the document with a light source. And a plurality of reflecting mirrors that reflect the light reflected by the original document a plurality of times to extend the optical path length, and collect the light reflected by the reflecting mirror at the last stage of the plurality of reflecting mirrors and on the optical axis during magnification adjustment. In an image reading unit in which an imaging lens that moves the imaging lens and an imaging unit that images the light condensed by the imaging lens are housed, the imaging lens is moved with respect to the imaging unit. An image reading unit characterized in that the magnification is adjusted by adjusting the optical path length by moving the imaging lens and the image pickup unit integrally along the optical axis after focusing.