Electrophotography – Image formation – Exposure
Reexamination Certificate
2002-06-28
2004-05-04
Grainger, Quana M. (Department: 2852)
Electrophotography
Image formation
Exposure
C399S088000
Reexamination Certificate
active
06731896
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to an image-reading device, an image-forming device, and a copying machine, and more particularly, to an image-reading device which exposes and scans an image of a subject copy by moving two travelers including an exposure lamp and mirrors at different velocities.
2. Description of the Related Art
Conventionally, there has been an image-reading device that exposes and scans an image of a subject copy placed on a contact glass by causing a stepping motor to drive a first traveler including an exposure lamp and a mirror, and a second traveler including two mirrors, along a sub (slow) scanning direction at a velocity ratio of 2:1.
Generally, in the image-reading device that causes the stepping motor to drive the first traveler and the second traveler, a driving velocity of the stepping motor is controlled to change gradually, because of structural requirements. Additionally, another type of image-reading device causing the stepping motor to drive the first traveler and the second traveler reads an image of a subject copy within a range where the driving velocity of the stepping motor is constant, because of an easier control required therefor and a quality of the read image achieved therefrom.
Such an image-reading device as mentioned above requires a dimension in the sub scanning direction to be equal to or larger than a total dimension of a dimension in the sub scanning direction of an image of a subject copy and a dimension in the sub scanning direction required for a run-up and a slowdown of the first traveler and the second traveler. In other words, the dimension of the image-reading device in the sub scanning direction can be theoretically decreased to equal the above-mentioned total dimension.
Additionally, for the purpose of miniaturization, there is still another image-reading device in which the first traveler and the second traveler are arranged close to each other in the course of traveling, or are arranged close to each other by being overlapped at a home position.
By the way, the above-mentioned exposure lamp is provided with a lamp harness used for supplying power to the exposure lamp. This lamp harness is connected to one end of a flexible cable the other end of which is connected to a power source. In some image-reading devices, this flexible cable is drawn around a travel-back side of the second traveler (i.e., a side toward which the second traveler travels back), because it becomes easy to assemble the image-reading device, or it becomes easy to draw around the flexible cable.
For the purpose of miniaturizing the image-reading device, it is preferred that the flexible cable be drawn around the travel-back side of the second traveler as closely as possible. However, when the flexible cable is positioned close directly to the second traveler, the flexible cable contacts the mirrors and other elements mounted on the second traveler. Moving the first traveler and the second traveler back and forth repeatedly with the flexible cable contacting the mirrors and other elements mounted on the second traveler may possibly cause the flexible cable and the mirrors to rub on each other so that a friction thereof damages the flexible cable.
To prevent this damage, a conventional image-reading device comprises a cable guide mounted on the second traveler such that a guide surface guiding the flexible cable is positioned between the mirrors and the flexible cable. This arrangement prevents the flexible cable and the mirrors from rubbing on each other, and thus prevents the flexible cable from being damaged therefrom. The cable guide is provided with guide ribs raised from both sides of the guide surface past the flexible cable. These guide ribs position the flexible cable on the guide surface, and prevent the flexible cable from shifting with respect to the guide surface.
By the way, in some cases, the lamp harness is connected to the flexible cable in a state where the lamp harness is deformed toward the second traveler due to a varying precision in assembling the image-reading device.
In the above-described image-reading device including the first traveler and the second traveler arranged close to each other for the purpose of miniaturization, when the first traveler and the second traveler are moved back and forth in the above-mentioned state where the lamp harness is deformed toward the second traveler, the lamp harness is more likely to contact the second traveler or the mirrors mounted on the second traveler. Since the first traveler and the second traveler are reciprocated at different velocities, moving the first traveler and the second traveler back and forth repeatedly may cause the lamp harness to be rubbed by the second traveler or the mirrors mounted on the second traveler, which may result in a fatigue breakage of the lamp harness.
Also, in the above-described image-reading device comprising the cable guide, the guide ribs are raised from both sides of the guide surface past the flexible cable. Therefore, when the first traveler and the second traveler are arranged close to each other for the purpose of miniaturization, the lamp harness deformed toward the second traveler is more likely to contact the guide ribs. Moving the first traveler and the second traveler back and forth repeatedly with the lamp harness contacting the guide ribs may result in a fatigue breakage of the lamp harness.
The fatigue breakage of the lamp harness results in a heteropolar leak involving a voltage difference between the damaged lamp harness and the flexible cable.
As a conceivable countermeasure thereagainst, the assembly of the image-reading device may be performed so that the lamp harness be provided at a prescribed position in consideration of various factors, such as a particular tendency of the lamp harness for bending. However, assembling the image-reading device in consideration of the various bending tendency of the lamp harness takes time so as to reduce a productivity of the assembly, which does not suit a mass production of the image-reading device.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide an improved and useful image-reading device and a copying machine in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide an image-reading device, and a copying machine using the image-reading device which can be miniaturized by having a first traveler and a second traveler arranged close to each other without damaging a harness, regardless of a varying precision in an assembly thereof.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention an image-reading device exposing and scanning an image of a subject copy by reciprocating a first traveler including an exposure lamp and a mirror, and a second traveler including two mirrors, along a sub scanning direction at a velocity ratio of 2:1, the image-reading device comprising a harness supplying power to the exposure lamp, a flexible cable having one end connected to the harness and the other end connected to a power source, and a contact prevention member provided on the first traveler so as to prevent the harness from contacting the second traveler and the mirrors included in the second traveler.
According to the present invention, the contact prevention member prevents the harness from contacting the second traveler and the mirrors included in the second traveler. Accordingly, for example, when the first traveler and the second traveler are arranged close to each other for the purpose of miniaturizing the image-reading device, the harness can be prevented from rubbing on the second traveler and the mirrors included in the second traveler and thus from being damaged thereby which would otherwise occur due to a difference between the velocities of the first traveler and the second traveler traveling back and forth. In addition, since the contact prevention member is provided on the fi
Grainger Quana M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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