Electricity: motive power systems – Portable-mounted motor and/or portable-mounted electrical...
Reexamination Certificate
2000-03-31
2001-05-22
Ro, Bentsu (Department: 2852)
Electricity: motive power systems
Portable-mounted motor and/or portable-mounted electrical...
C318S563000, C318S478000
Reexamination Certificate
active
06236171
ABSTRACT:
TECHNICAL FIELD
The present invention relates to image reading devices and more particularly to an image reading device including an image reading unit and a sheet feeding device attachable/detachable to/from the image reading unit, in which power is supplied from the image reading unit to the sheet feeding device only when the image reading unit and the sheet feeding device are securely engaged, whereby damage on an internal circuit of the sheet feeding device caused by an electric shock at the time of attachment/detachment is prevented.
BACKGROUND ART
In recent years, the information processing devices have become more multi-functional and one information processing device has become utilized for various purposes. In an image scanner, for example, a main scanner body with a reading portion for reading an image of an original is engaged in an attachable/detachable manner with a feeder feeding the original. A user can utilize the image scanner as a handy scanner by using the main scanner body in a detached state from the feeder.
In this case, if power is supplied to the side of the main scanner body via a code, for example, the feeder can be powered through a connector from the side of the main scanner body with no additional code provided for power supply to the feeder. With such an arrangement, the connection of the codes in use becomes simple and the device can be used more conveniently.
When power is supplied from the main scanner body to the feeder, however, if a power supply switch on the side of the main scanner body is left in an on-state at the time of attachment/detachment of the feeder to/from the main scanner body, an electric shock will be caused on the side of the feeder at the time of attachment/detachment and the internal circuit on the side of the feeder can be damaged.
To avoid such problem, a circuit component capable of enduring such electric shock may be mounted on the side of the feeder. This arrangement, however, may lead to a complexity of the structure on the feeder side and increase in cost.
Alternatively, it is possible to oblige the user to turn off the power supply switch on the side of the main scanner body at the time of attachment/detachment of the main scanner body to/from the feeder. Then, the damage on the circuit due to an electric shock caused by an unstable state of electrical connection of the connector at the time of attachment/detachment can be prevented. This solution, however, affects the operability of the device. In addition, according to this solution, the circuit would not be protected when the user attaches/detaches the feeder to/from the main scanner body by mistake while the power supply switch is in an on-state.
The present invention is made to solve the above described problems and an object of the present invention is to provide an image reading device capable of protecting an internal circuit at a low cost from generation of an electric shock at the time of attachment/detachment of the image reading unit and the sheet feeding device.
DISCLOSURE OF THE INVENTION
According to one aspect of the present invention, an image reading device includes an image reading unit being supplied with power and a sheet feeding device being supplied with power from the image reading unit when being mounted on the image reading unit. The image reading device includes a detection portion detecting the attachment/detachment of the sheet feeding device and a supply portion supplying power to the sheet feeding device, the sheet feeding device includes a drive portion feeding a sheet of paper and so on, and the image reading unit includes a control portion controlling the supply of power from the supply portion according to the result of detection by the detection portion and a drive signal output portion supplying a drive signal as an output to the drive portion.
As the control portion provided in the image reading unit controls the supply of power from the supply portion according to the result of detection by the detection portion, the image reading unit can be operated to start the supply of the power to the sheet feeding device when the sheet feeding device is mounted on the image reading unit. In addition, the image reading unit can be operated to stop the supply of the power to the sheet feeding device when the sheet feeding device is detached from the image reading unit. Thus, the internal circuit of the device can be protected from the generation of an electric shock at the time of attachment/detachment of the two devices.
Preferably the image reading unit includes a first connector and the sheet feeding device includes a second connector connected to the first connector. The supply portion includes a first terminal provided on the first connector supplying the power to the sheet feeding device and a second terminal provided on the second connector, connected to the first terminal and receiving the supply of the power.
As the supply portion is constituted of the first terminal on the first connector and the second terminal on the second connector, the cost would not increase significantly.
Preferably, the detection portion includes a third terminal provided on the first connector and connected to a first reference potential and a fourth terminal connected to a second reference potential of a different level from the first reference potential with its potential changed from the second reference potential when the second connector is connected, a fifth terminal provided on the second connector and connected to the third terminal and a sixth terminal connected to the fourth terminal and the fifth terminal.
As the detection portion is constituted of third and fourth terminals provided on the first connector and fifth and sixth terminals provided on the second connector, the cost would not increase significantly.
Preferably, the first reference potential is ground potential.
Then, as the first reference potential can be obtained simply by grounding the third terminal, the structure is simplified and the cost would not increase significantly.
Preferably, the second reference potential is the power supply potential via a pull-up resistance.
Then, as the second reference potential can be obtained simply by pulling up the potential on the fourth terminal, the structure is simplified and the cost would not increase significantly.
Preferably, after the detection portion detects that the sheet feeding device has been mounted, the control portion causes the supply portion to start the supply of the power after an elapse of a predetermined time.
Then, even when the sheet feeding device is engaged for an instant, the supply of the power by mistake can be prevented.
Preferably, third and fourth terminals are arranged at opposite ends of the first connector and, fifth and sixth terminals are arranged at opposite ends of the second connector.
Through the arrangement of third and fourth terminals and fifth and sixth terminals at the ends of the opposite sides of first and second connectors, respectively, the power supply to the sheet feeding device can be prevented from being started when the sheet feeding device is not correctly engaged with the image reading unit.
Preferably, first and second connectors have a plurality of rows of terminals.
The device is applicable even when the number of signals transmitted between the image reading unit and the sheet feeding device increases.
REFERENCES:
patent: 5907748 (1999-05-01), Kawana
patent: 5909603 (1999-06-01), Suzuki et al.
patent: 5987276 (1999-11-01), Kumar et al.
patent: 03074068A (1991-03-01), None
patent: 3-127945 (1991-12-01), None
patent: 08185931A (1996-07-01), None
patent: 09148035A (1997-06-01), None
patent: 9197740 (1997-07-01), None
patent: 09319669A (1997-12-01), None
Chujo Hideki
Kinoshita Ikuo
Nakanishi Takashi
Dickstein , Shapiro, Morin & Oshinsky, LLP
Omron Corporation
Ro Bentsu
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