JPH0219066A - Picture reader - Google Patents

Abstract

PURPOSE:To avoid waste of power consumption by detecting an original size by an original size sensor and lighting only consecutive light emitting diodes by a block corresponding to the size. CONSTITUTION:A CCD contact image sensor where lots of CCD sensors are provided side by side and lots of light emitting diodes are provided side by side as light sources in the same direction of each CCD sensor and plural original size 5-8 detecting the size of a original to be read are provided to the reader. Then plural blocks comprising light emitting diodes 16 are provided to a width below the original size at minimum to be read and the light emitting diodes 16 are subject to light control by the combination in the unit of consecutive blocks in response to the detection of the original size of the original size sensors 5-8. Thus, the LEDs 16 with a width matching the size of the original to be loaded are lighted in each case and the waste of power consumption of the LEDs 16 is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application J] The present invention relates to an image reading device provided with a CCD contact image sensor.

[Prior Art] As shown in FIG. 2, a CCD contact image sensor used in this type of image reading device has a selfoc lens 2 disposed on the reading surface of a sensor body 1 in which CCD sensors are housed side by side. A large number of light emitting diodes (hereinafter referred to as LEDs) are placed on both sides of the SELFOC lens 2.
3 as a light source.

As shown in FIG. 3, for example, a document size sensor 5 detects an A4 size document 4a in a direction perpendicular to the insertion direction of the document 4, a document size sensor 6 detects an A3 size document 4b, and an A2 size document sensor 5. A document size sensor 7 for detecting a document 4C of size A, and a document size sensor 8 for detecting a document 4d of Al size are arranged side by side at a predetermined interval.

Therefore, when an A4 size document 4a is inserted, only the sensor 5 operates, when an A3 size document 4b is inserted, both sensors 5 and 6 operate, and when an A2 size document 4C is inserted, the sensor 5 operates. 5,6.7
When the Al-sized document 4d is inserted, all of the sensors 5, 6, and 7.8 are activated.

Conventionally, for example, as shown in FIG.
When the document size sensors 5 to 8 detect the insertion of a document, they output a control signal, turn on the switch 9, and connect all the LEs in series.
It was supposed to turn on D3. That is, even if only the A4 size document size sensor 5 is turned on, the switch 9 is turned on by the control signal and all the LEDs 3 are turned on.

[Problems to be Solved by the Invention] However, even when reading a relatively narrow document such as A4 size or A3 size, all LEDs 3 were controlled to light up, so the lighting of all the LEDs 3 was controlled at positions that were not directly related to the reading of the document. The LEDs in the image sensor are also turned on, which causes unnecessary power consumption and the heat generated by the LEDs causes the temperature of the image sensor to become higher than necessary.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an image reading device that can always turn on an LED having a width that matches the size of the inserted document, and can prevent wasteful power consumption due to LEDs.

[Means for Solving the Problems] The present invention provides a COD contact image sensor in which a large number of CCD sensors are arranged side by side, and a number of light emitting diodes are arranged in the same direction as each CCD sensor as a light source. Multiple document size sensors detect the size of the document, light emitting diodes are divided into blocks with a width at least less than the minimum document size to be read, and the light emitting diodes are connected in blocks in response to the document size detection by the document size sensor. A control means is provided for controlling the lighting according to the combinations of the lights.

[Function] In the present invention having such a configuration, when an original of a certain original size is detected by the original size sensor, consecutive light emitting diodes for blocks corresponding to that size are turned on, and light emitting diodes of other blocks are turned on. The light goes off.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

In Fig. 1, 5 is a document size sensor that detects A4 size documents, 6 is a document size sensor that detects A3 size documents, 7 is a document size sensor that detects A2 size documents, and 8 is a document size sensor that detects Al size documents. It is a size sensor.

The low-level detection outputs from each of the sensors 5 to 8 are input to one input terminal of a two-person circuit 11, 12, 13, 14, respectively. A low level signal is input to the other input terminal of each of the NOR circuits 11 to 14 via a switch 15 that is turned on by a control signal generated when each of the sensors 5 to 8 detects insertion of a document. It looks like this.

16 is an LED, and this LED 16 is divided into blocks with an A4 size document as the minimum size, and the first block 16a
corresponds to the width of A4 size, and the first block 16a and the second block
The consecutive combination of blocks 16b corresponds to the width of A3 size, the consecutive combination of first block 16a1 second block 16b and third block 16c corresponds to the width of A2 size, and Block 16b, third block 16c and fourth block 16d
The consecutive combinations correspond to the width of the Al size.

The output of the NOR circuit 11 is the L of the first block 16a.
It is supplied as power to the ED and is also input to one input terminal of the two-man AND circuit 17.

The output of the NOR circuit 12 is input to the other input terminal of the AND circuit 17. and the AND circuit 17
The output is supplied as power to the LED of the second block 16b, and is also input to one input terminal of the two-person couple circuit 18.

The output of the NOR circuit 13 is input to the other input terminal of the AND circuit 18. and the AND circuit 18
The output is supplied as power to the LED of the third block 16c, and is also input to one input terminal of the two-man power AND circuit 19.

The output of the NOR circuit 14 is input to the other input terminal of the AND circuit 19. and the AND circuit 19
The output of is supplied as power to the LED of the fourth block 16d.

In this embodiment having such a configuration, for example, when an A4 size document is inserted, only the document size sensor 5 is turned on, and a low level output from the sensor 5 is input to the NOR circuit 11.

Further, when the sensor 5 detects the insertion of a document, a feed roll signal is generated and the switch 15 is turned on. However, a low level signal is input to the NOR circuit 11 via the lever switch 15.

In this way, a high level output is sent from the NOR circuit 11, and only the LED of the first block 16a is lit.

Further, when an A2 size document is inserted, the document size sensors 5, 6.7 are turned on, and low level outputs from the sensors 5 to 7 are output from the NOR circuits 11, 12, .
13 respectively.

Further, when the sensors 5 to 7 detect the insertion of a document, a control signal is generated and the switch 15 is turned on. However, a low level signal is manually applied to the NOR circuits 11 to 13 via the lever switch 15.

In this way, high level outputs are sent out from the NOR circuits 11-13.

As a result, the output of the NOR circuit 11 causes the first block 16 to
LED a is lit, and NOR circuit 11 and NOR circuit 1
The output of the AND circuit 17 becomes high level due to the output of the AND circuit 17, and the LED of the second block 16b is turned on. Furthermore, the output of the AND circuit 18 becomes high level due to the output of the NOR circuit 13 and the AND circuit 17, and the output of the third block 16C becomes low.
ED is lit. In this way, the first block 16a to the third block
The LEDs up to block 16c will be lit continuously. And the width of the LED lit at this time is exactly A
This corresponds to the width of two sizes of originals.

Since the width of the LED 16 that is turned on is controlled in accordance with the size of the inserted document, unnecessary LEDs are not turned on when reading a document with a narrow width, and wasteful power consumption can be prevented. Also, compared to the conventional system in which all LEDs are always turned on, the temperature of the image sensor does not become higher than necessary.

Incidentally, in the above embodiment, the width of one block is not necessarily limited to A4 size, but finer lighting width control can be achieved by setting the width of one block to half of A4 size.

Further, in the above embodiment, the document size is A4°A3. A2
．． Although Al has been described, it is not necessarily limited to Al, and can be applied to originals of various sizes.

[Effects of the Invention] As described in detail above, the present invention provides an image reading device that can always light up an LED with a width that matches the size of the inserted document, and can prevent wasteful power consumption due to LEDs. It is possible.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an embodiment of the present invention, Figure 2 is a COD
FIG. 3 is a partial perspective view showing the external appearance of the contact image sensor, FIG. 3 is a diagram showing the arrangement relationship between the COD contact image sensor and document size sensor for documents of various sizes, and FIG. 4 is a circuit diagram showing a conventional example. 5.6, 7.8...Original size sensor 11゜12
．． 13.14...Nor circuit, 15...Switch, 1
6. LED, 16a, 16b, 16c. 16d...LED block, 17,18.19...
AND circuit. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] A large number of CCD sensors are arranged side by side, and each
A CCD contact image sensor has a large number of light emitting diodes lined up as light sources in the same direction as the CD sensor, a plurality of document size sensors detects the size of the document to be read, and the light emitting device has a width at least equal to or less than the minimum document size to be read. An image reading device comprising: a plurality of blocks of diodes, and a control means for controlling lighting of the light emitting diodes in successive combinations of blocks in response to document size detection by the document size sensor.