JP3842765B2 - Image forming apparatus - Google Patents

Description

BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine or a digital multifunction peripheral, and more particularly to a color-compatible image forming apparatus.
[Prior art]
In an image forming apparatus such as a copying machine or a digital multifunction peripheral, image reading means provided below a transparent contact glass on which an original is placed reads image information of the original.
In reading such a document image, an optical unit, which is a linear light source provided in the image reading means, moves in a direction (sub-scanning direction) perpendicular to the linear light source while irradiating light on the document, For example, the reflected light is read by a CCD image sensor or the like.
The image forming apparatus as described above has a function of detecting the document size. For example, when the document cover provided on the upper surface of the contact glass is opened and closed, the optical unit moved to a predetermined position is the document. The CCD image sensor detects the size of the CCD image sensor in the scanning direction (main scanning direction), and the sub-scanning size is detected by a reflective sensor arranged according to various document sizes. It is supposed to be.
Since the document size detection operation is performed immediately before the document cover is completely closed, the light emitted from the optical unit is visually recognized by the user. For this reason, there is a problem that the user feels this light dazzling and feels uncomfortable.
As a countermeasure against this, Japanese Patent Application Laid-Open No. 2004-228561 proposes reducing the amount of light emitted by the optical unit during the document size detection operation.
[Patent Document 1]
JP 7-177310 A [Problems to be solved by the invention]
White xenon lamps and cold cathode lamps are used in optical units used in recent color image forming apparatuses. This white light makes the user feel dazzling even when the amount of light is the same as that of a yellow-green lamp or a green lamp used in a conventional monochrome optical unit.
At this time, even if the technique disclosed in Patent Document 1 is applied to reduce the amount of light emitted by the optical unit, the light remains white, and the user feels this light dazzling. End up.
The present invention has been proposed based on the above-described conventional circumstances, and an object thereof is to provide an image forming apparatus capable of reducing glare that a user feels during an original size detection operation.
[Means for Solving the Problems]
First, the present invention is based on an image forming apparatus that detects the size of a document and reads image information of the document based on the detected document size.
In order to achieve the above object, according to the present invention, a document irradiating unit having a plurality of color light emitting units and a light emitting unit emitting at least one color to emit non-white light when detecting the document size. The apparatus includes a preliminary lighting unit and a main lighting unit that turns on all the light emitting units to emit white light when reading the image information.
The document irradiating means may be composed of a red light emitting part, a green light emitting part, and a blue light emitting part.
In this way, when detecting the size of the document, light of a color other than white is emitted, so that the glare felt by the user can be reduced.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic external view showing the image forming apparatus of the present invention. FIG. 2 is a schematic block diagram showing portions involved in image reading and document size detection in the image forming apparatus.
As shown in FIG. 1, an image forming apparatus 10 according to the present invention presses a flat contact glass 11 on which a document is placed and a document placed on the contact glass 11 as in the case of a conventional image forming apparatus. In addition, a document cover 12 that prevents external light from entering the contact glass 11 is provided at the top. The document cover 12 is connected to the upper surface of the machine body using a hinge 13 or the like, and can be opened and closed in the vertical direction. Below the contact glass 11, as shown in FIG. 2, the original irradiating means 1 that irradiates the original with linear light and is movable in the sub-scanning direction, and the original reflected from the reflected light of the original by the light. The image reading means 21 provided with the image reading sensor 2 for reading the image information is provided, and the image information read by the image reading means 21 is transferred to the image processing means 22 for performing various image processing to perform image processing. Is transferred to an image forming means (not shown), and an image is formed on a predetermined sheet or the like and output.
The document irradiating means 1 includes a red light emitting unit 1a, a green light emitting unit 1b, and a blue light emitting unit 1c, each of which is a linearly arranged light emitting diode (LED), and all the light emitting units 1a, 1b, and 1c are turned on. By doing so, linear white light can be irradiated. The light emission control of the document irradiating unit 1 is performed by the preliminary lighting unit 7 during the document size detection operation and by the main lighting unit 8 during the document reading operation.
When the original is irradiated from below the contact glass 11 by the original irradiating means 1, the reflected light from the original is condensed on the image reading sensor 2 including a CCD image sensor or the like via an optical system (not shown). The optical image information is converted into an analog electric signal (analog image data). The analog image data is A / D converted by the signal processing means 5 to become digital image data, which is input to the image processing means 22.
On the other hand, a document detection sensor 3 for detecting the document size in the sub-scanning direction is disposed below the contact glass 11, and an output signal of the document detection sensor 3 serves as a size detection means 9 for determining the document size. Entered.
As the original detection sensor 3, for example, a reflective sensor composed of a light emitting element such as an LED and a light receiving element such as a photoelectric element can be used. If such a reflective sensor is used, the light receiving element can detect whether or not the light emitted from the light emitting element is reflected by the placed document, and can detect the presence or absence of the document at the detection position. Can do.
In the present embodiment, the reflective sensor is provided at each position corresponding to the size in the sub-scanning direction when a standard size paper such as A4, B4, B5 or the like is placed vertically and horizontally on the contact glass 11. It is arranged. The size detection means 9 determines the document size in the sub-scanning direction from the output signals of these reflective sensors.
By the way, the document size detection operation is performed when an operation performed when the user places the document on the contact glass 11, that is, when the document cover 12 is opened or closed.
In the present embodiment, whether the document cover 12 is opened or closed is determined by detecting whether or not the document cover 12 is at a predetermined height or less from the upper surface of the contact glass 11 by the open / close sensor 4. Here, the predetermined height is a height at which the document detection sensor 3 does not erroneously detect the document cover 12 as a document.
The open / close sensor 4 may be, for example, a push button switch that switches on / off when a button as shown in FIG. 1 is pushed in a predetermined amount or more. Such a push button switch is placed on the upper surface of the machine body so that when the document cover 12 is at the predetermined height, the button contacts the document cover 12 and is pressed by the predetermined amount, for example, to turn off. When the document cover 12 is disposed at the predetermined height, it can be detected as an off state when the document cover 12 is below a predetermined height, and as an on state when it is above the predetermined height.
In the above configuration, as shown in FIG. 3, the image forming apparatus 10 first performs initial settings such as shading correction when the power is turned on and enters a standby state (S1).
When a signal indicating that the document cover 12 is open (above the predetermined height) is input from the open / close sensor 4 to the size detector 9 during standby (S2), the size detector 9 Then, the preliminary lighting means 7 is instructed to prepare for the document size detection operation (S3). At this time, the preliminary lighting unit 7 drives the motor 6 to move the document irradiating unit 1 to a detection position, for example, a reference position where the document end is disposed when the document is placed on the contact glass 11.
Subsequently, when the signal indicating that the document cover 12 is closed (the predetermined height is reached in the process of closing the document cover 12) is input from the open / close sensor 4 to the size detection means 9 (S4). The size detection unit 9 instructs the preliminary lighting unit 7 and the document detection sensor 3 to perform a document size detection operation (S5).
Upon receiving an instruction from the size detecting means 9, the preliminary lighting means 7 is a light emitting section of at least one color among the red light emitting section 1a, the green light emitting section 1b, and the blue light emitting section 1c provided in the document irradiating means 1 (this embodiment). Then, the green light emitting unit 1b) is turned on, and the document reading sensor 2 is caused to read the reflected light by this lighting.
On the other hand, the document detection sensor 3 receives an instruction from the size detection unit 9, performs a document size detection operation, that is, detects light emission and reflected light, and outputs a detection signal to the size detection unit 9.
After the above document size detection operation is completed, the size detection means 9 detects the size of the document in the main scanning direction from the digital image data obtained during the document size detection operation, and detects the document size. The size in the sub-scanning direction is detected based on the output signal of the sensor 3, and the document size is determined (S6). Then, the detected document size is input to the main lighting unit 8.
After the document size is detected in this way, when the user presses the execution button 14 (S7), the main lighting unit 8 turns on all the light emitting portions of the document irradiation unit 1 and executes the document reading operation (S8). ).
This document reading operation is performed by the document irradiating means 1 irradiating the document with white light and moving in the sub-scanning direction, as in the conventional image forming apparatus. At this time, the main lighting unit 8 limits the movement amount of the document irradiating unit 1 in the sub-scanning direction and the scanning width of the image reading sensor 2 in the main scanning direction according to the document size input from the size detecting unit 9. Then, image information is read only from the area corresponding to the document size.
As described above, the image forming apparatus of the present invention performs the document size detection operation by irradiating light of a color other than white, and thus can reduce glare that the user feels.
In FIG. 3, when the execution button 14 is pressed without detecting the opened state of the document cover 12 (S2 → S8), the document reading operation is performed based on the document size detected immediately before. . If the document size detected immediately before does not exist, such as immediately after the power is turned on, the document reading operation is executed assuming that the maximum document size has been detected.
If the document cover 12 is opened without pressing the execution button 14 despite the document size detection operation being performed (S7 → S2), the processing from step S2 onward in FIG. 3 is performed. Will be done.
In the above-described embodiment, the document irradiating means is composed of a red light emitting part, a green light emitting part, and a blue light emitting part. However, as long as all the light emitting parts are turned on, the document irradiating means emits white light. The luminescent color and the number thereof can be designed arbitrarily.
Further, the configuration of the document detection sensor and the open / close sensor described in the above embodiment is merely a specific example, and does not limit the technical scope of the present invention. Any configuration can be employed within the scope of the effects of the present application.
【The invention's effect】
As described above, according to the present invention, since the light other than white is emitted when detecting the size of the document, the glare that the user feels can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic external view of an image forming apparatus of the present invention. FIG. 2 is a schematic block diagram of an image forming apparatus of the present invention. FIG. 3 is a flowchart showing image reading processing of the image forming apparatus of the present invention. ]
DESCRIPTION OF SYMBOLS 1 Document irradiation means 1a Red light emission part 1b Green light emission part 1c Blue light emission part 2 Image reading sensor 3 Document detection sensor 4 Opening / closing sensor 7 Preliminary lighting means 8 Main lighting means 9 Size detection means 10 Image forming apparatus 11 Contact glass 12 Document cover 21 Image reading means 22 Image processing means

Claims (2)

In an image forming apparatus that detects the size of a document and reads image information of the document based on the detected document size.
A document irradiating means comprising a plurality of color light emitting sections;
Preliminary lighting means for illuminating at least one color of the light emitting unit to emit non-white light when detecting the document size;
When the image information is read, a main lighting unit that turns on all the light emitting units to emit white light;
An image forming apparatus comprising: The image forming apparatus according to claim 1, wherein the document irradiation unit includes a red light emitting unit, a green light emitting unit, and a blue light emitting unit.

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