JPH0543664U - Document driving device for image reading device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a document driving device of an image reading device that operates so that the moving range of the document table can be effectively utilized. [Structure] A standard reflector installed near the end of the platen is installed as a part of the means for correcting signal unevenness caused by the light source for illuminating the original, the optical system, and the line image sensor. , The stepping motor is used as a slow-up section and a slow-down section during high-speed sub-scanning. As a result, the area where the standard reflection plate is provided near the end of the document table is used without waste.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a document driving device for an image reading device.

[0002]

[Prior Art]

 In FIG. 3, the original 2 to be read placed on the original placing table 1 is main-scanned by the line image sensor LIS itself, and the original 2 is moved in the direction orthogonal to the main scanning direction. The line image sensor LIS and the line image sensor LIS are relatively moved in the space in the direction of the arrow X in FIG. 3 to perform sub-scanning, and the light reflected from the document 2 irradiated with the light emitted from the light source LS is reflected by a reflecting mirror. FIG. 1 is a diagram showing a schematic configuration of an image reading device in which an optical system including M1, M2, M3 and an image forming lens L collects light on a line image sensor LIS to read image information of an original. Yes, when the magnification is changed by using the imaging lens L having a variable focal length as the optical system used for reading the image information of the document, it is necessary to make the sub-scanning speed variable. Subscan Using the stepping motor as a power source of the location is carried out to facilitate the setting of the vertical scanning speed.

In a document driving device of an image reading apparatus that is configured by using a stepping motor as a power source of the sub-scanning device, conventionally, sequential scanning lines are formed at a predetermined scanning line interval in the sub-scanning direction. For example, the stepping motor is driven in a plurality of predetermined steps corresponding to the above-mentioned predetermined scanning line interval, or the stepping motor is driven so as to minimize the amount of vibration generated on the document table, for example. Select a frequency to drive the stepping motor, or otherwise set the driving current of the stepping motor to a small value when the driving frequency is low, and increase the driving current as the driving frequency increases. It is well known that the work has been carried out. Further, in FIG. 3, reference numeral 3 is an original restraint, and 4 is a standard reflection plate. As is well known, the standard reflection plate 4 has unevenness in the intensity distribution of the light emitted from the light source for illuminating the original, and pixels of the line image sensor. It is used to correct the unevenness of sensitivity for each type, and the standard reflector 4 is housed inside the fuselage of the image reading device to prevent dust from adhering to it. Sometimes it is moved into the optical path.

[0004]

[Problems to be solved by the device]

 As described above, in an image reading apparatus which is adapted to perform variable magnification, high-speed sub-scanning is performed by driving a stepping motor which is a power source of the sub-scanning apparatus used for varying the sub-scanning speed. Or a stepping motor for high speed sub-scan performed when a low-resolution rough preview screen is read by high-speed sub-scan before the normal image reading by the image reading device. The driving state of is a driving mode in which the self-starting frequency of the stepping motor is exceeded. Therefore, conventionally, as illustrated in FIG. 4, a slow-up area Zsu and a slow-down area Zsd are provided before and after the original reading area Zr in FIG. 4A in the sub-scanning direction to read the original. In the sub-scanning area Zsu before entering the area Zr, the sub-scanning speed is gradually increased as shown in FIG. 4B, and the sub-scanning area Zsd after passing the reading area Zr of the document. In FIG. 4, the sub-scanning speed is gradually reduced as shown in FIG. 4B. However, the sub-scanning in the slow-up area and the slow-down area described above is invalid for reading an original. It is a sub-scan.

[0005]

[Means for Solving the Problems]

 The present invention uses a standard reflection plate, which is used as part of a means for correcting signal unevenness caused by a light source for illuminating an original document, an optical system, a line image sensor, etc. Is a document driving device of an image reading device, which is provided near the end of the scanning device, and in which a stepping motor includes a variable speed sub-scanning device used as a power source of the sub-scanning device. In the image reading apparatus, the drive control of the stepping motor in the slow-up state or slow-down state is performed in the area where the above-mentioned standard reflection plate is provided near the end of the document table. A document driving device is provided.

[0006]

[Action]

 The standard reflector installed near the edge of the platen as part of the means for correcting signal unevenness caused by components such as the light source for the document illumination and the optical system and the line image sensor Since the motor is used as a slow-up section and a slow-down section, the area where the standard reflector is located near the edge of the platen is used without waste. When correcting the signal unevenness caused by the light source for illuminating the original, the optical system, and the components such as the line image sensor, etc., using the standard reflector described above, the standard reflector described above should be used. The sub-scanning is performed at the normal sub-scanning speed so that the data for correcting the signal unevenness can be obtained.

[0007]

【Example】

 Hereinafter, specific contents of the document driving device of the image reading apparatus of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram used for explaining the principle and operation of the document driving device of the image reading apparatus of the present invention, and FIG. 2 is a diagram for explaining the mounting mode of the standard reflection plate at the position AA in FIG. It is a side view. In FIG. 1, Zr indicates an original reading area on the original placing table 1 of the image reading device, and Zpsr indicates an area where standard reflecting plates are provided outside the original reading area Zr and in front and rear portions in the sub-scanning direction. Is shown. In FIG. 2, which shows a cross section taken along the line AA in FIG. 1A, 1 is a document placing table, Psr is a standard reflection plate, and the standard reflection plate Psr is the original document. It is provided so as to be sandwiched between the mounting table 1 and the machine board 5 of the image reading apparatus. This prevents dust from adhering to the standard reflection plate Psr.

In the document driving device of the image reading apparatus of the present invention, a standard reflector used as a part of means for correcting signal unevenness caused by components such as a light source and an optical system for illuminating a document and a line image sensor. As shown in FIGS. 1A and 2, Psr is provided near the end of the document table 1 outside the document reading area Zr and is used as a power source for the sub-scanning device. When controlling the drive of the stepping motor in the slow-up state or the slow-down state, the drive control in the slow-up state or the slow-down state of the stepping motor described above is shown in Fig. 1 (a). This is done in the area Zpsr where the standard reflection plates Psr, Psr are provided near the end of the original table 1. Fig. 1 (b) shows the drive control in the slow-up and slow-down states of the stepping motor when the sub-scan is performed at high speed for the purpose of preview, etc. The areas Zpsr in which the standard reflectors Psr and Psr shown are used as the slow-up area Zsu and slow-down area Zsd, respectively, and the image reading area Zr shown in FIG. 6 is a velocity change diagram showing a state in which sub-scanning is performed at a predetermined constant velocity.

That is, in the document driving device of the image reading apparatus of the present invention, the standard reflector P sr is located outside the document reading area Zr as shown in FIGS. 1A and 2. When the stepping motor provided near the end of the table 1 and used as the power source of the sub-scanning device is driven and controlled in the slow-up state or slow-down state, Areas Zsu and Zsd in which the drive control is performed in the slow-up state or the slow-down state are the standard reflection plate Psr, which is provided near the end of the document table 1 shown in FIG. Since the area Ppsr exists in the area Zpsr, the document driving apparatus of the image reading apparatus of the present invention slows up the stepping motor like the conventional apparatus. Area of the slow-down Zsu, is never wasted Zsd. Of the two standard reflectors Psr, Psr provided near the end of the document table 1, one of them is a white reflector and the other is a black reflector, or a gray reflector. It goes without saying that a plate or the like can be arbitrarily selected.

[0010]

[Effect of the device]

 As is apparent from the above detailed description, the original driving device of the image reading apparatus of the present invention is a means for correcting signal unevenness caused by the light source and optical system for illuminating the original, the line image sensor and the like. The part where the standard reflector is installed near the edge of the platen is used as the slow-up section and slow-down section of the stepping motor. The area where the standard reflection plate exists near the part is used without waste, and the standard reflection plate is used to configure the light source and optical system for illuminating the original and the components such as the line image sensor. When correcting the generated signal unevenness, the above-mentioned standard reflection plate portion is sub-scanned at a normal sub-scanning speed to obtain data for signal unevenness correction. Moving mechanism for further standard reflector also are unnecessary.

[Brief description of drawings]

FIG. 1 is a diagram used for explaining a configuration principle and an operation of a document driving device of an image reading apparatus of the present invention.

FIG. 2 is a side view for explaining a mounting mode of a standard reflection plate at a position of line AA in FIG.

FIG. 3 is a diagram showing a schematic configuration of an image reading device.

FIG. 4 is a diagram illustrating that invalid sub-scanning is performed by providing a slow-up region and a slow-down region before and after the original reading region in the sub-scanning direction.

[Explanation of symbols]

1 ... original placing table, 2 ... original, 3 ... original holding, 4, Psr
… Standard reflector, 5… Image reader plate, LIS… Line image sensor,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaoru Kitami 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Japan Victor Company of Japan, Ltd. (72) Asako Kato 3--12 Moriya-cho, Kanagawa-ku, Yokohama Address inside Victor Company of Japan, Ltd.

Claims (1)

[Scope of utility model registration request] 1. A standard reflector which is used as a part of means for correcting signal unevenness caused by a light source for illuminating a document, an optical system, and a component part such as a line image sensor is provided on a document table outside a document reading area. Is a document driving device for an image reading apparatus, which is provided near the end of the scanning device and includes a variable speed sub-scanning device in which a stepping motor is used as a power source of the sub-scanning device. A document of an image reading apparatus in which the drive control of the stepping motor in the slow-up state or the slow-down state is performed in the area where the above-mentioned standard reflector provided near the end of the document table exists. Drive.