JPH11155047A - Picture read device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a read device from being suddenly unusable due to failure generated by the spark discharge of an inveter being the light source of a xenon lamp for illuminating an original, and to prevent a read device from being unusable even when lamp failure is generated in one part of lamps in a picture read device for illuminating an original by plural light sources. SOLUTION: The output part of an inverter 12 being the light source of a xenon lamp 13 is provided with a spark discharge detecting means 14. Even at the time of detecting spark discharge, when the number of times of generation is low, picture reading is operated by limiting the number of pages by a page counter 16. When failure is generated in one part of the plural original lamps, picture reading is operated by using a normal lamp with the decreased read speed. These above mentioned control is operated by a control part 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading an image and converting the read image into an electric signal, and more particularly, to a control when an abnormality occurs in a document illumination lamp and its power supply.

[0002]

2. Description of the Related Art In the field of digital copiers and printers, with increasing needs as network devices,
Higher speed is demanded. For this reason, there is a demand for a high-speed image reading apparatus, and it has been studied to illuminate a document with a light source having a large light emission amount and perform high-speed reading.

[0003] Xenon lamps, which generate relatively little heat due to light emission, can keep the temperature rise of components near the lamp low, and emit a large amount of light, are attracting attention as light sources that meet such needs and are being used. is there.
In particular, a xenon lamp is used in an image reading apparatus such as a copying machine and a facsimile as a light source for reading a so-called sheet-through type image in which a stationary reading head reads a document while transporting the document.

[0004]

An inverter is used as a power source for a xenon lamp. However, the inverter outputs a high voltage of several kV, so that a spark discharge easily occurs at an output destination. When spark discharge occurs on the output side of the inverter,
An accident such as formation of an abnormal image or inability to read an image may occur, and the device may become unusable. Conventionally, after a failure such as an error or inability to read the image to be reproduced occurs, it becomes impossible to use it due to a sudden failure in order to know for the first time that the inverter has an abnormality as a result of investigation. There were many.

Further, in an image reading apparatus having a plurality of exposure lamps, the apparatus stops when one lamp is cut off, so that the apparatus cannot be used until the lamp is replaced. Was.

According to the first and second aspects of the present invention, there is provided an image reading apparatus which detects in advance the possibility of occurrence of the above-described failure in the image reading apparatus and performs a measure corresponding to the possibility. With the goal.

An object of the present invention is to reduce the inconvenience as described above, and in particular, by using another normal exposure lamp even if a part of the plurality of exposure lamps does not turn on. It is an object of the present invention to provide an image reading apparatus that can read an image and can be used according to the degree of the failure even in the case of a failure.

[0008]

The object of the present invention is as follows.
(1) In an image reading apparatus having a xenon lamp as a light source for image reading and an inverter as a power supply for the xenon lamp, a spark discharge detecting means for detecting a spark discharge of the inverter and a detection signal from the spark discharge detecting means (2) a plurality of xenon lamps as light sources for image reading, and respective xenon lamps as power sources for the xenon lamps In the image reading apparatus having an inverter connected to the control unit, when the spark discharge is detected by a spark discharge detecting means for detecting a spark discharge of the inverter and a part of the inverter, control is performed so as to reduce the reading speed and perform reading. An image reading device having a control unit that performs 3) An image reading apparatus provided with a plurality of exposure lamps as a light source for image reading, comprising a reference density plate, and a detecting means for detecting the amount of light from the reference density plate illuminated by the exposure lamp. Determining whether the detection value of the detection means is a value within a predetermined range lower than a normal value, and when the detection value is within the predetermined range, lowers the reading speed and performs image reading. And an image reading device.

[0009]

(Embodiment 1) Embodiment 1 of the present invention will be described with reference to FIG. In the image reading apparatus shown in FIG. 1, originals G stacked on a paper feed tray 4 are sent out one by one by a paper feed roller 1, conveyed by a conveyance roller 2 and a paper discharge roller 3, and discharged to a paper discharge tray 5. Is done. Reading of a document is performed at a reading position R in the document conveying path, and light from a document illumination lamp 6 is incident on a reading sensor 9 via a reflecting mirror 7 and a lens 8. The embodiment shown in FIG. 1 is a so-called sheet-through type image reading apparatus in which an image of a document is read by a stationary reading sensor 9 while conveying the document, and a line CCD is used as the reading sensor 9. In the present invention, the present invention can be applied to a system in which a stationary document is read by a moving optical system, and an image reading device that reads a document using a two-dimensional reading sensor while both the document and the reading unit are stationary. Can be used.

In the present invention, a xenon lamp is used as a document illumination lamp. Xenon lamps are used in high-speed image reading devices because they provide high illuminance with a relatively small amount of heat generation. Even if the xenon lamp continues to illuminate the original in a stationary state, the heating value of the xenon lamp is low and the lamp itself and the nearby components will not be overheated. Particularly suitable.

FIG. 2 is a block diagram of a power supply circuit of the xenon lamp 13. A DC voltage of several tens of volts supplied from a power supply 11 is converted into an AC of several thousand volts by an inverter 12 and supplied to a xenon lamp 13. Reference numeral 14 denotes a spark discharge detection sensor (spark discharge detection means) connected to the output unit of the inverter 12. A control unit 15 controls on / off of the inverter 12 and controls a reading device described later. The control unit 15 performs control based on information from the spark discharge detection sensor 14 and a page counter 16 that counts the number of pages of a document to be read. I do.

The control of the control unit 15 will be described with reference to FIG.

When the image reading is started, the power supply 11 is turned on, the inverter 12 is operated, and the xenon lamp 1 is turned on.
3 emits light. Along with the light emission, the spark discharge detection sensor 14
The spark discharge is monitored based on the information from
1). If there is no spark discharge, reading is performed (S8).
At the same time, the detection of spark discharge is continued. If spark discharge is detected, the number is counted (S2).
Count value P in the next step S3, whether or not exceeded the predetermined number P ₀ is determined. When the number of spark discharges is very small, the light emission of the xenon lamp 13 is hardly affected, and the image reading may be continued. However, the detection of spark discharge indicates that this phenomenon has become so serious that it may be necessary to stop reading, and it is necessary to monitor spark discharge, If the reading operation is continued for a long time, there is a high possibility that abnormal reading will be performed. In the present embodiment, such malfunction is prevented beforehand,
The device is designed to work as efficiently as possible.

That is, in step S3, it is determined whether or not the count value P of the number of spark discharges exceeds a predetermined value P ₀ , for example, five times. If it exceeds five times, it is determined that a failure has occurred.
The reading is stopped and a fault is displayed (S6).
If it is less than five times, the number of read pages Q is counted based on information from the page counter 16 that counts the number of pages of the document on which the image has been read, and whether or not the number exceeds a predetermined number of pages Q ₀ , for example, 50 pages Is determined. If it is within 50 pages, reading is performed, and spark discharge detection and counting of the number of times are repeated. When the reading is continued and there is no more document on the sheet feeding tray, the reading is terminated (S8). If the number of pages to be read of the documents stacked on the paper feed tray is larger than the predetermined page number Q ₀ (for example, 50 pages), it is determined in step S5 that the read page number Q has exceeded the predetermined page number Q _0. Then, the reading operation stops (S7). As described above, this stop is based on the design concept that when a spark discharge is detected, abnormal reading is likely to be performed, and it is necessary to prohibit the reading from being continued for a long time. Then, a reset display, that is, a display urging the resetting of the image reading device with respect to the remaining documents is performed, and the control process ends.

As described above, the image reading apparatus according to the present embodiment monitors whether or not a spark discharge has occurred at the output of the inverter 12 for driving the xenon lamp 13, and detects the spark discharge. Also, the operation of the image reading apparatus is continued depending on the number of times. However, in such a case, the number of pages to be read is limited to reduce reading in an unstable state. In such a case, in step S7, a display recommending repair of the power circuit of the xenon lamp may be displayed together with or instead of the reset display.

In this embodiment, when a spark discharge is detected, the reading operation is performed within a certain time, and the xenon lamp 13 is continuously turned on beyond the certain time to prohibit the reading. Is desirable. If the image reading device is designed to be able to read documents of various sizes, or if it is designed so that single-sided reading and double-sided reading can be arbitrarily selected, it is necessary to read one document. The time depends on the size of the document or on both sides or one side. Thus, a predetermined reading page number Q ₀ in step S5 of the is desirably set to a numerical value different to correspond to the original size or both sides one side.

Further, the operation of the reading device when a spark discharge is detected becomes a problem when the operation is continuously performed for a long time. It is unlikely that the reading operation will become unstable even if reading is repeated. For this reason, the above-described embodiment is designed so that reading can be resumed by performing a reset display and resetting by the operator. May be reset to restart the operation of the reading device. That is, instead of the reset display in step S7, a timer may be operated, and after a certain time has elapsed, the operation may return to "START" and the reading operation may be resumed.

(Embodiment 2) Embodiment 2 of the present invention will be described with reference to FIG.

In this embodiment, xenon lamps 131 and 132 are provided as light sources for illuminating the original. These xenon lamps 131 and 132 are arranged on both sides of the document reading position, for example, like lamps 30 and 31 shown in FIG. 5 and described later. Xenon lamp 1
Inverters 31 and 132 are power supply circuits, respectively.
1,122. A spark discharge detection sensor (spark discharge detection means) 1 is provided at the output of the inverters 121 and 122.
41 and 142 are provided, and each of the spark discharges is monitored by the control unit 15. Reference numeral 17 denotes a document conveying motor, and reference numeral 18 denotes a clock generator for generating a clock for driving a CCD which is an image reading sensor. The frequency of the driving clock of the image reading sensor is controlled.

When the spark discharge is detected by one of the spark discharge detection sensors 141 and 142 and one of the xenon lamps becomes unusable, the control unit 11 stops the operation of one of the inverters 121 and 122. At the same time, the rotation speed of the motor 17 is reduced to reduce the document conveyance speed. The scanning speed in the sub-scanning direction decreases due to the decrease in the document conveyance speed. Further, the clock frequency of the clock generator 18 is reduced. As a result, the scanning speed in the main scanning direction decreases. Under the control of the control unit 11, image reading is performed at a low reading speed corresponding to turning off one of the two light sources, and the reading device performs image reading without stopping despite the failure of the light source. Reading continues.

When no spark discharge is detected in any of the inverters, the image is read at a normal reading speed.

(Embodiment 3) Embodiment 3 of the present invention will be described with reference to FIG.

The document is conveyed by a document conveying means (not shown) between the document supporting and document conveying guide plate 33 for supporting the document at the reading position R and the supporting glass plate 36.
Reference numeral 34 denotes an entrance guide plate for guiding the document to the reading position R, and reference numeral 35 denotes a discharge guide plate for guiding the document conveyed from the reading position R. Lamps 30 and 31 illuminate the document at the reading position from both sides. The lamp is preferably a xenon lamp, but is not limited to a xenon lamp. Any conventional lamp such as a halogen lamp and a fluorescent lamp can be used.

Reference numeral 37 denotes a white reference plate which is an example of a reference density plate, and is provided for monitoring the light emitting state of the lamps 30 and 31. Reference numeral 38 denotes a reflecting mirror for guiding the reflected light from the document to the reading sensor 39. The reflecting mirror is located at a position indicated by a solid line when reading the image of the document, and guides the reflected light from the reading position R to the reading sensor 39. The reading sensor 39 receives the reflected light from the white reference plate 37 and
It also functions as detecting means for detecting the light emitting state of the first light emitting device.

In this embodiment, the lamps 30, 3
1 is configured to be able to monitor the light emission state. Prior to reading the original, the lamps 30 and 31 and the reflecting mirror 38 are used.
Moves to the position indicated by the dotted line. Thereby, the reflected light from the white reference plate 37 enters the reading sensor 39. The control unit (not shown) stores a level in a normal state in which two lamps are lit and a level in a state in which only one lamp is lit as a criterion for determining the light emitting state of the lamps 30 and 31. When it is detected based on the storage level that the two lamps are turned on, the control unit controls to perform reading in a normal operation. On the other hand, when it is detected that only one lamp is turned on, the control unit performs reading at a reduced reading speed without stopping the reading device. In this way, the control for reading an image at a reduced reading speed can be performed by controlling a document feed motor and a clock generator that generates a drive clock for a reading sensor. The control is performed in the second embodiment. As described.

It is a matter of course that reading is not performed when the two lamps do not emit light. Also, as a result of long-term use, the decrease in the amount of light that occurs does not occur suddenly,
It is often a phenomenon that progresses slowly. In such a decrease in the amount of light, since the reduced state is relatively stable, it is often possible to read even if the reading speed is reduced. The present embodiment can be configured so that the apparatus can be used continuously without stopping even when the light amount is reduced due to such long-term use. That is, the lowering level in the case of the result of long-term use is stored in the control unit in advance as a predetermined range value, and when the lowering level is reached, reading is performed at a predetermined low scanning speed corresponding to the level. The control unit can be provided with a control function to perform.

[0027]

According to the first aspect of the present invention, by detecting a spark discharge at the output of the inverter which is a power supply of the xenon lamp, it is possible to predict in advance a failure due to the spark discharge and to detect the spark discharge. By performing reading control in response to the detection of the image reading device, the image reading device can be used effectively, and a failure can be prevented.

According to the second aspect of the present invention, when a spark discharge is detected in a part of the inverter which is a power supply of a plurality of xenon lamps, reading is performed using another normal xenon lamp. This makes it possible to eliminate the inconvenience that the device stops due to a sudden failure and becomes unusable.

According to the fourth aspect of the present invention, even if a part of the plurality of original illumination lamps are burned out or the amount of light of the original illumination lamps is reduced, they can be used. At the time, it was possible to perform reading at the reading speed according to the decrease, so that the device can be used even before performing full-scale repairs such as replacement of parts,
The inconvenience caused by the sudden stop of the device is eliminated.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an image reading apparatus according to a first embodiment;

FIG. 2 is a block diagram of a xenon lamp driving circuit of the image reading apparatus shown in FIG.

FIG. 3 is a flowchart of a control process of a control unit of the image reading apparatus shown in FIG.

FIG. 4 is a block diagram of a xenon lamp driving circuit of the image reading device according to the second embodiment;

FIG. 5 is a diagram illustrating a configuration of an image reading unit of the image reading device according to the third embodiment;

[Explanation of symbols]

9, 39 Reading sensor 12, 121, 122 Inverter 13, 131, 132 Xenon lamp 14, 141, 142 Spark discharge detection sensor (spark discharge detection means) 15 Control unit 17 Document transport motor 18 Clock generator

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Hiroshi Koyama 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation

Claims (6)

[Claims] 1. An image reading apparatus having a xenon lamp as a light source for image reading and an inverter as a power supply for the xenon lamp, wherein a spark discharge detecting means for detecting a spark discharge of the inverter and a signal from the spark discharge detecting means. An image reading apparatus, comprising: a control unit that limits the number of pages of a read document based on a detection signal. 2. An image reading apparatus comprising: a plurality of xenon lamps as a light source for image reading; and an inverter connected to each of the xenon lamps as a power source for the xenon lamp. An image reading apparatus, comprising: a control unit configured to perform reading at a reduced reading speed when a spark discharge is detected by a unit and a part of the inverter. 3. The image according to claim 1, wherein the control unit has a counting unit that counts spark discharges, and performs control to stop image reading when the count value reaches a predetermined value. Reader. 4. An image reading apparatus provided with a plurality of exposure lamps as a light source for image reading, a reference density plate, and detection means for detecting the amount of light from the reference density plate illuminated by the exposure lamp. It is determined whether the detection value of the detection means is within a predetermined range lower than a normal value, and when the detection value is within the predetermined range, the reading speed is reduced to perform image reading. An image reading device characterized by the above-mentioned. 5. The image reading apparatus according to claim 4, wherein the predetermined range is a range corresponding to a light amount when a part of the plurality of exposure lamps does not emit light. 6. The image reading apparatus according to claim 4, wherein the predetermined range is a range corresponding to a light amount when the light emission amount of the exposure lamp decreases.