JP2001007993A - Original reader and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly and properly detect a fault of abnormal discharge such as spark discharge externally by providing an abnormal discharge detection circuit and a warning means, which issues a warning to the external device on the basis of an output of the abnormal discharge detection circuit, to the inverter. SOLUTION: A current of a higher frequency exceeding a frequency of a drive current in a steady-state lighting is generated at abnormal discharge. An abnormal discharge detection circuit 106 detects a current with a higher frequency than that of a drive current in this steady-state lighting to detect abnormal discharge, and its output is extracted from a terminal OUT1. A current level detection circuit 107 detects a level of the drive current from an output of a drive current detection circuit 105, and provides an output in high level at lighting or an output in low level at non-lighting. Then a control means 50 is connected to output terminals Out1, Out2 and controls a warning means 103 on the occurrence of abnormal discharge such as spark discharge or a fault of light/non-lighting to allow the warning means 103 to display a warning to inform the occurrence of a hazard to an operation section and transmission of a warning signal to a host device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading apparatus having a light source for illuminating a document and an image pickup device for receiving light from the illuminated document and converting the light into an electric signal, wherein a xenon lamp is used as the light source. The present invention relates to a document reading device and an image forming apparatus having the document reading device.

[0002]

2. Description of the Related Art Xenon lamps have the advantage that they generate less heat during light emission and that they have high light emission intensity, and are used as light sources for reading originals in digital copying machines and the like. Since a high voltage of several tens of kV is applied to the xenon lamp, an abnormal discharge such as a spark discharge may occur. , And is configured to detect an abnormality in the inverter and automatically stop the output when the abnormality is detected.

[0003]

However, since the original reading apparatus and the image forming apparatus incorporating the original reading apparatus do not have means for externally detecting an abnormality detected in the inverter, Even when the inverter stops outputting, the reading and the image formation based on the reading are continued, and a defective image such as a solid black image or a black band image is formed. Since there are other causes for the formation of the defective image, it sometimes takes time to determine the cause of the failure or the cause cannot be determined.

[0004] It is an object of the present invention to eliminate the disadvantages of the prior art caused by the failure of such a xenon lamp or an inverter which is a driving means of the xenon lamp.

[0005]

The object of the present invention is as follows.
This is achieved by any of the following inventions.

(1) A document reading apparatus having a xenon lamp for illuminating a document, an inverter for driving the xenon lamp, and an image pickup device for receiving light from the document illuminated by the xenon lamp and converting the light into an electric signal. The inverter includes an abnormal discharge detection circuit for detecting abnormal discharge, an output terminal of the abnormal discharge detection circuit, and a warning unit for issuing a warning to the outside based on an output of the abnormal discharge detection circuit. Document reading device.

(2) A document reading apparatus having a xenon lamp for illuminating a document, an inverter for driving the xenon lamp, and an image sensor for receiving light from the document illuminated by the xenon lamp and converting the light into an electric signal.
The inverter is provided with a current level detection circuit for detecting the level of the driving current of the xenon lamp and an output terminal of the current level detection circuit, and a warning unit for issuing a warning to the outside based on an output of the current level detection circuit. An original reading device, comprising:

(3) A xenon lamp for illuminating a document, an inverter for driving the xenon lamp, an image sensor for receiving light from the document illuminated by the xenon lamp and converting the light into an electric signal, and a reference white plate In an original reading apparatus having an amplifying means which is automatically gain-controlled and amplifies the output of the image pickup device, the output of the amplifying means is monitored, and the output of the amplifying means does not reach a predetermined value even when the gain is maximized. And a warning means for giving a warning.

(4) The document reading apparatus according to any one of (1) to (3), wherein the warning unit performs a warning display.

(5) The warning means performs a warning display and stops a reading operation.
13. The document reading device according to claim 1.

(6) A xenon lamp for illuminating a document, an inverter for driving the xenon lamp, an image sensor for receiving light from the document illuminated by the xenon lamp and converting the light into an electric signal, and illuminating with the xenon lamp A document reading apparatus having an image sensor that receives light from the read document and converts the light into an electric signal, and an image forming apparatus that forms an image based on image information from the reading apparatus, wherein abnormal discharge is caused to the inverter. An image forming apparatus comprising: an abnormal discharge detection circuit for detecting; an output terminal of the abnormal discharge detection circuit; and a warning unit for issuing a warning to the outside based on the output of the abnormal discharge detection circuit.

(7) A document reading device having a xenon lamp for illuminating a document, an inverter for driving the xenon lamp, and an image pickup device for receiving light from the document illuminated by the xenon lamp and converting the light into an electric signal, and In the image forming apparatus for forming an image based on image information from the document reading device, the inverter is provided with a current level detecting circuit for detecting a level of a driving current of the xenon lamp and an output terminal of the current level detecting circuit. And an alarming means for issuing an alarm to the outside based on the output of the lighting / non-lighting detection circuit.

(8) A xenon lamp for illuminating a document, an inverter for driving the xenon lamp, an image sensor for receiving light from the document illuminated by the xenon lamp and converting the light into an electric signal, and a reference white plate Automatic gain control, an image forming apparatus for forming an image based on image information from an original reading apparatus and an original reading apparatus having an amplifying means for amplifying the output of the image sensor,
An image forming apparatus comprising: a warning unit that monitors an output of the amplification unit and issues a warning when the output of the amplification unit does not reach a predetermined value even when the gain is maximized.

(9) The image forming apparatus according to any one of (6) to (8), wherein the warning unit displays a warning.

(10) The warning means stops a warning display and a reading operation.
(8) The image forming apparatus according to any one of the above (8).

[0016]

FIG. 1 is a view schematically showing an image forming apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 10 denotes an image forming unit for forming an image on a recording paper by an electrophotographic system, 20 denotes a document reading device for reading an image of a document and outputting image data, 3
A post-processing unit 0 performs post-processing such as sorting, stapling, and punching on the recording paper discharged from the image forming unit 10.

The image forming section 10 has a photoreceptor 11, image forming means 12 for forming a toner image on the photoreceptor 11 by charging, exposing, and developing, and transferring the toner image on the photoreceptor 11 to recording paper. Transfer unit 17, paper feed units 13 a, 13 b, 13 c, 13 d for storing recording paper on which an image is formed and conveying the recording paper toward image forming unit 12, recording paper reversing and conveying unit 14 for double-sided image formation, and recording The image forming apparatus has a fixing unit 15 for fixing a toner image on paper. Reference numeral 16 denotes a registration roller that temporarily stops the conveyed recording paper and then conveys the recording paper toward the transfer unit 17 in synchronization with the formation of the toner image on the photoconductor 11.

The toner image formed on the photoreceptor 11 by charging, exposure and development is transferred to a recording paper by a transfer means 17, and a toner image is formed on the recording paper.
Is fixed by

The paper supply section 13a is operated by a paper supply start signal, and has paper supply means 131a for separating the recording paper stored in the cassette 132a one by one and starting the conveyance of the recording paper. Similarly, the paper feeding units 13b and 13c
b and cassette 132b, sheet feeding means 131c and cassette 1
32c. The paper feeding unit 13d includes a large-capacity cassette 132d, and has paper feeding means 131d.

The document reading device 20 includes a document feed table 21 on which a document is placed, a platen roller 22 for conveying the document and forming a reading position, and a document discharge table 2 on which a read document is placed.
3. It has a CCD 24 as an image sensor for receiving image light and converting it into an electric signal, a platen glass 25 on which a document is placed, and a xenon lamp 100 as a light source for illuminating the document.

The document feeding table 21 is provided with sensors S1 and S2 for detecting a document. These sensors S1, S2
Detects the size of the document and detects whether or not there is a document on the document feeder 21.

The document reading device 20 reads a document while transporting the document from a document feeder table 21 and transporting the document by a platen roller 22 or reading a document placed on a platen glass 25. Do.

FIG. 2 is a block diagram showing the image data processing system of the image forming apparatus according to the embodiment of the present invention. The document reading device 20 includes a CCD 24 as an image sensor, a CCD
24, an A / D converter 2 for converting the output of the amplifier 26 into a digital signal
Seven. Reference numeral 40 denotes a processing / storage unit that performs image processing such as filter processing, scaling processing, and density conversion processing on image data from the document reading apparatus 20 and stores the image data in an image memory. The image forming unit 10 is an image forming unit that forms an image on a recording sheet based on image data from the processing / storage unit 40. Write. 50 is control means for controlling the whole. Reference numeral 103 denotes a warning unit. The warning unit 103 will be described later.

The reflected light from the document 60 illuminated by the xenon lamp 100 is incident on the CCD 24,
After amplification by the A / D converter 27, the data is converted into digital image data by the A / D converter 27. The image data processed and stored in the processing / storage unit 40 is read out at the time of image formation, and is recorded on a recording sheet in the image forming unit 10. 70 is FIG.
The reference white plate provided at the end of the platen glass 25 is used to adjust the characteristics of the image reading apparatus in FIG. 2, particularly, the gain of the amplifier 26 according to the emission intensity of the xenon lamp 100.

FIG. 3 is a block diagram of a xenon lamp driving circuit according to the embodiment of the present invention. The inverter 101 for driving the xenon lamp 100 includes a power terminal Va, a ground terminal G, and a trigger terminal V connected to a power supply of several tens of volts.
b, an output terminal Out1 for outputting a detection signal of an abnormal discharge such as a spark discharge, and an output terminal O for outputting a current level detection signal
ut2. In the inverter 101, a drive current detection circuit 105, an abnormal discharge detection circuit 106, and a current level detection circuit 107 are provided. When a trigger signal is input to the trigger terminal Vb, the xenon lamp 100 is turned on, and in steady lighting, the xenon lamp 100 outputs light of a controlled and constant intensity.

Since a high voltage is applied to the xenon lamp 100, spark discharge may occur due to poor contact at the connector portion or damage to the electrode of the lamp. An abnormal discharge such as a spark discharge is detected by an abnormal discharge detection circuit 106 from an output of a drive current detection circuit 105 for detecting a drive current for lighting the xenon lamp 100.

At the time of abnormal discharge, a high-frequency current exceeding the frequency of the drive current in steady light emission is generated. The abnormal discharge detection circuit 106 detects an abnormal discharge by detecting a current having a higher frequency than the drive current in such a steady light emission, and an output thereof is taken out from a terminal Out1. The current level detection circuit 107 detects the level of the drive current from the output of the drive current detection circuit 105, and outputs a high level during lighting and a low level during non-lighting. Alternatively, the output may be reversed. The output of the current level detection circuit 107 can be extracted from Out2, and whether or not the xenon lamp 100 is normally lit is detected by comparison with a trigger signal input to the trigger terminal Vb.

The control means 50 is connected to the output terminal Out1 of the abnormal discharge detection circuit 106 and the output terminal Out2 of the current level detection circuit 107, and generates any one of the abnormal discharge such as the above-described spark discharge and the abnormal lighting / non-lighting. Then, the warning unit 103 is controlled, and the warning unit 103 displays a warning, such as displaying on the operation unit or transmitting a warning signal to the host device through the communication unit. Warning means 1
03 stops the reading operation of the document reading device 20 together with the warning display.

In the image forming apparatus according to the embodiment of the present invention, when the main switch of the image forming apparatus is turned on and the warm-up is completed, the automatic gain control of the amplifier 41 shown in FIG. Done. In this control, the reference white plate 70 shown in FIG. 2 is illuminated by the xenon lamp 100, the reflected light is received by the CCD 24, and its output is amplified by the amplifier 42, so that the level of the amplified signal becomes constant. The gain 41 is automatically adjusted to obtain image data that is always constant with respect to the reference white.

Due to the significant deterioration of the xenon lamp 100 or other reasons, even when the gain of the amplifier 42 is maximized, the above-mentioned constant value may not be obtained. In the present embodiment, the control unit 50 detects such an abnormality from the output of the A / D converter 27, and issues a warning by the warning unit 103. The warning by the warning unit 103 is a warning for stopping the reading of the document and displaying the warning in the same manner as in the case of the abnormal discharge and the abnormal lighting / non-lighting.

[0032]

According to the first or sixth aspect of the present invention, a failure of abnormal discharge such as a spark discharge can be promptly and accurately detected from the outside, and a prompt response to the failure becomes possible. Was. As a result, problems such as continuing formation of a defective image are prevented.

According to the second or seventh aspect of the present invention, when the xenon lamp does not light up normally, it is possible to quickly cope with a failure. As a result, problems such as continuing formation of a defective image are prevented.

According to the third or eighth aspect of the present invention, when an abnormal decrease in the amount of light emitted from the xenon lamp occurs, it is possible to take a prompt action. As a result, problems such as continuing formation of a defective image are prevented.

According to the fourth or ninth aspect of the present invention, it is possible to quickly and accurately grasp the failure of the reading light source, and to prevent a problem such as the formation of a defective image is continued.

According to the fifth or tenth aspect of the present invention, when a failure occurs in the reading light source, the reading is immediately stopped, so that a problem such as the continued formation of a defective image is reliably prevented.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of an image data processing system in the image forming apparatus according to the embodiment of the present invention.

FIG. 3 is a block diagram of a driving unit of the xenon lamp according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Image forming part 24 CCD 26 Amplifier 50 Control means 60 Document 70 Reference white plate 100 Xenon lamp 101 Inverter 103 Warning means 105 Drive current detection circuit 106 Abnormal discharge detection circuit 107 Current level detection circuit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazumichi Yamauchi 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H109 AA02 AA28 AB04 AB24 AB62 AB64 5C072 AA05 BA20 CA02 EA05 FB27 XA01

Claims (10)

[Claims] 1. A document reading apparatus comprising: a xenon lamp that illuminates a document, an inverter that drives the xenon lamp, and an image sensor that receives light from the document illuminated by the xenon lamp and converts the light into an electric signal. The inverter is provided with an abnormal discharge detection circuit for detecting abnormal discharge, an output terminal of the abnormal discharge detection circuit, and a warning unit for issuing a warning to the outside based on an output of the abnormal discharge detection circuit. Document reading device. 2. A document reading apparatus comprising: a xenon lamp that illuminates a document; an inverter that drives the xenon lamp; and an image sensor that receives light from the document illuminated by the xenon lamp and converts the light into an electric signal. The inverter is provided with a current level detection circuit for detecting the level of the drive current of the xenon lamp and an output terminal of the current level detection circuit, and has an alarm unit for issuing an external alarm based on the output of the current level detection circuit. An original reading apparatus, comprising: 3. A xenon lamp that illuminates a document, an inverter that drives the xenon lamp, an image sensor that receives light from the document illuminated by the xenon lamp and converts the light into an electric signal, and a reference white plate. In a document reading apparatus having automatic gain control and an amplifying means for amplifying an output of the image sensor, an output of the amplifying means is monitored, and when an output of the amplifying means does not reach a predetermined value even when a gain is maximized. And a warning device for giving a warning. 4. The document reading apparatus according to claim 1, wherein the warning unit performs a warning display. 5. The document reading apparatus according to claim 1, wherein the warning unit displays a warning and stops a reading operation. 6. A xenon lamp for illuminating a document, an inverter for driving the xenon lamp, an image sensor for receiving light from the document illuminated by the xenon lamp and converting the light into an electric signal, and illuminated by the xenon lamp A document reading device having an image sensor that receives light from a read document and converts the light into an electric signal; and an image forming device that forms an image based on image information from the reading device. An abnormal discharge detection circuit, an output terminal of the abnormal discharge detection circuit, and a warning unit for issuing a warning to the outside based on an output of the abnormal discharge detection circuit. 7. A document reading apparatus having a xenon lamp for illuminating a document, an inverter for driving the xenon lamp, and an image sensor for receiving light from the document illuminated by the xenon lamp and converting the light into an electric signal; An image forming apparatus that forms an image based on image information from a document reading device, wherein the inverter is provided with a current level detection circuit that detects a level of a driving current of the xenon lamp and an output terminal of the current level detection circuit. An image forming apparatus comprising: a warning unit that issues a warning to the outside based on an output of the lighting / non-lighting detection circuit. 8. A xenon lamp that illuminates a document, an inverter that drives the xenon lamp, an image sensor that receives light from the document illuminated by the xenon lamp and converts the light into an electric signal, and a reference white plate. Automatic gain control is performed, and in an image forming apparatus that forms an image based on image information from an original reading apparatus and an original reading apparatus having an amplifying unit that amplifies the output of the image sensor, monitoring an output of the amplifying unit, An image forming apparatus comprising: a warning unit that gives a warning when the output of the amplification unit does not reach a predetermined value even when the gain is maximized. 9. The image forming apparatus according to claim 6, wherein the warning unit displays a warning. 10. The image forming apparatus according to claim 6, wherein the warning unit displays a warning and stops a reading operation.