JP2001242557A - Image reader and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the electromagnetic radiation noise of an image reader with simple constitution. SOLUTION: A metallic supporting material 407 for supporting an exothermic section 406 of a heater to be mounted at a fluorescent lamp is provided with a louvering soldering section 408 for connecting a grounding line. A coated electric wire connected to the exothermic section 406 is soldered to the soldering section 408 and is connected to a grounding terminal of a heater driver 402 via a connector 405 or/and a easing 402 of the image reader or to an external ground 409 (Figures (a), (c) and (d)) via a casing 402. The grounding terminal of the header driver 404 may be connected to the grounding line of a receptacle with an earth wire via the ground of a DC power source.

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 of a document, and an image forming apparatus such as a copying machine for outputting the read image to paper.

[0002]

2. Description of the Related Art A sectional view of a fluorescent lamp as a light source for reading an original of a copying machine is shown in FIG. 5, and a side view thereof is shown in FIG.

In FIG. 6, a mercury gas and a rare gas 901 are sealed in a glass tube 801 by caps 902 at both ends of the glass tube 801. Further, a glass tube 801
At both ends are electrodes 903 of a tungsten coil coated with an electron emitting material, the electrodes being supported by a stem 904. The base 902 is provided with a conductive portion 905 for supplying a current. As shown in FIG. 5, a reflective film 804 that reflects light generated inside the glass tube is applied on the inside of the glass tube 801, and a phosphor 803 is applied further on the inside thereof. Since the reflection film 804 or the phosphor 803 is not applied to the aperture 805 on the side of the glass tube, light passes through the aperture 805.

When the fluorescent lamp is turned on, electrons emitted from the electrode 903 collide with mercury atoms, and the mercury atoms are excited to emit ultraviolet rays. This ultraviolet light is converted into visible light having a wavelength specific to the phosphor by the phosphor on the inner wall of the discharge tube. Light generated inside the glass tube is reflected by the reflection film 804,
The light is emitted from the aperture unit 805. This reflection film 804
By the action of the aperture 805, strong light is output in the direction of the arrow in FIG.

FIG. 7 shows an optical system of an image reading apparatus using a fluorescent lamp. In FIG. 7, light emitted from the aperture 805 of the fluorescent tube 801 is
The light is reflected at 1002 and irradiates near the reading line 1005 of the original 1004 on the platen glass 1003.
The light emitted from the original reading line 1005 is reflected by the mirror 1
006, 1007, 1008, and a lens 1009, a CCD image sensor (image reading unit) 1010
It is led to. A light shielding plate 1011 is provided so that light emitted from the back surface of the fluorescent tube 801 is not directly irradiated on the original 1004. Reference numerals 801, 1001, 1002, and 1011 move the document surface as one scanner unit 1012. The mirror 100 is moved according to the movement of the scanner unit.
7, 1008 is a CCD1 from the reading line 1005;
It moves so that the optical path up to 010 is kept constant.

[0006] As described above, the light amount of the light source of the image reading apparatus, that is, the fluorescent lamp, depends on the amount of ultraviolet rays emitted from the excited mercury atoms in the tube. It is considered that the light intensity of the fluorescent lamp is represented by the product of the power supplied to the fluorescent lamp and the luminous efficiency. Then, when the mercury atom density decreases, the number of atoms excited by collision of electrons decreases as the mercury atom density decreases, and on the contrary, when the mercury atom density increases, the probability of electron reabsorption increases, so it also decreases. I do. Therefore, there is a mercury vapor pressure at which the luminous efficiency is maximized. Also, the mercury vapor pressure depends on the temperature of the lowest part of the temperature inside the tube (the coldest part temperature). That is, there is a coldest part temperature at which the luminous efficiency is maximized.

FIG. 8 is a graph showing the relationship between the temperature of the coldest part or the mercury vapor pressure of the fluorescent lamp and the luminous efficiency. The mercury vapor pressure at which the luminous efficiency becomes maximum varies depending on the inner diameter of the tube. For example, when the inner diameter of the tube is 15 mm, the mercury vapor pressure at which the luminous efficiency becomes maximum is about 1 Pascal, and the temperature of the coldest part is about 4 Pascals.
It is said to be around 4 ° C. When the fluorescent lamp for normal lighting is turned on at the use environment temperature, for example, 25 ° C., the temperature of the coldest part (usually the temperature inside the both ends of the tube) when the heat stable state is reached by its own heat generation and heat radiation is the aforementioned optimum coldest part. Designed to be temperature.

FIG. 9 is a block diagram of a light quantity control circuit of the fluorescent lamp, and FIG. 10 is a peripheral view of the fluorescent lamp. In FIG. 10, a fluorescent lamp 1206 is supported by a socket 1301, and current is supplied from pins on the socket 1301. The fluorescent lamp has an aperture 80 in the required direction.
5 (optical aperture) is provided. In FIG. 10, strong light is output in the direction of the arrow, and relatively weak light is output in the opposite direction.

A fluorescent lamp light quantity sensor 1201 is provided to measure the light quantity of the fluorescent lamp. The light amount sensor 1201 uses a photodiode or the like, and outputs a current proportional to the fluorescent lamp light amount. Fluorescent lamp 12
Reference numeral 06 controls the light amount to be constant by feeding back the light amount measured value obtained by the fluorescent lamp light amount sensor 1201.

FIGS. 11A, 11B and 11C are timing charts for explaining the operation of the light quantity control circuit of FIG. 11A shows a case where the light amount is appropriate, FIG. 11B shows a case where the current value is increased because the light amount is small, and FIG. 11C shows a case where the current value is decreased because the light amount is large.

In FIG. 9, a light quantity signal output from a light quantity sensor 1201 is converted into a voltage value by an amplifier 1202 and amplified. The comparator 1203 compares the voltage corresponding to the observed light quantity with the desired light quantity value and outputs the result.
The light amount controller 1204 outputs a pulse width modulation (PWM) signal. This pulse width modulation signal is phase-synchronized with a synchronization (SYNC) signal as shown in FIG. 11, so that when the observed light quantity is larger than the desired light quantity, the duty becomes smaller, and the observed light quantity becomes smaller than the desired light quantity. When it is small, the duty is controlled to be large.

When the input pulse width modulation signal is at "H" level, the inverter 1205 supplies an AC current, that is, an AC current, to the fluorescent lamp at a frequency sufficiently higher than the pulse width modulation signal (generally, about 10 to 100 times). It is controlled so that the lamp is turned on by supplying the lamp current, and when the lamp is at the "L" level, the lamp current is cut off and turned off. This turning on / off is repeated according to the cycle of the pulse width modulation signal. The frequency of the pulse width modulation signal is higher than the optical response frequency for turning on and off the fluorescent lamp. That is, although the lighting / extinguishing is electrically repeated in accordance with the cycle of the pulse width modulation signal, it looks as if the light is lit with a constant light amount corresponding to an average current value.

As described above, the fluorescent lamp 1206 is controlled so that the light quantity is constant by controlling the duty of the cycle of turning on and off.

The amount of light of the fluorescent lamp is determined by the ON-OF of the tube current.
It changes as shown in FIG. During a period in which no current flows, some light is emitted due to the persistence of the phosphor, but the amount of light is small.

On the other hand, an image reading element such as a CCD operates during one cycle of a SYNC signal, that is, during one scanning period.
The read image information is stored as electric charges. That is, C
The output of the CD is an output value having a magnitude obtained by integrating the light amount during one scanning period. Therefore, if the flashing of the fluorescent lamp and the scanning of the CCD are synchronized in the same cycle, a constant CCD output can be obtained.

When a fluorescent lamp is used as the light source of the image reading apparatus, it is desired that the amount of light after lighting reaches a required value quickly. After the light amount reaches the required value, the light amount needs to be stable, and it is better that the light amount distribution characteristic or the emission spectrum is stable. Otherwise, when the fluorescent lamp is turned on continuously to read many images continuously, the density of the first document and the last document will be different, uneven density will occur, and color shift will occur. Or you will.

However, with a fluorescent lamp, immediately after lighting,
Until the thermal stable state is reached, for several tens of seconds, due to instability of the mercury vapor pressure due to uneven temperature and the movement of mercury atoms,
The light intensity, light intensity distribution, and emission spectrum become unstable and change.

As a method of solving this problem, there is a case where a method is used in which a heater is attached to the fluorescent lamp and the temperature is kept at a predetermined temperature or more even when the fluorescent lamp is turned off. FIG. 12 shows a mounting example of the fluorescent lamp heater. This method is effective for improving the rising speed of the light amount immediately after lighting, improving the stability of the light amount, improving the stability of the light amount distribution characteristic, improving the color stability, and the like.

In FIG. 12, the aperture 805 of the fluorescent lamp 1206 is directed in the direction of the arrow, and emits strong light in the direction of the arrow. It is focused on the original.
The lamp heater 213 is mounted so as to cover a portion other than the aperture 805.

The light quantity sensor 1201 is a fluorescent lamp 1206
And measures the amount of light output from the fluorescent lamp 1206. A notch 1302 is provided in the lamp heater 213 so that light input to the light amount sensor is not blocked.

There are two types of lamp heaters: resin heaters and metal heaters. FIG. 13 shows an example of the structure of a metal lamp heater. In FIG. 13, (a) is a sketch and (b) is a sectional view.

In FIG. 13A, reference numeral 201 denotes a semi-cylindrical metal support member which is fitted into a fluorescent lamp for use. One or more cement resistors 202 are wired in series and used as a heating element. The cement resistor 202 wraps the heating conductor wire with an insulating material such as cement that does not conduct electricity but conducts heat. The cement resistor 202 is mounted on the back of the metal support 201. FIG.
As shown in (b), a part of the metal supporting member 201 is processed to provide a nail 203, and the cement resistance is fixed by the nail 203. The support member 201 is provided with a notch similar to the lamp heater of FIG. 12 so as not to block light input to the light control sensor.

The fluorescent lamp heater is effective for improving the rising speed of the amount of light immediately after lighting of the fluorescent lamp, improving the stability of the amount of light, improving the stability of the characteristics of the amount of light distribution, and improving the color stability.

Further, since the metal lamp heater has better heat conductivity than that made of resin, the heating performance, the heat retention performance and the temperature uniformity performance for the fluorescent lamp can be secured with a simple structure.

[0025]

However, since it is made of metal, it may have an effect on the noise generated by equipment.

FIG. 14 is an example of actual measurement of electromagnetic radiation noise generated from the image reading apparatus. Although the measurement is performed in a wider range, for example, in the range of 30 Mhz to 1 Ghz, a part of the noise spectrum distribution is shown in the range of 100 Mhz to 200 Mhz. Of the two lines in the graph, the thin line is the noise in the measurement environment that is not related to the device under test, and the dark line with the X mark is the radiation noise of the image reading device in the same environment. . It is required that the radiation noise of the image reading device be equal to or less than a predetermined reference value in all frequency ranges.

This noise level increases and decreases every moment depending on the state and operating conditions of the image reading apparatus. In the example of FIG.
Noise peaks are concentrated around 40 Mhz to 160 Mhz, which are harmonic components of the system clock used in the circuit of the image reading apparatus. This portion also increases or decreases every moment depending on whether the image reading apparatus is operating or on standby, and in what operation mode it is operating.

Since the fluorescent lamp heater is driven by a commercial AC power supply or a DC power supply, it is not originally a component that generates noise itself, nor does a high-frequency current that emits noise flow. However, as a material of the support material of the fluorescent lamp heater, when a metal material is used, compared with a case where a resin material is used,
The noise level may temporarily increase under certain operating conditions of the image reading apparatus, and may exceed an allowable value.

This is because the radiation noise generated from the substrate of the image reading apparatus is amplified by the metal support member of the lamp heater which is not grounded but is floating in electric potential, serving as an antenna. That's why.

When a fluorescent lamp is lit at a high frequency using an inverter, radiation noise generated from the fluorescent lamp itself may be a problem depending on the lighting current waveform.

In any case, device noise is likely to be generated when the lamp heater is used, largely because the metal support of the lamp heater is floating in potential.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to reduce electromagnetic radiation noise of an image reading apparatus with a simple configuration.

[0033]

In order to achieve the above object, the present invention provides a light source lamp for generating light for irradiating a document, and heating the light source lamp to a predetermined temperature or higher before the light source lamp is turned on. A heater having at least part of a metal portion made of a metal material, and image reading means for reading reflected light from a document irradiated by the light source lamp and outputting an image signal. And a potential holding means for holding the metal portion at a predetermined potential.

In this way, it is possible to realize a heater for a light source lamp of an image reading apparatus, which has good thermal conductivity and does not amplify radiation noise.

The heater has a heating element for emitting heat, and a heating element supporting portion for supporting the heating element, at least a part of which is made of a metal material. It is preferable to include a connection member that connects the metal part of the body support part and the housing of the image reading device.

The heater has a heating element for emitting heat, and a heating element supporting portion for supporting the heating element, at least a part of which is made of a metal material. It is preferable to include a connecting member for connecting the metal part of the body supporting part and the ground line to be grounded.

The heater has a heating element that emits heat, and a heating element supporting portion that supports the heating element, at least a part of which is made of a metal material, and supplies a current to the heating element. It is preferable that a heater drive unit is provided, and the potential holding unit includes a connection member that connects a metal part of the heating element support unit and a ground terminal of the heater drive unit.

In this way, it is possible to realize a heater for a light source lamp of an image reading apparatus, which has a simple structure, is easy to mount, has good thermal conductivity, and does not amplify radiation noise.

Further, a DC power supply unit for supplying a DC voltage to the heater drive means is provided, and the potential holding means is a connecting member for connecting a metal part of the heating element support part and a ground wire of the DC power supply part. It may be included.

Further, the heater may have a connector for inputting a current to the heating element, and the connection member may be connected to a metal portion of the heating element support via the connector.

In this manner, it is possible to realize a heater for a light source lamp of an image reading apparatus, which has a simple structure, is easily mounted, has good thermal conductivity, and does not amplify radiation noise.

Further, it is preferable that a metal base on which at least the light source lamp and the heater are mounted is provided, and the potential holding means includes a connecting member for connecting the metal part and the base. is there.

An image forming apparatus comprising: an image reading unit that reads an image of a document; and an image forming unit that forms an image read by the document reading unit on a recording material.
The image reading unit may include the image reading device according to the present invention.

[0044]

FIG. 1 shows an embodiment of a lamp heater used in an image reading apparatus according to the present invention. The schematic configuration of the image reading apparatus is the same as the configuration shown in FIG.

In FIG. 1A, a supporting member (heating element supporting portion) 101 is made of metal. The support member 101 has a plurality of cut-and-raised claws 103 and 108 for fixing and holding the cement resistor 102 and the protective tube 105.

A plurality of cement resistors 102 are wired in series and used as a heating element. Cement resistance 10
Numeral 2 encloses the heating conductor wire with an insulating material such as cement. The cement resistor 102 is mounted on the back surface of the semi-cylindrical support member 101 made of metal.

FIG. 1 is a sectional view of the lamp heater shown in FIG.
(B). As shown in FIG. 1B, a part of the metal support member 101 is processed to provide a nail 103, and the cement resistance is fixed by the nail 103. The support member 101 is provided with a cutout similar to that of the lamp heater of FIG. 12 so as not to block the light input to the light amount sensor, but is located at a position that cannot be seen in FIG.

One wire from the cement resistor 102 is connected to a covered electric wire 104 via a terminal. Insulated wire 104
Is connected to one pin of the connector through the protective tube 105.

The protective tube 105 encloses the covered electric wire 104 and is supported by a plurality of cut-and-raised claws 108 on the support member 101.
Fixed to

The other end terminal of the cement resistance row 102 is soldered to a ground wire connecting cutout 107 provided on the support member 101. If the support material is a material such as aluminum which is difficult to solder, a hole is cut in the cut-and-raised portion 107 and an eyelet is used to solder a cement resistance terminal to the eyelet. In this part, a covered wire 10
9 is also soldered at the same time, and the coated electric wire 109 is connected to the other terminal of the connector 106. This terminal is the ground terminal. Thus, the ground terminal of the connector 106 and the metal support member 101 are electrically connected.

In place of the cement resistance, a heating wire included in a quartz glass tube may be used.

The lamp heater having the above configuration is used by being fitted into a fluorescent lamp (light source lamp) 1206 and mounted in the same manner as in FIG. When the fluorescent lamp 1206 is not turned on, a current is supplied to the cement resistor 102 to heat the lamp heater 213 so that the fluorescent lamp 1206 is maintained at a predetermined temperature or higher.

FIG. 2 is a schematic circuit diagram showing the relationship between the ground terminal of the lamp heater and the ground line of the image reading apparatus as four embodiments.

FIG. 2A shows a connection method in which the ground terminal of the lamp heater is connected to the ground terminal of the heater driver (heater drive means) and further connected to the housing of the image reading apparatus. In FIG. 2A, power is supplied from a commercial AC power supply 401 to a DC power supply (DC power supply unit) 403, from which a DC voltage is supplied to a heater driver 404, and from there, a lamp heater heating unit 407 through a lamp heater connector 405. Necessary power is supplied to the vehicle. The lamp heater may be provided with a temperature detecting means such as a thermistor (not shown). In such a case, the heating section 40 corresponds to the temperature detected by the temperature detecting means.
7 is supplied with power.

The ground wire of the lamp heater is connected to a metal support member 406 via a ground wire connecting cut-and-raised soldering portion 408.

This ground line is connected to the ground terminal of the heater driver 404 and the image reading apparatus housing 402 via the connector 405. Further, there is a case where it is further connected to the external ground 409 from there.

In the present embodiment, a potential is provided by a member for connecting the cut-and-raised soldering portion 408 for ground line connection, the ground terminal of the heater driver 404, the image reading device housing 402, and the external ground 409 via the connector 405. Holding means is configured.

FIG. 2B shows a case where a power outlet with a ground wire is used. The line of the ground 410 is connected to the cable of the commercial power supply 401 together. This ground line is connected to the ground of the DC power supply 403 in the image reading apparatus, further connected to the ground of the heater driver circuit 404, further connected to the lamp heater connector 405, and to a cut-and-raised soldering portion for connecting the ground line of the lamp heater. 408 is connected to the metal support member 406 and the ground side terminal of the lamp heater heating section 407.

In the present embodiment, the grounding of the DC power supply 403 and the heater driver circuit 4 via the cut-and-raised soldering portion 408 for ground line connection and the connector 405 are provided.
A member connecting the ground 410 and the ground 410 forms a potential holding unit.

FIG. 2C shows a case where the voltage of the commercial AC power supply is supplied to the lamp heater as it is. The AC power supply voltage is set to the AC heater switch 411 and the lamp heater connector 4.
05, and is supplied to the lamp heater heat generating section 407.
Since the AC heater switch 411 is constituted by a photo triac or a relay, it is insulated from circuit wiring in the image reading device 411. The lamp heater connector 405 is provided with a dedicated ground terminal 412 in addition to the two terminals for supplying heater power, through which the housing 402 of the image reading apparatus and the metal support member 4 of the lamp heater are provided.
06 is connected.

In this embodiment, the cut-and-raised soldering portion 408 for ground line connection and the housing 402 of the image reading apparatus are provided.
A member that connects the external ground 409 to the external ground 409 via the ground terminal 412 of the connector 405 forms a potential holding unit.

FIG. 2D shows a case where the housing 413 of the image reading apparatus is made of a nonmetallic material such as resin. Also in this case, since the metal support member 406 of the lamp heater and the ground terminal 414 of the heater driver board are connected via the ground line connection portion 408 and the connector 405, there is an effect of reducing electromagnetic radiation noise.

In this embodiment, a member for connecting the ground wire connection cut-and-raised soldering portion 408 and the ground terminal 414 of the heater driver 404 constitutes a potential holding means.

The lamp heater may be provided with a temperature fuse for safety and a temperature sensor for temperature measurement in addition to the heating element 407, and their wiring is not shown in these wiring diagrams. However, the present invention can be similarly realized and effective even if a circuit of a temperature fuse or a temperature sensor is added. FIG. 3 shows an example of a circuit diagram of a lamp heater provided with a thermal fuse and a thermistor. 407 in FIG.
Is a heating element, 501 is a thermal fuse, and 502 is a thermistor. A common ground line between the thermistor 502 and the thermal fuse 501 is connected to the metal support member 406 via a ground line connection cut-and-soldered portion 408. Further, this common ground line is connected to the ground terminal of the heater driver or the housing of the image reading apparatus via the ground terminal 503 of the connector 405.

In the present embodiment, a member for connecting the cut-and-raised soldering portion 408 for ground line connection to the ground terminal of the heater driver or the housing of the image reading apparatus via the ground terminal 503 of the connector 405 serves as a potential holding means. Constitute.

FIG. 4 shows a lamp heater and a part of a scanner unit of an image reading apparatus according to another embodiment of the present invention. In FIG. 4, a fluorescent lamp 1206 to which a metal lamp heater 604 is mounted is mounted on a scanner unit (base) 601 by a socket 1301. On the scanner unit, the condensing mirror 1001 shown in FIG.
Although 1002 and a light shielding plate 1011 are also provided, they are omitted in FIG. 4 for explanation. As the scanner unit moves, it receives power supply from the fluorescent lamp and the lamp heater via the flexible cable 604. The current of the heater is supplied to the heater element of the lamp heater 604 from the flexible cable via the connector 1401 of the lamp heater. A terminal 107 for separately soldering a cable is provided on a part of the metal part of the lamp heater, and the cable 605 (potential holding means) soldered there is connected to the screw terminal 60.
2 and connected to the scanner unit by a screw 603.

With the above configuration, the lamp heater metal part 604 and the scanner unit 601 have the same potential. Since the scanner unit is more stable in electric potential than the lamp heater, the radiation noise reduction effect of the image reading device appears only by itself.

Further, when the scanner unit 601 and the lamp heater 604 are held at the ground potential by connecting the ground line of the power supply section of the main body to the scanner unit 601 via the flexible cable 604, the radiation noise reduction effect is further increased.

Even if the lamp heater metal part 604 is not directly connected to the ground of the image reading apparatus, but is connected through a somewhat small resistor, the lamp heater metal part 604 is held at the ground potential. A radiation noise reduction effect appears.

Further, even if the lamp heater metal part 604 is not connected to the ground of the image reading apparatus, and is connected to a predetermined voltage portion having a stable potential, the same effect as when it is connected to the ground appears. In short, as long as the lamp heater is connected directly or indirectly to the predetermined voltage section, the object of the present invention is achieved and radiation noise reduction can be realized.

The present invention can be applied to an image reading apparatus such as a scanner or a facsimile. However, the image reading apparatus according to the present invention is provided as an image reading section, and the read image is read by a known method such as an electrophotographic method. The present invention can be similarly applied to an image forming apparatus such as a copying machine having an image forming unit for forming an image on a recording material such as paper by an image forming method.

[0072]

As described above, according to the image reading apparatus provided with the heater according to the present invention, the metal portion of the light source lamp heater is maintained at a predetermined potential, so that the structure is simple and the cost is low. Thus, the electromagnetic radiation noise of the image reading device can be reduced.

Further, since the heater according to the present invention has higher thermal conductivity than the conventional resin heater, the entire tube can be uniformly heated before the light source lamp is turned on. The rise reaches the desired light amount in a short time, and once the desired light amount is reached, stable lighting with little change in light amount is achieved, the light amount distribution characteristics and emission spectrum immediately after lighting are stable, and almost no transient infrared emission. Therefore, the image reading processing speed is increased, and at the same time, the image reading quality is improved. Alternatively, the structure of the lamp heater can be simplified by an amount corresponding to the high thermal conductivity, so that the cost can be reduced accordingly.

Further, as compared with an image reading apparatus which does not use a heater, the rising of the light amount immediately after the lighting reaches the desired light amount in a short time, and once the light amount reaches the desired light amount, the lighting becomes stable with little change in the light amount. Immediately thereafter, the light quantity distribution characteristics and the emission spectrum are stable, and almost no transient infrared emission occurs, so that the image reading processing speed is increased and the image reading quality is improved.

[Brief description of the drawings]

FIG. 1A is an external view of a lamp heater used in an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the lamp heater used in an embodiment of the present invention.

FIGS. 2A, 2B, 2C, and 2D are schematic circuits illustrating an embodiment of the present invention and illustrating a relationship between a ground terminal of a lamp heater and a ground line of an image reading apparatus. FIG.

FIG. 3 is a circuit diagram of a lamp heater showing another embodiment of the present invention.

FIG. 4 is a partial external view of a lamp heater and a scanner unit showing another embodiment of the present invention.

FIG. 5 is a sectional view of a fluorescent lamp for an image reading device.

FIG. 6 is a side view of a fluorescent lamp for an image reading device.

FIG. 7 is an optical system configuration diagram of the image reading apparatus.

FIG. 8 is a graph showing the relationship between the mercury vapor pressure and the luminous efficiency of a fluorescent lamp.

FIG. 9 is a block diagram of a fluorescent lamp dimming circuit.

FIG. 10 is a peripheral view of a fluorescent lamp.

FIG. 11 is a timing chart for explaining the operation of the light quantity control circuit.

FIG. 12 is a peripheral view of a fluorescent lamp equipped with a lamp heater.

FIG. 13 is an external view showing an example of a conventional lamp heater.

FIG. 14 is an example of an electromagnetic radiation noise spectrum of the image reading apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Support material 102 Cement resistance 103,108 Cut-and-raised claw 107 Ground-line connection cut-and-raised 401 Commercial AC power supply 402 Housing 403 DC power supply 404 Heater driver 405 Connector 406 Support material 407 Heating portion 408 Ground-line connected cut-and-raised soldering portion 409 External ground 412 Ground terminal 414 Heater driver board ground 503 Connector ground terminal 605 Cable

Claims (8)

[Claims] A light source lamp for generating light for irradiating an original; and a heater for heating the light source lamp to a predetermined temperature or higher before the light source lamp is turned on, wherein at least a metal portion made of a metal material is provided. An image reading unit that reads a reflected light from a document irradiated by the light source lamp and outputs an image signal, wherein the heater has a heater provided in a part thereof, and a potential that holds the metal portion at a predetermined potential. An image reading apparatus comprising a holding unit. 2. The heating device according to claim 1, wherein the heater emits heat.
A heating element supporting portion that supports the heating element, at least a part of which is made of a metal material, wherein the potential holding unit connects a metal portion of the heating element support section and a housing of the image reading apparatus; The image reading device according to claim 1, further comprising a connecting member. 3. The heating device according to claim 1, wherein the heater is configured to emit heat.
A heating element supporting portion that supports the heating element, at least a part of which is made of a metal material, wherein the potential holding unit connects a metal portion of the heating element support section to a ground line that is grounded; The image reading device according to claim 1, further comprising a connecting member. 4. The heater according to claim 1, wherein the heater is configured to emit heat.
A heating element supporting portion for supporting the heating element, at least a part of which is made of a metal material; and a heater drive unit for supplying a current to the heating element; 2. The image reading apparatus according to claim 1, further comprising a connecting member for connecting a metal part of the body supporting part and a ground terminal of the heater drive unit. 5. A power supply unit for supplying a DC voltage to the heater drive unit, wherein the potential holding unit includes a connecting member for connecting a metal part of the heating element support unit and a ground line of the DC power supply unit. The image reading device according to claim 4, wherein the image reading device includes: 6. The heater according to claim 2, wherein the heater has a connector for inputting a current to the heating element, and the connection member is connected to a metal portion of the heating element support via the connector. 6. The image reading device according to claim 5, wherein 7. A metal base on which at least the light source lamp and the heater are mounted, wherein the potential holding means includes a connection member for connecting the metal part and the base. The image reading device according to claim 1. 8. An image forming apparatus comprising: an image reading unit that reads an image of a document; and an image forming unit that forms an image read by the document reading unit on a recording material. Item 8. An image forming apparatus comprising the image reading device according to any one of Items 1 to 7.