JP2978571B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a color copying machine.

[0002]

2. Description of the Related Art In a copying machine, a lamp having a large optical power is used as an illumination device for illuminating a document.
The heat generated by the light-emitting lamp of this lighting device is large. Particularly, in a color copying machine in which a halogen lamp is used as the light-emitting lamp to perform exposure processing, a large amount of light is required. In addition, an appropriate exposure amount cannot be obtained due to the sensitivity characteristics of the photoconductor and the spectral transmittance of the color separation filter. Therefore, it is conceivable to reduce the heat generation energy of the light-emitting lamp by decreasing the linear velocity of the photoconductor and the exposure amount, but the copying speed per sheet is reduced, and , The number of copies becomes smaller, so that the copying efficiency is reduced.

Further, a cooling fan is mounted on a traveling unit to cool a light emitting lamp (for example, disclosed in Japanese Utility Model Application Laid-Open No. 62-109157). In this case, if the cooling capacity of the cooling fan is increased to increase the cooling air, toner and dust from the inside and outside of the machine are liable to float.
Adhering to a lens system, a mirror system, or the like adversely affects a copy image. For this reason, it is not desirable to sharply lower the heat-generating energy (power) of the light-emitting lamp.
Therefore, in a color copying machine, in order to obtain an appropriate exposure amount based on the sensitivity of the photoreceptor and the spectral transmittance of the color separation filter, the light emitting lamp can be varied over a wide range of lamp power and a sufficient light amount range can be obtained. It is necessary to have it.

[0004]

However, in the above-mentioned prior art, when the light-emitting lamp has a wide range of lamp power, the heat generated by the light-emitting lamp also changes. Depending on the temperature of the bulb wall of the halogen lamp, an appropriate halogen cycle does not work and blackening and fusing of the filament are likely to occur. As a result, the life of the halogen lamp is significantly reduced, frequent replacement of parts is required, and
There is a problem that the screw cost is high.

The present invention has been made in view of the above, and has as its object to maintain a halogen cycle of a lamp and to suppress a rise in the temperature of contact glass.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a light emitting lamp which is constituted by a plurality of halogen lamps and illuminates a reading section of a document, and which emits light from the light emitting lamp in the direction of the document. A reflecting plate for reflecting, and a mirror mechanism for reflecting the reflected light from the reading unit to an optical system
A transport member equipped with a
Perform at least R exposure, G exposure, and B exposure
Each exposure for each exposure to form a full color image
Each time the transport member is moved relative to the original document
An image forming apparatus that illuminates the document with the light-emitting lamp
In the blower means disposed near one end of the moving range of the transport member to cool each of the light-emitting lamp and the reflector, while controlling the driving of the light-emitting lamp,
And control means for variably for according the blowing amount of the blower means to a driving condition of the light emitting lamp, the control means, B dew
At the time of relative movement of the transport member corresponding to light, R and
In the case of relative movement of the transport member corresponding to each G exposure
In comparison, while increasing the light amount of the light emitting lamp,
Image formation controlled to increase the amount of air blown by blower
An apparatus is provided.

[0007]

In the image forming equipment according to the present invention, the air blowing amount of the blower means in accordance with the exothermic energy varies depending on the driving conditions of the light emitting lamp is switched. Therefore, the light-emitting lamp is always kept properly, reducing abnormal images and filament breaks caused by uneven light distribution on the document surface due to blackening of the lamp and exposure distribution, extending the life and replacing parts. Can be reduced.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to the present invention and a color copying machine employing the same.
As shown in FIG. 1, a color copying machine includes an illuminating device 101 for illuminating a document placed on a contact glass 116,
A mirror member 102 for reflecting light reflected from the original by illumination to the exposure position side, a lens carriage 103 holding a projection lens, a color separation filter 104 as color separation means,
A photosensitive drum 105 exposed through a projection lens and a color separation filter 104, a black developing unit 106 for performing development corresponding to black of color separation, and developing each color of green, blue and red other than black Color phenomena 10 for
7. Remover 108, photoreceptor cleaning device 109 for removing residual toner on the transferred photoreceptor surface, transfer drum device 110 on which a transfer sheet (such as plain paper for recording) is wound, Fixing device 111 for fixing toner image on recording paper, transfer drum device 11
Paper feeder 1 for supplying specified paper to sheet 0
12, a control unit 113 for integrally controlling various driving members such as a motor and a solenoid and the lighting device 101, a power supply unit 114 for supplying power to each member and a circuit, and cooling a lamp and a contact glass of the lighting device 101. For example, an illumination cooling fan 115 is provided.

FIG. 2 is a plan view showing a main part of the lighting device, FIG. 3 is a side sectional view of the lighting device shown in FIG. 2, and FIG. 4 is a side view of the lighting device shown in FIG. The light-emitting lamp 201, the main reflector 202, the opposing reflector 2
03, a first mirror 301 is provided to face the contact glass 116. As shown in FIG. 2, the plurality of light-emitting lamps 201 arranged in a row are
Opening 30 provided between an elliptic curved main reflector 202 located at the lower part of the main body and a subsequent upper upper reflector 302
3, the axis of which is inserted in parallel with the optical scanning direction, and is mounted such that a light emitting portion is located on each focal plane of the main reflector 202 and the upper reflector 302. In the light from the light-emitting lamp 201, the reflected light from the main reflector 202 directly reaches the slit-shaped irradiation part 304 on the contact glass 116, but the reflected light from the upper reflector 302 is directed to the tip of the main reflector 202. The formed opposing reflector 30
The upper reflector 302 is also formed into an elliptic curve so that it is reflected by 5 and arrives at the slit-shaped irradiation section 304.

The reflected light from the original on the contact glass 116 passes through a slit 216 provided in a stepped portion between the main reflector 202 and the opposing reflector 203, and passes through the leaf spring 3
06, the photosensitive drum 1 is guided to the lens system via a first mirror fixed thereto, and further through a color separation filter or the like.
05. Reference numeral 203 denotes a light-shielding plate.
Reference numeral 04 denotes an illuminance correction plate, and the scanner body 205 together with the main reflection plate 202, the opposing reflection plate 305, and the upper reflection plate 302.
(Conveyance member) with a set screw 206. Further, 207 is a scanner guide rod, 208 is a side reflector, 209 is a lamp power supply cable, 210 is a guide rail, 211 is a printed circuit board for fixing the light emitting lamp 201, and 212 is a lighting unit support.

FIG. 5 is a plan view of a printed circuit board for an illumination lamp. In the present embodiment, the light-emitting lamps 201 are arranged in a horizontal line on the printed circuit board 211 for the illumination lamp as shown in FIG.
The main reflection plate 202 is set by inserting and connecting the lamp pin terminal 213 to the pin connection hole 502 on the first printed circuit 501 and fixing the main reflection plate 202 to the pin connection hole 502 by soldering or the like.
The light-emitting lamp axis is fixed to the illuminating part support body 212 fixed by a stepped screw 215 via a spacer 214 so as to be parallel to the optical scanning direction.

As shown in FIG.
The light-emitting lamps L101, L102, L103, L105, and the light-emitting lamps L101, L102, L103, and L105 are located at symmetrical positions around the light-emitting lamp L104 fixed to the optical axis XX.
A group of light-emitting lamps composed of L106 and L107, and distances a,
L201, L202, L20 arranged at each position of b and c
3, L204, L205, and L206, and two groups of light-emitting lamps.

FIG. 6 is a circuit diagram showing details of a control device for driving the two groups of light emitting lamps. A CPU (Central Processing Unit) 601 that executes various processes in accordance with a preset program is used to drive a halogen lamp control device 602 for lighting the light-emitting lamps L101 to L107 and L201 to L206 and the illumination cooling fan 115. Are connected. In this way, the light-emitting lamps L are arranged so as to obtain a required illumination distribution under all conditions. For details of the control configuration, see, for example, Japanese Patent Application No. 61-42998.
There is a description in the issue.

[0014] W of the halogen light-emitting lamp of the present invention
An example of the (watt) number is as follows. That is,
L101, L104, L107 are 40W, L102, L
103, L105, L106, L202 to L205 are 5
0W, L201 and L206 are 60W. The W number of each group is 320 W in the L1 halogen lamp group and 320 W in the L2 halogen lamp group, which is 640 W in total. As shown in FIG. 2, the lamp interval of each group is left and right on the basis of the optical axis XX.
mm, B = 106 mm, C = 153 mm,
L2 group: a = 29 mm, b = 93 mm, c = 140 m
m. By arranging as described above, the light distribution on the original surface as shown by the characteristic b in FIG. 7 is obtained. As a result, as shown in the characteristic b in FIG. And a flat exposure distribution is obtained.

FIG. 9 is a table showing the numerical values of the graph shown as the characteristic b in FIG. In the arrangement of the lamps in the present invention, as shown in FIG. 10, the light emitting lamps L104 belonging to the L1 group are arranged on the optical axis XX, and two light emitting lamps are arranged on both sides thereof. With this configuration, an appropriate light distribution on the document surface can be obtained regardless of whether the halogen lamp group L1 is turned on, L2 is turned on, or both L1 and L2 are turned on. .

Here, the halogen lamp group L1 is set to 85V,
When turned on at 320 W, the current consumption becomes 3.76 A.
Similarly, when the halogen lamp group L2 is turned on at V and 320 W, the current consumption is also 3.76 A, and the total current consumption is 7.52 A. In the conventional lamp configuration using only one lamp, if a halogen lamp of 85 V and 640 W is required (for example, a lamp power of 320 W is required for one lamp), it is necessary to change the voltage applied to the lamp.
Applying voltages V ₁ in this case is as follows. That is, V ₁
= (W / W ₀ ) ^{1 / k} × V ₀ , and when a numerical value is substituted into this equation, V ₁ = (320/640) ^{1 / 1.54} × 85 ≒ 5
^{_{6.5V, R 0 = V 0 2}} / W 0 = 85 2/640 ≒ 5
1.29Ω, where W is the required lamp power, W ₀ is the rated lamp power, V ₀ is the rated lamp voltage, and k is a constant (1.
54). In order to make the required lamp power of 320 W from the conventional single lamp 85 V, 640 W, the applied voltage is 5
When the lamp is turned on at 6.5 V, the current consumption is V ₁ / R ₀ = 56.5 / 11.29 = 5, where R ₀ is the lamp resistance.
Become A. Also, by greatly reducing the applied voltage,
The color temperature fluctuation of the halogen lamp increases. In this way, by switching the lamps divided into two groups, current consumption can be reduced as compared with the case of a single lamp, so that power is saved.

When a halogen bulb is used as the light-emitting lamp 201 of the lighting device, for example, an appropriate halogen cycle does not work due to the temperature of the bulb of the bulb. Therefore, appropriate cooling is required to maintain a proper halogen cycle. In order to keep the halogen bulb at a constant halogen cycle, it is recommended to keep the bulb wall temperature in the temperature range of 250C to 550C. For this reason, the lighting cooling fan 11
5 (in this embodiment, a DC fan motor is used), but as shown by the arrow in FIG.
2, 305, and 302, and
01 can be cooled. Further, the lighting cooling fan 115 can also prevent the contact glass 116 from being discolored and damaged due to an abnormal rise in temperature of the lighting device by blowing air onto the contact glass 116.

Incidentally, in order to cope with an abnormal rise in the temperature inside the lighting device, as shown in FIG.
04 is provided. This thermal fuse 604 is connected between an intermediate connection point between the lamp groups L1 and L2 and a control terminal of the halogen lamp control device 602, and is mounted on the pin connection hole 503 of FIG. The pins of the table are inserted and connected, and are fixed by soldering or the like so that the plane part of the mounting table is perpendicular to the printed circuit board 211. Then, a cylindrical insulating tube (a material such as Teflon or silicon because heat resistance is required) is provided on the sensing surface of the thermal fuse 604.
And mounted so as to be in close contact with the printed circuit board 211.

The over-temperature prevention means is provided, for example, because an overvoltage is continuously applied to the light-emitting lamp 201 due to an abnormality of the lighting device (short circuit accident when a bidirectional thyristor is used as a control element), or the illumination cooling fan 115. It is provided to prevent the discoloration and breakage of the contact glass 116 due to an abnormal temperature rise of the lighting device due to the abnormal (stop) of the lighting device, the falling off (off) of the light emitting lamp 201 from the printed circuit board, and the burning of the printed circuit board. When the temperature rises to the set temperature, the halogen lamp control device 602 cuts off the application of voltage to the light emitting lamps L1 and L2. For example, a thermoswitch may be used as the overheat prevention means, in addition to the thermal fuse.

The illumination cooling fan 115 cools the reflectors 202, 302, 305, the light emitting lamp 201 and the printed circuit board 211 for the illumination lamp as described above, but is shown in FIG. 3 to further enhance the cooling effect. As described above, the cooling air from the illumination cooling fan 115 is positively sent to the lower surface of the illumination unit support 212 by the bending unit 308 in which one side of the illumination device support unit 307 of the scanner body 205 is bent downward. In addition, as shown in FIG.
The cooling air that has passed through the opening 309 opened along with the position of the light-emitting lamp 201 on the seat surface of the light-emitting lamp 201,
The reflectors 202, 302, and 305 are also cooled.

FIG. 11 is a circuit diagram showing details of the fan drive circuit 603. The fan drive circuit 603 mainly includes two switch circuits including a Darlington transistor 1101 and a Darlington transistor 1102 provided corresponding to the fan trigger signal 1 and the fan trigger signal 2, respectively. , Different power supply voltages (+24 V and +15 V) are applied, and a voltage applied to the illumination cooling fan 115 serving as a load can be selected. Note that a diode 1103 connected to the collector of each transistor,
Reference numeral 1104 is provided to prevent one output voltage from being applied as a reverse voltage to the other circuit.

FIG. 12 is a flowchart showing switching processing of the illumination cooling fan. In controlling the light emitting lamp,
The light emitting lamp groups L1 and L2 and the lamp output voltage are switched for each exposure so as to obtain an appropriate exposure amount. However, when only the light-emitting lamps L1 or L2 are turned on and when both of the light-emitting lamp groups L1 and L2 are turned on at the same time, there is a difference in the color temperature of the light-emitting lamps. When one lamp is turned on, the lamp wall temperature becomes low. Conversely, when both of the light emitting lamp groups L1 and L2 are turned on at the same time, the lamp wall temperature becomes high. Therefore, for example, the copy mode (black and white copy mode,
Single color mode, full color mode)
By changing the air volume of the illumination cooling fan 115, the temperature of the lamp wall must be kept constant and an appropriate halogen cycle must be performed. In this embodiment, for example, each color exposure (BK: black, B: blue, G: green, R: red)
The airflow of the illumination cooling fan 115 is changed by switching the lighting of the light emitting lamps L1 and L2 every time.

As shown in the flowchart of FIG. 12, the copy mode is started by pressing a copy button (not shown) of the operation unit (STEP 1). B
As in K, G, and R exposures, the light emitting lamp group L1 or L2
When only one of the lights is turned on (STEP2, 7)
Turns off the fan trigger 1 signal and sets the fan trigger 2
By turning on the signal, +15 V is applied to the illumination cooling fan 115, and the illumination cooling fan 115 rotates (STEP 8). In the case of B exposure, the light emitting lamp group L
1 and L2 are turned on (STEP 3), so that the fan trigger 2 signal is turned off and the fan trigger signal 1 is turned off.
Is turned on, +2 is supplied to the illumination cooling fan 115.
4 V is applied, and the illumination cooling fan 115 rotates (S
TEP4). When the copy operation stops (STE
P5), the fan trigger 1 signal and the fan trigger 2 signal are both turned off, and the illumination cooling fan 115 stops rotating (STEP 6).

In this embodiment, the air volume of the illumination cooling fan is switched. However, a copy size, a lighting voltage, a temperature detection element is provided at an appropriate place of the illumination device and the contact glass, and the illumination is calculated according to the calculation result. If the air volume of the cooling fan is changed stepwise, a more stable halogen cycle of the light emitting lamp can be obtained.

[0025]

As is apparent from the above description, according to the present invention, a light emitting lamp which is constituted by a plurality of halogen lamps and illuminates a reading section of a document, and which reflects the light of the light emitting lamp in the direction of the document. A plate, and a mirror mechanism for reflecting light reflected from the reading unit to an optical system .
A transport member is provided, and a small number of
At least R exposure, G exposure, and B exposure are performed and full color
For each exposure, the transport is performed at each exposure to form an image.
The feeding member is moved relative to the document, and
In the image forming apparatus for illuminating the original by a lamp, a blower disposed near one end of a moving range of the conveying member to cool each of the light-emitting lamp and the reflection plate; and driving the light-emitting lamp. Control means for controlling the amount of air blown by the air blowing means according to the driving condition of the light emitting lamp, wherein the control means corresponds to B exposure.
In the case of relative movement of the conveying member,
In comparison with the case of the relative movement of each corresponding transport member,
The light amount of the light emitting lamp is increased, and
Because it was controlled to increase the air flow of
The light-emitting lamp is always maintained properly, reducing abnormal images and filament breaks caused by uneven light distribution on the document surface due to blackening of the lamp and exposure distribution, extending the life and reducing parts replacement. And furthermore,
Halo during multiple exposures to obtain a full-color image
Gen lamp's halogen cycle can be maintained properly
You.

[Brief description of the drawings]

FIG. 1 is a schematic structural view showing an embodiment of a lighting device according to the present invention and a lighting device of a copying machine to which the lighting device is applied.

FIG. 2 is a plan view showing a main part of the lighting device.

FIG. 3 is a side sectional view of the lighting device shown in FIG. 2;

FIG. 4 is a side view of the lighting device shown in FIG. 2;

FIG. 5 is a plan view of a printed circuit board for an illumination lamp.

FIG. 6 is a circuit diagram showing details of a control device for driving two groups of light-emitting lamps.

FIG. 7 is a characteristic diagram showing a light distribution on a document surface according to the present invention.

8 is an exposure distribution characteristic diagram corresponding to the characteristics shown in FIG.

FIG. 9 is a characteristic table showing numerical values of the characteristic shown in FIG. 7;

FIG. 10 is an explanatory view of an arrangement of lamps according to the present invention.

FIG. 11 is a circuit diagram showing details of a fan drive circuit.

FIG. 12 is a flowchart showing switching processing of the illumination cooling fan.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 101 Illumination device 102 Mirror member 103 Lens carriage 105 Photoreceptor drum 115 Illumination cooling fan 201 Emission lamp 202 Main reflection plate 205 Scanner main body 301 First mirror 601 CPU 602 Halogen lamp control device 603 Fan drive circuit 604 Thermal fuse 1101, 1102 Darlington transistor L101-L107 Light-emitting lamp L201-L206 Light-emitting lamp

Claims (1)

(57) [Claims] 1. A light emitting lamp comprising a plurality of halogen lamps and illuminating a reading section of a document, a reflecting plate for reflecting light of the light emitting lamp toward the document, and optically reflecting light from the reading section. A mirror mechanism to reflect light to the system
, And at least R exposure and G corresponding to the original on the image carrier.
Exposure and B exposure to form a full-color image
In addition, for each exposure, the transport member is moved to the original for each exposure.
Relative to the original, and the light source
In an image forming apparatus for illuminating a document, a blower disposed near one end of a moving range of the conveying member to cool each of the light emitting lamp and the reflecting plate, and controlling driving of the light emitting lamp , and control means for variably for according the blowing amount of the blower means to a driving condition of the light emitting lamp, the control means, relative to the conveying member corresponding to the B exposure
When moving, the transport unit corresponding to each of R and G exposure
Compared to the case of relative movement of the material,
At the same time, the amount of air blown by the blower will be increased.
An image forming apparatus comprising: