JPH0239136A - Original lighting device - Google Patents

Abstract

PURPOSE:To effectively cool only a part where temperature rises by providing a cooling means in a lighting unit and sending air to the part to be lighted of an original platen and the lighting unit so that they may be cooled. CONSTITUTION:A cooling fan 27 is attached to the upper part of the lighting unit 2 to be near to the original platen 1 and it sends the air in a direction shown by an arrow B which is opposite to a scanning direction (direction shown by an arrow ). Most of the air sent form the cooling fan 27 goes toward the original platen 1 by a shade 28 obliquely folded and a part of the air therefrom goes toward a temperature fuse 23 through a gap between the shade 28 and a lighting unit platen 26. A part of the latter air goes downward through the inner part of the lighting unit platen 26 and cools an element on a printed board PCB, and then it reaches an image sensor 25. Since the part to be lighted of the original platen 1 and the lighting unit 2 can be directly cooled, cooling efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a document illumination device for illuminating a document in a copying machine or the like, which is provided with a cooling means for cooling a document table.

(Prior Art) Conventionally, in order to cool an illumination system including a lamp unit, a document table, etc. in a copying machine or the like, a cooling operation is performed by forming an air flow that lowers the internal temperature of the machine. In this case, a fan or the like is generally used as the cooling means, and a plurality of fans have been used that are fixed to the inner surface of the device body.

(Problem to be Solved by the Invention) However, in such a conventional example, since the illumination system is configured to cool the entire illumination system, for example, when the copying magnification is large and only a portion of the document table is illuminated, Coupled with the slow scanning speed of the illumination unit, there is a problem in that even if a fairly large and expensive fan is used, the relevant portion of the document table cannot be sufficiently cooled. Furthermore, in a large device capable of reading originals of approximately A1 size, it is difficult to cool parts far from the fans even if several fans are provided.

For this reason, in the above conventional example, it is necessary to set the switching temperature of the temperature fuse for safety measures, which is usually installed near the lamp, to a high value, and as a result, the lamp power supply or control means may malfunction, causing the lighting lamp to malfunction. If the light continues to light up, etc.
The drawback was that the temperature fuse could not be blown unless the temperature of the lighting system became high.

Furthermore, if the lighting unit stops near the cooling fan due to poor running and the above-mentioned failure occurs, the temperature fuse etc. will be cooled and will not be able to blow. There was a drawback that the temperature of the illuminated part of the document table gradually rose, and safety was not maintained, such as the glass breaking.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art, and its purpose is to efficiently cool an illumination unit and document table, and to provide a document with high safety against temperature rise. An object of the present invention is to provide a lighting device at a low cost.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, an illumination lamp is moved at a predetermined speed in order to guide an optical image of a document placed on a document table to a reading section, etc. A document illuminating device equipped with a lighting unit that illuminates a document, characterized in that the lighting unit is provided with a cooling means that cools the illuminated portion of the document table and the lighting unit by blowing air thereto. do.

(Function) In the present invention having the above configuration, the illuminated portion of the document table and the illumination unit are cooled by blowing air from the cooling means provided in the illumination unit. Therefore, it is possible to cool only the portions whose temperature increases due to illumination in close proximity and in a constant positional relationship.

(Example) Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1 shows a schematic configuration of a document reading device to which an embodiment of the document illuminating device according to the present invention is applied. In the figure, reference numeral 1 denotes an original table made of glass on which an original is placed, and is illuminated by an illumination unit 2 made up of various members to be described later. That is, at the top of the lighting unit 2,
A lamp 20 for illumination is provided, and the light from the lamp 20 is guided to the document table 1 by reflective shades 21 and 22 provided on both sides of the lamp 20. Further, below the lamp 20, a temperature and a needs 2 electrically connected to the lamp 20 are provided.
3 is provided. Further, below the temperature fuse 23, there is provided a lens 24 for condensing the original/stripe image light and an image sensor 25 consisting of a CCD for reading the original. In addition, the lamp 2o, the reflective shades 21 and 22, the temperature fuse 23, the lens 24, and the image sensor 25
is attached to the lighting unit stand 26.

A cooling fan 27 as a cooling means for cooling the illumination unit 2 and document table 1 is provided on the upper part of the illumination unit stand 26;
The wind from the cooling fan 27 is transmitted to the illumination lamp 20 and the document table 1.
A shade 28 is provided to allow the water to flow.

Here, the operations of the lamp 20 and the cooling fan 27 are controlled by the following means. That is, the lamp 20 is connected to the control section 41 via the timer 40, the cooling fan 27 is connected to the control section 41 via the timer 42, and the control section 41 is further connected to the operation section 43 of the document reading device. It is. Here, timer 4° is a timer that controls the rotation time of the cooling fan 27.
The timer 42 controls the lighting time of the lamp 20. The control unit 41 also controls the illumination unit 2 during document reading.
movement, the brightness of the lamp 2o, and the ○N of the cooling fan 27
10 FF etc.

Figure 2 shows the lamp 20. Temperature fuse and cooling fan 27
FIG. 2 is a circuit diagram showing electrical connections.

As shown in the figure, the lamp 20 and the temperature fuse 23 are connected in series, and the lamp 2o and the cooling fan 27 are connected in parallel. That is, with such a configuration, when the potential difference between both ends of the run 120 is increased and the amount of light is increased, the cooling fan 27 is automatically turned off.
The air volume can be increased and wiring can be reduced. In addition, as will be described later, since the temperature fuse is cooled by the wind from the cooling fan 27, the cooling fan 27 cools the temperature fuse.
If the fan 27 stops due to a failure in the fan 7 or its wiring, the temperature fuse 23 and lamp 20 are immediately cut off, thereby preventing accidents such as temperature rise.

FIGS. 3(a) and 3(b) are a plan view and a perspective view showing essential parts of the document reading device. As shown in the figure, the illumination unit 2 of this embodiment is mounted so as to be movable within a plane parallel to the document surface. That is, the lighting unit stand 26 has a lens 24. It holds the image sensor 25 and the like and reciprocates on a pair of rails 61a and 61b provided in the main scanning direction (arrow A or B direction). This rail 61a, 6
1b is held between the sub-scan front side plate 62 and the rear side plate 63. The lighting unit stand 26 is mounted on this rail 61.
Main scanning for one line is performed by reciprocating a and 61b in the directions of arrows A and B. In this case, the reciprocating drive is performed by moving the wire 65 wound around a wire boot 964 press-fitted into the stepping motor M.

When the lighting unit stand 26 is moved in the direction of the arrow to perform reading by the image sensor 25, the lighting unit stand 26 is driven via the wire 65 and the spring 66a connected to the lighting unit stand 26, and the stepping motor M is driven. The vibrations are not transmitted to the lighting unit stand 26. Therefore, the illumination unit stand 26 moves smoothly along the rails 61a and 61b, and a clear read image without expansion or contraction can be obtained. Further, the tension spring 66b is the spring 66
It is a weak spring, almost the same as a, and absorbs shocks at the start of driving and long-term wire elongation.

The sub-scanning front and rear side plates 62, 63 are arranged in the sub-scanning direction (arrow C or D).
direction) on a pair of sub-rails 6768. When the main scan is performed once, the motor 69 is rotated, and the timing belt 7 rotates the small pulley 70.
1 to the large pulley 72 and the sub-scanning wire pulley 73
is rotated, and these sub-scanning front and rear side plates 62,63 are moved in the direction of arrow C by wires 74,75. Conventionally, it has been said that if the drive side is caused to reciprocate through an elastic body such as a spring, uneven reading will occur due to transient vibrations, but the spring 66a.

If an appropriate spring constant is selected for 66b, this unevenness will not occur and the lighting unit 2 can be moved smoothly.

In addition, in FIG. 3(b), S represents the lighting unit stand 26.
The illumination unit 2 starts scanning from this position, and reading of the document starts from the position of a sensor S2 provided near the sensor S1. Further, S3 is a sensor that detects the stop position of the illumination unit stand 26 in the sub-scanning direction.

Further, in FIG. 3(a), F+ is a fan for taking in outside air into the device, and F2 is a fan for discharging air inside the device.

FIG. 4 schematically shows the movement of the lighting unit 2. Here, when reading the original on the original platen 1, the illumination lamp 20 is turned on and the illumination unit 2 is moved to the scanning position P.
The optical image of the document is guided to the image sensor 25 by scanning in the direction of arrow A. Then, the scanning position P2, which is the other end of the document,
When the illumination unit 2 reaches , the lamp 20 is turned off and the unit 2 is driven in the directions of arrows B and C to move diagonally backward and reach the scanning position MP. moreover,
From this position, the lamp 20 is turned on and the illumination unit 2 is scanned in the six directions of the arrows to read the next part. Thereafter, the original image is read by repeating the same operation.

Incidentally, the reading range and moving speed of the illumination unit 2 differ depending on the copying and reading magnification.

For example, if the magnification ratio is 1200% and the printing width on the printing means is 16.2mm, the reading width will be 1.4mm.On the other hand, if the width of the roll of printing paper is 594m, the scanning distance will be 49.5mm. Become. In this case, the area read in one scan is 1.4 mm x 49.5 mm, which is a very small area.

In such a case, a portion of the document table 1 will be illuminated and the moving speed of the illumination unit 2 will also be slowed down.
The cooling efficiency is low, and it is impossible to avoid a partial temperature rise on the document table l.

Therefore, in this embodiment, a cooling fan 27 is attached to the lighting unit 2 to directly cool the heated portion. In other words, with this configuration, the amount of light (heat) and amount of air (cooling) per unit time are always constant, so it is possible to balance the amount of heat and cooling regardless of the reading magnification (moving speed). becomes.

FIG. 5 shows the flow of air during cooling.

As described above, the cooling fan 27 is attached to the upper part of the illumination unit 2 and is close to the document table 1. Then, air is sent in the direction of arrow B, which is the opposite direction to the scanning direction (six directions of arrows).

Most of the air sent from the cooling fan 27 is directed toward the document table 1 by the obliquely bent shade 28, and part of it is directed to the temperature fuse 23 through the gap between the shade 28 and the lighting unit stand 26. Also, a part of this wind is directed downward through the inside of the lighting unit stand 26, and is directed downward to the printed board PCB.
After cooling the upper element, it reaches the image sensor 25. In this way, in this example,
Since the illuminated portion of the document table 1 and the illumination unit 2 can be directly cooled, the cooling efficiency is significantly higher than that of conventional devices. Further, since the relative positional relationship between the portion to be cooled and the cooling fan 27 does not change, cooling can be performed under constant conditions.

Note that in this embodiment, the air is sent in the direction of arrow B, which is the opposite direction to the reading direction, but with this configuration, the air volume during scanning can be increased, and the cooling Efficiency can be further increased. Therefore, the size of the cooling fan 27 can be reduced, and the cost can be reduced.

Further, when the illumination unit 2 is moved in the direction of the arrow B, the temperature of the document table 1 etc. does not rise because the lamp 20 is not lit. However, since the temperature rise state of the document table 1 etc. differs depending on the reading magnification, that is, the moving speed of the illumination unit 2,
It is desirable to rotate the cooling fan 27 accordingly. That is, for example, when the reading magnification is large, the moving speed of the illumination unit 2 is slow, so even with the above-mentioned configuration, the heating and cooling may be exceeded. Therefore, when backing up, the cooling fan 27 is kept rotating, while when the reading magnification is small, the illumination unit 2 moves at a high speed, so the rotation speed of the cooling fan 27 is lowered or stopped when backing up. Note that when the lighting unit 2 moves quickly, the vibration increases, but since the cooling fan 27 has a damper effect, the vibration of the unit is small.

Next, the timer 4 connected to the lamp 20 and the cooling fan 27
0.42 will be explained.

As mentioned above, if a malfunction occurs in the control means or the lamp power supply and the lamp 20 continues to be lit without turning off, the temperature of the document table l and its surrounding area will rise, creating a risk of fire or the like. . For this reason, this type of device is generally provided with a temperature fuse, which detects the temperature to prevent fires and the like.

However, when the entire unit and its surroundings are forcibly cooled as in this embodiment, there is a possibility that protection cannot be achieved quickly depending on the location of the temperature fuse.

Therefore, in this embodiment, a timer is connected to each of the lamp 2o and the cooling fan 27, and these are controlled to operate only for a certain period of time, thereby overcoming the drawbacks of control using a temperature fuse.

First, let's start with Figures 6 and 7 regarding the operation during normal document illumination.
This will be explained using figures.

In FIG. 6, by pressing the start switch of the operation section 43, the original reading operation is started. in this case,
First, in order to operate the lamp 20 and the cooling fan 27, the respective timers 40 and 42 are cleared (step ■), and the lamp 20 and the cooling fan 27 are turned on.
Output a signal (step ■). Here, the lamp 2
0. If it is necessary to operate the cooling fan 27,
As shown in FIG. 7, a timer clear signal is input before the timer time expires (step ■), and the lamp 20 and cooling fan 27 are operated continuously. Then, when the reading of the original is completed, the operation signals for the lamp 20 and the cooling fan 27 are turned OFF, thereby ending the operation of the lamp 20 and the cooling fan 27 (step (2)).

Next, two examples will be described where an abnormality occurs in document illumination.

(1) If a problem occurs with the lamp power supply, that is,
This is a case where the lamp 20 remains lit even if the lamp lighting signal is turned off, while the cooling fan 27 continues to rotate. In this case, while the timer 42 is sending out the ON signal, the lighting unit 2 is being cooled by the cooling fan 27 (steps 2 and 3 in FIG. 8), so the temperature of the unit 2 increases only gradually. However, when the operating time of the timer 42 ends, the cooling fan 27 stops (step ■)
Therefore, the temperature of the lighting unit 2 rises (steps (2), (2)), the temperature fuse 23 is blown, and the lamp 20 is turned off (step (2)). Here, in this embodiment, the temperature fuse 2
Since the cooling effect of the lighting unit including the lighting unit 3 is large, a temperature fuse that can be cut at a lower temperature can be used, and as a result, the lamp 20 can be turned off while the temperature rise is low, increasing safety.

(2) If a malfunction occurs in the control unit, the control signal for the lamp 20 is turned ON due to the control unit 41 running out of control, etc.
I have something to continue. In this case, Figures 7 and 9
The lamp 20 can be turned off by following the steps shown in the figure. Note that the flow on the right side of FIG. 9 (steps ■ to ■) is the same as the steps ■ to ■ in FIG. 8 described above, so only the flow on the left side (steps ■ to ■) will be explained. That is, due to runaway or the like, the control signal from the control unit 41 becomes ONI,
If it continues (step ■), the lamp 20 also continues to light (step ■), but in this case, the clear signal is not input to the timer 40 for the lamp 20, so the timer 40
When the operating time has elapsed (step ■), the timer signal turns O.
The switch becomes FF (as shown in FIG. 7), and as a result, the lamp 20 can be turned off (step ■).

(Embodiment 2) FIG. 10 shows another embodiment of the present invention. The above embodiment is effective when the illumination area of the illumination unit 2 is small, but it is not sufficient when using a illumination unit having a length comparable to the short side of an A3 sheet of paper, such as in a so-called analog copying machine. It is not possible to create a configuration that provides adequate cooling.

Therefore, in this embodiment, as shown in FIG.
Cooling fans 53 and 54 are provided at both ends of the lighting unit stand 52 to which the lighting lamp 50 and the reflective shade 51 are attached to form a flow of air in the direction of the arrow in the figure, that is, in the longitudinal direction of the lighting lamp 50. In this case, if the direction of the airflow from the cooling fan 53 is directed slightly upward, the illuminated portion of the document table (not shown) and the long illumination lamp 50 can be efficiently cooled.

(Embodiment 3) Furthermore, in the embodiment shown in FIG. 1, by using a halogen lamp as the illumination lamp, the lamp can be turned on
The signal and timer clear signal can be combined into one.

In other words, when using a halogen lamp, ON, OF
The response time at F time is as long as several hundred ms, while the timer clear signal in the case where the timer circuit is constituted by a gate circuit requires less than 1 μs. Therefore, the control unit 41 and the timer 40 are connected by one control line, and as shown in FIG.
If the configuration is such that a timer clear signal is sent out at the same time, a control line for clearing the timer can be omitted. Here, when the timer clear signal is sent, the halogen lamp is turned off in terms of the signal, but as described above, the response speed of the halogen lamp is slow, so no problem occurs.

Furthermore, since the cooling fan 27 does not stop immediately due to inertia, the number of control lines can be omitted by one by adopting the same configuration. Therefore, it is possible to omit a total of two control lines. The rest of the structure and operation are the same as those of the previous embodiment, so the explanation thereof will be omitted.

(Effects of the Invention) In the present invention having the above configuration and operation, the illumination unit is provided with a cooling means, and air is blown to the illuminated portion of the document table and the illumination unit to cool them. Only the heated portion can be efficiently cooled, and as a result, it is possible to prevent the temperature of the document table from rising during enlarged reading of the document.

Furthermore, since the cooling efficiency is high as described above, there is no need to use a large fan or the like, and it is possible to downsize the device and reduce costs.

Furthermore, the set temperature of the temperature detection means such as a temperature fuse can be lowered, and even if an abnormality occurs in the control of the lighting operation, there will be no deviation in the detected temperature.
The lighting lamp can be quickly turned off. Therefore, it is possible to prevent fires and the like due to abnormal temperature rise of the document table and to improve safety.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a document reading device to which an embodiment of the document illumination device according to the present invention is applied, and FIG. 2 is a circuit diagram showing electrical connections of a lamp, a temperature fuse, and a cooling fan in the same embodiment. , FIGS. 3(a) and 3(b) show the main parts of the device shown in FIG. 1, with FIG. 3(a) being a plan view and FIG.
b) is a perspective view, Fig. 4 is an explanatory diagram schematically showing the movement of the lighting unit, Fig. 5 is a vertical cross-sectional view of the lighting unit showing the air flow by the cooling fan, and Fig. 6 is a diagram of the cooling fan and lamp. Flowchart showing the control operation, FIG. 7 is a time chart showing the control timing of the lamp and timer, FIG. 8 is a flowchart showing the control operation of the cooling fan and the lamp when the lamp continues to be lit when the lamp power supply fails, and FIG. Figure 10 is a flowchart showing the control operation of the cooling fan and lamp when the control unit goes out of control.
The figure is a perspective view showing the main parts of another embodiment of the invention, and FIG. 11 is a time chart showing the control timing of the lamp and timer in still another embodiment of the invention. Explanation of symbols 1... Original table 2... Lighting unit O...
・Lamp (illumination lamp) 3...Temperature fuse 25...Image sensor 7・
...Cooling fan (cooling means) 8...Shade 40.42...Taimad...
control part

Claims (6)

[Claims] (1) In a document illumination device including an illumination unit that illuminates the document with an illumination lamp while moving at a predetermined speed in order to guide an optical image of the document placed on a document table to a reading unit, the illumination unit includes: A document illuminating device characterized in that a cooling means is provided for cooling the illuminated portion of the document table and the illumination unit by blowing air thereto. (2) ON and OFF of the lighting lamp in the lighting unit
2. The document illuminating device according to claim 1, further comprising a temperature detecting means for controlling F, and the temperature detecting means is cooled by said cooling means. (3) The document illumination device according to claim 1 or 2, wherein the illumination unit is provided with a sensor for reading an optical image of the document, and the sensor is cooled by the cooling means. (4) The document illumination device according to any one of claims 1 to 3, wherein the moving speed of the illumination unit changes depending on the magnification of document reading or the like. (5) The document illuminating device according to any one of claims 1 to 4, wherein the illumination lamp and the cooling means are connected in parallel. (6) The document illuminating device according to any one of claims 1 to 5, characterized in that the air blowing direction of the cooling means is opposite to the moving direction of the illuminating unit.