JP2945560B2 - Document reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an original reading apparatus for a copying machine and an original reading apparatus for reading and transmitting an original image by a facsimile or the like.

[0002]

2. Description of the Related Art Conventionally, in a document reading apparatus such as a copying machine or a facsimile, there is a method in which a document is placed on a platen and scanned by a scanning optical system under the platen.

In this copier, an original is placed on a platen glass of an original platen on an upside down, a light source such as a halogen lamp is irradiated on the original surface, and the reflected light is guided to a photosensitive drum to form an image. ing. For this purpose, a strong light source is placed on the scanning optical system, and scanning is performed from the scanning start position to the end of the original to perform exposure over the entire surface. For this reason, the exposure light source and the scanning mirror for guiding to the photoreceptor integrally move reciprocally under the document table.

Exposure is usually lit to perform on the outward path,
The return light is turned off because no exposure is performed. The reason for turning off the lights is that halogen lamps used as a light source have a short lamp filament life and are as close as possible to other parts of the copier body. That's why.

The return speed of the return scan is much faster than the forward speed for exposure in order to improve the copying speed, and the ratio is usually set to 3 to 7 times.

The temperature of the vicinity of the scanning optical system rises due to the heat of the halogen lamp irradiating the original, so that the original does not deform due to heat, and a malfunction occurs due to the internal temperature rise of the entire apparatus. To prevent this, a cooling fan is provided, and the cooling fan is arranged so as to blow air to the platen glass and the halogen lamp. This fan is operated continuously from the start to the end of the copying operation.

There is also an original moving type reading system in which an original illumination lamp and an optical system for guiding reflected light of an original are fixed without using a scanning optical system, and original paper is conveyed and read at a constant speed. In the case of such a system, when reading a large number of documents, the illumination light source remains lit because almost no time is spent for moving and inserting the next successive document. The cooling fan is operated in accordance with the start and end of reading in the same manner as in the example of the method of scanning and reading the scanning optical system.

[0008]

However, the above conventional example has a drawback that the lamp life of the illumination optical system is extremely shortened depending on the method of using the copying apparatus.

That is, the usage of the copying apparatus varies depending on the user's intention. The apparatus is not used only by a limited number of people. Some perform copying operations. Despite such differences in usage, the sequence of turning on and off the illumination lamp during the copying operation, and ON / OFF of the cooling fan
The sequence is determined uniformly, and the sequence does not change even when one or many sheets are operated.

For this reason, when one copy is made, for example, if the illumination light source is a halogen lamp, the light is turned on only at the time of the outward exposure and the return light is turned off. The light is turned off before the cycle rises and the temperature inside the tube rises. Therefore, while the tungsten, which is the light emitting electrode of the halogen lamp, becomes thin, the wire is easily broken. In addition, since the speed of the return trip is increased in order to increase the continuous copying speed, even a single copy returns quickly. The vibration at this time gives a further impact to the filament, which makes the filament more severe.

[0011] Similarly, the cooling fan starts cooling even with one copy, which hinders the temperature of the tube from being raised and serves to accelerate the disconnection. There are disadvantages as described above.

Further, the above-mentioned drawbacks have inconvenienced users of the copying machine incapable of performing the copying operation and interrupting the copying operation until the repair is completed.

[0013] In addition, the degree of difficulty in adjustment at the time of replacement has increased for the service person of the copier to be repaired, and there has been an economic loss that it takes time for adjustment.

That is, since the lamp of the illumination optical system uniformly irradiates the light amount to the original and performs a high-quality copying operation, its light distribution characteristics are adjusted by a shading plate or the like in the optical path at the time of shipment from the factory. Is what it is.

If such a key part becomes defective, it is necessary to take time to make the same adjustment as in the factory after replacing the key part with a replacement part. As a result, it may not be possible to maintain high image quality conditions. Particularly in a color copying machine or the like, the spectral sensitivity characteristics must be matched.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to extend the life of a light source lamp without depending on the conditions of multiple users, and to achieve high image quality of a copying machine and the like. It is an object of the present invention to provide a document reading apparatus which has been developed.

[0017]

According to the present invention, there is provided a scanning optical system having a light source for irradiating a document and scanning the document, and reading the scanning light by the scanning optical system. In a document reading apparatus provided with a light receiving unit and a cooling unit for cooling the vicinity of the light source, the scanning optical system is turned on at least at the time of the last read-back operation according to the number of times of reading, and the scanning optical at the time of normal reading. The switching is controlled so as to be slower than the return speed of the system and weaker than the cooling capacity of the cooling means during normal reading.

An optical system having a fixed light source for irradiating a moving document; a light receiving unit for reading light guided by the optical system; cooling means for cooling the vicinity of the light source;
In the document reading apparatus provided with the above, the switching is controlled so that the cooling capacity is weaker than the cooling capacity of the cooling unit at the time of normal reading in accordance with the number of times of reading.

In a document reading apparatus provided with a light receiving portion for forming an image by reflected light from a document illuminated by a light source, when the number of times of reading of a document within a predetermined period is less than a predetermined number, the power is turned off. When the power is turned on for the first time later, the image forming operation is automatically inhibited and the light source is controlled to be turned on for a certain time.

[0020]

According to the present invention having the above-described structure, the light source is turned on at least at the time of the last read-back operation in accordance with the number of times of reading of the original, and the speed of the scanning optical system at the time of normal read is lower than the return speed. The switching can be performed so as to be slower and weaker than the cooling capacity of the cooling means during normal reading.

Thus, even when the number of readings is small, the temperature of the light source can be raised, and disconnection of the light source can be prevented.

Therefore, it is possible to extend the life of the light source and to improve the image quality of a copying machine without depending on the conditions of the user.

In the original reading apparatus of the movable type, when the number of times of reading is small, the temperature of the light source can be raised by switching the cooling capacity to be lower than the cooling capacity of the cooling means during normal reading. Disconnection of the light source can be prevented.

If the number of times of reading the original during the predetermined period is less than the preset number, the image forming operation is automatically inhibited at the first power-on after the power is turned off, and the light source is turned on for a predetermined time. By doing so, the temperature of the light source can be raised, and disconnection of the light source can be prevented.

[0025]

【Example】

First Embodiment FIG. 1 is a diagram showing an embodiment in a copying machine or a document reading apparatus using a facsimile.

Reference numeral 10 denotes a copying apparatus and a facsimile apparatus. To explain the embodiment of the present invention in detail, parts other than the document reading device are omitted.

An original glass 3 is placed on the original glass 3 with the original 4 on the back side. Reference numeral 7 denotes a document illumination lamp as a light source, which uses a halogen lamp as an example. Reference numeral 6 denotes a scanning optical system, which illuminates the original 4 with an original illumination lamp 7 and guides the reflected light by a reflecting mirror as indicated by a dotted line. An objective lens 8 is provided on the way, and an image is formed by a reflection mirror 5 on a photosensitive drum 12 for a lower copying machine (not shown) or a light receiving unit 12 such as a CCD sensor for a facsimile. . The original illumination lamp 7 has a belt 2 coupled to the original illumination lamp 7 via a pulley bearing 9 from a pulley of a motor shaft driven by a scanning motor 1 to scan and move the entire surface of the original 4. Move left and right. The direction and speed can be freely changed by using a DC motor or the like for the scanning motor 1. Reference numeral 11 denotes a cooling fan as cooling means for suppressing a rise in temperature near the document illumination lamp. The lamp 7 and the document table 3 are directly cooled and disposed at a place where heat is discharged from the inside to the outside.

FIG. 2 is a block diagram of a controller unit for explaining an embodiment of the present invention. Reference numeral 51 denotes a controller which controls the present invention. The CPU 52 is an arithmetic / program processing processor such as a microcomputer. The RAM 53 is a volatile memory, and the reference numeral 54 is a non-volatile memory for storing a sequence control program of the copying apparatus and a program as described in the present invention. I / Os 55 are expansion terminals for transmitting command signals to the outside from the controller 51. Devices 52 to 55 are connected to each other by a bus 59. The motor driver 56 switches the rotation direction of the original scanning motor 1 and controls the rotation speed. The motor driver 56 receives an instruction from the CPU 52 such as a rotation direction signal, a start / stop signal, and a rotation speed control value through an I / O 55. I do. Cooling fan 11
Is turned on / off by CPU 52 through 55 I / Os.
The CVR 57, which operates in response to the OFF command, controls the amount of light of the document illumination lamp 7 and the lighting and extinguishing. Operation unit 58
Numeral keypad 58-3 for setting the number of copies, a number display segment 58-1 for displaying the number of copies, and a copy key for instructing the start of copying. 58-2 and so on. These pieces of information are similarly exchanged with the CPU 52 through 55 I / Os.

The timing chart will be described in more detail with reference to FIG. 3. In the example of FIG. 3A, in the case where the number of copies is 2 or more (the number of copies means the number of copies by the user, especially the number of readings in the present invention). The original illumination lamp is turned on when the original is exposed, as shown in a, at the time of exposing the original, when the scanning optical system of FIG. .

Also, as shown in FIG.
Turns on at the start of copying and turns off at the end of copying.
The state in which the temperature changes with the elapsed time t of the number of copies at the temperature near the document illumination lamp at this time is shown in d. As shown in the figure, by rotating the fan and turning off the lamp for a short time on the return trip, the temperature rise can be suppressed and kept constant even for a large number of continuous copies.

Next, in the example of (B), the number 1 is set as follows:
As shown at a ', the original illumination lamp is turned on from the start to the end of the copy regardless of the forward / backward movement of the c' scanning optical system.

As shown at b ', the cooling fan is kept stopped. Also, as shown at c ', the speed of the scanning optical system when returning is reduced and returned. Therefore, as shown by d ', since the light is not cooled by the fan and the lighting time is lengthened, the temperature rises sharply, and the temperature can be set to a temperature at which a halogen cycle occurs even in the case of one copy. Also, the vibration at the time of return can be suppressed.

An example of this control program is shown in the flowchart of FIG. The contents are installed in the ROM 54, and the CPU 52 reads out the program from the operation unit 58 to determine that the numeral setting by the user's numeric keypad 58-3 has been performed, and presses the copy key 58-2. Operate and execute.

Second Embodiment In the first embodiment, the system in which the scanning optical system is moved has been described. However, in the other system in which the original paper is conveyed and read, since the original illumination lamp is fixed, the return path of scanning is reduced. Therefore, it can be performed only by controlling the cooling fan and the lighting lamp lighting time.

Third Embodiment The temperature rise near the document lamps c 'and c' varies depending on the arrangement of the lamps and fans and the exposure scanning speed. It is only necessary to rotate the cooling fan weakly and to set the lighting conditions at the time of return to the same as those at the time of exposure. Obviously, any method can be used as long as the method is created by changing the conditions in Equations 1 and 2 or more.

Similarly to the fourth embodiment, the number condition is described as 1 and 2 or more in this example. However, the number condition may be set to a small number and a large number, or the value may be set to the environment where the apparatus is placed. If the temperature can be easily influenced, the temperature may be set programmable.

Fifth Embodiment In this embodiment, an example of a copying machine has been described. However, in the case of a digital system such as a facsimile, reading is performed once using a memory or the like.
Since a number of copies may be read out from the memory and output, in the case of the digital method, the number is the number of readings.

Sixth Embodiment In this embodiment, the number is selectively switched according to the number of digits. However, the halogen cycle is determined based on the ratio between the number of decimals and the number of large numbers within a certain period of time (for example, every half day or every day). Achievement level is CP
The same object as that of the present invention can be achieved by creating a program for performing an activation sequence based on only the lamp lighting, in which the copying operation is determined by U52 and is not performed.

Seventh Embodiment In this embodiment, the halogen cycle was performed in the example of the halogen lamp. However, in the case of a fluorescent lamp which is also used frequently, the optimum temperature around the electrode portion deviates from the optimum temperature for a long time. ON /
By repeatedly turning off the light and turning on the light, the blackening development is likely to occur, and the same effect can be obtained by adding the control as in this embodiment.

[0040]

As described above, in the present invention,
According to the number of times of reading of the document, the light source is turned on at least at the time of the resuming operation of the last reading, and is slower than the reversing speed of the scanning optical system at the time of normal reading and the cooling capacity of the cooling means at the time of normal reading. Can also be switched to be weaker.

Thus, even when the number of readings is small, the temperature of the light source can be raised, and disconnection of the light source can be prevented.

Therefore, it is possible to extend the life of the light source and to improve the image quality of a copying machine without depending on the conditions of the user.

Even in the original reading apparatus of the movable original type, when the number of readings is small, the temperature of the light source can be increased by switching the cooling means during normal reading so that the cooling capacity is weaker. Disconnection of the light source can be prevented.

If the number of original readings during the predetermined period is less than a predetermined number, the image forming operation is automatically inhibited at the first power-on after the power is turned off, and the light source is turned on for a predetermined time. By doing so, the temperature of the light source can be raised, and disconnection of the light source can be prevented.

By extending the life of parts, the cost of parts can be reduced, the work time for replacement can be reduced, the economical effects of reducing the complicated adjustment time after replacement adjustment, the field adjustment can be maintained, and the initial performance can be maintained. For the user who maintains the high image quality, the effect of removing the trouble and the inconvenience during the repair can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a document reading apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of the same device.

FIG. 3 is a timing chart of the same device.

FIG. 4 is a flowchart showing the operation of the device.

[Explanation of symbols]

 7 Document illumination lamp (light source) 6 Scanning optical system 12 Light receiving unit 11 Cooling fan (cooling means)

Claims (3)

(57) [Claims] 1. A document comprising: a scanning optical system having a light source for irradiating the document and scanning the document; a light receiving unit for reading scanning light by the scanning optical system; and cooling means for cooling the vicinity of the light source. In the reading device, the light source is turned on at least at the time of the last read-back operation in accordance with the number of times of reading, and the cooling speed of the cooling means is slower than the returning speed of the scanning optical system at the time of normal reading. A document reading apparatus characterized in that switching is performed so as to be weaker than the capability. 2. A document reading apparatus comprising: an optical system having a fixed light source for irradiating a moving document; a light receiving unit for reading light guided by the optical system; and cooling means for cooling the vicinity of the light source. An apparatus according to claim 1, characterized in that the apparatus is controlled so as to be switchable in accordance with the number of times of reading so as to be weaker than the cooling capacity of the cooling means during normal reading. 3. A document reading apparatus provided with a light receiving section for forming an image by reflected light from a document illuminated by a light source, the power supply being turned off when the number of document readings during a predetermined period is less than a predetermined value. An original reading apparatus, which automatically inhibits the image forming operation when the power is turned on for the first time and controls the light source to be turned on for a predetermined time.