JPH01232373A - Copying machine - Google Patents

Abstract

PURPOSE:To improve the efficiency of copying by controlling the position of a lighting means according to the temperature of a contact glass. CONSTITUTION:An entire copying machine is controlled by a central processing unit (muCPU) 100. The temperature detected by a contact glass temperature detecting sensor (thermistor) 36 is converted into an electrical signal by an A/D converter 101 and transmitted from an I/O interface 102 to a unit 100. Since the unit 100 switches a scanner position according to the detection of temperature, it controls scanner stopping positions (A and B positions) where a scanner motor 103 and the sensors for stopping the scanner (photosensor) 104 and 105 are provided. Thus, the abnormal rising of temperature in the contact glass can be prevented, so that a cooling fan, etc., can be miniaturized and the efficiency of copying can be improved.

Description

Detailed Description of the Invention Technical Field The present invention relates to a copying machine equipped with a sheet-through method in which a document transported by an automatic document feeder and moving on a contact glass is illuminated by an illumination device that illuminates a fixed position on the contact glass. Regarding.

Prior Art In conventional sheet-through copying machines, a stopped illumination lamp illuminates a certain position on the contact glass from below the document reading section, so The high temperature limit caused problems such as cracking and deformation of the contact glass and other parts, as well as burns caused by the driver touching the document reading section.

To solve this problem, conventional methods have been to install a powerful fan to lower the temperature of the document reading section, and to increase the number of copies per unit time (CPM) so that the temperature rise is low and the above problems do not occur even when continuous copying is performed. ). However, with these methods, the installation of a powerful fan means that there is no room for placement inside the copying machine, making it necessary to make the copying machine larger, and the fan noise becomes louder.
Furthermore, since the copying machine must make copies at a CPM lower than its original copying capacity, there are problems in that work efficiency is reduced.

As a method of preventing the temperature of the contact glass from rising, a method is known in which a scanning illumination means is moved for each cycle of recycling sheet through in a recycling type automatic paper feeding system in which a set of documents is circulated a required number of times for copying. (see U.S. Pat. No. 4,684,237). However, in this case, the scanning illumination means is often moved even when the temperature of the contact glass is not rising and there is no need to move the scanning illumination means, resulting in problems such as a corresponding decrease in work efficiency.

Purpose The present invention solves the above-mentioned problems in the conventional technology, prevents abnormal temperature rise of contact glass, etc., without increasing the size of the cooling fan, or reducing copy efficiency, and improves driver safety. It is an object of the present invention to provide a good copying apparatus in which the occurrence of abnormalities such as breakage of contact glass is prevented.

In order to achieve the above object, the present invention provides a sheet-through method in which a document transported by an automatic document feeder and moving on a contact glass is illuminated by an illumination device that illuminates a certain position on the contact glass. A copying machine comprising: means for moving and stopping the illumination means at a plurality of positions; a temperature detection means for the iWI contact glass; and when the sheet-through method is used, the temperature detected by the temperature detection means is a predetermined temperature. and a control means for controlling the illumination means, which has been stopped at one of the plurality of stop positions, to move to another stop position when the stop position is exceeded.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention will be described in detail based on the Example shown in drawing.

FIG. 1 is an example to which the present invention can be applied.
This figure shows the configuration of the main parts of a copying machine that can make copies using both a scanner type (scanning type) and a sheet-through type. However, it goes without saying that the present invention can be applied to copying machines using only the sheet-through method.

First, the operation of a copying machine with a single scanner will be explained. FIG. 1 shows a state in which only one scanner is used.

When the document l is separated one by one by the document separating section and sent onto the contact glass 4 by the conveyor belt 3, which is an example of automatic document feeding means, and stopped at a predetermined position, an illumination lamp 5, which is an example of illumination means, 1 mirror 6
The scanner 7 has a speed V and a second mirror 8 and a third mirror 9.
The second scanner 10, which has
The image is projected onto the photosensitive drum 13 via the mirror 12.

Further, the transfer paper 15 in the paper feed tray 14 is transferred to the transfer paper separating section I6.
The images on the photoreceptor drum I3 are separated one by one by the resistor rollers 17, are developed by the developer 18, are transferred to the photoreceptor drum 13 by the transfer charger 19, and are then transferred to the photoreceptor drum I3 by the separation charger 20. The scanner home detection sensor 24 is separated from the body drum 13 and transfers the image thereon to the fixing device 21. The scanner 7.1
The leading edge of the transfer paper 15 is aligned with the image by controlling the stop position at the time of zero return and controlling the timing of the registration roller I7 according to the start timing.

FIG. 2 shows a configuration in which a photo sensor is used as an example of the scanner home detection sensor 24. A filler 25 is attached to the first scanner 7, and a scanner home detection sensor 24, which is a photosensor, detects the filler 25.

Next, the case of the sheet-through method will be explained.

FIG. 3 shows the situation in this case.

As in the case of a one-sided scanner, the original 1 is separated one by one by the original separation unit 2 and sent onto the contact glass 4 by the conveyor belt 3, but in this case, the original 1 is not stopped on the contact glass 4. , and is transported at a constant speed ■ and discharged to the discharge section 26.

At this time, the scanner 7.10 is stopped at a predetermined position below the contact glass 4, and while the original l is moving on the contact glass 4, the illumination lamp 5 is turned on to expose the original. Here, numeral 27 is a document detection sensor,
The leading edge of the document 1 moving on the contact glass 4 is detected, and the timing of the registration rollers 17 is controlled based on the detection timing to align the image and the leading edge of the transfer paper I5.

Further, a cooling fan is provided, which serves to cool the illumination lamp 5 and the contact glass in the vicinity thereof, thereby reducing the temperature rise thereof.

FIG. 4 schematically shows a scanner fixing device 29 as an example of means for stopping the illumination means during sheet through.

The scanner 7.10 moves guided by a guide rod 30. The fixed arm 31 is rotatable by a solenoid 32 and a spring 33, and a fixing pin 34 is provided for the first scanner 7, and when the solenoid 32 is turned off, the fixing pin 34 is rotated by a fixing spring 35. is pressed against the fixed arm 31 to fix the first scanner 7. Next, when the solenoid 32 is turned on, the fixing arm 31 is rotated and released from the fixing pin 34, allowing the first scanner 7 to move.

Note that the scanner fixing method shown in Fig. 4 uses a mechanical mechanism, but in addition to this, a sensor similar to the scanner home detection sensor 24 shown in Fig. 2 is installed at a position corresponding to the scanner fixing position. By detecting this, the stop position of the scanner 7 can be controlled,
Furthermore, there is a method of controlling the stop position of the scanner 7 by moving the scanner 7 by a pre-calculated amount of movement based on the scanner home position.

FIG. 5 shows an example of how the temperature of the contact glass 4 increases when continuous copying is performed using the sheet-through method with the scanner 7 at a fixed position. Assuming that the outside temperature (environmental temperature) is 25°C, the temperature at the start is 25°C, and when continuous copying starts, the temperature of the contact glass 4 will rise as shown in the figure, and the driver will have to Assuming that the temperature at which it is dangerous to touch is 75° C., this temperature will be reached in about 18 minutes, and if the temperature at which the contact glass 4 breaks is assumed to be 100° C., this temperature will be reached in about 45 minutes.

The degree of this temperature rise depends on the type and voltage of the illumination lamp 5.
Although it varies depending on the distance from the lamp 5 to the contact glass 4, the presence or absence of the cooling fan 28, its air volume, installation location, etc., it generally shows the tendency as shown in FIG. For this reason, in conventional copying machines, in order to prevent the temperature from reaching a temperature that is dangerous to the touch or will cause the contact glass to break even during continuous copying, the cooling fan 4 must be made quite powerful, and the unit time It was necessary to reduce the per-copy rate and the ratio of the lighting time of the illumination lamp 4.

Therefore, in the present invention, in the copying machine of the above embodiment, a contact glass temperature detection means is provided, and the irradiation position of the illumination means, and therefore the stop position of the first scanner 7, is switched based on the detected temperature. In this case, in order to equalize the conjugate lengths, the position of the second scanner IO is also switched in this embodiment.

FIG. 6 shows details of the first scanner 7. lighting lamp 5
A temperature detection sensor 36, which is an example of temperature detection means for the contact glass 4, is provided near the contact glass 4. In this embodiment, the sensor 36 is brought into contact with the contact glass 4, but a non-contact type sensor may also be used.

The temperature detection sensor 36 is preferably mounted as close as possible to the position where the temperature is highest, and although this varies depending on the position of the cooling fan 28, it is preferably near the retro-illumination lamp 5.

FIG. 7 illustrates a case where the scanner 7.10 is provided with three stopping positions (A, B, and C, D) during sheet through. Of course, it is also possible to provide a greater number of stopping positions. When the temperature detected by the contact glass temperature detection sensor 36 reaches the preset upper limit temperature t1 from the viewpoint of driver safety and contact glass cracking, the stop position of the scanner 7.10 is changed to another stop position. Performs control to switch to

As described above, any method may be used to provide a plurality of scanner stop positions, such as the method shown in FIG. 4, the method using the sensor shown in FIG.

FIG. 8 shows how the temperature of the contact glass 4 changes when the upper limit temperature t is 75°C and the scanner 7.10 is stopped at three locations. As in the case of FIG. 5, the temperature of the contact glass 4 reaches the upper limit temperature [1, which is 75° C., in about 18 minutes. Assuming that the scanner 7 is stopped at the position shown in FIG. 7, the scanner 7 moves to the B position upon detection of the upper limit temperature t. Since the B position is far from the A position, the temperature of the contact glass 4 at the location irradiated by the B position does not exceed that temperature and is in a temperature state that allows copying. Then, when continuous copying is started at position B, the contact glass 4 reaches a temperature of J29. j l
, reaches the upper limit temperature t1. During this time, the contact glass portion corresponding to position A is cooled down to a temperature that allows copying, so the scanner position is now moved to position A again. When the position of the scanner 7 is switched between A and B, the position of the scanner IO is also switched between C and D accordingly.

By repeating such control, the temperature of the contact glass 4 does not exceed a predetermined temperature limit, and safety is ensured.

Although the copying operation is interrupted while the position of the scanner 7.10 is moved (usually for one to several seconds), the reduction in work efficiency due to this is hardly a problem, and according to the present invention, the above-mentioned This is advantageous because there is no need to install a powerful fan or reduce the copy rate.

FIG. 9 is a block diagram showing an example of the control system of the present invention. The entire copying machine is controlled by a central control unit (μCPU) 100, and a contact glass temperature detection sensor 36
The detected temperature is converted into an electrical signal by the A/D converter 101, and the temperature detected by the I10 interface
from there to the μCPU 100. And as mentioned above, μ
CP Uloo switches the scanner position based on this detected temperature, so it uses a scanner motor 103 and scanner stop sensors (photo sensors) 104 and 105.
Controls the scanner stop positions (A, B positions) where

FIG. 10 to FIG. 12 show an example of a flowchart of the following control.

FIG. 10 shows the overall flow of the copying machine. After turning on the main switch (Step 1), normal jam detection (Step 2),
After checking the fixing temperature (step 3), etc., the scanner stop position detection subroutine (SUBg) related to the present invention is executed.
(step i), scanner movement subroutine (SUB
I) (step i+1) is executed. This is 5 to 10
Executes repeatedly every second.

FIG. 11 shows the contents of 5tJBQ in FIG. 1O.

Step l) to determine whether the A position sensor is on or not.
, when it is on, set the A position flag (Step 2)
Turn off the B position flag (step 3), if the A position sensor is off and the B position sensor is on (step 4)
), set the B position flag (step 5) and turn off the A position flag (step 6). When both A and B position sensors are off, an abnormality is displayed (step 7).

FIG. 12 shows the contents of 5UBI in FIG. 10.

Read the temperature Lc of the contact glass 4 (step 1
), when this exceeds a predetermined critical temperature t1 (step 2
), the scanner position is detected by determining whether the A position flag is on (step 3), and if the scanner is stopped at position A, the scanner is moved from position A to position B (step 4). When the A position flag is not on, it is determined whether the B position flag is on (step 5), and when it is on, the scanner is moved from the B position to the Δ position (step 6).

EFFECTS - As described above, according to the present invention, the position of the lighting means is controlled according to the temperature of the contact glass to prevent an abnormal rise in temperature of the contact glass, thereby ensuring the safety of the driver and preventing the contact glass from cracking. As a result, the cooling fan and the like can be made smaller and the copying efficiency can be improved compared to conventional copying machines.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of the main parts of a copying machine as an example to which the present invention can be applied, Fig. 2 is a perspective view of a scanner home detection sensor, and Fig. 3 is an optical copying machine in the case of a sheet-through method. FIG. 4 is a side view of the scanner fixing device; FIG. 5 is a curve diagram showing the temperature rise of the contact glass during continuous copying; FIG. 6 is a side view of the first scanner; The figure is a vertical sectional view of the optical system part showing the scanner stop position, Figure 8 is the temperature curve of the contact glass when moving the scanner stop position, Figure 9 is a control block diagram, and Figures 10 to 12 are the control This is a flowchart. 1...Document 3...Transport belt (automatic document feeding means) 4...
--- Contact glass 5 --- Illumination lamp (illumination means) 29 --- Scanner fixing device (movement/stopping means for illumination means) 36 --- Temperature detection sensor (temperature detection of contact glass) Means) 100...Central control unit (control means) +03...Scanner motor (means for moving/stopping the illumination means) 104.105...Scanner stop sensor (means for moving/stopping the illumination means) (1 other person) Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Copy series J size P) (Peng) Fig. 9

Claims (1)

[Scope of Claims] A copying machine equipped with a sheet-through method in which a document transported by an automatic document feeder and moving on a contact glass is irradiated by an illumination means that illuminates a fixed position on the contact glass, the illumination means being means for moving and stopping the contact glass at a plurality of positions; a temperature detection means for the contact glass; and when the temperature detected by the temperature detection means exceeds a predetermined temperature when using the sheet-through method, one of the plurality of stop positions; A copying machine comprising: control means for controlling the illumination means, which has been stopped at one time, to move to another stop position.