JP2642123B2 - Copier - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine having a sheet-through system in which a document conveyed by an automatic document feeder and moving on a contact glass is illuminated by an illuminator illuminating a fixed position of the contact glass. About.

Conventional technology In a conventional sheet-through type copying machine, a stopped illumination lamp irradiates a fixed position such as a contact glass from a lower portion of a document reading unit such as a contact glass. The temperature rise was large, causing problems such as cracking and deformation of the contact glass and other parts, and the driver touching the document reading section and getting burned.

Conventionally, a powerful fan is installed to lower the temperature of the document reading unit, and the number of coby sheets per unit time (CPM ) Was adopted. However, in these methods, since a powerful fan is provided, there is no room for arrangement in the copying machine, and it becomes necessary to increase the size of the copying machine, or the noise of the fan becomes intense.
In addition, there is another problem that the copying efficiency must be lower than the original copying ability of the copying machine, so that the working efficiency is reduced.

As a method to prevent the temperature of contact glass from rising,
2. Description of the Related Art In a recycle-type automatic paper feeder in which a set of a plurality of originals is circulated and copied a required number of times, a method of moving a scanning illumination unit for each cycle of a recycle sheet through is known (see US Pat. No. 4,684,237). ). However, in this case, the contact glass temperature is not raised, and the scanning illumination means is often moved even when it is not necessary to move the scanning illumination means, which causes a problem such as a reduction in work efficiency.

Objective The present invention solves the above-mentioned problems in the prior art, prevents the abnormal temperature rise of the contact glass and the like without increasing the size of the cooling fan and the like, and lowering the copying efficiency. An object of the present invention is to provide a good copying apparatus which is secured and is free from occurrence of abnormalities such as contact glass breakage.

Configuration In order to achieve the above object, the present invention has a sheet-through system in which a document conveyed by an automatic document feeder and moved on a contact glass is illuminated by an illuminator illuminating a fixed position of the contact glass. In the copying machine, means for moving / stopping the illuminating means to a plurality of positions; temperature detecting means for the contact glass; and when the temperature detected by the temperature detecting means exceeds a predetermined temperature when using the sheet-through method. And control means for controlling the illumination means stopped at one of the plurality of stop positions to be moved to another stop position.

Hereinafter, the configuration of the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows a configuration of a main part of a copying machine capable of copying by both a scanner system (scanning system) and a sheet-through system, which is an example to which the present invention can be applied. However, it goes without saying that the present invention can be applied to a copying machine using only the sheet-through system.

First, the operation of the copier in the case of the scanner system will be described. FIG. 1 shows a state of the scanner system.

When the originals 1 are separated one by one by an original separating unit, and are fed onto a contact glass 4 by a transport belt 3 as an example of an automatic original feeder and stopped at a predetermined position, an illumination lamp 5 as an example of an illuminator and a light The first scanner 7 having the first mirror 6 moves at a speed V, and the second scanner 10 having the second mirror 8 and the third mirror 9 moves at a speed of 1/2 V below the contact glass 4, and The image is projected onto the photosensitive drum 13 via the first mirror 6, the second mirror 8, the third mirror 9, the lens 11, and the fourth mirror 12. The transfer paper 15 on the paper feed tray 14 is separated one by one by a transfer paper separation unit 16, sent to the photosensitive drum 13 via a registration roller 17, and developed by the developing device 18.
After the upper image is transferred by the transfer charge 19, the image is separated from the photosensitive drum 13 by the separation charger 20, and the image thereon is fixed by the fixing device 21, and then is discharged onto the discharge tray 23 by the discharge roller 22. Is discharged.

The scanner home detection sensor 24 includes the scanner 7,
The leading end of the transfer paper 15 is aligned with the image by controlling the stop position at the time of return of 10 or controlling the timing of the registration roller 17 by 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 this is detected by a scanner home detection sensor 24 which is a photo sensor.

Next, the case of the sheet through system will be described. Third
The figure shows the state in this case.

As in the case of the scanner system, the original 1 is separated from the original separating unit 2.
The original 1 is conveyed onto the contact glass 4 by the conveyor belt 3 in this case. In this case, the original 1 is conveyed at a constant speed V without stopping on the contact glass 4 and discharged to the discharge section 26.

At this time, the scanners 7 and 10 are stopped at predetermined positions below the contact glass 4, and while the original 1 is moving on the contact glass 4, the illumination lamp 5 is turned on to expose the original. Here, reference numeral 27 denotes a document detection sensor, which detects the leading end of the document 1 moving on the contact glass 4,
The timing of the registration roller 17 is controlled based on the detection timing, and the leading end of the image and the transfer paper 15 are aligned.

In addition, a cooling fan 28 is provided, which cools the illumination lamp 5 and the contact glass and the like in the vicinity thereof, and plays a role of reducing the temperature rise thereof.

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

The scanners 7 and 10 are guided and moved by the guide rod 30. The fixed arm 31 is rotatable by a solenoid 32 and a spring 33. A fixed article pin 34 is provided for the first scanner 7, and when the solenoid 32 is turned off, the fixed pin 34 is fixed to the fixed spring 35. The first scanner 7 is pressed against the fixed arm 31 to fix the first scanner 7. Next, when the solenoid 32 is turned on, the fixed arm 31 rotates, is released from the fixed pin 34, and the first scanner 7 becomes movable.

The scanner fixing method shown in FIG. 4 uses a mechanical mechanism. In addition, a sensor similar to the scanner home detection sensor 24 shown in FIG. 2 is provided at a position corresponding to the scanner fixing position. There is a method of controlling the stop position of the scanner 7 by detecting this, and further controlling the stop position of the scanner 7 by moving a movement amount calculated in advance based on the scanner home position.

FIG. 5 exemplifies a state in which the temperature of the contact glass 4 rises when continuous copying is performed when the scanner 7 is at a fixed position by the sheet-through method.
Assuming that the outside air temperature (environmental temperature) is 25 ° C., the temperature at the start is 25 ° C., and when the continuous copying is started, the temperature of the contact glass 4 rises as shown in FIG. Assuming that the temperature is 75 ° C, this temperature is reached in about 18 minutes, and the temperature at which the contact glass 4 breaks
Assuming 100 ° C., this temperature is reached in about 45 minutes.

The degree of the temperature rise varies depending on the type of the illumination lamp 5, the voltage, the distance from the lamp 5 to the contact glass 4, the presence or absence of the cooling fan 28, the scene, the installation location, and the like. It shows.
For this reason, in the conventional copying machine, in order to prevent a dangerous temperature or a temperature of contact glass breakage from being reached even if continuous copying is performed, the cooling fan 4 is required to have a considerably high power or a unit time. The copy rate per hit must be reduced, and the ratio of the lighting time of the illumination lamp 4 must be reduced.

Therefore, in the present invention, in the copying machine of the above embodiment,
A contact gauss temperature detecting means is provided, and the irradiation position of the illuminating means, that is, the stop position of the first scanner 7 is switched according to the detected temperature. In this case, in order to make the conjugate lengths equal, in this embodiment, the position of the second scanner 10 is also switched.

FIG. 6 shows the details of the first scanner 7. In the vicinity of the illumination lamp 5, a temperature detecting sensor 36, which is an example of a temperature detecting means for the contact glass 4, is provided. In the present embodiment, the sensor 36 is brought into contact with the contact glass 4, but a non-contact type sensor may be used. The mounting position of the temperature detection sensor 36 is desirably as close as possible to the position where the temperature is highest, and this depends on the position of the cooling fan 28, but usually it is desirable to be near the illumination lamp 5.

FIG. 7 illustrates a case where the scanners 7, 10 are provided with two stop positions (A, B, C, and D) at the time of sheet through. Of course, more stop positions can be provided. When the temperature detected by the contact glass temperature detection sensor 36 reaches a preset upper limit temperature t ₁ in terms of driver safety, contact glass breakage, and the like, the stop positions of the scanners 7 and 10 are stopped by another stop. Control to switch to the position.

As described above, any method of providing a plurality of scanner stop positions may be used, such as the method shown in FIG. 4, the method using the sensor shown in FIG. 2, or the method of moving the calculated amount of movement with a motor.

FIG. 8 shows the case where the upper limit temperature t _{1 is set} to 75 ° C. and the scanner 7
The state of the temperature change of the contact glass 4 when two stop positions are provided at 10 positions is shown. As in the case of Fig. 5, about 18
The temperature of the contact glass 4 is 75 ° C. _per minute.
Reach When the scanner 7 and was stopped at the position of A shown in FIG. 7, the scanner 7 by the upper limit temperature t ₁ detected
Moves to the B position. Since the position B is distant from the position A, the contact glass 4 at the location irradiated by the position B
Has not risen so much and is in a temperature state where copying is possible. Subsequently, when starting the continuous copying B position, a contact glass 4 reaches the upper limit temperature t ₁ rises temperature. During this time, the portion of the contact glass corresponding to the position A is cooled to a temperature at which copying can be performed, so the scanner position is moved to the position A again. When the position of the scanner 7 is switched between A and B, the position of the scanner 10 is also switched between C and D correspondingly.

By repeating such control, the contact glass 4 does not become higher than the predetermined upper limit temperature, and safety is ensured.

Although the copying operation is interrupted during the movement of the scanners 7 and 10 (typically for one second to several seconds), the reduction in work efficiency due to this is not so much a problem that the present invention is applied. It is not necessary to provide a powerful fan as described above or to lower the copy rate, which is advantageous.

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 the temperature detected by the contact glass temperature detection sensor 36 is converted into an electric signal by an A / D converter 101 and sent from the I / O interface 102 to the μCPU 100. . As described above, the μCPU 100 controls the scanner stop positions (A and B positions) where the scanner motor 103 and the scanner stop sensors (photo sensors) 104 and 105 are provided in order to switch the scanner position based on these detected temperatures. I do.

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

FIG. 10 shows the flow of the entire copying machine. After turning on the main switch (Step 1), normal jam detection (Step 2),
After confirming the fixing temperature (step 3), the scanner stop position detecting subroutine related to the present invention is checked. (Step i) Scanner moving subroutine (SUB
1) and (Step i + 1) are executed. This is 5 to 10
It is repeated every second.

FIG. 11 shows the contents of SUB0 in FIG. Judge whether the A position sensor is on or not (step 1).
The A position flag is set (step 2), the B position flag is turned off (step 3), and if the A position sensor is off and the B position sensor is on (step 4), the B position flag is set (step 5). The A position flag is turned off (step 6). When both the A and B position sensors are off, an abnormal display is made (step 7).

FIG. 12 shows the contents of SUB1 in FIG. It reads the temperature tc of the contact glass Open (Step 1), which exceeds a predetermined critical temperature t ₁ (step 2), to detect the scanner position by position A flag to determine whether one, (step 3) When the scanner is stopped at the position A, the scanner is moved from the position A to the position B (step 4). If the A position flag is not on, it is determined whether the B position flag is on (step 5). If it is on, the scanner is moved from the B position to the A position (step 6).

As described above, according to the present invention, the safety of the driver is ensured by controlling the position of the illuminating means by the temperature of the contact glass to prevent an abnormal rise in the temperature of the contact glass, and to prevent the contact glass from breaking. An accident can be prevented, and as a result, the cooling fan and the like can be reduced in size and the copying efficiency can be improved by the conventional copying machine.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part 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. 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, FIG. FIG. 8 is a longitudinal sectional view of the optical system portion showing the scanner stop position, FIG. 8 is a temperature curve of the contact glass when the scanner stop position is moved, FIG. 9 is a control block diagram, and FIGS. It is a flowchart. 1 Document 3 Conveyor belt (automatic document feeding means) 4 Contact glass 5 Illumination lamp (illumination means) 29 Scanner fixing device (moving / stopping means of illumination means) 36 Temperature sensor (Contact glass temperature detecting means) 100 Central control unit (Control means) 103 Scanner motor (Lighting means moving / stopping means) 104,105 Scanner stop sensor (Lighting means moving / stopping means)

Claims (1)

(57) [Claims] 1. A copying machine equipped with a sheet-through system in which an original conveyed by an automatic original feeder and moved on a contact glass is illuminated by an illuminator illuminating a fixed position of the contact glass. Means for moving / stopping to a position of; a temperature detecting means for the contact glass; and a temperature detected by the temperature detecting means exceeding a predetermined temperature when using the sheet-through method. Control means for controlling the illuminating means, which has been stopped, to be moved to another stop position.