JPS6027006B2 - Copy machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying machine, in particular, to create an image by scanning a manuscript placed on a manuscript table with an exposure lamp and by scanning it with a manuscript scanning means. The present invention relates to a copying machine that returns a scanning means to a starting position, and in which the distance traveled by the scanning means during scanning is variable.

- Logarithm In this type of document table scanning type electrophotographic copying machine, the exposure lamp uses a high-intensity one such as a halogen lamp, so it emits a large amount of heat rays, The temperature rise on the glass surface becomes a problem.

This kind of temperature rise on the glass surface is particularly important in copying machines where the document scanning means has a variable scanning distance depending on the length of the document. This becomes more noticeable as the distance becomes shorter. That is, as an example of a copying machine whose scanning distance changes in accordance with the length of the original, there is a copying machine that uses roll copying paper and cuts it into lengths corresponding to the length of the original.

This type of copying machine has an index set on the side of the original glass that is set according to the length of the original, a movable switch for cutting the roll paper and returning the original to the original plate integrally with this index, and an optical system. Alternatively, this switch is actuated by scanning the document table to cut the roll paper corresponding to the length of the document and perform the scanning system glue turn. Therefore, if the document is short (A5 size or less) and a large number of sheets are continuously copied using the scanning system return method as described above, the exposure lamp will be turned off at the end of scanning, and then the scanning system will return to the starting position. Since the time required for exposure is extremely short and the next exposure and scanning steps begin immediately, there is almost no time for the exposure lamp to cool down, resulting in a significant temperature rise on the document table glass. In particular, the return speed of a device that uses the return force of a spring that is stored as the scanning means moves during scanning as the driving force during return is extremely slow, and is becomes a big problem. As a means to prevent such a rise in temperature on the document table, measures such as installing a heat-absorbing glass between the exposure lamp and the document table glass, or providing an air blower to cool the document table have been explored. It is being

However, although heat-absorbing glass has a higher heat-insulating effect as its heat-absorbing efficiency increases, it also lowers the temperature required for exposure. Measures such as increasing the voltage are required, which adversely affects the life of the Fukko lamp. Moreover, those that are low in price and have low heat absorption effect are extremely weak in terms of heat insulation effect. Further, in the case where a blowing means is provided to cool the document table glass, a special means such as a fan or a duct for blowing the air is required, and the cooling effect is extremely weak if only this means is used. Therefore, in order to prevent the temperature of the platen glass from rising, the inventors of the present invention decided to set the time interval between the first copy and the second copy during continuous copying, that is, the time interval during which the exposure lamp is turned off during continuous copying. We conducted a controlled experiment to investigate the temperature rise on the platen glass.

The experimental results are shown in the graph shown in Figure 1, and a halogen lamp (80V, 350W) was used as the exposure lamp.
I used this book. What is Tatefuji's manuscript table saturation temperature (deg)?A
When continuous copying is performed in 5 sizes, the temperature rise of the document glass reaches a saturation state after about 1 hour, which is the temperature of the document glass after 1 hour of continuous copying. The horizontal axis indicates the time interval of continuous copying, that is, the time during which the exposure lamp is turned off. However, this time does not include the scanning system return time, etc., and the exposure lamp is turned off at the time of return, so the exposure lamp turn-off time is calculated by adding about 1 second required for return to the time on the horizontal axis. You should think about it.
Considering this experimental result, when copying documents shorter than A5 size continuously, after the first copy,
If you make a second continuous copy after the exposure lamp has been turned off for at least 1 second, the temperature of the platen glass will rise within the desired temperature range (
5Weg).

This desired temperature range is based on the Japanese crab catching standard that states that when a continuous Japanese weave copy is taken under the highest temperature conditions, the saturation temperature at that time must be 59 eg or less. The present invention has been made focusing on the above-mentioned experiment to prevent the temperature rise of the document platen glass, and when the return start position of the scanning means is less than a predetermined movement distance, the return start position detection means Along with the operation, the exposure lamp is turned off, and in order to prevent the glass surface temperature of the light section from exceeding a predetermined value, the exposure lamp is kept in the off state for a predetermined period of time. If the length is short, the original platen glass may be set, or the exposure lamp may be turned off at the evening start position, by delaying the turn or by preventing the start of the copying operation for a predetermined period of time after returning. An object of the present invention is to provide a copying machine that prevents temperature rises such as the above.

The present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a schematic front view of a static latent image transfer type copying machine using roll copying paper as an example of a copying machine to which the present invention is applied. First, an outline of the copying operation will be explained using this diagram. A document (not shown) placed on the document table glasses 1, 1 is irradiated with an exposure lamp 2, and the reflected document image is reflected by a first reflecting mirror 3a, a second reflecting mirror 3b, a third reflecting mirror 3c, and a lens. 4. 4th
It is projected onto the photosensitive drum 6 via the reflecting mirror 3d and the slit section 5.

The exposure lamp 2 and the first reflecting mirror 3a are fixed to a support 8 that is movable on a guide rail 7 as shown in FIGS. The image is scanned at a constant speed V in the direction shown in FIG. In addition, the second and third reflecting mirrors 3b
, 3c are scanned at a constant speed of (V/2) by another support (not shown) which is movable on the guide rail. These optical systems 10 are scanned to the left by a main motor (not shown), and the driving force at the time of return is the second and third
A coil spring 11, one end of which is fixed to the support of the reflecting mirrors 3b, 3c, utilizes the return force accumulated during scanning. On the other hand, copy paper 12 is stocked in a roll, and is pulled out from the stock position by a paper feed roller 13 and cut into a predetermined length by a cutter 14 activated by a cutter activation signal, which will be described later.

As mentioned above, the original image scanned by the optical system 10 is projected onto the photosensitive drum 6 which is picked up by the charger 15 to become a static latent image, and the image is transferred to the copy paper 12 which is synchronously conveyed by the transfer unit 16. transcribed. After the transfer, the copy paper 12 is separated from the photosensitive drum 6 by a separating claw 17, passes through a developing device 18 to be developed, and is fixed by a drying and fixing device 19 to complete the copying. Further, after the transfer, the photosensitive drum 6 is passed through two erasers to remove residual charges, and the photosensitive drum 6 enters the next copying process. Next, the temperature rise prevention device will be explained.

In FIG. 3, the switch SW functions as a detection means for detecting that the return device of the scanning means 10 is shorter than a predetermined travel distance, that is, A5 size, and is a switch SW, which functions as a detection means for detecting that the return device of the scanning means 10 is shorter than a predetermined moving distance, that is, the A5 size. It is operated by a guide 24 attached to a support plate 23 of a freely adjustable random cut lever 22.

Further, the support plate 23 is provided with a switch SW2 for operating the cutter 14 and a switch SW3 for turning off the exposure lamp 2.
The switches SW, , SW2 are operated by a guide 9 fixed to the support 8 of the exposure lamp 2. Further, as described later, when the switch SW is turned on by the guide 24, the switch SW3 causes the optical system 10 to further scan, and the switch SW3 causes the optical system 10 to further scan.
, has the function of returning the optical system 10 when it is turned off. The switch SW4 functions as a return means to prevent temperature rise, and if the document is A5 size or smaller, the exposure lamp 2 must be off for at least one second, so the optical system 10 turns on the switch SW3. The optical system 10 is installed at a predetermined distance from the exposure lamp OFF switch SW3 so that the guide 9 is activated after the optical system 9 has moved for one second or more after the exposure lamp is turned on.

In FIG. 5, the switch SW, o functions as a means for detecting the stop (start) position of the optical system 10, and is turned on only when the optical system 10 is in the stop position (relay Ry1
3 is in the active) state, and is off while the optical system 10 is moving. The operation of the temperature rise prevention device configured as described above will be explained.

Since the optical system 10 is at the stop position when copying starts, the switches SW,o are in the ON state, the relay Ry13 is activated, and the contacts 13b, 13Q, 13O are turned OFF. When the print switch SW2o is turned on in this state, the drive circuit is activated through the contact 110 of the relay Ryll, and the lamp circuit is activated through the contact 11b of the relay Ryll, and lighting of the exposure lamp 2 and scanning by the optical system 101 are started. Ru. Switch SW, by moving the optical system 10.

is turned off, relay Ry13 is turned off, and each contact 130
, 13Q, and 13b3 are turned on, and the drive circuit and lamp circuit remain in operation. Now, if the document is smaller than the predetermined size of A5 and the random cut lever 22 is set corresponding to the length of the document, the guide 24 turns on the switch SW.

When the optical system 10 starts scanning in this state, the switch SW2 is first turned on by the guide 9, the cutter 14 is activated, and the roll copying machine 12 is cut according to the length of the document.

Next, switch SW3 is turned on, relay Ryl1 is turned on, contacts 110 and 11b2 are turned off, and contact 11a is turned on. When the contact 11a is turned on, the relay Ryll is self-held because the contact 130 is kept on, and when the contact 110 is turned on, the exposure lamp 2 is turned off. However, even if the contact 1 1b2 is turned off, the drive circuit continues to operate because the switch SW and the contact 12b of the relay Ry12 are turned on.

Therefore, the optical system 10 continues to move even after the exposure lamp 2 is turned off, and when the guide 9 turns on the switch SW4, the relay Ry12 is activated, and then the point 12b is turned off, so that the drive circuit is stopped, and the optical system 10 is turned by the return spring 11 shown in FIG. After the optical system 10 has returned, switch SW is pressed. When turned on, the self-holding of relays Ryll and Ry12 is released. In addition, if the original is larger than the specified size, the random cut lever 2
2 is set corresponding to the length of the document, and when the switch SW is in the off state, the guide 9 of the optical system 10 sets the switch SW.
When W3 is turned on, the driving cycle is stopped together with the lamp circuit, and the optical system 10 is returned at the same time as the exposure lamp 2 is turned off.

Note that the switch SW4 only needs to be moved at the same time as the random cut lever 22, but if the document is A5 size or larger, there is no need to move it because the circuit does not operate.

Therefore, as shown in FIG. 4, the switch SW4 is movable by being guided by a long groove 26 via a roller 25, and has a coil spring 27 fixed at one end and a wire 28 connected to a random cut lever 22 at the end. It is fixed and is constantly biased to the left by a coil spring 27.
Only when the random cut lever 22 is set to A5 size or less, it may be pulled by the wire 28 and interlocked. Also, a delay circuit such as a timer is inserted in place of the switch SW4, the signal from the switch SW3 is input to this delay circuit, and after the exposure lamp 2 is turned off by the signal from the switch SW3, the time set in the delay circuit is set. (
The optical system 10 may be moved for 1 second) and then returned.

Furthermore, as shown in Fig. 7, if the document table temperature rise prevention device is turned off when the circuit is A5 size or smaller and the switch SW is turned off, the relay R
y2 is in an off state, and the signal for lighting the exposure lamp 2 does not directly enter the drive circuit, but instead enters a delay circuit, and after a certain period of time, the signal enters the drive circuit.

As is clear from the above explanation, this delay time needs to be 1 second or more. The signal that activates this delay circuit is the input signal from the continuous copy. On the other hand, the manuscript is A
If the switch SW is turned on when the size is 5 or more, the copy signal is input directly to the drive circuit without turning off the relay Ry2. Therefore, only when the original is A5 size or smaller, after one copy has been made, the exposure lamp 2 is turned on for a certain period of time (1 second or more) before starting to make the next copy.
It stays lit in the designated place. Then, by inputting the signal from the delay circuit to the drive circuit, the optical system 10
moves and starts the next copying operation. It may be after the optical system 10 has returned to the stopping position with the exposure lamp 2 turned off, or after the optical system 10 has moved by the required length of the document, it can be stopped at the same time as the exposure lamp 2 is turned off.
It may be returned after stopping for a certain period of time set in the delay circuit. Note that even when copying an original of A5 size or smaller, if the number of continuous copies is small (less than 1 liter), the exposure lamp 2 is turned off while the original is replaced with a new one after continuous copying, so the There is a tendency to prevent temperature rises.

Therefore, even if the original is short in size, when the number of continuous copies is small, the relay Ry2 is not operated (the delay circuit is not operated), and the optical system may be configured as a circuit that performs normal scanning and return. Furthermore, in the case of one copy of one original, the time interval between each copying operation is secured by the original exchange operation, so the temperature rise of the document table is not a problem, and it is known that the document table temperature rise prevention device is activated. Therefore, the copying speed will decrease.

Therefore, in such a case, the device may not operate. As is clear from the above explanation, the present invention
When the return start position of the scanning means is less than the moving distance of the predetermined position, the exposure lamp is turned off in accordance with the operation of the return start position detection means, and the temperature of the glass surface of the light part becomes equal to or higher than the predetermined value. In order to prevent
Since a means for keeping the exposure lamp off for a predetermined period of time is provided, when the document size is short and temperature rise on the document table becomes a problem, it is possible to reliably provide a period of time during which the exposure lamp is not turned on and is cooled down. It is possible to prevent a temperature rise around the document table, especially on the document table glass. Furthermore, there is no need to use thermal violet absorbing glass that lowers the light intensity or air blowing means that unnecessarily increases the size of the copying machine as in the prior art.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the saturation temperature of the original table glass, FIG. 2 is a schematic front view of a copying machine to which the present invention is applied, and FIGS. 3 and 4 are front views showing an embodiment of the present invention. FIG. 5 is an electric circuit diagram thereof, FIG. 6 A is an explanatory diagram of operation, and FIG. 7 is an electric circuit diagram of another embodiment. 1...Original table glass, 2...Exposure lamp,
3a, 3b, 3c, 3d...reflector, 4...lens, 6
...Photosensitive drum, 8...Support, 9...
...Guide, 10...Optical system, 22...
Random cut lever, 24...Guide, SW
．． ...Detection means switch, SW2...
Cutter operation switch, SW3...Exposure lamp turn-off return position setting means switch, SW4...Return switch for preventing temperature rise. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 [a] Figure 6 [mouth] Figure 7

Claims (1)

[Claims] 1. A copying machine that scans an original placed on an original platen with an exposure lamp and scans it with an original scanning means while irradiating it with an exposure lamp, and returns the scanning means to the starting position after the scanning is completed, In the device in which the distance traveled by the scanning means is variable, when the return start position of the scanning means is less than or equal to a predetermined travel distance, the exposure lamp is turned off in conjunction with the operation of the return start position detection means. A copying machine further comprising means for keeping the exposure lamp off for a predetermined period of time in order to prevent the glass surface temperature of the exposure section from exceeding a predetermined value.