JPS5932791B2 - Copy machine safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safety device for preventing a jam in a copying machine.

Specifically, it relates to a safety device for preventing jams of copying materials caused by erroneous operation of the power supply such as power outages in copying machines that separate copying materials such as transfer paper using separation mechanisms such as separation claws. It is.

2. Description of the Related Art Devices for detecting jams caused by developed or transferred copy materials in copying machines are generally known. However, there are relatively few devices that prevent such jams. In view of this point, an object of the present invention is to prevent jams caused by incorrect operation of the power supply. Conventionally, many methods for separating photosensitive paper or transfer paper from a transfer drum or the like utilize external force using a separation claw, an electrostatic roller, a corona charger, or the like.

For example, in the case of a transfer-type electrophotographic device that completes a series of processes such as exposure, development, and transfer in one step by rotating a photosensitive drum, a separating claw is constantly in contact with the photosensitive drum to separate the transferred transfer paper. ing. However, this method has disadvantages such as the separation claws easily damaging the photoreceptor and frictional electrification. Furthermore, in the case of a device that repeats the above process multiple times, especially an electrophotographic device that reproduces color by transferring the image onto a copying material on a transfer drum as shown in Fig. 1, the transfer drum can perform three or more colors on one sheet of transfer paper. Since the transfer drum rotates multiple times in response to disassembly, it is impossible to separate the transfer drum while keeping the separation claw in contact with the transfer drum. Therefore, it is common practice to keep the separating claw out of contact with the transfer drum during periods when the separating claw is not needed, and to operate the separating claw only when the leading edge of the transfer paper reaches the position of the separating claw and a separating operation is necessary. The same applies not only to separation claws but also to corona chargers. However, since the separation operation is performed in synchronization with the rotation of the transfer drum, if the synchronization is lost, separation will not be possible, resulting in a jam as shown in the following example. Regarding the transfer type color electrophotographic apparatus using three-color separation shown in FIG. 1, the copying process and the transfer mechanism will be explained. The front two layers of the three-layered photoconductor 2 wound around the surface of the photoconductor drum 1 are divided into three parts by a metal spacer 3, and as the original platen 4 moves, a light image from a light source 5 is exposed onto the photoconductor in color. This is done through a decomposition filter 6.

On the photoreceptor that has been primarily charged by the corona charger T, a photoimage is exposed simultaneously with the secondary charging by the corona charger 8,
Furthermore, an electrostatic latent image is formed by exposing the entire surface to light from the light source 9. The latent image is developed by toner therein as the developing device 10 sequentially operates according to the number of separated colors. This image is transferred onto transfer paper fed from the paper feed case 11 to the transfer drum 12. One color is transferred onto the divided photoreceptor by one rotation of the transfer drum,
Therefore, three rotations complete the transfer of all colors. The leading edge of the transferred transfer paper is lifted as the separation claw 13 descends, and the transfer paper is separated from the transfer drum 12, thermally fixed while being conveyed by the fixing belt 14, and discharged to the outside. Here, since the operation of separating the transfer paper by the separation claw 13 is synchronized with the rotation of the transfer drum 12, etc., if the power is cut off before being ejected to the outside, the synchronization signal is canceled and the transfer drum 12 is also added, and even if the power is restored next time, the separation claw 13 will not be able to operate at that time. Therefore, if copying is continued as is, the transfer paper will be torn by the separating claw 13 that descends midway, or jammed by the subsequent fed transfer paper. The present invention eliminates the above-mentioned drawbacks, and includes a main switch for turning on the power necessary for copying operations, and a memory for storing the time period from when copy material starts feeding until it is ejected, that copying operations are in progress. and means for retaining the memory in the storage means after shutting off the main switch and generating a warning signal based on the storage signal in the storage means and the restart signal for the copying machine when the copying machine is restarted; The present invention provides a safety device for a copying machine, which is characterized in that it warns of copying material remaining in the machine due to erroneous operation of the main switch.

Furthermore, the basic operating system of the present invention will be explained with reference to FIG.

In the figure, 1 is a power-on signal, 2 is a copy start signal, 3 is a mechanical storage means that maintains that a copy operation is in progress by signal 2, 4 is a copy completion signal, and 5 is a copy start signal by signal 4. 6 is an AND gate circuit, and 7 is an alarm generating means and a copy start blocking means. To explain its operation, the power-on signal 1 is generated when the power is turned on, but generally the copy start signal 2 cannot be issued at the same time as the signal 1 is generated. Therefore, the storage means 3 does not operate immediately, but remains released, and the output of the AND gate circuit 6 is zero. Therefore, the memory state is maintained until the memory state is canceled. Therefore, even if the power is cut off before the paper is ejected, or before the fed paper is ejected, the state will still be maintained even if the power is restored.
The AND gate circuit is operated by the signal from the storage means 3 and the signal 1 when the power is restored. Therefore,
Before a jam occurs, the alarm means 7, such as a buzzer, can be used to notify the user that copying material has accumulated in the apparatus, thereby preventing the start of the next copy. Furthermore, if the copy completion signal 4 is a so-called completion signal that will occur after a certain period of time from the time when the paper is fed, there will be an inconvenience that the copy will be indicated as complete even though the paper has not actually been ejected due to a jam due to another cause. . However, this problem can be solved by blocking the copy completion signal 4 in advance with a jam signal 8 shown by a dotted line from a known jam detection means which is constructed independently. Next, a specific example will be described with reference to FIG.

The figure shows the case during normal copying operation.

In the figure, PF is a contact that is turned on by a signal when copying starts, that is, paper feeding, A is a holding relay that has contact a and serves as a mechanical storage means, A is a reset coil for releasing holding relay A, and JAM is a The contact, Cup, which is turned off by a signal from an independently set jam detection circuit, is used to feed the next paper before the previous paper has been ejected. TL is a timer relay that turns on contact TL after a certain period of time; C1 is a capacitor that keeps the potential of trigger diode D2 at zero for a while after the power is turned on; D1 is a power supply. A diode for discharging the charge of C1 when cut off, D2 is a trigger diode such as a diac for operating the thyristor Q1, D3
, D4 and R4 are diodes and resistors that constitute an AND gate circuit, Q2 is a transistor that amplifies the output of the AND gate, K is a relay that has a contact K and is used to operate an alarm buzzer (not shown), etc. D5 is relay K
, and SW is a power switch. To explain the operation, first, when the power is turned on by turning on the switch 8V, C is charged via R1.

However, immediately after turning on the voltage across C1 is the trigger diode D.
Thyristor Q1 does not operate until the trigger voltage of 2 is reached. Therefore, the anode voltage of the thyristor Q1, that is, the voltage applied to the negative terminal of the diode D3 of the AND gate circuit is the power supply voltage. The direction contact PF remains off since copying has not yet started. Therefore, the coil of holding relay A is not energized, its contact a remains on, and the voltage applied to the negative terminal of diode D4 is zero. As a result, the output of the AND gate circuit is zero, that is, the base potential of the transistor Q2 is zero, indicating that the transistor Q2 is in an off state and the relay K does not operate, that is, a copying operation is possible. If the power supply is erroneously operated at this time, the above series of steps will simply be repeated. Next, when the copying operation is started using a copy button (not shown) that specifies the number of copies, the copying material is first fed, and at the same time, the contact is activated by the paper feed detection means (not shown). PF is turned on. Therefore, the coil of holding relay A is energized and contact a is opened.
Holding relay A mechanically stores this state. Therefore, contrary to the above, the power supply voltage is applied to the negative terminal of the diode D4. However, on the other hand, the potential of the negative terminal of the diode D3 shows zero because the potential of the capacitor C1 reaches the trigger potential of the trigger diode D2 and the thyristor Q1 is conductive. Therefore, the output of the AND gate circuit is zero as described above, indicating that the relay K does not operate and the copying operation is normal. Next, when the specified number of copies is completed, a count-up signal indicating the completion of the calculation of the number of sheets is generally issued at the time of the final sheet feeding, so that the contact Cup is turned on and the timer relay TL is operated.

The contact t1 is a contact that is turned on after a period of time has elapsed until the final copy material, which has been fed, separated, and conveyed, is delivered to the outside of the apparatus. As a result, unless a jam occurs within the apparatus, that is, unless contact JAM is turned off, the set coil A is energized and the holding relay K is reset to return to the state before the start of copying. That is, the reset A detects that the fed copying material, such as transfer paper, does not remain in the apparatus, and prepares the apparatus for re-copying. Here, if the designated number of sheets is one, the signals PF and Cup are the same. After reset coil A is activated, relay K will not operate even if there is an erroneous operation of the power supply, such as a power outage, because contact a is on as described above. Here, to explain the case where the power supply is erroneously operated before the copying material such as transfer paper remains attached to the transfer drum etc. and is removed from the apparatus, firstly, the power supply is cut off due to a power outage during the copying operation or the power supply is intentionally cut off. Then, even if the count-up Cup signal is output, if the operation of timer relay TL is not completed, contact tl remains off, and therefore holding relay A is not reset and contact a performs the copying operation. The signal inside is maintained in the off state.

Since the holding relay A is a mechanically locked storage means, this state is maintained as described above even when the power is restored next time. For a while after the power is restored, capacitor C1 begins to charge, so thyristor Q1 remains off until trigger diode D2 turns on and the first switch S
A potential similar to that at power-on is obtained at one end of the diode D3. On the other hand, when contact a is turned off, diode D4
One end of indicates the power supply potential. Therefore, an output is obtained to the AND gate circuit constituted by the diode, transistor Q2 is turned on, and the coil of relay K is energized to operate an alarm buzzer, etc. (not shown). Since the contact k of the relay K is closed, the relay K is held through the contact k even if the voltage across the capacitor C1 exceeds the trigger voltage and the output of the AND gate circuit becomes zero. In other words, an alarm is issued and the start of copying is prevented until the retained paper is removed and holding relays A and K are manually released.

FIG. 4 shows another embodiment. This uses relay B and relay E as an AND gate circuit, and when contacts b and e are turned on, the coil of relay K is energized and self-held by contact k.

Contact a is turned on by the paper feed signal PF, contrary to the case shown in FIG. Relay E corresponds to a switching element such as a thyristor in FIG. 3, and the coil of relay E is excited when the power is turned on. The rest is the same as in FIG. 3. To briefly explain the operation, switch 8V
When is turned on, contact e of relay E, which is excited via capacitor C, is turned on for a while. At this time, the holding ri, , and ray A are released and contact a is off, so contact b
is off and relay K does not operate. However, when holding relay A stores the copying operation state, contact a is on, that is, contact b is on, and relay K is activated by turning on contact e. Therefore, an alarm will be issued to prevent jamming. Here, it is desirable that the relay E has a sharp start-up and that the capacitor C has a large capacity. The resistor r is for discharging the charge of the capacitor C. Contact point a and contact point b can be used together. FIG. 5 shows another embodiment.

This is an AND gate circuit with transistors Q3 and Q5.
It has something made up of.

In addition, in order to set the holding relay A with a delay from the Cup signal, a transistor Q4 is used, which does not go through a relay, but directly delays and amplifies the signal.
, a resistor R2, and a capacitor C2. Also, as Q2, a PUT (PrOgramable) with a large trigger voltage is used instead of a trigger diode.
ijunctiOntrangistOr) is used. The rest is the same as in FIG. 3. The difference from FIG. 3 is that the reset coil 8 is operated by a directly delayed pulsed Cup signal. Furthermore, since the AND gate circuit using a transistor has an amplification effect, it is possible to directly operate the relay K. As described above, the present invention has a memory means that stores the fact that the copying operation is in progress even if the power switch is cut off during normal copying operation due to an erroneous operation of the power supply, and restarts the copying machine. If the storage means remembers that the copying operation is in progress, a warning is output using the storage signal and the restart signal. Therefore, it is possible to warn in advance of copying material remaining in the machine due to incorrect operation of the power switch.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a transfer type color electrophotographic device having a separation claw, FIG. 2 is a system diagram showing the basic operation system of the present invention, and FIG. 3 is an example of a circuit of a safety device based on the present invention. FIGS. 4 and 5 show other embodiments.

Claims (1)

[Claims] 1. A main switch for turning on the power necessary for the copying operation, a memory means for storing the information that the copying operation is in progress from the time when the copying material starts to be fed until it is ejected, and the above-mentioned after the main switch is shut off. means for retaining the memory in the storage means and generating a warning signal based on the storage signal in the storage means and the restart signal for the copying machine when the copying machine is restarted, so that no copy material remains in the machine due to erroneous operation of the main switch. A safety device for a copying machine characterized by warning.