JP2009227418A - Paper feeding cassette - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding cassette preventing a failure and the damage of an interface circuit, a computer and a memory element as an electric circuit constituent article by an intrusion current from the outside in a non-electrically activated state. <P>SOLUTION: The paper feeding cassette 2 can be attached to and detached from an image forming device body 1, and a cassette electric circuit 2a is provided with: a capacitor 2b for receiving electricity fed from a body electric circuit part 1b and accumulating an electric charge; and a switching transistor 4a connected to the capacitor 2b and performing switching action. The switching transistor 4a perform switching to secure a discharge route designed to discharge the electric charge of the capacitor 2b by shutting off the body electric circuit 1b and the cassette electric circuit 2a when the paper feeding cassette 2 is removed from the image forming device body 1 in the cassette electric circuit 2a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a paper feed cassette used in an image forming apparatus.

  Image forming apparatuses such as printers, scanners, copiers, facsimiles, and multi-functional machines including them are detachably equipped with paper feed cassettes that have an electric drive system for loading paper and feeding the paper to the image forming apparatus. Is provided. This paper feed cassette may not have a built-in power supply for operating the electric drive system, and is supplied with power from the power supply in the image forming apparatus.

  When the paper feed cassette is removed from the image forming apparatus, electric power is accumulated in a capacitor included in an electric circuit for controlling the electric drive system of the paper feed cassette by power supply from the power source of the image forming apparatus. . When the image forming apparatus is mounted in this state, when the image forming apparatus is in a non-energized state, an inrush current flows from the capacitor to the image forming apparatus side, so that an interface circuit constituting an electric circuit in the image forming apparatus Damage the computer, memory element, etc.

  In order to reduce the damage of the electric circuit due to such inrush current, a FET that controls the supply of current to the supplied side is provided on the downstream side of the power supply that supplies current to the supplied side, and the gate of this FET A control unit for controlling the gate voltage is connected to the side, and the inflow of the inrush current to the supplied side is controlled by controlling the FET. The circuit between the gate and the source of the FET An inrush current limiting circuit having a capacity has been proposed (see Patent Document 1).

Japanese Patent Laid-Open No. 2005-33869

  The inrush current limiting circuit in Patent Document 1 controls an inrush current from a live power source, and is not applicable to a paper feed cassette connected to an inactive image forming apparatus. Inrush current control means that can be applied to various paper cassettes is desired.

  An object of the present invention is to prevent damage or damage to an interface circuit, a computer, a storage element, or the like as an electric circuit component due to an inrush current from the outside when the electric circuit of the image forming apparatus main body is in a non-energized state. It is to provide a paper feeding cassette.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above-described problems, the sheet feeding cassette of the present invention is equipped with a cassette electric circuit unit and attached to the image forming apparatus main body with respect to an image forming apparatus main body that has a main body electric circuit unit and can supply DC current. In this mounted state, the main body electric circuit portion and the cassette electric circuit portion are connected, and power is supplied from the main body electric circuit portion to the cassette electric circuit portion, while in the detached state, the power supply state is A paper feed cassette that is cut off and can be attached to and detached from the image forming apparatus main body even when the main body electric circuit section is in an active state, and the cassette electric circuit section receives electric power from the main body electric circuit section and is charged. And a switching transistor connected to the capacitor and performing a switching operation. The switching transistor includes the paper feed cassette. When the printer is detached from the image forming apparatus main body, a discharge path is formed in the cassette electric circuit portion so that the electric charge of the capacitor is discharged by blocking the main body electric circuit portion and the cassette electric circuit portion. It is characterized by switching to ensure.

  With the above configuration, the cassette electrical circuit section of the paper feed cassette is supplied with power from the main body electrical circuit section of the image forming apparatus main body while the paper feed cassette is mounted on the main body of the image forming apparatus, and charges are accumulated in the capacitor. In this state, when the paper feeding cassette is detached from the main body of the image forming apparatus, switching is performed so as to ensure a discharge path in the cassette electric circuit unit that discharges the electric charge of the capacitor of the cassette electric circuit unit. The capacitor charge is discharged through this discharge path, and the inrush current when the paper feeding cassette is connected to the inactive image forming apparatus body can be eliminated. A paper feed cassette that can prevent damage and damage to the interface circuit, computer, and storage elements that make up the main circuit section. It can provide Tsu door.

  In order to solve the above problems, the paper feed cassette according to the present invention is detachable from the main body of the image forming apparatus for forming an image on the paper, and the paper for feeding paper to the main body of the image forming apparatus can be stacked. A cassette electrical circuit unit, and the cassette electrical circuit unit includes a connector connected to a body electrical circuit unit including a power supply unit provided in the image forming apparatus body. A power supply line and a ground line are connected to each other, and when the power supply unit is in an active state, power is supplied. A capacitor included in the cassette electric circuit unit is connected to a switching circuit, and the switching circuit is a transistor. And connecting the positive electrode of the capacitor to the emitter of the transistor, and connecting the negative electrode of the capacitor to the collector via a consumption resistor, The base of serial transistors, characterized by connecting the negative electrode of the capacitor via the pull-down resistor.

  With the above configuration, when the paper cassette is connected to the image forming apparatus main body and the power supply unit of the image forming apparatus main body is in an active state, the cassette electrical circuit unit of the paper feeding cassette is powered, When the capacitor is charged, the connector is released when the paper cassette is removed from the image forming apparatus main body in this state, and the base of the transistor is grounded via the pull-down resistor through the ground line. ), The charge of the capacitor connected to the emitter and the collector is consumed via the consumption resistor, so that the discharge is performed rapidly, and the power supply unit of the paper cassette is in an inactive state. The inrush current when connected to the main body of the apparatus can be eliminated, and the interface circuit and the computer constituting the main body electric circuit section in the main body of the image forming apparatus can be eliminated. Over data, a paper feed cassette capable of preventing the breakage and damage, such as a storage element can be provided only by adding a simple switching circuit.

  In order to solve the above problem, when the power supply line and the ground line of the switching circuit in the paper feeding cassette are separated so that the connector is disconnected, the ground line is behind the power supply line. It is characterized by being separated and disconnected.

  With the above configuration, the capacitor can be discharged more rapidly by securing a new discharge path while the connection of the ground line terminal is continued. The effect of inrush current can be eliminated.

  In order to solve the above problems, a first engaging member having conductivity as a mechanical structure is connected to the ground line of the switching circuit, and a mechanical structure is connected to the ground line of the power supply unit. A second engaging member having conductivity as a body is connected, and the first engaging member and the first connector are disconnected after the sheet feeding cassette is detached from the image forming apparatus main body and the connector is disconnected. The second engagement member is in a disconnected state.

  With the above configuration, the capacitor is discharged more rapidly by newly securing a discharge path while the connection of the ground line is continued by the first engagement member and the second engagement member. And the effect of inrush current can be eliminated.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an electric circuit configuration diagram showing a connection relationship between a paper feed cassette of the present invention and an image forming apparatus main body. In FIG. 1, an image forming apparatus main body 1 includes an image reading apparatus, an automatic document conveying apparatus, a sheet post-processing apparatus, and a sheet supply apparatus, each of which is a peripheral device. Yes.

  The image forming apparatus main body 1 includes a main body electric circuit unit 1b including a power source unit 1a for supplying direct current power (DC current) to various apparatuses. The main body electric circuit portion 1b is provided with a socket 3a for a connector 3 to be electrically connected when a paper feed cassette 2 as an external device is mounted on the main body 1. The socket 3a has at least a power supply line V1 and a ground line G1 in the main body electric circuit portion 1b.

  The paper feed cassette 2 is detachably attached to the image forming apparatus main body 1 so that paper (not shown) for feeding paper to the image forming apparatus main body 1 can be stacked.

  The sheet feeding cassette 2 includes a cassette electric circuit unit 2a. The cassette electric circuit unit 2a has a plug 3b of a connector 3 attached to a main body electric circuit unit 1b including a power source unit 1a provided in the image forming apparatus main body 1. The power line V2 and the ground line A2 of the cassette electric circuit part 2a are connected to the power line V1 and the ground line G1 of the main body electric circuit part 1b via the socket 3a of the connector 3.

  In this way, the paper feed cassette 2 is electrically connected to the image forming apparatus main body 1 by the connector 3 and is supplied with power when the power supply unit 1a in the image forming apparatus main body 1 is in a live state.

  The switching circuit 4 is connected to the capacitor 2b included in the cassette electric circuit unit 2a. The switching circuit 4 includes a transistor (switching transistor) 4a that performs a switching operation. In addition, one electrode of the capacitor 2b is connected in series with the consumption resistor R1 between the emitter 4E and the collector 4C of the transistor 4a, and the base 4B of the transistor 4 has a bias voltage for conducting between the emitter 4E and the collector 4C. Is connected to the other electrode of the capacitor 2b.

  If the transistor 4a of the switching circuit 4 is an example of a PNP type of PNP type or NPN type, one positive electrode of the capacitor 2b is connected to the emitter 4E of the transistor 4, and a consumption resistor R1 is connected to the collector 4C. The other minus electrode of the capacitor 2b is connected through the via. Further, the other negative electrode of the capacitor 2b is connected to the base 4B of the transistor 4 via the pull-down resistor R2.

  One end of a pull-up resistor R3 is connected to the base 4B of the transistor 4a of the switching circuit 4. The other end of the pull-up resistor R3 is connected to the socket 3a side of the connector 3. In addition, a pull-up line V1a divided from the power supply line V1 of the main body electric circuit portion 1b of the image forming apparatus main body 1 is connected to the plug 3b side of the connector 3. When the connector 3 is connected, a pull-up resistor R3 is connected to the pull-up line V1a.

  Next, the action of discharging the capacitor 2b in the cassette electric circuit section 2a in the paper feed cassette 2 will be described. When there is no discharge path, a general capacitor charge is due to spontaneous discharge. However, especially when the capacitance component of the capacitor 2b is large (the scale of the cassette electric circuit portion 2a), it is necessary for natural discharge for a long time. Therefore, the paper feed cassette according to the present invention enables the discharge to be performed quickly. It is.

  When the image forming apparatus main body 1 is in operation with the paper feeding cassette 2 being inserted and connected (attached) to the image forming apparatus main body 1, the power supply unit 1a is in an active state, so The cassette electric circuit portion 2a of the cassette 2 is supplied with power, and the capacitor 2b is charged.

  Therefore, when the paper feed cassette 2 is detached from the image forming apparatus main body 1, the socket 3a and the plug 3b of the connector 3 are separated. Then, since the base 4B of the transistor 4a is grounded by the ground line G2 via the pull-down resistor R2, when the transistor 4a is turned on (conductive), the charge of the capacitor 2b connected to the emitter 4E and the collector 4C is As indicated by the arrow X1 (discharge path), it is consumed via the consumption resistor R1, so that the discharge is performed rapidly.

  Next, another embodiment of the paper feed cassette will be described. The detailed description of other configurations according to this example is the same as the configurations in the other embodiments described above. As shown in FIG. 2, other terminals corresponding to the ground line terminal 3a1 as the contact terminal of the plug 3b of the connector 3 and the contact terminal of the socket 3a and the contact length L of the ground line terminal 3b1 as the power line V1 as the contact terminal. The contact length L1 of 3a2, 3b2 is set longer.

  The discharge of the capacitor 2b due to the use of the connector 3 is such that when the plug 3b and the socket 3a of the connector 3 are separated from each other while the capacitor 2b is charged, the terminals 3a2 and 3b2 having a short contact distance first. Even if the connection is disconnected and the connection is cut off, the ground line terminal 3a1 and the ground line terminal 3b1 remain connected. While this connection is made, as indicated by an arrow X2 in FIG. 1, a new discharge path is ensured to flow through the ground line G1 of the power supply unit 1a, whereby the ground line terminal 3a1 and the ground line terminal 3b1 of the connector 3 are secured. Discharge is performed until the connection of is disconnected. Thereafter, similarly to the above, the capacitor 2b is discharged through the discharge path indicated by the arrow X1 in FIG.

  Next, another embodiment of the paper feed cassette will be described. Since the other constituent members according to this example are the same as the constituent members in the other embodiments described above, detailed description thereof will be omitted. As shown in FIG. 3, a first engaging member 2 c having conductivity as a mechanical structure is connected to the ground line G <b> 2 of the switching circuit 4 of the paper feed cassette 2. Further, a conductive second engagement member 1c as a mechanical structure is connected to the ground line G1 of the power supply unit 1a of the image forming apparatus main body 1. With this configuration, the first engaging member 2c and the second engaging member 1c are moved after the sheet feeding cassette 2 is detached from the image forming apparatus main body 1 and the socket 3a and the plug 3b of the connector 3 are disconnected. It is supposed to be disconnected.

  The discharge of the capacitor 2b by using the first engagement member 2c and the second engagement member 1c is performed after the plug 3b and the socket 3a of the connector 3 are separated from each other in a state where electric charges are accumulated in the capacitor 2b. However, the ground line G1 of the power supply unit 1a and the ground line G2 of the switching circuit 4 remain connected. While this connection is made, as indicated by an arrow X3, a discharge path that flows through the ground line G1 of the power supply unit 1a is newly secured, thereby connecting the first engagement member 2c and the second engagement member 1c. The discharge of the capacitor 2b is efficiently performed by both the discharge after the interruption.

FIG. 3 is an electric circuit configuration diagram showing a connection relationship between the paper feed cassette of the present invention and the image forming apparatus main body. Schematic of the connector of the other paper feed cassette of the present invention. The schematic block diagram which shows the other paper feed cassette of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 1a Power supply part 1b Main body electric circuit part 1c First engagement member 2 Paper feed cassette 2a Cassette electric circuit part 2b Capacitor 2c Second engagement member 3 Connector 4 Switching circuit 4a Transistor 4E Emitter 4C Collector 4B Base R1 Consumption resistance R2 Pull-up resistance V1, V2 Power line G1, G2 Ground line

Claims (4)

A main body electric circuit section and the cassette electric circuit are mounted on the main body of the image forming apparatus with a cassette electric circuit section, with respect to an image forming apparatus main body having a main body electric circuit section and capable of supplying a DC current. Part is in a connected state and power is supplied from the main body electric circuit part to the cassette electric circuit part, while in a detached state, the power supply state is interrupted, and even in the live state of the main body electric circuit part, A paper feed cassette that can be attached to and detached from the image forming apparatus main body,
The cassette electric circuit unit is a capacitor that receives electric power from the main body electric circuit unit and stores electric charges;
A switching transistor connected to the capacitor and performing a switching operation;
The switching transistor discharges the charge of the capacitor by disconnecting the main body electric circuit portion and the cassette electric circuit portion when the paper feeding cassette is detached from the image forming apparatus main body. Is switched so as to be secured in the cassette electric circuit section. A paper feed cassette that is detachably attached to an image forming apparatus main body that forms an image on paper, and capable of stacking paper for feeding to the image forming apparatus main body;
The paper feed cassette includes a cassette electric circuit unit,
The cassette electric circuit unit is connected to a main body electric circuit unit including a power source unit provided in the image forming apparatus main body through a connector, and the power source unit is in an active state. At some point, you get power
A switching circuit is connected to the capacitor included in the cassette electric circuit unit. The switching circuit includes a transistor. One electrode of the capacitor is connected to the emitter of the transistor, and the capacitor is connected to the collector via a consumption resistor. The other cassette electrode is connected, and the other electrode of the capacitor is connected to the base of the transistor via a pull-down resistor.   When the power supply line and the ground line of the switching circuit in the paper feed cassette are separated so that the connector is disconnected, the ground line is separated from the power supply line and disconnected. The paper feed cassette according to claim 2.   A first engaging member having electrical conductivity as a mechanical structure is connected to the ground line of the switching circuit, and a conductive material serving as a mechanical structure is connected to the ground line of the power supply unit. The first engagement member and the second engagement member are not connected after the two engagement members are connected and the sheet feeding cassette is detached from the image forming apparatus main body and the connector is disconnected. The paper feeding cassette according to claim 2, wherein the paper feeding cassette is in a connected state.

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