KR19980029916A - Paper quantity sensing device and method of image forming apparatus - Google Patents

Abstract

end. The technical field to which the invention described in the claims belongs

An apparatus and method for detecting the amount of paper loaded in a paper feed cassette in an image forming apparatus having an automatic paper feeder.

I. The technical problem to be solved by the invention

The paper running out condition is detected before the paper in the paper feed cassette runs out.

All. Summary of Solution of the Invention

The amount of paper loaded in the paper feed cassette is detected as one of sufficient, none, and low conditions.

la. Important uses of the invention

Used to detect the amount of paper in the paper feed cassette.

Description

Paper quantity sensing device and method of image forming apparatus

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an apparatus and method for sensing an amount of paper loaded in a paper feed cassette in an image forming apparatus having an automatic paper feeding apparatus.

Typically, an image forming apparatus such as a printer, copier, plain paper facsimile, multifunction printer, etc., is equipped with an automatic sheet feeder. The automatic document feeder is used to feed the paper loaded in the paper feed cassette into the inside of the device when printing or copying. If the paper runs out of paper in the paper cassette, printing or copying cannot be done or paper must be fed using the manual feeder. Accordingly, the image forming apparatus having the automatic paper feeder has been informed to the user by adopting a paper detecting device for detecting the presence or absence of paper in the paper feed cassette, and displaying a paper supply request status when it is detected that there is no paper in the paper feed cassette.

However, the paper sensor as described above could only detect the presence or absence of paper in the paper feed cassette, but did not know the extent of the paper amount. That is, as long as even one sheet of paper remains in the paper cassette, it is displayed as normal, and even if only one sheet or a very small amount of paper remains in the paper cassette, the user could not know this in advance unless the user checks the paper cassette.

Accordingly, in the past, when printing a large number of documents, one or a few sheets are printed and the paper is not found. Therefore, the printing or copying or facsimile reception stops printing, prepares paper, and loads the paper in the cassette. Particularly, in case of urgent printing or copying, there is a problem that causes work interruption due to time delay due to paper loading during printing. In addition, if a fax is received in the absence of the user due to leaving the office with only a small amount of paper remaining, and a document is received that exceeds the memory capacity after the remaining amount of paper is consumed, the sender may not be able to transmit or information may be lost. There was a problem that the delivery is not made correctly.

Accordingly, an object of the present invention is to provide a paper amount detecting device capable of detecting a small amount of paper in advance before all the paper in the paper feed cassette is exhausted.

Another object of the present invention is to provide a paper amount detecting device capable of informing a user by detecting a small amount of paper in a paper feed cassette.

Still another object of the present invention is to provide a paper amount sensing method capable of controlling the operation of the image forming apparatus by detecting a small amount of paper in the paper feed cassette.

1 is a block diagram of a paper detection apparatus according to an embodiment of the present invention;

2A to 2C are operation state diagrams of the sensor lever of FIG. 1 according to the change in the amount of paper;

3 is a circuit diagram of an image forming apparatus according to an embodiment of the present invention;

4 is a state diagram of an output change of the sensor circuit of FIG. 3 according to a change in paper amount;

5 is a control flowchart according to an embodiment of the present invention.

The paper amount sensing device of the present invention for achieving the above objects comprises a sensor circuit having an optical sensor composed of a light emitting portion and a light receiving portion opposed to each other and generating a sensing voltage value corresponding to the amount of light received by the light receiving portion, and from a rotating shaft. The first and second movable parts extend in different directions, and the first movable parts are installed to be in contact with the paper loaded in the paper cassette, and rotate according to the amount of paper. And a sensor lever that moves between the separation position when there is enough paper and the blocking position when there is no paper, and the control unit that senses the amount of paper in the paper cassette as one of sufficient, none, and low from the detected voltage value. It features.

And the paper amount detection method of the present invention for achieving the above object is characterized by warning the user when the paper amount is small by checking the paper amount in the paper feed cassette before starting each print.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description and the annexed drawings, like elements are denoted by like reference numerals wherever possible. In addition, many specific details, such as specific device or component structures, circuits, or process flows, are shown to provide a more general understanding of the invention. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And a detailed description of known functions and configurations that may obscure the subject matter of the present invention will be omitted.

1 is a perspective view showing a configuration of a paper detecting apparatus according to an embodiment of the present invention, which is composed of an optical sensor 100 and a sensor lever 106. 1 is configured to detect a case where there is only a small amount of paper, unlike the conventional paper sensing device only detects the presence or absence of paper in the paper feed cassette.

2A to 2C show an operation state of the sensor lever 106 of FIG. 1 according to the change in the amount of paper in the paper feed cassette 200. FIG. 2A shows a state where the paper 206 is sufficiently loaded in the paper feed cassette 200, that is, the paper sufficient state. 2B shows a state in which only a small amount of paper 206 is loaded in the paper feed cassette 200, that is, a paper low state. 2C shows a state where no paper 206 is present in the paper feed cassette 200, that is, no paper state.

1 and 2A to 2C, a paper sensing apparatus according to an embodiment of the present invention will be described. First, the optical sensor 100 is a conventional transmissive optical sensor having a light emitting unit 102 and a light receiving unit 104, the sensor lever 106 is the first, elongated at a predetermined angle in different directions from the rotating shaft 112, It has a second movable part (108, 110). The first movable part 108 is installed to be in contact with the paper 206 to be loaded in the paper feed cassette 200 and rotates about the rotating shaft 112 according to the paper amount. As the first movable part 108 rotates as described above, the second movable part 110 completely separates the position of the optical sensor 100 between the feet and the light-receiving parts 102 and 104. Move.

The paper 206 is loaded on a knock up plate 202 installed in a conventional paper cassette 200 used for sheet feeding in an image forming apparatus, and the knock up plate 202 is lifted up when feeding. The paper 206 is supported. In this case, the knockup plate 202 is typically lifted by a compression spring (not shown) installed between the bottom surface of the paper feed cassette 200 and the knockup plate. As a result, the uppermost sheet of paper 206 is brought into close contact with the surface of the pickup roller (not shown), and is picked up by the pickup roller and fed into the image forming apparatus one by one. The knockup plate 202 then has an opening 204 formed in the defined position. The opening 204 is typically formed in a slit shape coinciding with the feeding direction.

The sensor lever 106 is spaced apart upwards by a predetermined distance with respect to the knock-up plate 12 surface of the paper feeding cassette 200, and is rotatably installed on the rotating shaft 112 installed perpendicular to the paper feeding direction. In this case, the first movable part 108 of the sensor lever 106 is installed to face the opening 204 of the knockup plate 202. Then, the first movable part 108 of the sensor lever 106 is changed in position according to the presence or absence of paper and the amount of paper on the knock-up plate 202 surface, and accordingly, the sensor lever 106 is rotated accordingly. The position changes.

That is, the first movable part 108 of the sensor lever 106 is in contact with the uppermost surface of the paper when the paper 206 is stacked on the knockup plate 202 as shown in FIG. 2A or 2B. The position changes. In contrast, when the paper 206 is not stacked on the knockup plate 202, the first movable part 108 is inserted into the opening 204 of the knockup plate 202 as shown in FIG. 2C. Therefore, the second movable unit 110 moves between the position when the sheet 206 in the paper feed cassette 200 is full and the position when there is no. If the paper 206 is sufficiently loaded in the paper feed cassette 200 as shown in FIG. 2A, the second movable part 110 of the sensor lever 106 may completely separate the feet and the light receiving parts 102 and 104 of the optical sensor 100. Escape On the other hand, as shown in FIG. 2B, when only a small amount of paper 206 is not loaded in the paper feed cassette 200, the second movable part 110 of the sensor lever 106 is the foot and light receiving parts 102 and 104 of the optical sensor 100. Block only part of your liver. When the paper 206 is not in the paper cassette 200 as shown in FIG. 2C, the second movable part 110 of the sensor lever 106 completely blocks the feet and the light receiving parts 102 and 104 of the optical sensor 100. The present invention is to detect not only the presence or absence of paper in the paper feed cassette 200 but also the paper low state from these three states.

3 is a block diagram of the image forming apparatus which detects the amount of paper by using the sheet sensing device. The controller 300 controls the print unit 306 according to various commands input from a host computer (not shown) such as a personal computer (PC) or an operation panel 302 to print according to data received from the host computer. Performs various functions including At this time, the controller 300 performs an operation according to the flowchart of FIG. 5 to detect the amount of paper loaded in the paper feed cassette 200 from the sensing voltage value VT output from the sensor circuit 304. The operation panel 302 includes a plurality of keys for inputting various commands, and a display device for displaying various types of information under the control of the controller 300. The print unit 306 includes various mechanisms for conveying and printing paper and performs printing under the control of the controller 300. The buzzer driver 308 drives the buzzer 310 under the control of the controller 300.

Referring to the sensor circuit 304, the light emitting diode LED corresponding to the light emitting unit 102 of the optical sensor 100 is connected in a forward direction between the power supply voltage Vcc and the ground through the resistor R1 and the light receiving unit 104. The phototransistor PT, which is a light receiving element corresponding to the Rx, is connected between the power supply voltage Vcc and the ground through the resistor R2. In this case, since the light emitting diode LED and the photo transistor PT correspond to the light emitting unit 102 and the light receiving unit 104 of FIGS. 1 and 2, the signal having the voltage level corresponding to the paper amount is output from the photo transistor PT. Is generated and applied to an analog-to-digital converter (ADC) 312. The ADC 312 converts a signal input from the photo transistor PT into digital data having a value corresponding to the voltage level thereof, and outputs it to the controller 300 as a sensed voltage value VT.

The sensing voltage value VT output from the sensor circuit 304 is changed according to the amount of paper in the paper feed cassette 200, which is shown as FIG. FIG. 4 illustrates the continuous detection voltage value VT corresponding to the second movable part 110 of the sensor lever 106 from the state in which the feet and the light receiving parts 102 and 104 of the optical sensor 100 are completely shut off. It is a change.

If the paper 206 is sufficiently loaded in the paper feed cassette 200 as shown in FIG. 2A, the second movable part 110 of the sensor lever 106 may completely separate the feet and the light receiving parts 102 and 104 of the optical sensor 100. Escape Accordingly, the photo transistor PT is completely 'on' by the light received from the light emitting diode LED, so that the voltage level of the signal output from the photo transistor PT becomes 0V as shown in FIG. 4. In this state, if the paper 206 in the paper feed cassette 200 is gradually consumed according to the continuous printing, the second movable part 110 is separated between the feet and the light receiving parts 102 and 104 of the optical sensor 100 as shown in FIG. 2B. Gradually start blocking. Then, the amount of light received by the photo transistor PT is gradually reduced, so that the voltage level of the signal output from the photo transistor PT is gradually increased as shown in FIG. 4. Since the paper 206 is continuously consumed and there is no paper 206 in the paper feeding cassette 200 as shown in FIG. 2C, the second movable part 110 of the sensor lever 106 is moved by the feet of the optical sensor 100. It completely blocks between the light receiving units 102 and 104. Then, since the photo transistor PT does not receive any light at all, the photo transistor PT is turned off, and thus the voltage level of the signal output from the photo transistor PT becomes the power supply voltage Vcc as shown in FIG. 4.

According to the present invention, the second movable part 110 of the sensor lever 106 defines a predetermined range of the paper less state among the ranges partially blocking the feet and the light receiving parts 102 and 104 of the optical sensor 100. That is, in FIG. 4, a blocking range between T1, which is a time point at which the second movable part 110 of the sensor lever 106 starts to cut off the feet and light receiving parts 102 and 104 of the optical sensor 100, is completely blocked. A certain range is defined as paper low state. In consideration of the amount of documents printed at one time on the average, the predetermined range is preferably set in a state in which one to twenty sheets of paper 206 are stacked in the paper feeding cassette 200, for example. At this time, the sheet sensing device is provided such that the sensing voltage value VT is, for example, 3V to 4.5V. In this way, the first and second reference values respectively set to correspond to the minimum and maximum blocking positions of the blocking range between the light emitting and receiving sections 102 and 104, which are defined as the paper low state, are denoted by V1 and V2, respectively.

5 is a flowchart of the controller 300 for detecting and controlling the paper amount according to the embodiment of the present invention in the above state. The operation according to the flowchart of FIG. 5 is performed by the controller 300 every print. Before starting each print, the controller 300 checks the paper amount in steps 500 and 504. At this time, the controller 300 reads the sensing voltage value VT applied from the sensor circuit 304 and compares it with the first and second reference values V1 and V2 set as described above. If the sensed voltage value VT is smaller than the first reference value, the controller 300 detects that the paper is in a sufficient state and performs normal printing in step 506 and ends.

On the other hand, when the sensing voltage value VT is between the first and second reference values V1 and V2 in steps 500 and 504, the controller 300 detects that the paper is low, and in step 508, one sheet of paper is detected. After printing normally, perform steps 512 to 518 to warn the user. In this case, the controller 300 displays a paper supply request state through the display device on the operation panel 302 in step 512. The display device displays a paper supply request state by, for example, installing a light emitting diode on the operation panel 302 and turning it on. The controller 300 generates an alarm sound by turning on the buzzer 310 through the buzzer driver 308 for a predetermined time in steps 514 to 518. Accordingly, the user knows that the paper 206 in the paper feed cassette 200 is not enough, so that the paper 206 can be replenished before the paper 206 is completely exhausted.

When the detected voltage value VT is greater than the first reference value V1 in steps 500 and 504, the controller 300 detects a paper free state and stops printing in step 510. Step 518 warns the user. Accordingly, when the paper 206 in the paper feed cassette 200 is completely exhausted, the user can replenish the paper 206 by notifying the user of the paper without further printing.

Therefore, it is possible not only to run out of paper, but also to replenish the paper in advance by warning the user before the paper in the paper cassette is completely exhausted.

As described above, the present invention can warn the user by detecting the amount of paper in advance before all the paper in the paper cassette is exhausted. Therefore, the printing must be stopped and the paper must be prepared and loaded in the paper cassette during printing or copying or fax reception. Inconvenience and consequent time delay can be prevented. In addition, it is possible to prevent the information transmission from being made impossible due to the lack of paper when the fax is received while the user is absent or the data transmission due to the loss of data.

Claims (11)

An image forming apparatus having an automatic paper feeder for feeding paper loaded in a paper cassette, A sensor circuit having an optical sensor composed of a light emitting unit and a light receiving unit opposed to each other and generating a sensing voltage value corresponding to the amount of light received by the light receiving unit; And a first movable part extending in different directions from the rotating shaft, wherein the first movable part is installed to be in contact with the paper loaded in the paper feed cassette, and rotates according to the amount of paper. A sensor lever that moves between the foot and the light-receiving section between the separation position when there is enough paper and the blocking position when there is no paper, And a control unit for detecting the amount of paper in the paper feed cassette as one of sufficient, none, and low from the sensed voltage value. According to claim 1, wherein the control unit, the first and second reference value and the sensing voltage set to correspond to the minimum and maximum cut-off position of the prescribed range of the blocking range between the light-receiving portion and the light receiving unit by the second movable unit, respectively Paper amount sensing device, characterized in that for detecting the paper amount by comparing the value. The first and second reference values of claim 2, wherein the control unit is configured to enter the paper sufficient state when the detected voltage value is smaller than the first reference value, and to set the paper sufficient state when the detection voltage value is larger than the second reference value. When the paper amount sensing device, characterized in that for detecting each of the paper low state. The apparatus of claim 3, wherein the control unit displays a paper supply request state through a display device and generates a warning sound through the buzzer when the paper low state is detected. . The paper amount sensing device according to claim 4, wherein the display device is a light emitting diode lamp provided on an operation panel. 6. The paper amount sensing device according to claim 5, wherein the paperless state corresponds to a state in which the second movable part is completely out of the feet and the light receiving parts. The paper amount sensing device according to claim 6, wherein the paper low state is set so that 1 to 20 sheets of paper are stacked in the paper feed cassette. A paper amount sensing method of an image forming apparatus, comprising: means for detecting the amount of paper loaded in a paper feed cassette as one of sufficient, none, and low conditions, A method of detecting a paper quantity, characterized in that for inspecting the amount of paper in the paper feed cassette before starting each print and alerting the user when the paper amount is small. A paper amount sensing method of an image forming apparatus, comprising: means for detecting the amount of paper loaded in a paper feed cassette as one of sufficient, none, and low conditions, Checking the paper amount before starting each print, If the paper amount is sufficient, the process of normal printing; If the amount of paper is low, the process of warning the user after printing one sheet, The paper amount sensing method characterized in that the process of stopping the printing and the warning if there is no paper. 10. The paper amount sensing method according to claim 9, wherein the warning indicates a paper supply request state through a display device on an operation panel and generates a warning sound through a buzzer for a predetermined time. 11. The paper amount sensing method according to claim 10, wherein the paper low state is set so that 1 to 20 sheets of paper are stacked in the paper feed cassette.