KR100477692B1 - Method of detecting paper - Google Patents

Abstract

A paper detection method is disclosed. The disclosed paper detecting method includes determining whether the paper to be conveyed is detected by the paper detecting device, adjusting the counter when the paper is detected by the paper detecting device, and conveying the paper having an image formed on one surface by rotating the driving motor in reverse. Conveying along the path, determining whether the conveyed sheet is detected by the sheet detecting device, and adjusting the counter when the sheet is detected by the sheet detecting device.

Description

Method of detecting paper

The present invention relates to a paper detection method, and more particularly, to a paper detection method capable of detecting a jam generated even when an image is formed on both sides of the paper.

In general, an electrophotographic image forming apparatus such as a laser beam printer is an apparatus for receiving an image signal and transferring the image to a sheet in the form of a visible image. In the image forming process, the developing apparatus receives a digital image signal and attaches toner to an electrostatic latent image formed on the photosensitive medium to form a toner image. When such a toner image is transferred onto a sheet and fused, the image signal is fused to the sheet with a desired toner image.

In the paper used in the electrophotographic image forming apparatus, curl is generated, which is a phenomenon in which the paper is curled due to humidity and temperature, and jams are caught between the devices during the transfer or delivery process. The jam interferes with the smooth operation of the image forming apparatus and delays the work. Therefore, if a jam occurs due to the paper being transported, a jam detection device can be installed to check where the jam occurred in the transfer process so that the user can grasp the jam location and remove the jam smoothly. have.

1 is a partial side view schematically showing a configuration according to an example of a conventional electrophotographic image forming apparatus provided with a sheet detecting device.

Referring to FIG. 1, the paper P on which the toner image is transferred from the developing apparatus is transferred along the A path and subjected to heat and pressure while passing through the fixing nip of the pair of fixing rollers 110 installed to face each other. At this time, the toner image is fixed to the paper P by heat and pressure. The paper P on which the toner image is fixed is transferred between the discharge guide 140 and the housing 160 by a transfer guide 120 installed in the transfer path, and passes between the pair of discharge rollers 150 to the outside. Discharged. The transfer guide 120 is provided with a paper detection device 130 that is in contact with the paper to be transported to detect the jam of the paper.

If the paper P to be conveyed does not pass through the paper detection device 130 within a predetermined time or the paper P that has passed through the fixing roller 110 does not reach the paper detection device 130 within a predetermined time, The jam is detected in the user, so the user can know where the jam occurred on the paper.

Meanwhile, in order to form an image on both sides of the paper P, the paper P having an image formed on one surface thereof is moved along the A path and then fed by a driving device not shown in the drawing to follow the arrow B path. Will be conveyed accordingly. The feed guide 170 is installed in the path B to guide the paper P to be conveyed toward the developing apparatus. The paper P, to which the toner image is transferred to the rear surface again in the developing apparatus, passes through the fixing roller 110, and the toner image is fixed to the paper P. FIG. The paper P is then transported along the A path and discharged.

However, since the paper detection device 130 exists only on the A path, the paper detection device 130 can only detect the jam of the paper generated through the fixing device 110, and again develop the device along the B path to form an image on the back of the paper. There is a problem that can not detect the jam caused by the feed. Therefore, it is not easy for the user to know where the jam occurred on the B path. In order to overcome this problem, the paper detection apparatus may be separately installed on the B path, but in this case, there is a problem of additional cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a paper detection method which can grasp a jam occurrence position even when an image is formed on both sides of a paper using one paper detection device.

In order to achieve the above object, the inventors of the paper detection method

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According to another aspect of the invention, a) determining whether the paper to be conveyed is detected by the paper detection device, b) adjusting the counter if the paper is detected by the paper detection device, c) driving motor Conveying the paper having an image formed on one surface along the conveyance path by rotating the sheet; d) determining whether the conveyed paper is detected by the paper detecting device; and e) if the paper is detected by the paper detecting device. The paper can be detected even when images are formed on both sides of the paper as well as the counter, including adjusting the counter. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. .

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FIG. 2 is a block diagram showing a schematic configuration of an image forming apparatus to which a paper detection apparatus according to the present invention is applied, and FIG. 3 is a view showing a discharge operation and a conveying operation of the paper shown in FIG.

2, the electrophotographic image forming apparatus 200 includes a pickup roller 220, a transfer roller 230, a developing apparatus 240, a transfer apparatus 250, a fixing apparatus 260, and a discharge roller 280. ).

The pickup roller 220 picks up the sheet of paper P loaded on the sheet feeding plate 210 sheet by sheet. The paper feeding plate 210 is elastically biased upward by a spring 211, so that the paper P is pushed toward the pickup roller 220, so that the pickup roller 220 easily picks up the paper P. You will be able to pick up.

The conveying roller 230 is installed on the conveying path of the paper P to convey the paper P picked up by the pick-up roller 220. A plurality of feed rollers 230 may be installed.

The developing device 240 receives an image signal to form an electrostatic latent image on the photosensitive medium 242 by the laser scanning unit 243, and from the plurality of ink cartridges 241 installed adjacent to the photosensitive medium 242. Toner is supplied to form a toner image on the electrostatic latent image.

The transfer device 250 is supported by the plurality of support rollers 254 and the transfer backup roller 252 and rotated in the shape of a closed curve while transferring the toner image formed on the photosensitive medium 242 onto the paper P. The intermediate part is installed to face the transfer backup roller 252 with the belt 253 and the paper P therebetween so that the toner image transferred to the intermediate transfer belt 253 is transferred to the paper P. The transfer belt 253 is provided with a transfer roller 251 to closely adhere toward the transfer backup roller 252.

The fixing device 260 is installed to face each other with the paper P to be conveyed therebetween to heat the toner image transferred to the paper P and simultaneously pressurize the toner image to fuse the toner image to the paper P. A plurality of fixing rollers 261 and 262 are provided.

The discharge roller 280 discharges the paper P, which has passed through the fixing device 260, to the discharge table 281. A discharge guide 272 is provided adjacent to the discharge roller 280 to guide the paper P toward the discharge roller 280.

In the paper P conveyance path between the fixing device 260 and the discharge roller 280, a conveyance guide 271 for guiding the paper P from the fixing device 260 toward the discharge roller 280 is provided. It is provided along the axial direction of the fixing device 260. Accordingly, the paper P passing through the fixing device 260 is discharged through the discharge roller 280 after passing through the discharge guide 270 and accumulated in the discharge tray 281.

It is installed adjacent to the transfer guide 271 and guides the paper P, which has a toner image formed on its front surface, to the developing device 240 by a separate driving device in order to form a toner image on the back surface of the paper P. The conveyance guide 290 is provided.

Referring to FIG. 3, when printing only on one side of the paper P, the paper P is moved along the C path and discharged. On the other hand, when printed on the back side of the paper P, the paper P conveyed along the C path is conveyed along the D path by the driving device again and passes through the developing device 240 to form a toner image. It is transported along the C path and discharged.

At the position where the C path and the D path, which are transfer paths of the paper P, overlap with each other, a paper detecting device 300 which contacts the paper P and detects the paper P, is located above the image forming apparatus 200. It is provided in the housing 291.

The paper detection device 300 not only detects the paper P by contacting the paper P conveyed along the C path, but also detects the paper P by contacting the paper P conveyed along the D path. can do. Reference numeral 350 denotes a feed sensor. The feed sensor 350 is for detecting the paper P to be transferred, and a plurality of feed sensors 350 may be installed on the paper transfer path as necessary.

4 is a perspective view showing a first embodiment of a paper detection apparatus according to the present invention.

Referring to FIG. 4, the paper detection device 300 is rotatably installed on the support 310 and the support 310, and the sensor unit 321 contacting the paper P transferred to one side thereof and the other. The rotating part 320 provided with the contact part 322 in the side part is provided. Adjacent to the contact portion 322, a switch portion 330 composed of a first switch 331 and a second switch 332 that is in contact with the contact portion 322 on or off is provided.

When the paper P to be conveyed is moved while being in contact with the sensor unit 321, the pivoting unit 320 is supported by the support 310 in the direction in which the paper P is conveyed and is rotated.

When the paper P is conveyed in the C direction, the contact part 322 contacts the first switch 331 to turn on the first switch 331. On the contrary, when the paper P is conveyed in the D direction, the contact portion 322 is in contact with the second switch 332 to turn on the second switch 332. Therefore, when the paper P is conveyed or conveyed, the paper P can be detected. At this time, the rotating part 320 is preferably configured to return to its original state by its own weight when the paper P does not come into contact with the paper P after passing through the sensor part 321.

5 is a perspective view showing a second embodiment of a paper detection apparatus according to the present invention.

Referring to FIG. 5, the paper detecting device 400 is rotatably installed on the support 410 and the support 410, and the sensor unit 421 contacting the paper P transferred to one side thereof and the other. The rotating part 420 provided with the blocking part 422 in the side part is provided.

The support 410 located on both sides of the pivoting part 420 is opposed to the irradiation part 430 and the irradiation part 430 including a first irradiation part 431 and a second irradiation part 432 for irradiating light. The light receiving unit 440 includes a first light receiving unit 441 and a second light receiving unit 442 that are installed to receive light emitted from the first and second irradiation units 431 and 432, respectively.

The blocking unit 422 serves to block light emitted from the irradiating unit 430. The irradiation unit 430 continuously radiates the light to the light receiving unit 440 when the paper detection device 400 is operated.

When the paper P to be conveyed is in contact with the sensor unit 421, the pivoting part 420 is supported by the support 410 in the direction in which the paper P is conveyed and is rotated.

When the paper P is transferred in the C direction, the blocking unit 422 blocks the light irradiated from the first irradiation unit 431. On the contrary, when the paper P is conveyed in the D direction, the blocking unit 422 blocks the light emitted from the second irradiating unit 432. Therefore, when the paper P is conveyed or conveyed, the paper P can be detected. At this time, the rotation unit 420 is preferably configured to return to its original state by its own weight when the paper P passes the sensor unit 421.

6A and 6B are flowcharts showing a paper detection method according to the present invention.

2, 6A and 6B, when the pickup roller 220 picks up the paper P loaded on the paper feed plate 210 and is transported by the feed roller 230, the photosensitive medium ( The toner image formed on 242 is transferred to the intermediate transfer belt 253 and then transferred to the paper P by the transfer roller 251. The paper P on which the toner image is transferred is passed through the fixing device 260, and the toner image is fused to the paper P.

When the paper P passes through the fixing device 260, the control unit (not shown) detects the paper P and starts the counter by operating the entry counter (S601). It is determined whether the paper P conveyed to the paper detection apparatus 300 is detected (S602). When it is determined that the paper P is detected by the paper detector 300, the entry counter is initialized. That is, the entry counter is reset to zero. At the same time, counting is started by operating the discharge counter (S603).

On the other hand, when the paper P is not detected by the paper detection apparatus 300, the entry counter is continuously operated to measure the count value. The measured count value is compared with the preset value set in operation S606, and when the measured count value exceeds the set value, a jam occurrence message is output (S607). The set value is set in advance by measuring the time that the paper P reaches the paper detection device 300 through the fixing device 260. Therefore, the value measured by the entry counter larger than the set value indicates that the paper P is jammed in the path between the fixing device 260 and the paper detecting device 300.

After the step S603, it is determined whether the paper P has passed the paper detecting apparatus 300 (S604). If the paper P does not pass through the paper detecting apparatus 300, the discharge counter is continuously operated to measure the count value. The measured count value is compared with the preset value set in operation S608, and when the measured count value exceeds the set value, a jam occurrence message is output (S607). If the paper P has passed through the paper detection device 300, it is determined whether both sides of the paper P are printed (S605). If both sides of the paper P have been printed, the paper detecting operation is terminated and discharged to the discharge table 281 by the discharge roller 280.

If both sides of the paper P are not printed, the discharge counter is initialized (S609). In other words, the emission counter is reset to zero. In order to convey the paper P back to the transfer device 250 and to form an image on the rear surface thereof, the driving motor is rotated in reverse (S610). The discharge counter is counted to count the time for transporting the conveyed paper P (S611).

It is determined whether the paper P is detected by the paper detecting apparatus 300 (S612). When it is determined that the paper P is detected by the paper detector 300, the discharge counter is initialized. In other words, the emission counter is reset and the coefficient value measured up to this point is zero. Then, the counting is started by operating the entry counter (S613). On the other hand, when the paper P is not detected by the paper detecting apparatus 300, the discharge counter is continuously operated to measure the count value. When the measured count value exceeds the set value by comparing the measured count value with a preset setting value (S615), a jam occurrence message is output (S616).

After the step S613, it is determined whether the paper P has passed the paper detecting apparatus 300 (S614). If the sheet P does not pass through the sheet detecting apparatus 300, the entry counter is continuously operated to measure the count value. When the measured count value exceeds the set value by comparing the measured count value with a preset setting value (S617), a jam occurrence message is output (S616). If the paper P has passed the paper detecting apparatus 300, the paper detecting operation is terminated.

As described above, the paper detection method according to the present invention can detect the paper not only when the image is printed and transported on only one side by using a single paper detection device but also when the image is printed and transported on the back side thereof. Quick and accurate location of jams can be identified and cost can be saved.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a view schematically showing a configuration according to an example of a conventional electrophotographic image forming apparatus equipped with a sheet detecting apparatus;

2 is a configuration diagram showing a schematic configuration of an image forming apparatus to which a paper detection apparatus according to the present invention is applied;

3 is a view showing a discharge operation and a conveying operation of the paper shown in FIG. 2;

4 is a perspective view showing a first embodiment of a paper detecting apparatus according to the present invention;

5 is a perspective view showing a second embodiment of a paper detection apparatus according to the present invention;

6A and 6B are flowcharts showing a paper detection method according to the present invention.

<Description of the symbols for the main parts of the drawings>

300,400 ... paper detection device 310,410 ... support

320,420 ... Rotating part 321,421 ... Sensor part

322 Contact point 422 Breaking point

330 ... switch section 430 ... irradiation section

440 ... Receiver

Claims (11)

delete delete a) determining whether the paper to be conveyed is detected by the paper detector; b) adjusting the counter when the paper is detected by the paper detecting device; c) rotating the driving motor to convey the paper having an image formed on one surface along the conveying path; d) determining whether the paper to be conveyed is detected by the paper detection device; e) adjusting a counter if a sheet is detected by the sheet detecting device, A paper detection method that can detect paper even when images are formed on both sides as well as on one side of the paper. The method of claim 3, wherein Step b) is a paper detection method comprising the steps of initializing the entry counter, the operation of the discharge counter when the paper to be conveyed is detected. The method of claim 4, wherein If the paper conveyed in step b) is not detected Counting by continuously operating the entry counter, And comparing the counted value in the counting step with a value already set. The method of claim 4, wherein And displaying a jam occurrence message if the counted value is greater than a set value in the comparing step. The method of claim 3, wherein And between step b) and step c), further comprising determining whether printing is also performed on the back side of the paper. The method of claim 3, wherein The step d) is a paper detection method comprising the steps of initializing the discharge counter and operating the entry counter when the conveyed paper is detected. The method of claim 8, If the paper conveyed in step d) is not detected Counting by continuously operating the discharge counter, And comparing the counted value in the counting step with a value already set. The method of claim 8, And displaying a jam generation message when the counted value is larger than a set value in the comparing step. The method of claim 3, wherein The paper detection device is characterized in that the paper detection path is installed at a position where the image delivery path is printed on only one side of the paper and the conveyance path of the paper being conveyed so as to print the image on both sides of the paper. Way.