KR20070000730A - Image forming apparatus and control method thereof - Google Patents

Abstract

An image forming apparatus and a control method thereof are provided to scan a test pattern at the image correction mode and monitor the skew of a printing medium at the printing mode. An image forming member(120) prints the image on the printing medium at the printing mode and forms a test pattern at an image correction mode. The image forming member includes color containing members(121,122,123,124). Toner images are formed on the circumferential surfaces of the color containing members. The toner images are transferred on the printing medium by a transfer belt(B) so that the print image is formed. The printing medium is discharged to a paper discharge stand(111) through a paper discharge opening(115) via a fusing unit(170) and a paper discharge roller(160). An optical sensor unit(S1) is controlled by a control member(180) and used for monitoring skew of the printing medium.

Description

Image forming apparatus and control method of the image forming apparatus

1 is a view showing an image forming apparatus according to a preferred embodiment of the present invention;

2 is a view showing an operating state of the image forming apparatus according to the preferred embodiment of the present invention, in which the image correction mode is executed;

3 is a view showing an operating state of the image forming apparatus according to the preferred embodiment of the present invention in which the print mode is executed;

4 is a flowchart illustrating the operation of the image forming apparatus according to the preferred embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: image forming apparatus 120: image forming unit

121,122,123,124: Consultation delay 131,132,133,134: Toner supply unit

141,142,143,144: Transfer roller B: Transfer belt

S1: optical sensor unit S2: first sensor

S3: second sensor T: test pattern

P: Print Media

The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus capable of driving in a print mode and an image correction mode, and a control method thereof.

Typically, the image forming apparatus is for printing an image corresponding to the input image data on a print medium, and includes an image forming unit, a paper feeder, and a print medium transporting device.

In such an image forming apparatus, the quality of a printed image may be degraded due to various causes. Such deterioration of the print image is most often caused by a driving error of the image forming unit or by a printing error in the image forming unit not being properly supplied to the image forming unit by a driving error of the paper feeder and the transfer device. Accordingly, the conventional image forming apparatus is configured to perform various image correction operations to correct the driving error, and to monitor the correct transfer of the print medium when printing the image.

The image correction operation is performed by reading the test pattern formed by the image forming unit before the actual print job starts, and then updating the settings related to the drive control of each drive unit to correspond to the read result. To this end, the image forming apparatus includes an optical sensor unit for reading the test pattern.

On the other hand, the proper transport monitoring of the print medium is performed by monitoring a so-called Jam phenomenon, or a so-called skew phenomenon in which the print medium is obliquely entered into the image forming unit, on the print medium transport path. Among them, the skew monitoring of the printing medium is generally performed through an optical sensor unit installed upstream or downstream of the image forming unit along the conveying direction of the printing medium.

However, according to the conventional image forming apparatus configured as described above, while there is an advantage that the quality deterioration of the print image can be suppressed through image correction and skew detection of the print medium, the optical sensor unit and printing for image correction are Since the optical sensor unit for the skew detection of the medium must be provided separately, a problem arises in that the manufacturing cost of the image forming apparatus increases and the drive control is complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object thereof is to provide an image forming apparatus and a method of controlling the image forming apparatus, which reduce manufacturing costs and simplify driving control.

An image forming apparatus according to the present invention for achieving the above object comprises: an image forming unit for printing an image on a print medium when the print mode is executed, and forming a test pattern when the image correction mode is executed; At least one optical sensor unit disposed downstream of the image forming unit along a conveying direction of the print medium, and configured to read the test pattern when the image correction mode is executed; And processing the signal output from the optical sensor unit when the image correction mode is executed to update the setting value for driving control of the image forming unit, and the printing discharged while the image is printed from the image forming unit when the print mode is executed. And a controller for controlling the at least one optical sensor unit to detect skew of a medium.

In this case, the control method of the image forming apparatus according to the preferred embodiment of the present invention, after confirming the execution of any one of the print mode and the image correction mode, using the optical sensor unit at the time of executing the print mode. Preferably, the image forming unit detects the amount of skew of the print medium discharged after the image is printed, and reads the test pattern using the optical sensor unit when the image correction mode is executed.

According to this, a single optical sensor unit can be used both in the execution of the image correction mode and in the execution of the print mode, thereby providing an image forming apparatus having a simple structure and easy driving control.

On the other hand, according to a preferred embodiment of the present invention, the optical sensor unit includes a plurality of optical sensors are installed in pairs to correspond to each of the front edges of the front end of the print medium in the transport direction of the print medium desirable. According to this, even the skew amount of the printing medium can be detected.

According to this, execution of the print mode may include: stopping image printing being performed on the print medium and discharging the print medium when the skew amount of the print medium detected by the optical sensor unit is abnormal; And reprinting the image where printing has been stopped on a new print medium.

Image printing to the print medium is executed after the input image information is stored. If the skew amount of the print medium is normal, the image information is deleted after the printing of the image in progress is completed, and the skew amount of the print medium is abnormal. In the case where is more preferably deleted after the reprint is normally completed.

Accordingly, when the print image is abnormally output due to the skew of the print medium, the user can automatically reprint the image without any user's manipulation, thereby providing convenience to the user.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 illustrates an image forming apparatus capable of printing a multicolor image as an example of an image forming apparatus according to the present invention. Referring to this, the image forming apparatus 100 according to the present invention includes an image forming unit 120 and an optical sensor unit S1.

 The image forming unit 120 prints an image on the print medium P (see FIG. 3) in the print mode, and forms a test pattern T in the image calibration mode. The image forming unit 120 according to the present embodiment includes a counseling member 121, 122, 123, 124, toner supply parts 131, 132, 133, 134, transfer rollers 141, 142, 143, 144, and a transfer belt B. In the counseling members 121, 122, 123, and 124, a toner image formed of toner supplied for each color from the toner supply units 131, 132, 133, and 134 is formed on the outer circumferential surface thereof. The toner image is transferred to the print medium P which is transferred to the medium between the consultation bodies 121, 122, 123 and 124 and the transfer rollers 141, 142, 143 and 144 by the transfer belt B when the image forming apparatus 100 is executing the print mode. To form a printed image. The print medium P on which the print image is formed is discharged to the discharge tray 111 through the discharge port 115 via the fixing unit 170 and the discharge roller 160. On the other hand, the image forming unit 120 in this embodiment forms the image calibration test pattern T directly on the transfer belt B when the image correction mode is executed.

The optical sensor unit S1 is controlled by the controller 180 to be used for the image calibration operation when the image calibration mode is selected. In the case of the image forming apparatus 100 for printing a multi-color image as in the present embodiment, a color registration operation is performed as an example of the image calibration operation. The color registration operation is to suppress the deterioration of the print image caused by the toner image formed by the counseling members 121, 122, 123, and 124 not being accurately superimposed on the print medium. This color registration operation is started by forming a predetermined test pattern T on the transfer belt B, and then reading the test pattern T, as shown in FIG. Then, the color registration operation is finished by updating the setting relating to the drive time control of each drive unit for forming the toner image in accordance with the read result. Here, the optical sensor unit S1 is used for reading out the test pattern T. To this end, the optical sensor unit S1 in this embodiment is installed downstream of the consultation bodies 121, 122, 123, and 124 along the conveying direction of the print medium to enable reading of the test pattern T formed on the transfer belt B. desirable.

On the other hand, the optical sensor unit S1 is controlled by the controller 180 to be used to monitor the skew of the print medium when the print mode is selected. To this end, the optical sensor unit (S1) may be installed on the printing medium transport path upstream or downstream of the image forming unit 120 along the transport direction of the print medium (P), the optical sensor in the present embodiment The unit S1 is installed downstream of the image forming unit 120. According to this, the skew of the print medium P discharged from the consultation bodies 121, 122, 123, 124 and the transfer rollers 141, 142, 143, 144 and the transfer rollers 141, 142, 143, 144 can be monitored through the optical sensor unit S1, and the test pattern T when the image calibration mode is executed. ) Can also be read. For reference, the optical sensor unit S1 according to the present exemplary embodiment of the printing medium P of the image forming unit 120 may be connected to the second sensor S3 provided upstream of the image forming unit 120. Also detect jams. For reference, since the second sensor S3 may be configured in various forms such as an optical sensor and a contact sensor, a description thereof will be omitted here. On the other hand, the jam monitoring of the print medium (P) as described above, after the print medium (P) has passed through the second sensor (S3), the print medium (P) by the optical sensor unit (S1) within a predetermined time period. If the entrance is not detected, the image forming apparatus 100 may be configured to determine that the jam of the print medium P has occurred in the section between the second sensor S3 and the optical sensor S1.

On the other hand, the optical sensor unit (S1) in the present embodiment, as shown in Figures 2 and 3, the direction orthogonal to the traveling direction of the print medium (P) so as to correspond to both side edges of the front end of the print medium (P) A plurality of optical sensors are installed in pairs along the. According to this, as shown in Figure 3, the print medium (P) is inclined discharged by detecting that one edge enters the optical sensor unit (S1) earlier than the other edge to tilt the print medium (P) The print media P skew, which is a phenomenon of being transferred, can be detected. As described above, when the optical sensor unit S1 is configured to include a plurality of optical sensors paired with each other, the optical sensor unit S1 in this embodiment detects a skew of a simple print medium P. In addition to this, the amount of skew of the print medium P can be monitored. That is, as described above, when both edges of the print medium P are sequentially transferred, the skew amount of the print medium P may be inspected using the difference in entry time of each edge and the transfer speed of the preset print medium P. You can do it.

According to this, the image forming apparatus 100 according to the present exemplary embodiment may provide a user with convenience by performing a function of changing a printing method corresponding to the amount of skew of the print medium P. FIG. This will be described with reference to FIG. 4. First, when the print signal is input (S110), the image information to be printed is stored in units of pages (S120), and then the print media is picked up one by one to execute image printing (S130 and S30). When the printing of the image proceeds as described above, the optical sensor unit S1 detects the amount of skew of the print medium and outputs a signal corresponding thereto to the controller 180 (S150). In this case, the controller 180 compares the preset reference skew amount with the detected skew amount (S160). If it is determined that the detected skew amount is normal, the controller 180 proceeds to print the image being printed and ejects the print medium on which image printing is completed. In operation S170, the image information stored in step 120 is deleted, and then the printing operation is completed (S180, S50). Here, the discharge confirmation of the print medium P is detected by the first sensor S2 (see FIG. 1). Since the first sensor S2 may be configured in various forms such as an optical sensor and a contact sensor, a description thereof will be omitted. However, if it is determined that the detected skew amount is abnormal, the printing of the image proceeding to the skew-detected print medium is stopped and the print medium is discharged through the discharge port (S161). Thereafter, the new printing medium P is resupplied to the image forming unit, and then the process returns to step 150 while re-executing printing of the image from which printing was interrupted from the beginning.

According to the present invention described above, since the optical sensor unit can read the test pattern in the image calibration mode and monitor the skew of the print medium in the print mode, the image forming apparatus is simpler and easier to control than the conventional method. It can be provided.

And, since the optical sensor unit is installed in a form that can detect the skew amount of the print media, if it is determined that the image is not printed correctly on the print media due to the abnormal transport of the print media, no user intervention is required. Reprinting of the abnormally printed portion is automatically executed. Accordingly, the driving stop of the image forming apparatus due to the skew of the print medium can be avoided and the image printing speed can be improved, thereby providing convenience to the user.

In the above, the preferred embodiment for illustrating the principle of the present invention has been shown and described, but the present invention is not limited to the configuration and operation as shown and described. Rather, those skilled in the art will appreciate that changes and modifications can be made to the present invention without departing from the spirit and scope of the appended claims. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

Claims (5)

An image forming unit which prints an image on a print medium when the print mode is executed and forms a test pattern when the image correction mode is executed; An optical sensor unit installed downstream of the image forming unit along a conveying direction of the print medium, the optical sensor unit reading the test pattern when the image calibration mode is executed; And The print medium which processes the signal output from the optical sensor unit when the image correction mode is executed to update the setting value for driving control of the image forming unit, and the print medium which is discharged while the image is printed from the image forming unit when the print mode is executed. And a control unit controlling the at least one optical sensor unit to detect skew of the at least one optical sensor unit. The method of claim 1, The optical sensor unit includes a plurality of optical sensors installed in pairs to correspond to each of the front edges of the front end of the print medium in the transport direction of the print medium. An image forming unit for forming an image on the print medium when executing the print mode and improving a test pattern when executing the image correction mode, and an optical sensor unit installed downstream of the image forming unit along the conveying direction of the print medium. In the control method of the image forming apparatus, After confirming execution of any one of the print mode and the image calibration mode, when the print mode is executed, the amount of skew of the print medium discharged after the image is printed by the image forming unit is printed using the optical sensor unit. And detecting the test pattern using the optical sensor unit when the image calibration mode is executed. The method of claim 3, wherein the execution of the print mode, If the skew amount of the print medium detected by the optical sensor is abnormal, discontinuing image printing being performed on the print medium and discharging the print medium; And And reprinting the image where printing has been stopped onto a new print medium. The method of claim 4, wherein Image printing to the print medium is executed after the input image information is stored, And the image information is deleted after the printing of the ongoing image is completed when the skew amount of the print medium is normal, and is deleted after the reprinting is completed normally when the skew amount of the print medium is abnormal. .

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