KR20000065854A - Method for detecting of paper skew in a printer - Google Patents

Abstract

PURPOSE: A method for sensing paper skew of a printer is provided to prevent paper jam caused by skew of a paper and prevent printing error that data is printed in the tilted state. CONSTITUTION: A method for sensing paper skew of a printer including at least two or more paper sensing sensors and connected with a computer for performing a print operation by receiving document data prepared in an application program of the computer includes the steps of picking up a paper if receiving a printing command, and transferring the paper following a paper transfer channel; respectively detecting transfer point information of the paper sensed in the two or more printing sensors(S1); determining the skew of the paper according to the detected transfer point information(S2); discontinuing printing operation if the paper is determined as skew state; and performing a normal printing operation if the paper is determined as non-skew state(S3).

Description

How to detect paper skew in printer {METHOD FOR DETECTING OF PAPER SKEW IN A PRINTER}

The present invention relates to a paper skew detection method of a printer, and more particularly, to a paper skew detection method of a printer to detect the skew occurrence of the paper by detecting the paper fed using two paper detection sensors. .

To this end, the present invention detects the detection time of the paper detected by the two paper detection sensors, determines whether the paper is normally fed according to the detected time difference, and if the paper is fed in a crooked state, the feeding operation of the paper Stops and reverse feeds to remove the paper, thereby preventing printing errors due to paper skew.

A representative printer of an office automation (OA) device is a device that prints document data and image data created on a computer in connection with a computer. The printer stacks a plurality of sheets of paper and feeds the sheets one by one according to a user's printing command to provide them to the printing area of the printer, thereby enabling continuous printing.

There are three types of paper jams that can occur when paper is provided to the printing area in the printer and the printing process is finished and discharged.

First, when a paper jam occurs before the paper loaded in the cassette reaches the printer's print area (JAM0).

Second, when the paper reaches the print area and a paper jam occurs while the print job is being performed (JAM1).

Third, a paper jam occurs before the paper for which the print job is completed reaches the output tray (JAM2).

There are many reasons for a paper jam. For example, when the paper is in a wet state or in a bad state, when the feeding roller and the pickup roller are in an abnormal state, and the paper is fed in a skewed state.

In a typical printer, at the moment when the paper supplied from the cassette enters the main body of the printer, it is determined whether the paper jam (Jam0) has occurred by checking whether the paper has entered, and the printing position is determined by checking the position of the paper leading edge.

Here, when the paper is fed in a skewed state due to an abnormality in the pickup roller or the feeding roller or other causes, the printer itself cannot detect this. As a result, the printer prints the print data in a skewed state on the paper or a paper jam occurs in the printer.

However, according to such a conventional printer, the following problems occur.

First, since there is no method of detecting that the paper is fed in a skewed state, the skew state of the paper cannot be detected in advance, resulting in poor printing. That is, the outer periphery of the paper and the printed contents are misaligned or distorted, resulting in a loss of value as a printed matter and deterioration in print quality.

Second, the paper jammed in the severely skewed state does not pass the normal paper feed path smoothly, causing a paper jam, and the jammed paper cannot be detected by the sensor differently from the fed or discharged state. Since the area is the same, the printer continues to perform the printing operation, and serious abnormalities (such as damage to the machine and removal of paper jams) occur in the printer.

Accordingly, the present invention is to solve such problems, an object of the present invention to detect the skew state of the paper supplied in the printing area by using the two paper sensor, thereby preventing printing defects or smooth printing The present invention provides a method of detecting a paper skew of a printer so that a job can be performed.

1 is a schematic block diagram of a printer applied to the present invention,

2 is a front sectional view showing a state in which two paper detection sensors are installed on a paper feed path.

3 is a flowchart illustrating an operation of the paper skew detection method according to the first embodiment of the present invention.

4 is an operation state diagram illustrating a state in which paper is sensed by a pair of paper detection sensors in a state where skew occurs in the paper being conveyed by the paper feed path.

5 is an operation flowchart showing a process of performing a paper skew detection method according to a second embodiment of the present invention.

6 is a flowchart illustrating an operation of the paper skew detection method according to the third embodiment of the present invention.

<Description of the code | symbol about the principal part of drawing>

101: central processing unit 102: memory

103: operation panel 104: engine controller

105: printer engine 106: parallel port

107: sensor unit 107a, 107b: paper detection sensor

108: paper 109: actuator

110: light sensor

A feature of the present invention for achieving the above object is a paper skew detection method of a printer that includes at least two or more paper sensor, and receives the document data created by the application program of the computer in connection with the computer to perform a print job When: a print command is received, the paper is picked up and transported along the paper feed path; Detecting conveying time information of sheets detected by at least two sheets of sensor; Determine the skew state of the paper according to the detected transfer time information; If the sheet is judged to be skewed, the print job is stopped; If it is determined that the paper is not in the skewed state, it includes the step of performing a normal print job.

Here, the at least two paper detection sensors are installed on the paper transport path in a state spaced apart by a predetermined distance from the pick-up point of the paper, in a direction orthogonal to the paper transport direction so as to simultaneously detect the leading edge of the paper being transported. Installed side by side; In this case, the at least two paper detection sensors transfer the paper corresponding to the leading edge of the left or right edge of the paper with respect to the transfer direction of the paper so as to detect any one of the leading edge of the left or right edge of the leading edge of the paper to be fed. And a first sheet detection sensor provided on the path, and a second sheet detection sensor provided at an approximately center portion on the sheet conveying path with respect to the conveying direction of the sheet.

The at least two paper detection sensors may be provided with a first paper detection device installed at a point spaced apart by the same distance in the left and right directions with respect to the center part of the paper transport path such that the left and right sides are symmetrically contacted with respect to the leading edge of the paper to be conveyed. It may also include a sensor and a second sheet sensor.

In addition, if the conveying time points of the sheets respectively sensed by the at least two or more sheet detection sensors are the same, it is determined that the sheets are not skewed; It may be determined that the paper is in a skewed state when the feeding time points of the papers respectively detected by the at least two paper detection sensors are different from each other.

And, if the difference in the time of conveyance of the paper respectively detected by the at least two paper detection sensors is within the preset reference time range, it is determined that the paper is not skewed; If the difference in the time of conveyance of the sheets respectively detected by the at least two paper detection sensors exceeds the preset reference time range, it may be determined that the paper is in a skewed state.

In addition, if the difference in the time of conveyance of the paper respectively detected by the at least two paper detection sensors is within the preset first reference time range, it is determined that the paper is not in a skew state; If the difference in the time of conveying the paper respectively detected by the at least two paper detection sensors is within the preset first reference time and the preset second reference time, it is determined that the paper is skewed, and the user decides whether to perform a print job. Display for selection; Determining that the paper is in a skewed state if the difference in the time of conveyance of the paper respectively sensed by the at least two paper detection sensors exceeds the preset second reference time range; If the user chooses to continue the print job, the user may perform a print job performing step. If the user chooses to stop the print job, the user may set the print job to stop.

Further, when it is determined that the sheet is in the skew state, it is preferable to display a predetermined identification code indicating that the sheet is in the skew state.

In addition, when it is determined that the paper is in the skewed state, it is preferable to feed the conveyed paper in the reverse direction to return the paper to the position where it was originally loaded.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the elements of each drawing, it should be noted that the same elements are denoted by the same reference numerals as much as possible even if they are displayed on different drawings. In addition, in the following description there are shown a number of specific details, such as components of the specific circuit, which are provided only to help a more general understanding of the present invention that the present invention may be practiced without these specific details. It is self-evident to those of ordinary knowledge in Esau. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a schematic block diagram of a printer applied to the present invention, and FIG. 2 is a front sectional view showing a state in which two paper sensors are installed on a paper feed path, and FIG. 3 shows a paper according to the present invention. An operation flow chart showing a process of performing a skew detection method is shown, and FIG. 4 is an operation state diagram illustrating a state in which a paper is detected by a pair of paper detection sensors in a state where a skew occurs in the paper being transferred to the paper transport path. Is shown.

Referring to Fig. 1, central processing unit 101 generally controls each component in a printer according to a predetermined program. In particular, the central processing unit 101 detects a state where a skew has occurred in the paper to be conveyed, thereby notifying the user of the skew occurrence state after reverse feeding the conveyed paper.

The memory 102 stores program data, document data created by application programs of a computer, and various other data.

An operation panel (OPE) 103 is provided with a plurality of function keys arranged so that a user can select various functions, and includes a display window for displaying an operation state of a printer.

The engine controller 104 converts the document data stored in the memory 102 into bit map data and transmits the document data to the print engine 105. Control various operation status and start time and power supply status and time.

The print engine 105 receives the converted bitmap data from the engine controller 104 and prints the converted bitmap data on the printed document.

The parallel port 106 is connected to a computer to interface a computer and a printer, and receives document data created by an application program of the computer and stores the document data in the memory 102.

The sensor unit 107 includes first and second sheet detection sensors 107a and 107b for detecting a feeding state of the sheet. At this time, the first and second sheet sensors 107a and 107b correspond to the actuator 109 rotated in the conveying direction of the sheet 108 by the sheet of sheet 108 and the rotational movement of the actuator 109. It consists of an optical sensor 110 for detecting the presence or absence of the paper (108).

On the other hand, Figure 2a and 2b is a view showing a line feed type printer of the various types of printers as an embodiment, referring to Figures 2a and 2b, the pickup roller is adjacent to the paper inlet through which the paper 108 is inserted; It is installed at the position, and picks up a plurality of sheets loaded in the cassette one by one and transfers them to the paper feed path.

The first and second paper detection sensors 107a and 107b are installed on a conveying path of the paper 108 spaced apart from the pickup roller by a predetermined distance, and the paper (for detecting the front end of the conveyed paper 108 at the same time) 108 are installed side by side in a direction orthogonal to the conveying direction.

For example, the first paper sensor 107a may be positioned on the left or right limit line on the paper conveying path with respect to the conveying direction of the paper 108 so as to detect the front end of the left or right end of the front end of the conveyed paper 108. The second sheet sensor 107b may be configured to be installed at an approximately center portion of the sheet conveying path with respect to the conveying direction of the sheet 108.

Similarly, the first and second sheet detection sensors 107a and 107b may be configured such that the left and right sides are symmetrically installed on the basis of the center portion of the tip of the sheet of paper 108 to be transferred.

<1st Example of this invention>

An operation according to the first embodiment of the present invention having such a configuration will be described below with reference to FIGS. 3 and 4.

FIG. 3 is a flowchart illustrating an operation of the paper skew sensing method according to the first embodiment of the present invention, and FIG. 4 is a pair of paper sensing sensors in a state where skew occurs in the paper being transported in the paper transport path. An operating state diagram showing a state in which a sheet is detected by the above is shown.

According to the first embodiment of the present invention, when a user selects a print job to print a document created by an application program of a computer, a printer driver program installed in the computer can recognize the created document data in a language (for example, PCL (Printer Control Language) and then send it to the printer.

The printer sequentially stores the printer language transmitted from the computer in the memory 102 and simultaneously transmits the stored print data to the printer engine 105 by a predetermined printing amount (for example, in band units). The printer engine 105 converts the transmitted print data in units of bands into bitmap data and performs a print job.

At this time, when a print command is received (S1), the printer engine 105 drives the pickup roller to sequentially pick up the sheets 108 loaded on the cassette or the tray one by one and transfer them to the printing area through the paper transfer path. . At this time, the first and second paper detection sensors 107a and 107b are installed between the pickup roller and the printing area to detect the conveying state of the paper 108. The switching state of the paper detection sensors 107a and 107b is changed, and the central processing unit 101 checks that the switching states of the first and second paper detection sensors 107a and 107b are changed to transfer the paper 108. Determine the state. In other words, when the paper 108 is not conveyed, the central processing unit 101 determines that the paper 108 is not present because the actuator 109 blocks the optical path of the optical sensor 110 as shown in FIG. 2A. When the paper 108 is conveyed, as shown in FIG. 2B, the actuator 109 is rotated by the paper 108, which causes the optical path of the optical sensor 110 to be opened. Determines that the paper 108 is being conveyed.

Therefore, the central processing unit 101 waits for a predetermined time after supplying the drive signal to the pickup roller, and checks the switching point of the switching state of the first and second sheet detection sensors 107a and 107b, respectively (S2). In this step 2 (S2), if the switching state change time points of the first and second sheet detection sensors 107a and 107b are equally checked, this means that the front end of the sheet of paper 108 to be conveyed is the first and second sheet detection sensors ( Since it means the contact with the 107a, 107b at the same time, the central processing unit 101 considers that no skew has occurred in the conveyed paper 108, and controls to continue normal printing operation (S3).

If, in step 2 (S2) above, when the switching state change points of the first and second paper detection sensors 107a and 107b are checked differently, this means that the front end of the paper 108 to be fed is the first and second paper. Since it means that the sensor sensors 107a and 107b are in contact with each other at different times, the central processing unit 101 considers that skew has occurred in the conveyed paper 108 as shown in FIG. An error message indicating that this has occurred is displayed on the display window of the operation panel 103 (S4).

Thereafter, the central processing unit 101 reverse feeds the paper 108 to be fed by rotating the feed roller for transporting the paper 108 for a predetermined time (S5), and prints the corresponding print data stored in the memory 102. After deleting (S6), the print job ends (S7).

<2nd Example of this invention>

On the other hand, with reference to Figures 4 and 5 will be described the operation according to the second embodiment of the present invention.

FIG. 4 is a diagram illustrating an operation in which paper is detected by a pair of paper sensor in a state where skew occurs in the paper conveyed by the paper feed path, and FIG. 5 is a second embodiment of the present invention. An operation flowchart showing a process of performing a paper skew detection method is shown.

According to the second embodiment of the present invention, when a user selects a print job to print a document created by an application program of a computer, the printer driver program installed in the computer may recognize a language (eg, PCL (Printer Command Language) and then send it to the printer.

The printer sequentially stores the printer language transmitted from the computer in the memory 103 and simultaneously transmits the stored print data to the printer engine 105 by a predetermined printing amount (for example, in band units). The printer engine 105 converts the transmitted print data in units of bands into bitmap data and performs a print job.

At this time, when a print command is received (S8), the printer engine 105 drives the pickup roller to sequentially pick up the sheets 108 loaded on the cassette or the tray one by one and transfer them to the printing area through the paper transfer path. . At this time, the first and second paper detection sensors 107a and 107b are installed between the pickup roller and the printing area to detect the conveying state of the paper 108. The switching state of the paper detection sensors 107a and 107b is changed, and the central processing unit 101 checks that the switching states of the first and second paper detection sensors 107a and 107b are changed to transfer the paper 108. Determine the state. In other words, when the paper 108 is not conveyed, the central processing unit 101 determines that the paper 108 is not present because the actuator 109 blocks the optical path of the optical sensor 110 as shown in FIG. 2A. When the paper 108 is conveyed, as shown in FIG. 2B, the actuator 109 is rotated by the paper 108, which causes the optical path of the optical sensor 110 to be opened. Determines that the paper 108 is being conveyed.

Therefore, the central processing unit 101 waits for a predetermined time after supplying the driving signal to the pickup roller, and checks the switching point of the switching state of the first and second sheet detection sensors 107a and 107b, respectively (S9). In step 9 (S9), if the difference ΔT between the switching state change points of the first and second paper detection sensors 107a and 107b is within a preset reference time, this means that the leading edge of the paper 108 to be conveyed is the first. And the second paper detection sensors 107a and 107b are in contact with each other at the same time or with a negligible time difference, so that the central processing unit 101 does not generate skew or the skew of the paper 108 to be conveyed. It is assumed that a small amount that can be neglected to occur is generated to control to continue normal printing (S10).

If, in step 9 (S9) above, the difference ΔT between switching points of the switching states of the first and second paper detection sensors 107a and 107b is out of the preset reference time range, it is conveyed to the paper 108. The front end of the) is in contact with the first and second paper detection sensors (107a, 107b) with a time difference of more than a predetermined reference time, respectively, so that the central processing unit 101 is conveyed as shown in FIG. It is assumed that skew has occurred in 108, and an error message indicating that a paper jam Jam0 has occurred is displayed on the display window of the operation panel 103 (S11).

Thereafter, the central processing unit 101 reversely feeds the paper 108 to be fed by rotating the feed roller for transporting the paper 108 for a predetermined time (S12), and prints the corresponding print data stored in the memory 102. After deleting (S13), the print job is finished (S14).

<3rd Example of this invention>

On the other hand, with reference to Figures 4 and 6 will be described the operation according to the third embodiment of the present invention.

FIG. 4 is a diagram illustrating an operation in which paper is detected by a pair of paper sensor in a state where skew occurs in the paper conveyed by the paper feed path, and FIG. 6 illustrates a third embodiment of the present invention. An operation flowchart showing a process of performing a paper skew detection method is shown.

According to the third embodiment of the present invention, when a user selects a print job to print a document created by an application program of a computer, a printer driver program installed in the computer may generate a language (eg, PCL (Printer Command Language) and then send it to the printer.

The printer sequentially stores the printer language transmitted from the computer in the memory 103 and simultaneously transmits the stored print data to the printer engine 105 by a predetermined printing amount (for example, in band units). The printer engine 105 converts the transmitted print data in units of bands into bitmap data and performs a print job.

At this time, when a print command is received (S15), the printer engine 105 drives the pickup roller to sequentially pick up the sheets 108 loaded on the cassette or the tray one by one and transfer them to the printing area through the paper transfer path. . At this time, the first and second paper detection sensors 107a and 107b are installed between the pickup roller and the printing area to detect the conveying state of the paper 108. The switching state of the paper detection sensors 107a and 107b is changed, and the central processing unit 101 checks that the switching states of the first and second paper detection sensors 107a and 107b are changed to transfer the paper 108. Determine the state. In other words, when the paper 108 is not conveyed, the central processing unit 101 determines that the paper 108 is not present because the actuator 109 blocks the optical path of the optical sensor 110 as shown in FIG. 2A. When the paper 108 is conveyed, as shown in FIG. 2B, the actuator 109 is rotated by the paper 108, which causes the optical path of the optical sensor 110 to be opened. Determines that the paper 108 is being conveyed.

Therefore, the central processing unit 101 waits for a predetermined time after supplying the drive signal to the pickup roller, and checks the switching point of the switching state of the first and second sheet detection sensors 107a and 107b, respectively (S16). In this step 16 (S16), if the difference between the switching state change point of the first and second sheet detection sensors 107a, 107b is within the predetermined first reference time, this means that the leading edge of the sheet of paper 108 to be conveyed is Since it means that the first and second paper detection sensors (107a, 107b) at the same time or in contact with the negligible time difference, the central processing unit 101 does not generate or skew the paper 108 to be conveyed Considering that a small amount of negligible amount of generation has occurred, it is controlled to continue normal printing operation (S17).

If, in step 16 (S16) above, if the difference ΔT of the switching state change time points of the first and second sheet detection sensors 107a and 107b is present within the preset first reference time and the second reference time, This means that the front end of the sheet of paper 108 is brought into contact with the first and second sheet detection sensors 107a and 107b with a time difference within a preset first reference time and a second reference time range, respectively. 101, it is assumed that skew within a predetermined range has occurred on the sheet of paper 108 to be conveyed as shown in FIG. 4, and text information on the display window of the operation panel 103 is displayed (S18). Instructs the user to select whether to continue printing (S19). If the user has selected to continue printing in this step 19 (S19), the central processing unit 101 proceeds to step 17 (S17) and controls the normal print job to be continued, and in step 19 (S19) above. If the user selects not to continue the print job in the central processing unit 101 by rotating the feed roller for transporting the paper 108 for a predetermined time to reverse feed the corresponding paper 108 to be transported (S20) After deleting the print data stored in the memory 102 (S21), the print job is terminated (S22).

If, in step 16 (S16) above, the difference ΔT of the switching state change time points of the first and second paper detection sensors 107a and 107b is out of the preset second reference time, this is the paper to be conveyed. Since the tip of the 108 is in contact with the first and second paper detection sensors 107a and 107b with a time difference of at least a preset second reference time, the central processing unit 101 is shown in FIG. 4. It is assumed that skew has occurred in the conveyed sheet 108, and an error message indicating that a paper jam Jam0 has occurred is displayed on the display window of the operation panel 103 (S23).

Subsequently, the central processing unit 101 proceeds to step 20 (S20) and reverse feeds the paper 108 to be fed by rotating the feed roller for transporting the paper 108 for a predetermined time, to the memory 102. After deleting the stored corresponding print data (S21), the print job is terminated (S22).

Therefore, it is possible to prevent the paper jam or print error from occurring due to the skew of the paper 108.

On the other hand, the present invention has been described as an example in which the pair of the paper sensor (107a, 107b) is configured as a pair, for the more precise skew detection may be configured of at least two or more of the paper sensor (107a, 107b).

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

As a result, according to the paper skew detection method of the printer according to the present invention the following advantages occur.

First, since the skew state of the paper can be detected in advance, the paper jam due to the skew of the paper can be prevented in advance.

Secondly, when a paper skew occurs in a state where a paper jam does not occur, a printing error in which the print data is printed in a skewed state on the printed matter can be prevented.

Claims (9)

In the paper skew detection method of the printer including at least two paper sensor, and connected to the computer to receive the document data created by the application program of the computer to perform a print job: If a print command is received, picking up paper and transferring the paper along a paper transfer path; Detecting transport time information of the paper detected by the at least two paper detection sensors, respectively; Determining a skew state of the paper according to the detected transfer time information; Stopping the print job if the sheet is judged to be skewed in the determining step; And And if it is determined in the determining step that the paper is not in a skew state, performing a normal print job. The method of claim 1, wherein the at least two paper detection sensors, It is installed on the paper transfer path in a state spaced apart from the pick-up point of the paper by a predetermined distance, characterized in that installed side by side in a direction orthogonal to the conveying direction of the paper so as to detect the leading edge of the paper to be conveyed at the same time To detect paper skew in the printer. The method of claim 2, wherein the at least two paper detection sensors, It is provided on the paper feed path corresponding to the leading end of the left or right end of the paper with respect to the conveying direction of the paper so that any one of the leading end of the left or right end of the paper to be conveyed can be detected. A first paper sensor; And And a second paper detection sensor provided at an approximately center portion on the paper conveyance path with respect to the conveying direction of the paper. The method of claim 1, wherein the at least two paper detection sensors, A first paper sensor and a second paper sensor installed at positions spaced apart by the same distance in the left and right directions with respect to the center of the paper feed path so that the left and right sides are symmetrically contacted with respect to the leading end of the paper to be fed; Paper skew detection method of the printer comprising a. The method of claim 1, wherein the determining step, Determining that the paper is not in a skewed state when the feeding time points of the papers respectively detected by the at least two paper detection sensors are the same; And determining that the paper is in a skewed state when the conveying time points of the papers respectively detected by the at least two paper detection sensors are different from each other. The method of claim 1, wherein the determining step, Determining that the paper is not in a skew state when a difference between the conveying time points of the papers respectively sensed by the at least two paper detection sensors is within a preset reference time range; The paper skew detection method of the printer, characterized in that the paper is determined to be skewed when the difference between the transfer time of the paper respectively detected by the at least two paper detection sensors exceeds a preset reference time range. The method of claim 1, wherein the determining step, Determining that the paper is not in a skew state when a difference between the conveying time points of the papers respectively sensed by the at least two paper detection sensors is within a preset first reference time range; If the difference between the conveying time points of the paper detected by the at least two paper detection sensors is within the preset first reference time and the preset second reference time, the paper is determined to be skewed, but the user Display for selecting whether to perform a print job; Determining that the paper is in a skew state when a difference between the conveying time points of the papers respectively detected by the at least two paper detection sensors exceeds the preset second reference time range; Performing the print job performing step if the user selects to continue the print job in the display step, and stopping the print job when the user chooses to stop the print job in the display step. How to detect paper skew in printer. The method of claim 1, And a display step of displaying a predetermined identification code indicating that the paper is in the skewed state, if the paper is determined to be in the skewed state in the determining step. The method of claim 1, And if the paper is determined to be skewed in the determining step, feeding the conveyed paper in a reverse direction and returning the paper to a position initially loaded.