JP2010215345A - Paper carrying device and image forming device - Google Patents

Abstract

In a sheet conveying apparatus that conveys a sheet continuously, a defect that is considered to be caused by deterioration over time of a mechanical component related to sheet conveyance is predicted, and the defect is dealt with in advance.
A transport sensor for detecting that the paper has passed is provided for each transport unit. A storage unit 1112 that stores the detection result of the conveyance sensor 1054 together with time information, a required time calculation unit 1111 that calculates a required time for paper conveyance between the two conveyance sensors 1054, and a roller counter 1113 that counts the number of paper passages Then, an average of the required time calculated by the required time calculating unit is calculated for a predetermined number of sheets, and slip correction is performed based on the calculated average of the required time and the number of passes counted by the roller count unit. A slip correction coefficient calculation unit 1114 for calculating a coefficient. The rotation speed of the transport motor 1053 is controlled so as to keep the slip correction coefficient constant.
[Selection] Figure 3

Description

  The present invention relates to a sheet conveying apparatus and an image forming apparatus, and more particularly to a sheet conveying technique suitable for application to an image forming apparatus such as a laser printer or a copying machine.

  Among the recording medium handling techniques in the image forming apparatus, in the technical field of the technique for suppressing the variation in the distance between the recording media continuously conveyed in the middle of the conveying path and maintaining the distance appropriately, Patent Document 1 and the like The technique described in is known.

  In the technique described in Patent Document 1, a conveyance sensor is provided in the middle of a conveyance path of continuously conveyed paper, and the leading edge of the succeeding sheet passes through the conveyance sensor after the leading edge of the preceding sheet has passed the conveying sensor. The time is measured, and the transport speed of the succeeding paper is made faster than the transport speed of the preceding paper based on the measured time.

  In an apparatus such as an electrophotographic image forming apparatus that is required to continuously convey a sheet at a high speed, it is an important problem to convey the sheet at a constant interval with high accuracy. For example, with regard to paper feeding, paper is fed at regular intervals to maintain a constant space between papers (inter-paper space), thereby improving productivity and aligning formed images. If variations in the accuracy of the paper feed interval are significant, problems occur in terms of productivity and quality of formed images.

  On the other hand, reducing the occurrence frequency and frequency of the phenomenon of “carrying jam” in which the paper is jammed for some reason along the paper conveyance path is also an important issue in an electrophotographic image forming apparatus or the like. This is because the conveyance jam hinders image formation desired by the user and increases maintenance costs.

  As for the problem of suppressing the variation in the interval between the continuously conveyed paper and the paper, the technology described in Patent Document 1 is known as seen in the above background art section. However, in Japanese Patent Application Laid-Open No. H10-228707, the problem related to the conveyance jam is not considered.

  However, there may be a common cause for both issues. For example, it is a deterioration due to aging or use of a mechanical component related to paper conveyance. Failures due to sudden and accidental causes are difficult to predict. However, in some cases, it is possible to predict a certain degree of a failure caused by deterioration of a mechanical part over time or contamination due to use.

  The present invention pays attention to this point and aims to reduce variations in the sheet conveyance interval. Another object of the present invention is to reduce the frequency of occurrence of conveyance jams. Regarding the mechanical parts related to the sheet conveyance, specifically, attention is paid to a conveyance roller that nipped and rotated the sheet together with the opposing roller and feeds the sheet nipped by the frictional force. This is because it is one of the parts most directly related to paper conveyance.

  The present invention has been made in view of the above circumstances, and in a paper transporting apparatus that continuously transports paper, predicts a problem that may be caused by deterioration over time of mechanical parts related to paper transport, etc. The purpose is to deal with.

  In order to achieve the above object, the present invention includes a conveyance roller, a counter roller, and a conveyance motor that rotates the conveyance roller, nips the sheet by the conveyance roller and the counter roller, and rotates the conveyance roller to rotate the sheet. A plurality of transport units to be sent, a transport sensor for detecting that the paper has passed for each of the transport units, storage means for storing the detection result of the transport sensor together with time information, and upstream of the transport path Based on the time information when the transport sensor of the transport unit detects the passage of the paper and the time information when the transport sensor of the transport unit located downstream of the transport path detects the passage of the paper, the upstream Required time calculating means for calculating a required time for transporting the paper between the transport unit and the downstream transport unit; A roller count unit that counts the number of times the sheet sensor detects the passage of the sheet, and an average of the required time calculated by the required time calculation unit for transporting a predetermined number of sheets, Control means for calculating a slip correction coefficient based on the average and the number of passes counted by the roller count means, and the control means rotates the transport motor so as to keep the slip correction coefficient constant. It is characterized by controlling the speed.

  According to the present invention, in a sheet conveying apparatus that conveys a sheet continuously, it is possible to predict a problem that may be caused by deterioration of a mechanical component related to sheet conveyance due to aging and to deal with the problem in advance. .

1 is a block diagram illustrating a functional configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a main part of a paper feeding unit of the image forming apparatus according to the embodiment of the present invention. 3 is a functional block diagram of a main control unit of the image forming apparatus according to the embodiment of the present invention. FIG. It is FIG. (1) which shows an example of the calculation process of the slip correction coefficient in embodiment by this invention. It is FIG. (2) which shows an example of the calculation process of the slip correction coefficient in embodiment by this invention.

  Hereinafter, modes for carrying out the present invention will be described. The following embodiment is an embodiment in which the paper conveyance technique according to the present invention is applied to an image forming apparatus. However, this is an example for description, and the present invention is not limited thereto.

  Next, the functional configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating a functional configuration of an image forming apparatus 1 according to the present embodiment. As illustrated, the image forming apparatus 1 is connected to a client apparatus 2 via a network 3.

  As shown in FIG. 1, the image forming apparatus 1 according to this embodiment includes a controller 100, an ADF (Auto Document Feeder) 101, a scanner unit 102, a paper discharge tray 103, a display panel 104, a paper supply A paper unit 105, a print engine 106, a paper discharge tray 107, and a network I / F 108 are included.

  The controller 100 includes a main control unit 111, an engine control unit 112, an input / output control unit 113, and an image processing unit 114. As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment is configured as a multifunction machine having a scanner unit 102 and a print engine 106. In FIG. 1, the electrical connection is indicated by a solid arrow, and the flow of a sheet or document bundle is indicated by a broken arrow.

  The display panel 104 is an output interface that visually displays the state of the image forming apparatus 1 and is an input when the user directly operates the image forming apparatus 1 or inputs information to the image forming apparatus 1 as a touch panel. It is also an interface (operation unit). The network I / F 108 is an interface for the image forming apparatus 1 to communicate with other devices via the network 3, and uses an Ethernet (registered trademark) or a USB (Universal Serial Bus) interface.

  The controller 100 is configured by a combination of software and hardware. Specifically, a control program such as firmware stored in a nonvolatile storage medium such as a ROM, a nonvolatile memory, and an HDD or an optical disk is loaded into a volatile memory (hereinafter referred to as a memory) such as a RAM to control the CPU. The controller 100 is configured by a software control unit configured according to the above and hardware such as an integrated circuit. The controller 100 functions as a control unit that controls the entire image forming apparatus 1.

  The main control unit 111 plays a role of controlling each unit included in the controller 100, and gives a command to each unit of the controller 100. The engine control unit 112 serves as a driving unit that controls or drives the print engine 106, the scanner unit 102, and the like. The input / output control unit 113 inputs a signal or command input via the network I / F 108 to the main control unit 111. The main control unit 111 controls the input / output control unit 113 to access the client terminal 2 via the network I / F 108 and the network 3.

  The image processing unit 114 generates drawing information based on image information to be printed out under the control of the main control unit 111. The drawing information is information for drawing an image to be formed in the image forming operation by the print engine 106 as an image forming unit.

  The image processing unit 114 processes image data input from the scanner unit 102 and generates image data. The image data is information stored in the image forming apparatus 1 as a result of the scanner operation or transmitted to the client terminal 2 via the network I / F 108. The input / output control unit 113 displays information on the display panel 104 or notifies the main control unit 111 of information input via the display panel 104.

  When the image forming apparatus 1 operates as a printer, first, the input / output control unit 113 receives a print job via the network I / F 108. The input / output control unit 113 transfers the received print job to the main control unit 111. When receiving the print job, the main control unit 111 controls the image processing unit 114 to generate drawing information based on document information or image information included in the print job.

  When drawing information is generated by the image processing unit 114, the engine control unit 112 performs image formation on the paper conveyed from the paper supply unit 105 based on the generated drawing information. As a specific aspect of the print engine 106, an image forming mechanism using an ink jet method, an image forming mechanism using an electrophotographic method, or the like can be used. A document on which image formation has been performed by the print engine 106 is discharged to a discharge tray 107.

  When the image forming apparatus 1 operates as a scanner, the input / output control unit 113 is operated in response to a scan operation instruction input from the external client terminal 2 or the like via the operation of the display panel 104 by the user or the network I / F 108. Transfers the scan execution signal to the main control unit 111. The main control unit 111 controls the engine control unit 112 based on the received scan execution signal.

  The engine control unit 112 drives the ADF 101 and conveys the document to be imaged set on the ADF 101 to the scanner unit 102. In addition, the engine control unit 112 drives the scanner unit 102 and images a document conveyed from the ADF 101. If no original is set on the ADF 101 and the original is directly set on the scanner unit 102, the scanner unit 102 images the set original under the control of the engine control unit 112.

  In the imaging operation, an imaging element such as a CCD included in the scanner unit 102 optically scans the document, and imaging information generated based on the optical information is generated. The engine control unit 112 transfers the imaging information generated by the scanner unit 102 to the image processing unit 114. The image processing unit 114 generates image information based on the imaging information received from the engine control unit 112 according to the control of the main control unit 111. Image information generated by the image processing unit 114 is stored in a storage medium attached to the image forming apparatus 1 such as the HDD 40.

  The image information generated by the image processing unit 114 is stored in the HDD 40 or the like as it is according to a user instruction, or is transmitted to an external device such as the client terminal 2 via the input / output control unit 113 and the network I / F 108. The

  Further, when the image forming apparatus 1 operates as a copying machine, the image processing unit 114 generates drawing information based on imaging information received from the scanner unit 102 by the engine control unit 112 or image information generated by the image processing unit 114. To do. Based on the drawing information, the engine control unit 112 drives the print engine 106 as in the case of the printer operation.

  The function provided by the sheet conveying device that realizes the flow of the sheet or document bundle indicated by the dashed arrow in FIG. 1 is one of the gist of the present embodiment. FIG. 2 shows an extracted portion of the conveyance path for feeding paper from the paper feed unit 105 to the print engine 106.

  FIG. 2 is a block diagram illustrating a main part of the paper feeding unit 105. As shown in the drawing, the paper feed unit 105 basically includes a paper feed tray 1051 and a plurality of transport units arranged along a paper transport path, which is a path through which paper transported from the paper feed tray 1051 passes. It is a simple configuration. There may be a plurality of paper feed trays 1051, and the paper conveyance path may be branched or merged.

  Each transport unit includes a transport roller 1052, a transport motor 1053 that drives the transport roller 1052, and a counter roller 1055 that is installed on the opposite side of the transport roller 1052 across the paper transport path. The conveyance unit is a mechanism that nips a sheet by the conveyance roller 1052 and the opposing roller 1055 and feeds the sheet by rotation of the conveyance roller 1052 driven by the conveyance motor 1053. In FIG. 2, the rotation direction of the conveyance roller 1052a and the counter roller 1055a is shown.

  In this embodiment, each transport unit includes a transport sensor 1054 that detects that a sheet has passed. If there are two transport units each including the transport sensor 1054 as in the example illustrated in FIG. 2, the speed at which the sheet passes between the two transport sensors 1054 can be calculated. The time when the sheet passing sensor 1054 on the upstream side of the sheet conveying path is detected is held in a temporary storage means such as a RAM, and the sheet passing detection time is similarly held in the downstream side transport sensor 1054. Since the distance between the two conveyance sensors 1054 is fixed, the distance can be calculated by dividing the difference between the paper passage detection times, that is, the time required for paper passage (required time).

  In order to adjust the speed at which the sheet passes between the two conveyance sensors 1054, the conveyance motor 1053 is controlled to control the rotation speed of the conveyance roller 1052.

  Note that one transport sensor 1054 is not necessarily provided for each transport unit, but may be provided at a location where transport control according to the present embodiment is desired.

  In this embodiment, the time is used to calculate the time required for the sheet to pass between the two conveyance sensors 1054. However, the time is not necessarily used. The time information is sufficient to measure the required time. For example, a timer that starts measuring the required time after the upstream conveyance sensor 1054 passes the paper may be used. However, in the configuration using time, when the conveyance sensor 1054 is disposed at three or more places, the time for detecting the passage of paper between the two points can be simply subtracted to measure the required time between any two points. Therefore, there is an advantage that the mounting becomes simple.

  Next, the function of the main control unit 111 that realizes the transport control of the transport unit of the present embodiment as shown in FIG. 2 will be described with reference to the functional block diagram of FIG. As illustrated, the main control unit 111 includes a required time calculation unit 1111, a storage unit 1112, a roller counter 1113, a slip correction coefficient calculation unit 1114, and a transport motor control unit 1115. Hereinafter, the function of each part will be described.

  The required time calculation unit 1111 has a function of calculating the time (required time) required for the sheet to pass between the two conveyance sensors 1054. In the example shown in the figure, the required time calculation unit 1111 receives the detection signal of paper passage from the first conveyance sensor 1054a and the second conveyance sensor 1054b in FIG. 2, and associates the detection time with each detection result in the storage unit 1112. Remember. The storage unit 1112 has a function of storing the detection result of the conveyance sensor 1054 together with the time.

  The roller counter 1113 has a function of counting the number of times that the sheet has passed through the conveyance roller 1052 of the conveyance unit that is the object of conveyance control according to the present embodiment, that is, the number of times that the conveyance sensor 1054 has detected the passage of the sheet. The roller counter 1113 performs an increment process when the sheet has passed the target roller. The number of times counted may be stored in the storage unit 1112. The counted number is cleared at an arbitrary timing. Although arbitrary timing is not limited, the timing of roller replacement is mentioned, for example. Further, regarding the counting process, 1 count may be used for a paper having a paper length of 216 mm or less, and 2 counts may be used for a paper exceeding 216 mm.

  The slip correction coefficient calculation unit 1114 is configured such that one sheet calculated by the required time calculation unit 1111 is between two conveyance sensors 1054 that are targets of conveyance control according to the present embodiment (in the illustrated example, the first conveyance sensor 1054a−). The required time required to pass through (between the second conveyance sensors 1054b) is accumulated for n sheets, and the average of the required time is calculated. In addition, the slip correction coefficient calculation unit 1114 calculates a slip correction coefficient based on the average of the calculated required time and the number of times of passage of the paper counted by the roller counter 1113.

  The conveyance motor control unit 1115 controls the conveyance motor 1053 of the conveyance unit that is the object of conveyance control according to the present embodiment based on the slip correction coefficient calculated by the slip correction coefficient calculation unit 1114, and the rotation speed of the conveyance roller 1052. Tweak the.

  Next, the slip correction coefficient calculation process in the slip correction coefficient calculation unit 1114 will be described in more detail with reference to FIG. FIG. 4 is a diagram illustrating an example of a slip correction coefficient calculation process in the present embodiment.

  As shown in the figure, the slip correction coefficient calculation unit 1114 calculates an “arrival time correction coefficient” based on the average required time between the conveyance sensors of the last n sheets (10 sheets in the illustrated example), and the roller counter 1113 Based on the count value, a “roller counter coefficient” is calculated, and a “slip correction coefficient” is calculated therefrom.

  The “arrival time correction coefficient” is calculated by dividing the required time average value by the theoretical value. The “roller counter coefficient” is calculated by having a table in which the threshold value of the count number and the roller counter coefficient are associated with each other in a nonvolatile memory or the like, and the slip correction coefficient calculating unit 1114 refers to it. The relationship between the count number threshold and the roller counter coefficient is preferably such that the larger the count number threshold, the greater the value of the roller counter coefficient.

The “slip correction coefficient” is calculated based on the following relational expression.
(Slip correction coefficient) = 1.0 * (arrival time correction coefficient) * (roller counter coefficient)

  It is conceivable that the required time between the conveyance sensors tends to become larger than the theoretical value with use due to a change with time of the conveyance roller 1052 or roller contamination due to paper dust. In this embodiment, the roller counter coefficient is set so as to increase as the roller counter value increases.

  Accordingly, the “slip correction coefficient” is quantified based on the usage frequency and the current state of the conveyance roller 1052 that is the object of conveyance control according to the present embodiment, and the rotation speed of the conveyance roller 1052 that is the object based on the numerical value. Therefore, it is possible to cope with possible problems in advance.

  As shown in FIG. 4, when the calculated slip correction coefficient exceeds a certain value (1.30 in the illustrated example), the slip correction coefficient calculation unit 1114 uses the limit value as the slip correction coefficient. In the case where the slip correction coefficient becomes too large or a value outside the prediction range, a configuration using the limit value as the slip correction coefficient is effective.

  Further, when the calculated required time average value exceeds a predetermined threshold in the previous stage of calculating the arrival time correction coefficient, the slip correction coefficient calculation unit 1114 is a conveyance roller that is a target of conveyance control according to the present embodiment. It is determined that 1052 is worn, and that effect is displayed on the display panel 104 or the client apparatus 2 via the input / output control unit 113. According to this configuration, it is possible to cope with problems such as a conveyance jam caused by wear of the conveyance roller 1052 in advance.

  As shown in FIG. 4, the slip correction coefficient calculation unit 1114 includes a paper jam detection timer, and controls the paper jam detection timer according to the slip correction coefficient. The paper jam detection timer is a period from when the leading edge of the paper passes through the transport sensor 1054 of the transport unit to be transported according to the present embodiment to when it passes through the transport unit positioned downstream of the transport sensor 1054. Time is measured. The slip correction coefficient calculation unit 1114 determines that a paper jam (conveyance jam) exists when the time measured by the paper jam detection timer exceeds a predetermined threshold. That is, the slip correction coefficient calculation unit 1114 has a function of detecting whether or not there is paper retention.

  The slip correction coefficient calculation unit 1114 controls the length of a predetermined threshold value of the paper jam detection timer according to the calculated slip correction coefficient. According to this configuration, the “slip correction coefficient” is quantified based on the number of times of use and the current state of the conveyance roller 1052 that is the object of conveyance control according to the present embodiment, and a conveyance jam is detected based on the numerical value. Therefore, it is possible to flexibly cope with changes in the characteristics of the mechanical parts based on changes over time.

  Further, the slip correction coefficient calculation unit 1114 is based on the area ratio of the image with respect to the sheet area when the conveyance unit to be subjected to conveyance control according to the present embodiment is located between the print engine 106 and the paper discharge tray 107. Modify the slip correction coefficient. FIG. 5 shows a conceptual diagram of the configuration.

  As shown in FIG. 5, in this configuration, in calculating the slip correction coefficient, the print image area ratio and the roller slip resistance during double-sided printing are determined as one of the factors contributing to the coefficient determination. According to this configuration, since the image density coefficient is used as one of the determining factors of the slip correction coefficient, it is possible to make correction determination according to the degree of roller wear.

  As shown in FIG. 4, the slip correction coefficient calculation unit 1114 corrects the image writing start timing and the setting value of the registration resumption trigger. According to this configuration, it is possible to predict a problem that may be caused by the deterioration of the mechanical parts related to paper conveyance and the like, and to deal with the problem in advance.

  According to the present embodiment described above, it is possible to reduce paper feed jams while maintaining optimum productivity. Also, for rollers that require paper interval conveyance accuracy, including paper feed intervals, the change in rollers over time (the number of sheets passing through), roller contamination due to paper dust, and the slip rate due to the image area ratio are predicted in advance to reduce the error in the paper interval. It is possible to improve the accuracy (suppress variation) to “0” as much as possible. Suppressing variations in paper spacing can increase jamming, productivity, image alignment, and post-processing accuracy, and also reduce the maintenance rate by reducing the replacement rate due to roller wear. .

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope that can be easily conceived by those skilled in the art.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Network 100 Controller 101 ADF
102 Scanner Unit 103 Output Tray 104 Display Panel 105 Paper Feed Unit 106 Print Engine 107 Output Tray 108 Network I / F
DESCRIPTION OF SYMBOLS 111 Main control part 112 Engine control part 113 Input / output control part 114 Image processing part 1051 Paper feed tray 1052 Conveyance roller 1053 Conveyance motor 1054 Conveyance sensor 1055 Opposite roller

JP 2004-315177 A

Claims (5)

A plurality of transport units, each of which includes a transport roller, a counter roller, and a transport motor that rotates the transport roller, nips the paper by the transport roller and the counter roller, and sends the paper by the rotation of the transport roller;
A transport sensor for detecting that the paper has passed for each transport unit;
Storage means for storing the detection result of the transport sensor together with time information;
Time information when the transport sensor of the transport unit located upstream of the transport path detects the passage of the paper, and time when the transport sensor of the transport unit located downstream of the transport path detects the passage of the paper A required time calculating means for calculating a required time for transporting the paper between the upstream transport unit and the downstream transport unit based on the information;
Roller count means for counting the number of times the transport sensor detects the passage of the paper;
An average of the required time calculated by the required time calculating means for a predetermined number of sheets is calculated, and a slip correction coefficient is calculated based on the calculated average of the required time and the number of passes counted by the roller count means. Control means for calculating
Have
The paper conveying apparatus, wherein the control means controls a rotation speed of the conveying motor so as to keep the slip correction coefficient constant. The control means includes
A paper jam detection timer for detecting a paper jam that exceeds a predetermined time as a paper jam and measuring the predetermined time;
2. The paper conveying apparatus according to claim 1, wherein the length of the predetermined time of the paper jam detection timer is controlled according to the calculated slip correction coefficient.   The control unit determines that the transport roller is worn when the average of the required time exceeds a predetermined threshold value, and notifies the operator to that effect. 2. The paper conveying apparatus according to 2.   2. The control unit according to claim 1, wherein when the calculated slip correction coefficient exceeds a limit value, the limit value is used as the slip correction coefficient used for controlling the rotation speed of the transport motor. 4. The sheet conveying apparatus according to any one of items 1 to 3. An image forming apparatus comprising the sheet conveying apparatus according to any one of claims 1 to 4 in a sheet conveying path after image formation,
The image forming apparatus according to claim 1, wherein the control unit modifies the slip correction coefficient based on an area ratio of the image with respect to a sheet area.

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