JP2017024845A - Sheet-like medium conveyance apparatus, image formation apparatus, and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like medium conveyance apparatus capable of continuing an operation by suppressing function limitation even when a conveyance detection sensor in a conveyance passage fails, and an image formation apparatus.SOLUTION: A sheet-like medium conveyance apparatus comprises: detection means for detecting conveyance of a sheet-like medium by a sensor; first determination means for determining whether the sensor has detected the conveyance of the sheet-like medium at first timing from a start of the conveyance when the sheet-like medium is conveyed by a conveyance roller provided in the vicinity of the sensor; second determination means for determining whether the sheet-like medium has plunged into the conveyance roller provided in the vicinity of the sensor; and conveyance abnormality determination means for determining a conveyance abnormality of the sheet-like medium by determining whether or not the sheet-like medium has plunged into the conveyance roller at second timing different from the first timing from the conveyance start of the sheet-like medium if a failure of the sensor occurs.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sheet-like medium conveyance device, an image forming apparatus, and a control method.

  As means for controlling the conveyance of the image forming apparatus, the conveyance of the recording medium is detected by a plurality of sensors on the conveyance path, and is controlled so that normal conveyance can be performed. However, if any one of the plurality of sensors installed in the transport path has failed, the normal transport of the recording medium may not be maintained.

  The recording medium conveyance program performs conveyance control when a predetermined sensor detects conveyance of the recording medium. When a sensor failure occurs, normal conveyance by the conveyance program cannot be maintained, and it is common to stop the operation of the entire apparatus as JAM, that is, a paper jam.

  In recent years, even if some sensor failures occur in an image forming device, etc., only the functions related to the failure sensor are stopped, and the components related to other functions not related to the failure are continuously operated to reduce downtime. Techniques for reducing this have been proposed.

  Patent Document 1 discloses a technique for prohibiting the use of a function related to a sensor when a predetermined sensor provided in the image forming apparatus fails.

  In the invention described in the above-mentioned patent document, when a sensor that detects conveyance of a recording medium fails, even if a component having a function such as image formation has not failed, the function is limited. The problem comes out. This is because control of conveyance of printing paper such as an image forming apparatus is entrusted to conveyance detection of various sensors provided in the conveyance path. If a sensor failure occurs, the failure The functions related to the sensor are not limited.

  Accordingly, the present invention has been made in view of the above-described problems, and the object of the present invention is to provide a sheet that can continue operation while suppressing functional restrictions even when a conveyance detection sensor in the conveyance path fails. And providing an image forming apparatus.

  In order to achieve the object, the present invention has the following features.

  The sheet-like medium conveyance device according to the present invention is configured to detect a sheet-like medium from a start of conveyance when the sheet-like medium is conveyed by a detection unit that detects conveyance of the sheet-like medium by a sensor and a conveyance roller provided near the sensor. First determination means for determining whether or not the conveyance of the sheet-like medium has been detected by the sensor at the first timing; and second judgment for determining whether or not the sheet-like medium has entered a conveyance roller provided in the vicinity of the sensor When the failure of the determination means and the sensor has occurred, it is determined whether or not the sheet medium has entered the conveyance roller at a second timing different from the first timing from the start of conveyance of the sheet medium. And a conveyance abnormality judging means for judging a conveyance abnormality of the sheet-like medium.

An image forming apparatus according to the present invention includes a detection unit that detects conveyance of a recording medium by a sensor,
A first determination unit configured to determine whether the sensor detects conveyance of the recording medium at a first timing from the start of conveyance when the recording medium is conveyed by a conveyance roller provided in the vicinity of the sensor; Second determination means for determining whether or not the recording medium has entered a conveyance roller provided in the vicinity of the sensor, and a second timing different from the first timing from the start of conveyance of the recording medium when the sensor has failed. And a conveyance abnormality determining means for determining whether or not the recording medium has entered the conveyance roller at the timing, thereby determining a conveyance abnormality of the recording medium.

  According to the present invention, even when the conveyance detection sensor in the conveyance path fails, the function restriction can be suppressed and the operation can be continued.

1 is a diagram illustrating a schematic mechanism of an image forming apparatus according to an exemplary embodiment. It is a functional block diagram of a sheet-like medium conveyance (image formation) device in this embodiment. It is a hardware block diagram of the sheet-like medium conveyance (image formation) apparatus in this embodiment. It is a block diagram of digital control of the DC motor in this embodiment. It is a figure which shows the flowchart in this embodiment. It is a figure which shows the change of the motor rotational speed with respect to the rush of the sheet-like medium (printing paper) to the conveyance roller in this embodiment, and omission. It is a figure which shows the change of the motor rotation position deviation with respect to the rush of the sheet-like medium (printing paper) to the conveyance roller in this embodiment, and omission. It is a figure which shows the change of the motor control voltage with respect to the rush of the sheet-like medium (printing paper) to the conveyance roller in this embodiment, and omission.

The printing paper conveyance of a very general electrophotographic image forming apparatus used as an example of an embodiment of the present invention will be described with reference to FIG.
An image forming apparatus used in the present invention includes a paper feeding device 2 that feeds printing paper, a paper feeding roller 5 that feeds and conveys printing paper, and temporarily stops the printing paper that has been sent to the image data. A registration roller 6 that conveys the paper in accordance with the finish, a paper discharge roller 7 that discharges and conveys the printing paper, an intermediate transfer belt 8 that transfers the toner onto the printing paper, and a transfer roller that transfers the toner onto the printing paper. 9, a fixing unit 10 that fixes an image by applying heat, a registration sensor 11 that detects conveyance of printing paper, a paper discharge sensor that detects discharge of printing paper, and a double-side sensor that detects conveyance of a double-sided conveyance path 13 and a double-sided roller for conveying the double-sided conveyance path.
The image forming apparatus in FIG. 1 is merely an example of the present embodiment, and is not limited to the image forming apparatus as long as the present invention can be implemented.

Next, the printing paper conveyance process of the image forming apparatus 1 of the present embodiment shown in FIG. 1 will be described.
First, when the operation of the image forming apparatus 1 is started, feeding of the printing paper 14 from the paper feeding device 2 is started by the paper feeding roller 5. After the registration sensor 11 detects the conveyance of the printing paper, the registration roller 6 measures the finish timing of image formation. An image is fixed by applying a transfer bias to the toner image before fixing formed on the intermediate transfer belt 8 by the transfer roller 9. The paper discharge sensor 12 detects the discharge of the print paper. In the case of double-sided printing, etc., after the discharge sensor 12 detects the discharge of the print paper, the paper discharge roller 7 is rotated reversely to print the print paper. Is conveyed to the double-sided path R.

The printing paper conveyed to the double-sided path R is then conveyed by the double-sided roller 100, and the double-sided sensor 13 detects the passage of the printing paper. Thereafter, after reaching the registration sensor 11, double-sided printing is performed by repeating the same printing operation.
The above is the conveyance process by the normal conveyance of the image forming apparatus 1 used in the present embodiment.

  Next, a functional configuration diagram of the present embodiment will be described with reference to FIG. The sheet-like medium conveyance (image forming) apparatus according to the present embodiment includes a detection unit 201, a first determination unit 202, a second determination unit 203, and a conveyance abnormality determination unit 204.

  The detection unit 201 is a sensor in the conveyance path of the sheet-like medium conveyance (image forming) apparatus and detects conveyance of the sheet-like medium. As a detection method, any detection method may be used as long as it can detect the conveyance of the sheet medium inside the computer, such as detection by light emission control and detection by an electric signal.

  Whether the first determination unit 202 detects the conveyance of the sheet medium by the sensor at the first timing from the start of conveyance when the sheet medium is conveyed by the conveyance roller provided in the vicinity of the sensor. Make a decision. Here, the first timing means that detection of conveyance by various sensors is performed at a predetermined time from the start of conveyance, but is not a setting from the start of conveyance, but between the sensor and the sensor. The first timing may be determined.

  Based on the motor control of the transport roller, the second determination unit 203 determines that any change in the rotational speed of the motor, rotational position deviation, and fluctuation of the motor control voltage, which will be described later, is caused by the sheet-like medium entering the transport roller. Judging by what happened. Here, the conveyance roller to be determined for the sheet-like medium may be in front of or behind the sensor in the traveling direction of the sheet-like medium. It may be before or after the first timing for determining the detection of the sensor, and it is sufficient if the sheet-like medium has entered.

  The conveyance abnormality judgment unit 204 has entered the conveyance roller at a second timing different from the first timing from the start of conveyance of the sheet-like medium when a sensor failure has occurred. By judging this, the conveyance abnormality of the sheet-like medium is judged. That is, the sheet medium is conveyed due to a sensor failure, and is determined by the second determination unit 203 that determines entry into the conveyance roller at a second timing different from the first timing. If the conveyance of the sheet-like medium can be detected at the second timing, it is determined as normal conveyance. If the conveyance of the sheet-like medium cannot be detected at the second timing, it is determined as abnormal conveyance.

Next, a hardware configuration diagram of the present embodiment will be described with reference to FIG.
The main body control unit 300 executes a predetermined program to turn on the power of the CPU 301 for realizing overall control of the sheet-like medium conveyance (image forming) apparatus and the sheet-like medium conveyance (image forming) apparatus. A read only memory (ROM) 303 for storing a program read by the CPU 301, a random access memory (RAM) 302 used as a working memory by the CPU 301, and a sheet. HDD 307 capable of holding a record when the power of the medium transport (image forming) device is cut off, a display 305 using a panel such as liquid crystal and organic EL, and a mouse and input keys I / F 306 for transmitting information between the input device 304 and the device And comprising.

The engine control unit 400 executes a predetermined program to realize operation control of various electrical components of the sheet-like medium, and a read-only memory (ROM) that stores a program read by the CPU 401 )) 403, a random access memory (RAM) 402 used as a working memory by the CPU 401, an I / F 405 for transmitting information between devices, a motor voltage control, etc. A motor driver IC 406 for controlling the operation and a sensor detection unit 407 for detecting the conveyance of the sheet medium by various sensors are provided.
The motor driver IC is attached to each transport roller, and detects a change in rotation, control voltage, and the like that occurs when the sheet medium enters and exits the transport roller.

  2, the main body control unit 300 realizes the first determination unit 202, the second determination unit 203, and the conveyance abnormality determination unit 204, and the engine control unit 400 realizes the detection unit 201. However, it is not limited to this configuration. For example, the engine control unit 400 may be configured to implement the first determination unit 202 and the second determination 203, and any configuration that can implement the present invention is sufficient.

  In the present invention, the rotational speed and rotational position information of the motor are detected by feedback control of the motor mounted on the conveying roller. The motor feedback control will be described. In this embodiment, the feedback control is performed by the motor driver IC 406.

  FIG. 4 is a block diagram of digital control of a general DC motor. In the following description, the motor is a DC motor, but the present invention is not limited to a DC motor. The digital control of the DC motor in FIG. 4 will be described.

  Using a calculation result of position feedback (position FB) as an element constituting a target speed component, speed feedback (speed FB) control is performed, and a control system for generating a control voltage (PWM signal) for driving a DC motor is formed. Yes. As will be described later, the portion surrounded by the broken line is realized by the CPU executing the program (software control), but may be realized by hardware logic.

  In FIG. 1, the target speed of the motor is given by a table. The target position of the motor is also given by a table, but when a stepping motor is assumed as a control target, the target position is given by a pulse signal (pulse rate signal). The actual detection position of the motor can be obtained, for example, by counting rising edges of encoder signals (pulse signals) that rotate in synchronization with the motor.

  The comparator 501 obtains the rotational position deviation of the motor by taking the difference between the target position and the detected position of the motor. Multiplier 502 multiplies this position deviation by a fixed gain (P control) and outputs position feedback information (position FB). This position FB information is one of the target speed information. On the other hand, the differentiation circuit 503 differentiates the target position of the motor and outputs position feedforward information (position FF). This position FF information is another component of the target speed information. By adding this position FF, the position followability can be improved.

  The differentiation circuit 504 differentiates the detected position of the motor and outputs motor rotation speed information. The rotation speed information may be calculated from the edge interval time of the encoder signal.

  The comparator 505 adds the position FB information and the position FF information to obtain target speed information, and obtains a speed deviation by taking the difference between the target speed information and the detected speed information. The PID calculation circuit 506 performs PID calculation (P: proportional, I: integration, D: differentiation) on the speed deviation and outputs speed feedback information (speed FB). This speed FB information becomes one of the values of the motor control voltage. On the other hand, the differentiation circuit 507 differentiates the target speed and outputs speed feedforward information (speed FF). This speed FF information is another value constituting the value of the motor control voltage. By adding this speed FF, it is possible to improve speed tracking.

The adder 508 adds the speed FB information and the speed FF information, and sends the addition result to the motor control voltage generation circuit 509 as the value of the motor control voltage. The motor control voltage generation circuit 509 generates a control voltage (PWM signal) for driving the DC motor according to the value of the motor control voltage, and controls a motor drive circuit (not shown).
Whether the printing paper or the like enters or leaves the conveyance roller is detected by the second determination unit 203 with respect to any change in the motor rotation speed, rotation position deviation, and motor control voltage detected by the above process. Make a decision.

  Using the image forming apparatus of FIG. 1, the conveyance process of printing paper conveyance has been described. An object of the present invention is to suppress downtime as much as possible even when a component failure occurs. The image forming apparatus of the present embodiment is an image forming apparatus that is generally used, and the operation control by the normal conveyance is widely known, and thus the description thereof is omitted. The operation in the case where it is considered that a predetermined sensor has failed will be described using the hardware configuration diagram of FIG.

  In the sensor and the conveyance roller installed in the vicinity of each other, the conveyance information of the sheet medium by the sensor behind the conveyance roller cannot be detected by the sensor detection unit 407, and the sheet driver of the sheet medium by the motor driver IC 406 of the conveyance roller in front of the sensor Consider the case where entry into the transport roller is detected.

  Information of the sensor detection unit 407 and detection information of the motor driver IC 406 are provided to the main body control unit 300 via the I / F 405 by a predetermined program of the CPU 401. The CPU 301 determines that the target sensor has failed according to a predetermined program. Based on the failure determination, the normal transfer program is switched to the transfer program at the time of sensor failure. The conveyance program for normal conveyance and sensor failure is stored in the ROM 303 and RAM 302 in advance.

  After the switching of the conveyance program is completed, the CPU 301 prohibits conveyance of a sheet thinner than a predetermined thickness, and displays it on the display 305 so that the user can recognize it. Here, the predetermined thickness may be determined in advance by a program or the like, or may be set arbitrarily by the user. Further, as an example of display on the display, there is a display such as “Prohibit use of thin paper” as a telop, but it is sufficient if the user can recognize the prohibition of use. In addition, a sensor that detects the thickness of the printing paper is provided on the paper supply sheet, and when a printing paper thinner than the predetermined thickness is set when the transport program is switched, a warning sound or the like is sounded. Thin print sheets may not be accepted.

  When the sheet 301 continues to be conveyed after the conveyance program is switched, the CPU 301 determines that the sheet-like medium has entered the conveyance roller in the vicinity of the failure sensor. Continue conveying.

Next, a specific procedure of this embodiment will be described. FIG. 5 is a diagram showing a flowchart of the present embodiment. Hereinafter, a specific procedure of the present embodiment will be described with reference to a flowchart.
The specific procedure according to the present embodiment is started when there is some abnormality in the sensor that detects the conveyance of the printing paper when the image forming apparatus shown in FIG. 1 performs the normal conveyance according to a predetermined program. It is an example.
Although the sensor is an abnormality target, the present invention can be applied to any of a plurality of sensors such as a registration sensor, a paper discharge sensor, and a double-sided sensor.

  The printing paper is conveyed in the conveyance path of the image forming apparatus, and the plurality of sensors detect the conveyance of the printing paper by a detection method according to a predetermined program (step 1). The sensor detects the conveyance of the printing paper at a predetermined first timing from the start of conveyance. As another example, the printing paper by the rear sensor is detected within a predetermined time after the detection of the printing paper by the front sensor. There are various detection methods, such as a method for detecting this, and a passing point is determined between the sensors, and conveyance is detected when a print sheet reaches the point. If there is a sensor response, detection of the conveyance of the printing paper is continued according to a predetermined program.

  When the case where the conveyance of the printing paper is not detected occurs at a predetermined first timing from the start of the conveyance, it is determined whether the printing paper has entered the conveyance roller near the abnormality target sensor (step 2). Here, as a means for determining whether the printing paper has entered the conveyance roller, it is performed by reading a change in the rotational speed of a motor provided in the conveyance roller. FIG. 6 shows a change in the rotational speed of the motor when the printing paper enters or leaves a certain conveying roller.

  When the printing paper does not enter the conveyance roller, the motor maintains a certain rotation speed. When the printing paper enters the conveyance roller, the rotational speed of the motor decreases, and the constant rotational speed changes. Further, when the printing paper is removed from the transport roller, the rotational speed of the motor is increased, and the constant rotational speed is changed. In the present embodiment, the change in the rotational speed at this time is used to determine whether the printing paper has entered the conveyance roller or has been removed. Here, in order to make a determination, it is also necessary to set a threshold value when a change in the rotation speed occurs, which is determined by a predetermined program.

  If it is not determined that the printing paper has entered the transport roller, it is determined that a JAM being transported, that is, a paper jam has occurred (step 3). The occurrence of JAM is displayed on a built-in display or the like (step 4), and the conveyance is stopped.

  If it is determined that the printing paper has entered the conveyance roller, it is determined that some abnormality, that is, a failure has occurred in the target sensor (step 5). If it is determined that a sensor failure has occurred, the printing paper conveyance control is switched (step 6).

  The transport control after the switching is a transport control that determines that the normal transport is being performed by determining that the printing paper has entered the transport roller in the vicinity of the sensor that is the failure target. Here, the conveyance roller to be determined may be in the vicinity of the sensor, before or after the first timing detected by the sensor, and may be any conveyance roller that can determine whether the printing paper has entered.

  After the transfer control is switched, the use of printing paper thinner than a predetermined thickness is prohibited (step 7). This is because the change in the motor rotation speed is difficult to read unless the thickness is equal to or greater than a predetermined thickness when the conveyance is determined by the entry of the printing paper into the conveyance roller. In other words, a change in the rotational speed of the motor cannot be detected unless the printing paper has a predetermined thickness or more.

  The prohibition of use of printing paper thinner than a predetermined thickness is displayed on a display or the like (step 8). Here, the notation is "Thickness ~ less than mm can not be accepted", or when printing paper thinner than the specified thickness is loaded when replenishing printing paper to the paper feeder, "This printing paper cannot be used" Any notation may be used as long as the display can be recognized by the user.

  In the conveyance of the printing paper after the conveyance control is switched, if the determination of the printing paper rush to the conveyance roller near the failure target sensor is not made at the second timing from the start of the conveyance (step 9), the conveyance abnormality (JAM) is determined (step 10). The occurrence of JAM is displayed on a built-in display or the like (step 11), and the conveyance is stopped.

If it is determined in step 9 that the printing paper has entered the conveyance roller near the failure target sensor at the second timing from the start of conveyance, it is determined that the printing paper is normally conveyed (step 12). . The second timing for determining the conveyance of the printing paper is different from the first timing before switching. For example, when the position of the sensor for detecting the conveyance of the printing paper is behind the conveyance roller, the determination of the conveyance of the printing paper can be made earlier by setting a timing earlier than the conventional timing.
Of course, it is possible to change the conveyance control without changing the timing for determining the conveyance of the printing paper. In any case, it is only necessary to detect the conveyance of the printing paper when the sensor fails based on the second determination unit 203. In addition, although the present embodiment is executed based on the operation control of the CPU 301 provided in the main body control unit 300, the operation control can also be performed by the CPU 401 provided in the engine control unit 400.

  The above is a specific example of this embodiment. According to the present embodiment, when a sensor failure occurs, the downtime for stopping the conveyance of the image forming apparatus can be suppressed by using the characteristics of the other components provided as a substitute for the sensor. As an example, in the case of a double-sided sensor failure, instead of the double-sided sensor, it can continue to operate without stopping the double-sided printing function by judging the printing paper entry to the transport roller near the double-sided sensor. Can be made.

  Heretofore, an example in which the present embodiment is performed in a suitable form has been described. Although a specific specific example has been shown and described here, various modifications and form changes of the specific example can be made without departing from the spirit and scope of the claims. For example, in the motor provided in the conveyance roller, not only the rotation speed of the motor but also the rotational position deviation, the motor control voltage, etc., as shown in FIG. 7 and FIG. Since the change occurs when the paper is pulled out, these may be used as a reference for determining whether the printing paper or the like has entered the transport roller and whether the paper has been pulled out. Furthermore, it is good also as a reference | standard which judges using combining them.

  In addition, in the transport control after switching, not only the transport control in the vicinity of the sensor determined to be faulty is changed, but if one sensor fails, all transport of printing paper and the like enters and exits the transport roller. It is also possible to control based on this determination. Further, in this embodiment, the conveyance is determined based on the entry of the printing paper into the conveyance roller. However, the determination may be based on the time when the printing paper has passed through the conveyance roller.

201 Detection means 202 First determination means 203 Second determination means 204 Conveyance abnormality determination means

JP 2002-139967 A

Claims (7)

Detecting means for detecting conveyance of the sheet-like medium by a sensor;
When the sheet-like medium is being conveyed by the conveyance roller provided in the vicinity of the sensor, it is determined whether the sensor has detected conveyance of the sheet-like medium at a first timing from the start of conveyance. 1 judging means,
Second judging means for judging whether or not the sheet-like medium has entered a transport roller provided in the vicinity of the sensor;
When the sensor has failed, it is determined whether or not the sheet medium has entered the conveying roller at a second timing different from the first timing from the start of conveyance of the sheet medium. And a conveyance abnormality determining means for determining a conveyance abnormality of the sheet-like medium,
Comprising
A sheet-like medium conveyance device. The second determination means determines the entry of the sheet-like medium into the transport roller by a change in the rotation speed of a motor provided in the transport roller.
The sheet-like medium conveyance device according to claim 1. The second determining means determines the entry of the sheet-like medium into the transport roller based on a change in rotational position deviation of a motor provided in the transport roller.
The sheet-like medium conveyance device according to claim 1. The second determination means determines the entry of the sheet-like medium into the transport roller by a change in a control voltage of a motor provided in the transport roller.
The sheet-like medium conveyance device according to claim 1. When the first determination unit determines that the conveyance of the sheet-like medium is not detected by the sensor, and the second determination unit determines the entry of the sheet-like medium into the conveyance roller Judging that the sensor has failed and not accepting a conveyance instruction for a sheet-like medium thinner than a predetermined thickness,
The sheet-like medium conveyance device according to claim 1, wherein Detecting means for detecting conveyance of the recording medium by a sensor;
When the recording medium is being transported by a transport roller provided in the vicinity of the sensor, a first timing for determining whether the sensor has detected transport of the recording medium at a first timing from the start of transport Judgment means,
Second determination means for determining whether or not the recording medium has entered a conveyance roller provided in the vicinity of the sensor;
When the sensor has failed, it is determined whether or not the recording medium has entered the conveyance roller at a second timing different from the first timing from the start of conveyance of the recording medium. A conveyance abnormality determining means for determining a conveyance abnormality of the recording medium;
Comprising
An image forming apparatus. Detecting the conveyance of the sheet-like medium by a sensor;
A step of determining whether the sensor detects conveyance of the sheet-like medium at a first timing from the start of conveyance when the sheet-like medium is conveyed by a conveyance roller provided in the vicinity of the sensor; When,
Determining whether or not the sheet-like medium has entered the transport roller provided in the vicinity of the sensor;
When the sensor has failed, it is determined whether or not the sheet medium has entered the conveying roller at a second timing different from the first timing from the start of conveyance of the sheet medium. And determining the conveyance abnormality of the sheet-like medium,
A control method for a sheet-like medium conveyance device.

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