JP2014038144A - Sheet material conveying device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convey a sheet material at a predetermined location to a downstream processing unit when there is an abnormality in the conveyance of the sheet material (paper etc.) and a location other than the predetermined location in the conveyance path is a cause of the conveyance abnormality. .
When an image forming apparatus detects a jam that is abnormal in conveyance, conveyance of all remaining sheets is stopped (S1). After that, when the jam is not detected by the registration sensor or the fixing outlet sensor (S2), if the place other than the predetermined place is the cause of the jam, the remaining paper detection target sensor other than the registration sensor and the fixing outlet sensor detects the remaining paper. Detection is performed (S7, S4). If there is a remaining sheet (S5), the position is displayed on the operation unit and a notification for urging removal of the remaining sheet is made (S6). When there is no remaining sheet (S5), it is determined whether or not the sheet being conveyed is removed from a position other than the predetermined position, and the sheet at the predetermined position is conveyed to the fixing unit 20 as a downstream processing unit (S8 to S12).
[Selection] Figure 4

Description

  The present invention relates to a sheet material conveying apparatus and an image forming apparatus including the sheet material conveying apparatus.

For example, in an electrophotographic image forming apparatus, a sheet conveying unit that conveys a sheet, and an image forming unit provided with processing units that perform charging, exposure, development, and transfer around a photosensitive member that is an image carrier, and And a fixing unit for fixing the toner image on the paper, for example, a series of image forming (hereinafter also referred to as “printing”) processing including the following image formation is performed.
That is, first, a drum-like or belt-like photoreceptor that moves in the sub-scanning direction is uniformly charged by a charging unit. The movement of the drum-shaped photosensitive member (rotating member) in the sub-scanning direction is also referred to as “rotating” or “rotating”. Further, the movement of a member (belt member) such as a belt-shaped photoconductor in the sub-scanning direction is also referred to as “turning”.

  Next, the exposure unit periodically deflects the light beam modulated according to the image data emitted from the light emitting element of the light source by using a deflecting means such as a rotary polygon mirror, and the charged surface of the photosensitive member is sub-charged. Exposure is performed by repeated scanning (main scanning) in the main scanning direction orthogonal to the scanning direction. Thereby, an electrostatic image by a light beam is written on the charged surface of the photosensitive member. Then, the electrostatic image is developed with toner from the developing unit to form a toner image (also referred to as “toner image”), and is transferred to a sheet of paper as a sheet material by the transfer unit. The sheet on which the toner image is transferred is fixed to the toner image through the fixing unit and is discharged outside the apparatus.

In an image forming apparatus that performs such an image forming process, a paper jam (hereinafter also referred to as “jam”), which is abnormal in conveyance, may occur during the image forming process. In this case, the image forming process is automatically stopped, and the user is notified of the occurrence of the jam and the position where the jam occurs, and the position of the paper remaining on the conveyance path (hereinafter also referred to as “remaining paper”). It is necessary to remove the paper and restore the device.
Therefore, when a jam occurs, the user has to pull out all the remaining sheets on the conveyance path (also referred to as “conveyance path”) one by one, which is troublesome.

Therefore, a technique for automatically conveying the remaining sheet and discharging it outside the apparatus has been considered and is already known.
Further, for example, image forming apparatuses described in Patent Documents 1 to 4 are also disclosed.
In the image forming apparatus described in Patent Document 1, a printing agent (toner image) that is installed between the image forming unit and the paper discharge unit and is printed during printing or immediately after printing when the printing operation is stopped due to an abnormality in the apparatus. ) Accommodates unfixed paper. Then, the accommodated sheet is conveyed to a spiral heater plate installed downstream of the image forming unit, and the printing agent is fixed on the sheet.

  In the image forming apparatus described in Patent Document 2, a toner adhesion detection unit that detects whether or not unfixed toner adheres to the remaining paper in the apparatus and the adhesion range thereof, and the fixing unit is held at a fixing temperature based on the adhesion range of the unfixed toner A fixing holding time calculating unit that calculates a fixing holding time. If there is adhesion of unfixed toner, the fixing unit is maintained at the fixing temperature for the fixing retention time, and the remaining paper in the apparatus is fixed and automatically discharged, while if there is no adhesion of unfixed toner. Immediately, the remaining paper in the machine is automatically discharged.

  In the image forming apparatus described in Patent Document 3, when an unfixed toner image transfer sheet exists in the transfer unit (fixing unit) at the time of jam detection, the toner image trailing edge position on the sheet reaches the timing at which the fixing unit enters the fixing unit. After waiting, the sheet conveyance by the fixing unit is stopped.

  In the image forming apparatus described in Patent Document 4, a first transport path for transporting a recording material (paper) to a stacking section (paper discharge section) on the downstream side in the transport direction of the fixing device (fixing section), and an image on one side. After the recording material is formed, the recording material is reversed, and a second transport path for transporting the recording material to form an image on the opposite surface of the recording material, and the recording material is guided to the first transport path or the second transport path. And a flapper. If the size of the input recording material does not match the size of the recording material fed and conveyed from the paper storage unit, the recording material on which images are formed is discharged to the stacking unit in the single-sided mode, and the flapper is used in the double-sided mode. The conveyance is stopped immediately after the trailing edge of the recording material guided to the second conveyance path passes through the fixing device.

  However, even with the above-described technology for automatically transporting the remaining paper and discharging it to the outside of the apparatus, when a jam occurs downstream from the fixing unit, the image forming process is automatically stopped. If there is a remaining sheet with an unfixed toner image attached upstream) from the fixing unit, it cannot be conveyed to the fixing unit. In this case, the user needs to remove the remaining paper to which the unfixed toner image is attached, and there is a problem that the unfixed toner image on the remaining paper is touched and soiled.

In the image forming apparatus described in Patent Document 1, an unfixed toner image on a remaining sheet that is being printed or just after printing after the occurrence of a jam can be fixed, but an unfixed toner image is also attached upstream of the jammed paper. If there is any remaining paper, it cannot be transported to the fixing unit, and there is a problem that when the user removes (collects) the remaining paper, the user touches the unfixed toner image on the remaining paper and gets dirty.
In the image forming apparatus described in Patent Document 2, the remaining paper can be conveyed so that the unfixed toner image is not touched by the user. However, the image forming apparatus described in Patent Document 1 also has the same problem.

  In the image forming apparatus described in Patent Document 3, the remaining paper can be conveyed without touching the unfixed toner image to the user. However, when a jam occurs downstream from the fixing unit, the remaining paper is upstream from the jammed paper. If there is a remaining sheet on which an unfixed toner image is attached, it cannot be conveyed to the fixing unit. That is, if there is jammed paper immediately after the fixing unit, if the remaining paper is passed through the fixing unit, it will collide with the jammed paper. As a result, there is a problem that the trouble of removing the jam is greatly increased.

In the image forming apparatus described in Patent Document 4, the remaining paper is conveyed when a jam occurs (when the size of the recording material input by the size input unit and the size of the recording material detected by the recording material detection unit do not match). As a result, the user can be prevented from touching the unfixed toner image, but the control cannot be applied when there is paper in the apparatus that cannot be conveyed.
Such a problem is not necessarily related to unfixed toner.

  The present invention has been made in view of the above points, and an object of the present invention is to reduce the burden of restoration work by the user when an abnormality occurs in the conveyance of the sheet material in the sheet material conveyance device.

  The present invention is a sheet material conveyance device that sequentially conveys a sheet material to a plurality of processing units along a predetermined conveyance path, and conveys the sheet material when an abnormality in conveyance of the sheet material is detected in order to achieve the above object. Stop means for stopping the operation is provided. Further, when a location other than the predetermined location in the conveyance path is the cause of the conveyance abnormality, after the stopping means stops conveying the sheet material, the conveyance path is conveyed from a location other than the predetermined location. When it is detected that the inner sheet material has been removed, the sheet material at the predetermined location is conveyed to a processing section downstream of the predetermined location.

  According to the sheet material conveyance device of the present invention, it is possible to reduce the burden of the restoration work by the user when an abnormality occurs in the conveyance of the sheet material.

FIG. 2 is a schematic diagram illustrating a configuration example of a mechanism unit of an image forming apparatus including a sheet material conveying device that implements the present invention. FIG. 2 is a block diagram illustrating a hardware configuration example of a control unit of the image forming apparatus 1 illustrated in FIG. 1. FIG. 3 is a plan view illustrating an example of a display screen displayed on a display unit of an operation unit 90 in FIG. 2 when a jam occurs in an engine unit (in-machine) of the image forming apparatus 1 illustrated in FIG. 1. 3 is a flowchart showing a first example of a jam removal control process by an engine control unit 110 shown in FIG. 2. 6 is a flowchart showing a second example of a jam removal control process by the engine control unit 110 shown in FIG. 2. 6 is a flowchart showing a third example of a jam removal control process by the engine control unit 110 shown in FIG. 2. It is a flowchart which shows the remainder of the process of jam removal control of FIG. 6 is a flowchart showing a fourth example of a jam removal control process by the engine control unit 110 shown in FIG. 2. FIG. 9 is a flowchart showing the rest of the jam removal control process of FIG. 8. FIG. FIG. 2 is an explanatory diagram for explaining a method of determining a state of a sheet in an engine unit of the image forming apparatus 1 illustrated in FIG. 1. FIG. 11 is an explanatory diagram illustrating an example of a relationship between a deviation from a predetermined standard time and a state of a sheet conveyance time between the sheet feeding sensor 200a and the registration sensor 200c in FIG.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration example of a mechanism unit of an image forming apparatus including a sheet material conveying device for carrying out the present invention. In addition, the dashed-dotted line has shown the predetermined conveyance path.
The image forming apparatus 1 is a tandem color printer, and includes an image forming unit 10, a fixing unit 20, a paper feeding unit 30, a registration unit 40, a paper discharge unit 50, a reversing unit 60, and a double-sided unit 70 that constitute an engine unit. , And a remaining paper storage unit 80. These correspond to a plurality of processing units, and by these, printing (image formation) processing (including conveyance of paper as a sheet material) can be performed.

The image forming apparatus 1 also includes an operation unit 90 that performs operations related to printing by a user, and a control unit (described later) that controls execution of print processing by each of the above-described processing units (not illustrated). I have.
Here, among the above-mentioned units, a sheet material conveying device that conveys a sheet (also referred to as “transfer sheet”) and performs conveyance control thereof sequentially conveys the sheet to a plurality of processing units along a predetermined conveyance path. Configure.

  The image forming unit 10 has four image carriers that are adjacent in the horizontal direction, that is, four photoconductors for generating toner images of Y (yellow), C (cyan), M (magenta), and K (black). Drums (hereinafter also simply referred to as “photoconductors”) 11Y, 11C, 11M, and 11K are provided. Further, an intermediate transfer belt 12, which is an intermediate transfer body that is in parallel with them and has a contact / separation mechanism with respect to the Y, C, M, and K photoconductors 11Y, 11C, 11M, and 11K, is provided.

Each of the photoconductors 11Y, 11C, 11M, and 11K uses toners of different colors Y, C, M, and K, but the other configurations are the same and are replaced when the lifetime is reached.
Although not shown, each processing unit (charging unit, charging unit, charging unit, developing unit, primary (intermediate) transfer, cleaning, and static elimination unit is provided around each of the photoconductors 11Y, 11C, 11M, and 11K. A developing unit, a primary transfer unit, a cleaning unit, and a charge eliminating unit).

Here, the operation of the photoconductor 11K and each processing unit for generating the K toner image will be described.
The charging unit uniformly charges the surface of the rotated photoreceptor 11K. The uniformly charged surface of the photoconductor 11K is exposed and scanned by a laser beam from an optical writing unit (not shown), and an electrostatic latent image (electrostatic image) for K is formed there.
The K electrostatic latent image is developed into a K toner image by a developing unit using K toner. Then, the K toner image is primarily transferred onto the surface of the intermediate transfer belt 12 by the primary transfer unit.

Thereafter, the surface of the photoconductor 10K is cleaned by a cleaning unit and a charge removal unit (not shown), and residual charges on the surface are discharged. This neutralization initializes the surface of the photoreceptor 10K and prepares for the next printing.
Similarly, Y, C, and M toner images are formed on the surfaces of the photoreceptors 11Y, 11C, and 11M, respectively, and are primarily transferred to the surface of the intermediate transfer belt 12. Here, the printing order is Y, C, M, K, but is not limited to this order, and depends on the characteristics of the toner and the finishing effect of the color image that is finally formed on the paper. To decide. Further, not only full-color printing of Y, C, M, and K but also monochrome printing of K or the like is possible.

  The optical writing unit performs, for example, the following operation. That is, by modulating and driving a laser light source in the optical writing unit based on image data from a controller, which will be described later, the corresponding laser light is emitted from the laser light source, and the laser light is rotated by a polygon mirror to rotate in the main scanning direction. , The surface of each of the photoconductors 11Y, 11C, 11M, and 11K is irradiated and exposed through a plurality of optical lenses and mirrors. By this exposure, electrostatic latent images for Y, C, M, and K are formed on the surfaces of the photoreceptors 11Y, 11C, 11M, and 11K, respectively.

The paper feed unit 30 includes a plurality of paper feed trays 31 and 32 on which different sizes of paper are set, paper feed rollers 33 and 34, and paper feed sensors 200a and 200b.
The sheets set in the plurality of sheet feeding trays 31 and 32 are fed by sheet feeding rollers 33 and 34, respectively, and conveyed toward the registration unit 40. Actually, each paper feed tray 31 or 32 is selected, and paper is fed therefrom by a corresponding paper feed roller. Also, a sheet material other than paper, such as an OHP sheet or cloth, can be used.

The registration unit 40 includes a registration roller (positioning roller) pair 41 and a registration sensor 200c.
In the registration unit 40, the paper conveyed from the paper supply unit 30 is temporarily stopped by the registration roller pair 41 to create a deflection, thereby correcting the skew of the paper. In addition, the sheet is fed to the secondary transfer portion between the intermediate transfer belt 12 and the secondary transfer roller 13 of the image forming unit 10 in timing with the toner image on the intermediate transfer belt 12.

To the intermediate transfer belt 12, toner images of Y, C, M, and K on the photoreceptors 11Y, 11C, 11M, and 11K are superimposed and primarily transferred.
As a result, a four-color superimposed toner image (four-color toner image) is formed on the intermediate transfer belt 12.
The secondary transfer roller 13 forms a secondary transfer nip with the intermediate transfer belt 12.
The four-color toner image formed on the intermediate transfer belt 12 is transferred to the paper at the secondary transfer nip.

When the sheet sent out from the secondary transfer nip passes, the fixing unit 20 transfers the sheet to one surface (front surface or back surface) of the sheet by, for example, heat from the fixing roller 21 with a built-in heater and pressure from the pressure roller 22. Fix the four-color toner image. The fixing unit 20 and the image forming unit 10 function as an image forming unit.
The paper discharge unit 50 includes a paper discharge roller pair 51, a paper discharge tray 52, and a fixing outlet sensor 200d. In the single-sided printing mode (the mode in which an image is formed only on one side of the paper), the paper discharge unit 50 discharges the paper on which the four-color toner image has been fixed to a paper discharge tray 52 outside the apparatus. Make paper. In the duplex printing mode, the sheet is fed to the reversing unit 60 disposed below the image forming apparatus 1 by a branching claw (not shown) provided on the conveyance path.

The reversing unit 60 reverses the sheet printed on one side sent from the paper discharge unit 50 in the duplex printing mode, and sends the reversed sheet to the duplex unit 70.
The double-sided unit 70 includes a double-sided exit sensor 200e. The double-sided unit 70 is for printing on both sides of the paper, holds the paper that is reversed and conveyed by the reversing unit 60, and re-feeds the paper at a predetermined timing. As a result, the reversed sheet is conveyed again to the registration roller pair 41, and after a color image is printed on the back surface, the sheet is discharged onto the discharge tray 52 by the discharge roller pair 51 and the like.

The remaining paper storage unit 80 includes a purge tray 81. When the remaining paper (remaining paper) is transported on the transport path of the image forming apparatus 1, the remaining paper storage unit 80 stores the remaining paper in the purge tray 81.
The operation unit 90 includes an input unit for receiving input of various operations including operations related to printing by the user, and a display unit for presenting information to the user. Of course, an external operation unit may be used.

The paper feed sensors 200a and 200b, the registration sensor 200c, the fixing outlet sensor 200d, and the double-sided outlet sensor 200e are paper detection sensors that detect the leading edge or the trailing edge in the paper transport direction. As the reference numerals of these paper detection sensors, reference numeral 200 may be used when the individual is not distinguished. Further, the front end in the paper transport direction is hereinafter simply referred to as “paper front end”, and the rear end in the paper transport direction is hereinafter simply referred to as “paper rear end”.
These paper detection sensors 200 can detect the state of the paper in the machine. For example, the conditions for determining (detecting) the presence or absence of jam (paper jam) or paper damage are the following (1) and (2). As shown in

(1) If the paper detection sensor 200 does not turn on at the timing when the paper should pass the paper detection sensor 200 (2) Even if a certain time elapses after the paper detection sensor 200 is turned on, When the paper detection sensor 200 is not turned off A specific method for determining the presence or absence of jam or paper damage will be described in detail later.

FIG. 2 is a block diagram illustrating a hardware configuration example of the control unit of the image forming apparatus 1 illustrated in FIG. 1. For convenience of explanation, only the paper transport motor 120, the paper detection sensor 200, and the door opening / closing detection sensor 201 are shown as sensors and motors connected to the I / O control unit 114 described later. There are other sensors and motors involved in the printing process.
The control unit of the image forming apparatus 1 includes a controller unit 100 and an engine control unit 110 as shown in FIG.

The controller unit 100 generates image data for printing based on data from an external device such as a personal computer.
The engine control unit 110 controls printing processing (including paper conveyance), and includes a CPU 111, a RAM 112, a ROM 113, an I / O control unit 114, and an NVRAM 115, and the controller unit 100 is connected to the bus 105. It is connected.
The CPU 111 performs overall control of the image forming apparatus 1 including reception of image data input from the controller unit 100 and transmission / reception control of control commands.

  The CPU 111 can also perform the following processing because the RAM 112 used for work, the ROM 113 storing the program, the I / O control unit 114, and the NVRAM 115 are connected to each other via the bus 105. That is, the program is executed, and according to an instruction from itself, data read / write processing, detection of each output of the paper detection sensor 200 and the door opening / closing detection sensor 201, and detection of input from the operation unit 90 are performed. Based on the processing result and the detection result, various controls including drive control of the sheet conveyance motor 120 related to the sheet conveyance are performed, and display control of a necessary operation screen on the display unit of the operation unit 90 is performed.

  The paper detection sensor 200 corresponds to the paper feed sensors 200a and 200b, the registration sensor 200c, the fixing outlet sensor 200d, and the double-sided outlet sensor 200e in FIG. Although only representative ones are illustrated, the sheet detection sensor 200 may be disposed everywhere (for example, between the registration sensor 200c and the fixing outlet sensor 200d) to such an extent that the position of the sheet on the conveyance path can be appropriately detected. .

The RAM 112 is used as a work area when executing a program stored in the ROM 113.
Since the RAM 112 is a volatile memory, necessary parameters and other data are stored in the NVRAM 115 which is a nonvolatile memory.
When the power is turned on or controlled, the CPU 111 expands the data in the NVRAM 115 on the RAM 112.
By referring to the display screen on the operation unit 90, the user can grasp the paper conveyance status and the jam occurrence status (such as the position of the remaining paper).

FIG. 3 is a plan view showing an example of a display screen displayed on the display unit of the operation unit 90 of FIG. 2 when a jam occurs in the engine unit (in-machine) of the image forming apparatus 1 shown in FIG.
The display screen of this example indicates that the sheet remains at locations A and B in the image forming apparatus 1. The user confirms the position of the remaining paper by looking at this display screen, and removes and collects the remaining paper.

Hereinafter, each embodiment of the jam removal control process (procedure) from the occurrence of jam to the completion of jam removal by the engine control unit 110 shown in FIG. 2 will be described.
[First embodiment]
First, the first embodiment will be described.
FIG. 4 is a flowchart showing a first example of a jam removal control process by the engine control unit 110 shown in FIG.

The engine control unit 110 of the image forming apparatus 1 performs the jam removal control of FIG. 4 when a jam that is a conveyance abnormality occurs in the apparatus and the jam is detected by the paper detection sensor 200 (when it is determined that a jam exists). Start.
First, in step S1, the conveyance of all sheets remaining in the apparatus is stopped. The function of performing this process corresponds to a function as a stopping unit.
Next, the process proceeds to step S2, and it is determined whether or not a jam is detected by the registration sensor 200c or the fixing outlet sensor 200d of FIG. 1 (Yes) or not (No). This determination is performed to determine whether or not the remaining sheet to which the toner image is attached in an unfixed state (the unfixed toner image is attached) is in a state where it can be conveyed.

Here, in this embodiment, the portion of the transport path from when the leading edge of the sheet enters the secondary transfer unit to when the trailing end of the sheet in the transport direction exits the fixing unit 20 is the toner image transferred to the sheet. It is a portion that is attached to the paper in an unfixed state (here, this is referred to as “predetermined portion”). Then, it is handled that an unfixed toner image is attached to the remaining sheet at a position detected by the registration sensor 200c or the fixing exit sensor 200d when a jam occurs. Therefore, when a jam is detected by the registration sensor 200c or the fixing exit sensor 200d, it is determined that an unfixed toner image is attached to the remaining paper (jam paper) that is jammed and cannot be conveyed. become.
Strictly speaking, just because it is detected by the registration sensor 200c or the fixing outlet sensor 200d does not necessarily mean that unfixed toner is actually attached, but in actual operation of the apparatus, it may be handled in this way. Absent.

  Of the cases in which a jam is detected by the registration sensor 200c, the trailing edge of the paper does not come out of the registration sensor 200c at the expected timing (the registration sensor 200c does not turn off at the expected timing) and is detected as a jam. In this case, it is assumed that an unfixed toner image is transferred to the leading edge of the paper. Therefore, it is determined that the remaining paper detected as a jam by the registration sensor 200c has an unfixed toner image attached and cannot be conveyed.

  In addition, the presence or absence of an unfixed toner image on the remaining paper is determined accurately based on the paper transport speed during the printing operation and the elapsed time after the paper reaches / passes each sensor. The determination may be made based on the calculation result and the positional relationship between the fixing unit 20 and the secondary transfer unit (the transfer unit between the intermediate transfer belt 12 and the secondary transfer roller 13) on the conveyance path.

The engine control unit 110 proceeds to step S3 when determining Yes in step S2 of FIG. 4 and proceeds to step S7 when determining No.
In step S3, as described above, it is determined that the remaining sheet to which the unfixed toner image is attached cannot be conveyed, and the remaining sheet detection target sensors in the apparatus are all the sheet detection sensors 200 (all sensors). ) And proceed to step S4.

In step S7, a portion other than the predetermined portion in the transport path is the cause of the jam, so that it is determined that the remaining paper to which the unfixed toner image is attached is in a transportable state, and the remaining paper in the apparatus is detected. The target sensor is the sheet detection sensor 200 other than the registration sensor 200c and the fixing exit sensor 200d, and the process proceeds to step S4.
In step S4, the remaining sheet is detected by the remaining sheet detection target sensor in the apparatus.
In the next step S5, the presence / absence of remaining paper is determined (checked) based on the detection result.
If it is determined that there is a remaining sheet, the process proceeds to step S6, where the position of the remaining sheet in the machine is displayed on the display unit 91 of the operation unit 90, and a notification is given to the user to remove the remaining sheet. Do it.

  That is, if the remaining sheet detection target sensors in the apparatus are all the sheet detection sensors 200 in step S3, the positions of all remaining sheets in the apparatus detected by the sheet detection sensor 200 in step S4 are displayed on the display unit of the operation unit 90. A notification is displayed to the user to prompt the user to remove all the remaining sheets. If the remaining sheet detection target sensor in the apparatus is set to the sheet detection sensor 200 other than the registration sensor 200c and the fixing exit sensor 200d in step S7, the sheet detected by the registration sensor 200c and the fixing exit sensor 200d is ignored. In S4, the position of the remaining sheet other than the remaining sheet to which the unfixed toner image in the apparatus is detected detected by the other sheet detection sensor 200 is displayed on the display unit 91 of the operation unit 90, and the remaining sheet is removed. A notification that prompts the user to perform is sent to the user. The function of performing this process corresponds to a function as a notification unit.

After the process of step S6 is completed, the process returns to step S4, and thereafter the same process as described above is performed.
After that, if it is determined in step S5 that there is no remaining paper, it is determined that the paper being transported (remaining paper) has been removed by the user from the location detected by the remaining paper detection target sensor at that time in the transport path. The process proceeds to step S8 (detecting removal), the remaining sheet detection target sensor in the apparatus is changed to the registration sensor 200c and the fixing outlet sensor 200d, and the process proceeds to step S9.
In step S9, the remaining sheet is detected by the remaining sheet detection target sensor in the apparatus.
In the next step S10, the presence or absence of remaining paper is determined based on the detection result.

If it is determined that there is no remaining paper, the jam removal control in FIG.
If it is determined that there is a remaining sheet, the process proceeds to step S11, where the fixing unit 20 in FIG. 1 is activated (energization of the heater in the fixing roller 21 is turned on) and unfixed toner is left on the remaining sheet. Get ready for fixing. At this time, since the image quality does not matter, the fixing temperature, which is the surface temperature of the fixing roller 21, may be set lower than that during normal printing (conveyance).
Thereafter, the process proceeds to step S12, where the remaining paper is resumed so that the remaining paper passes through the fixing unit 20, is transported to the purge tray 81, and is discharged. Then, the jam removal control in FIG.

Here, the engine control unit 110 determines that there is a remaining sheet in step S10, NO in step S2, and the determination in step S5 in a state where the registration sensor 200c and the fixing outlet sensor 200d are excluded from the remaining sheet detection target sensors. This is the case where
In this case, even if NO is determined in step S5, there is a possibility that the sheet remains at the position detected by the registration sensor 200c and the fixing outlet sensor 200d. The remaining paper at this position is considered to adhere to the paper in a state where the toner image is not fixed. On the other hand, it has been confirmed in step S2 that the remaining paper at this position is not the cause of the jam, so that it is considered that the conveyance can be continued.

Accordingly, without causing the user to remove these sheets in the steps S4 to S6, the processes in steps S11 and S12 are performed later to fix the unfixed toner image and then discharge the sheet to the purge tray 81. Thus, the image forming apparatus 1 can be returned to a jam-free state without the user touching an unfixed toner image.
On the other hand, if YES is determined in step S2, since the remaining sheet detection target sensor is common in steps S5 and S10, the determination result should be the same, and YES is not determined in step S10.

  As described above, according to the first embodiment, the image forming apparatus 1 detects a jam that is a conveyance error of a sheet (sheet material), and a portion other than a predetermined portion in the conveyance path is a cause of the jam. Is a processing unit downstream of the predetermined position when it is detected that the paper being conveyed has been removed from a position other than the predetermined position in the conveyance path after stopping the conveyance of the sheet. It is conveyed to the fixing unit 20. Accordingly, since the user does not have to touch the paper at the predetermined location, his / her hand is not soiled with toner, and the burden of recovery work by the user when an abnormality occurs in paper conveyance can be reduced.

In addition, when a location other than the predetermined location on the conveyance path is the cause of the conveyance abnormality, after stopping the conveyance of the sheet, the position of the sheet on the conveyance path is detected, and the user is not in the predetermined position on the conveyance path. Notification is made to prompt the user to remove the paper at the location. Even if there is a sheet at a predetermined position in the conveyance path, a notification that prompts the user to remove the sheet is not performed. If it does so, since a user will remove only the paper in places other than a predetermined place and will not check the presence or absence of the remaining paper of a predetermined place, it will lead to improvement in work efficiency.
Further, when the sheet at a predetermined location is conveyed to the fixing unit 20 in response to the detection that the sheet being conveyed is removed from a location other than the predetermined location in the conveyance path, the fixing temperature of the fixing unit 20 is normally set. Lower than during transport. Then, power consumption can be reduced.

[Second Embodiment]
Next, a second embodiment will be described.
FIG. 5 is a flowchart showing a second example of a jam removal control process by engine control unit 110 shown in FIG.
In the jam removal control of the second embodiment, the processes and determinations in steps S22 to S28 and S32 to S36 in FIG. 5 are the same as the processes and determinations in steps S1 to S12 in FIG.

In the second embodiment, the engine control unit 110 of the image forming apparatus 1 starts the jam removal control of FIG. 5 when a jam that is abnormal in conveyance occurs in the apparatus and the jam is detected by the paper detection sensor 200. To do.
First, in step S21, it is determined whether the jam is detected by the paper feed sensor 200a or 200b upstream of the secondary transfer unit (Yes) or not (No). If it is determined No, steps S22 to S28, S32 to S32 are performed. In S36, processing similar to that in steps S1 to S12 in FIG. 4 is performed.

If YES is determined in step S21, the process proceeds to step S29, where it is determined that a jam has occurred in the remaining paper being fed, but the printing operation of the preceding paper in the machine can be continued, and the paper feed is performed. Stop transport only.
Thereafter, the process proceeds to step S30 and waits for the completion of the printing operation other than the paper feed conveyance, that is, the printing operation of the preceding paper in the machine.

If it is determined that the printing operation for the preceding paper in the apparatus is completed, the process proceeds to step S31, and the remaining paper detection target sensors are set as the paper feed sensors 200a and 200b.
Thereafter, the process of steps S25 to S27 is performed to remove the remaining paper being fed by the user, and when it is determined in step S26 that there is no remaining paper in the apparatus, the processes after step S32 are performed.

Here, by performing the processing of steps S29 to S30 and S25 to S27, when a jam occurs on the upstream side of the secondary transfer unit, the conveyance of the sheet continues until the conveyance is completed on the downstream side of the jam occurrence point. Only the remaining paper that is being fed and that causes a jam present upstream from the next transfer section is detected by the paper feed sensors 200a and 200b.
Therefore, in this case, the user can return the image forming apparatus 1 to a jam-free state by removing only the remaining paper being fed. Accordingly, the number of remaining sheets to be removed is small, and there is no need to remove the remaining sheet on which an unfixed toner image is formed.

As described above, according to the second embodiment, in addition to the same functions and effects as those of the first embodiment, the following functions and effects can be obtained.
That is, when a jam that is an abnormality in the conveyance of the sheet occurs upstream of the secondary transfer unit, the image forming apparatus 1 conveys the sheet on the downstream side of the jam occurrence position until the conveyance is completed regardless of the stop of the conveyance. to continue. Then, even if a jam occurs, it is possible to print the paper that is being printed as much as possible, so the number of sheets to be removed and the number of sheets to be reprinted can be reduced to eliminate the jam. The user's workload can be reduced.

[Third embodiment]
Next, a third embodiment will be described.
6 and 7 are flowcharts showing a third example of the jam removal control process by the engine control unit 110 shown in FIG.
In the jam removal control of the third embodiment, the processes and determinations in steps S41, S42, S45 to S58 in FIGS. 6 and 7 are the same as the processes and determinations in steps S21 to S36 in FIG.

In the third embodiment, the engine control unit 110 of the image forming apparatus 1 stops the conveyance of all the sheets remaining in the apparatus in step S42 in FIG. 6, and then proceeds to step S43 to perform a reusable position. It is determined whether there is a remaining paper being fed (conveyed) at the position of the paper feed sensor 200a or 200b (Yes) or not (No).
And when it is judged No at step S43, it progresses to step S45 as it is.
If YES is determined in step S43, the process proceeds to step S44, and the remaining sheet being fed at the position of the sheet feed sensor 200a or 200b is in a blank sheet state. After carrying out reverse conveyance so that it may return to the paper feed tray 31 or 32 in a conveyance start position), it progresses to step S45.

In the third embodiment, the position of the paper feed sensors 200a and 200b is set as a reusable position, and it is determined whether or not there is any remaining paper. A position other than the position (however, a position upstream of the position where the jam has occurred and a position where the fed paper can be returned to the paper feed start position) may be a reusable position.
In the third embodiment, the processing and determination of steps S43 and S44 of FIGS. 6 and 7 are added to the jam removal control shown in FIG. 5 of the second embodiment. Processing and determination can also be added to the jam removal control shown in FIG. 4 of the first embodiment.

According to the third embodiment, in addition to the same functions and effects as those of the first or second embodiment, the following functions and effects can be obtained.
In other words, after the image forming apparatus 1 stops the conveyance of the sheet, if there is a sheet being conveyed at a reusable position upstream from the location where the conveyance of the sheet is abnormal, the sheet material is moved upstream. Back to the side and return to the transfer start position. If it does so, even if the paper once conveyed is in a blank state, it can be reused, leading to saving of paper.

[Fourth embodiment]
Next, a fourth embodiment will be described.
8 and 9 are flowcharts showing a fourth example of a jam removal control process by the engine control unit 110 shown in FIG.
Among the jam removal control of the third embodiment, the processes and determinations of steps S61 to S64, S66 to S70, S72 to S74, and S76 to S81 of FIGS. 8 and 9 are respectively performed in steps S41 to S41 of FIG. This corresponds to the processing of S44, S45 to S49, S50 to S52, and S53 to S58. Further, the processes of steps S65, S71, and S75 are added to the processes of FIGS.

In the fourth embodiment, when the engine control unit 110 of the image forming apparatus 1 determines Yes in step S63 of FIG. 8 (determines that there is no remaining paper being fed at the position of the paper feed sensor 200a or 200b). In the case of No.) or No, the remaining paper being fed is reversely transported back to the paper feed tray 31 or 32 at the paper feed start position in Step S64, and then the process proceeds to Step S65 to make a jam. Determine whether the remaining paper is damaged (damage of jammed paper).
If it is determined that the remaining jammed paper is damaged, the process proceeds to step S66. If it is determined that there is no damage, the process proceeds to step S71.

On the other hand, if it is determined in step S74 in FIG. 8 that the printing operation for the preceding paper in the apparatus has been completed, it is determined in step S75 whether the remaining jammed paper is damaged.
If it is determined that the remaining paper jammed is damaged, the process proceeds to step S76. If it is determined that there is no damage, the process proceeds to step S71.
In step S71, the remaining sheet detection target sensors in the apparatus are set as all the sheet detection sensors 200 (all sensors), and the process proceeds to step S78 in FIG.

Therefore, the processing of steps S78 to S81 restarts the conveyance of all the remaining paper in the apparatus including the jammed residual paper toward the purge tray 81.
Therefore, of the remaining paper that is jammed, the remaining paper that is not damaged is discharged to the purge tray 81, and compared with the first to third embodiments, the user has time and effort to remove the remaining paper. Can be reduced.

  Next, a method for determining the state of paper in the engine section (inside the machine) of the image forming apparatus 1 shown in FIG. 1 (presence / absence of jam and presence / absence of jam paper) will be described. For convenience of explanation, the case where the paper state is determined using the paper feed sensor 200a and the registration sensor 200c will be described, but the paper state can be determined using any paper detection sensor 200.

FIG. 10 is an explanatory diagram for explaining a method of determining the state of the paper in the apparatus.
In FIG. 10, “d1” indicates the conveyance direction length of the paper 500, and “d2” indicates the distance between the paper feed sensor 200a and the registration sensor 200c. It is assumed that the conveyance speed (linear speed) of the paper 500 is “v”.

FIG. 11 is an explanatory diagram illustrating an example of a relationship between a deviation from a predetermined standard time of the sheet conveyance time between the sheet feeding sensor 200a and the registration sensor 200c in FIG. 10 and the state.
The ROM 113 or NVRAM 115 in the engine control unit 110 in FIG. 2 stores in advance data indicating the relationship between the deviation from the standard time of the paper transport time between the paper feed sensor 200a and the registration sensor 200c in FIG. 10 and the state. Has been.

  The CPU 111 of the engine control unit 110 in FIG. 2 has a function of measuring time, and the time ta (d2) from the on detection of the paper feed sensor 200a (detection of the leading edge of the paper 500) to the on detection of the registration sensor 200c. / V) is measured. Further, a time tb (d1 / v) from the detection of the registration sensor 200c to the detection of the registration sensor 200c being turned off (detection of the trailing edge of the paper 500) is measured. The function of measuring (detecting) these times (the conveyance state of the paper 500) corresponds to a function as a conveyance status detection unit.

Here, since the CPU 111 determines the presence or absence of a jam, an allowable range of deviation from the standard time of the actual conveyance time (hereinafter referred to as “jamming margin”) M1 that can be determined that a jam has not occurred within this range is expressed by “ 100 msec ". On the other hand, since the CPU 111 determines whether or not the jammed paper is damaged, within this range, an allowable range of deviation from the standard time of the actual conveyance time that can be determined that the paper is not damaged (hereinafter referred to as “damage occurrence margin”). M2 is set to “130 msec”. This is because when the paper transport time deviates more than expected from the original jam occurrence time, the paper is in a “bellows-like” or “damaged (crying)” state, that is, in a state where it cannot be transported. Based on ideas.
The standard time can be determined by performing appropriate calibration based on the design values of d1, d2, and v.

The CPU 111 determines the state of the paper 500 based on the measurement time ta and the data shown in FIG. 11 (provided that “t = ta”). Further, the state of the paper 500 is determined based on the measurement time tb and the data shown in FIG. 11 (where “t = tb”).
That is, when the deviation W from the standard time of the measurement times ta and tb is within 100 msec, it is determined that the state of the paper 500 is not jammed and is not damaged.
Further, when the deviation W from the standard time of the measurement time ta or tb exceeds 100 msec, the state of the paper 500 is determined to be jammed. In this case, for example, the jam removal control shown in FIGS. 8 and 9 is started.

Furthermore, when the deviation W from the standard time of the measurement time ta or tb exceeds 130 msec, it is determined that the state of the paper 500 is damaged. In step S65 or S75 in FIG. 8, it is determined that the remaining paper that has been jammed is damaged.
Furthermore, if the deviation W from the standard time of the measurement time ta or tb exceeds 100 msec, but is within 130 msec, the state of the paper 500 is determined to be no damage. In step S65 or S75 of FIG. 8, it is determined that there is no damage on the remaining paper jammed.

If the paper transport timing is delayed due to slippage of the paper feed roller 33 and the registration roller pair 41, the toner image cannot be transferred to an appropriate position on the paper. Therefore, even if there is no damage, jam occurs if the conveyance timing is not as expected.
Therefore, the jam paper (damage remaining paper) in this embodiment is a jam paper whose deviation W from the standard time of the measurement time ta or tb exceeds 100 msec due to the slip or the like, but is within 130 msec. Assuming that jammed paper, the conveyance can be resumed as it is.

  Further, in the fourth embodiment, the processing and determination of steps S65, S71, and S75 of FIGS. 8 and 9 are added to the jam removal control shown in FIGS. 6 and 7 of the third embodiment. The processing and determination of steps S43 and S44 can be added to the jam removal control shown in FIG. 4 of the first embodiment or the jam removal control shown in FIG. 5 of the second embodiment.

According to the fourth embodiment, in addition to the same functions and effects as those of any of the first to third embodiments, the following functions and effects can be obtained.
That is, after stopping the conveyance of the sheet, based on the detection result of the conveyance state of the sheet, when it is determined that there is no damage to the sheet stopped on the conveyance path, the conveyance of the stopped sheet is resumed. . This eliminates the need for the user to manually remove the remaining paper without damage.

The description of the embodiment is finished as above, but in the present invention, the specific configuration of each unit, the content of processing, and the like are not limited to those described in the embodiment.
For example, the present invention is provided with a sheet material conveying device, and a plurality of electrostatic latent images respectively formed on a plurality of photosensitive drums are developed for each color plate with a plurality of color toners (developers). Although an embodiment has been described in which the present invention is applied to a color printer that forms a color image by sequentially superimposing and transferring toner images of each color plate on an intermediate transfer belt, the present invention is not limited to this.

That is, the present invention can be applied to other image forming apparatuses such as a digital color copying machine, a digital color complex machine, or a color facsimile apparatus that include a sheet material conveying device and performs color image formation as described above.
In addition, a sheet conveying device is provided, and a plurality of electrostatic latent images sequentially formed on a single photosensitive drum are sequentially developed for each color plate with a plurality of color toners, and the toner images of the respective color plates are intermediated. The present invention can also be applied to an image forming apparatus that forms a color image by sequentially superimposing and transferring on a transfer belt.

Furthermore, the present invention can also be applied to an image forming apparatus that includes a sheet material conveying device, in which the photosensitive drum is a photosensitive belt, and the intermediate transfer belt is an intermediate transfer drum.
Furthermore, the present invention can also be applied to a monochrome image forming apparatus such as monochrome equipped with a sheet material conveying apparatus or an image forming apparatus having two or three colors.
The present invention can also be applied to a sheet material conveying apparatus used in apparatuses other than the image forming apparatus.
Furthermore, a predetermined location is not restricted to the thing of embodiment. It may be determined independently of the toner.
Furthermore, it is needless to say that the configurations of the embodiments, operation examples, and modification examples described above can be implemented in any combination as long as they do not contradict each other.

1: Image forming apparatus 10: Image forming unit 11Y, 11C, 11M, 11K: Photoconductor drum 12: Intermediate transfer belt 13: Secondary transfer roller 20: Fixing unit 21: Fixing roller 22: Pressure roller 30: Paper feeding unit 31, 32: Paper feed tray 33, 34: Paper feed roller 40: Registration part 41: Registration roller pair 50: Paper discharge part 51: Paper discharge roller pair 52: Paper discharge tray 60: Reversing part 70: Double-sided part 80: Remaining Paper storage unit 81: Purge tray 90: Operation unit 91: Display unit 100: Controller unit 105: Bus 110: Engine control unit 111: CPU 112: RAM 113: ROM 114: I / O control unit 115: NVRAM 120: Paper transport motor 200: Paper detection sensor 201: Door open / close detection sensor 200a, 200b: Paper feed sensor 200c: Registration sensor 200d: Fixed Arrival / exit sensor 200e: Double-side exit sensor

JP 2009-204722 A JP 2006-065016 A JP 2011-033905 A JP 2008-268641 A

Claims (9)

A sheet material conveying apparatus that sequentially conveys a sheet material to a plurality of processing units along a predetermined conveying path,
Stop means for stopping the conveyance when the conveyance abnormality of the sheet material is detected,
When a portion other than the predetermined portion of the conveyance path is the cause of the conveyance abnormality, the stopping unit stops conveying the sheet material, and then is conveying from a portion other than the predetermined portion of the conveyance path. When detecting that the sheet material has been removed, the sheet material conveying apparatus conveys the sheet material at the predetermined location to a processing unit downstream of the predetermined location. In the sheet | seat material conveying apparatus of Claim 1,
When a location other than the predetermined location in the conveyance path is the cause of the conveyance abnormality, the stop means detects the position of the sheet material on the conveyance path after stopping the conveyance of the sheet material, and A sheet material conveying apparatus, comprising: a notification unit that issues a notification prompting removal of a sheet material at a location other than the predetermined location in the conveyance path. In the sheet material conveying apparatus according to claim 2,
The sheet conveying apparatus according to claim 1, wherein the notifying unit does not issue a notification prompting to remove the sheet material even when the sheet material is present at the predetermined position in the conveyance path. In the sheet material conveyance device according to any one of claims 1 to 3,
After the stopping means stops the conveyance of the sheet material, if there is a sheet material being conveyed at a reusable position upstream of the location where the conveyance of the sheet material is abnormal, the sheet material is moved upstream. A sheet material conveying apparatus comprising means for reversely conveying the sheet back to the conveyance start position. In the sheet material conveying apparatus according to any one of claims 1 to 4,
A conveyance status detection means for detecting the conveyance status of the sheet material on the conveyance path;
After the stopping means stops the conveyance of the sheet material, based on the detection result of the conveyance status, if it is determined that there is no damage to the sheet material stopped on the conveyance path, the stopped sheet material A sheet material conveying device which resumes conveyance.   An image forming apparatus comprising the sheet material conveying device according to claim 1. The image forming apparatus according to claim 6.
The processing unit includes at least a transfer unit that transfers a toner image to the sheet material, and a fixing unit that fixes the transferred toner image to the sheet material,
The image forming apparatus according to claim 1, wherein the predetermined portion of the conveyance path is a portion where the toner image transferred to the sheet material is attached to the sheet material in an unfixed state. The image forming apparatus according to claim 7,
When an abnormality occurs in the conveyance of the sheet material on the upstream side of the transfer unit, the conveyance of the sheet material is continued until the conveyance is completed on the downstream side of the abnormality occurrence point regardless of the stop of the conveyance by the stopping unit. An image forming apparatus. The image forming apparatus according to claim 6, wherein:
When conveying the sheet material at the predetermined location to the fixing unit which is the downstream processing unit in response to detecting that the sheet material being conveyed is removed from a location other than the predetermined location in the conveyance path, An image forming apparatus characterized in that a fixing temperature of the fixing unit is lower than that during normal conveyance.

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