JP2007070002A - Image forming device, and its control method and control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of adequately straightening the bend of a recording medium by controlling the rotation in the reverse direction of a register roller which can be rotated in both the forward and reverse directions, and less in occurrence of jam. <P>SOLUTION: The image forming device has a register roller 1 which is provided on a recording medium conveying path and rotated in both the forward and reverse directions, and a control means which performs the control so as to change at least one of the rotational speed and the time of the rotation in the reverse direction of the register roller based on the set value by the setting means for setting at least one of the kind, the basic weight, and the loop amount of a recording medium. The bend of the recording medium on the conveying path can be straightened, and jam occurs less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, a control method thereof, and a control program.

Conventionally, there is an image forming apparatus including a skew correction device for correcting a bending phenomenon of a recording medium. In such a skew correction device, after the leading edge of the recording medium reaches the registration roller pair, the recording medium is conveyed by an arbitrary distance in the recording medium conveyance direction, and is transferred to the recording medium between the registration roller pair and the loop roller pair. A first curve is formed, and further a second curve is formed downstream in the transport direction. Then, by rotating the registration roller pair in the reverse direction, the front end of the recording medium is uniformly brought into contact with the nip line of the registration roller pair, so that the bending of the recording medium can be corrected. (For example, Patent Document 1)
JP 2003-72982 A

  However, the reverse rotation time is made uniform when the registration roller is rotated in reverse to correct the bending of the recording medium. As a result, JAM may be caused when the recording medium leading edge comes off the nip of the registration roller due to excessive reverse rotation and re-conveys.

  Accordingly, an object of the present invention is to provide an image forming apparatus, a control method thereof, or a control program capable of appropriately correcting the bending of a recording medium and suppressing the occurrence of JAM.

  The object of the present invention can be achieved by the following constitution.

The invention according to claim 1
In an image forming apparatus that forms an image on a recording medium based on image data,
A registration roller provided in the recording medium conveyance path and capable of rotating in the forward and reverse directions;
An image forming apparatus comprising: a control unit configured to change at least one of a reverse rotation speed and a reverse rotation time of the registration roller.

The invention according to claim 2
The control means changes at least one of a reverse rotation speed and a reverse rotation time of the registration roller based on at least one of a basis weight, a type of the recording medium, and a loop amount formed by the registration portion. The image forming apparatus according to claim 1, wherein:

The invention according to claim 3
A setting unit configured to set at least one of the basis weight, type, and loop amount, and the control unit performs reverse rotation speed and reverse rotation time of the registration roller based on the setting by the setting unit; The image forming apparatus according to claim 2, wherein at least one of the two is changed.

The invention according to claim 4
The control unit controls the reverse rotation time of the registration roller with respect to the first loop amount to be shorter than the reverse rotation time of the registration roller with respect to the second loop amount that is larger than the first loop amount. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

The invention according to claim 5
The control means controls the reverse rotation speed of the registration roller with respect to the first loop amount to be smaller than the reverse rotation speed of the registration roller with respect to the second loop amount that is larger than the first loop amount. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

The invention according to claim 6
The control means is configured so that the reverse rotation time of the registration roller with respect to the first surface roughness is shorter than the reverse rotation time of the registration roller with respect to the second surface roughness that is larger than the first surface roughness. 6. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled.

The invention according to claim 7 provides:
The control means is configured so that the reverse rotation speed of the registration roller with respect to the first surface roughness is smaller than the reverse rotation speed of the registration roller with respect to the second surface roughness that is greater than the first surface roughness. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled.

The invention according to claim 8 provides:
When the JAM is generated in the registration roller, the control means does not reversely rotate the registration roller after canceling the JAM, or reduces the time for reverse rotation of the registration roller or the reverse rotation speed. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled as follows.

The invention according to claim 9 is:
In a control method of an image forming apparatus for forming an image on a recording medium based on image data,
A control method is characterized in that at least one of a reverse rotation speed and a reverse rotation time of a registration roller provided in a recording medium conveyance path that can rotate forward and backward is changed.

The invention according to claim 10 is:
The control method changes at least one of a reverse rotation speed and a reverse rotation time of the registration roller based on at least one of a basis weight of the recording medium, a type, and a loop amount formed by the registration portion. The control method according to claim 9, wherein control is performed so that the control is performed.

The invention according to claim 11 is:
Control is performed to change at least one of the reverse rotation speed and the reverse rotation time of the registration roller based on a setting value indicating at least one of the basis weight, type, and loop amount. A control method according to claim 10.

The invention according to claim 12
The control method performs control so that the reverse rotation time of the registration roller with respect to the first loop amount is shorter than the reverse rotation time of the registration roller with respect to the second loop amount that is larger than the first loop amount. The control method according to any one of claims 9 to 11, wherein

The invention according to claim 13 is:
The control method is controlled so that the reverse rotation speed of the registration roller with respect to the first loop amount is smaller than the reverse rotation speed of the registration roller with respect to the second loop amount that is larger than the first loop amount. The control method according to any one of claims 9 to 12, wherein:

The invention according to claim 14 is:
The control method is such that the reverse rotation time of the registration roller with respect to the first surface roughness is smaller than the reverse rotation time of the registration roller with respect to the second surface roughness that is larger than the first surface roughness. The control method according to claim 9, wherein control is performed.

The invention according to claim 15 is:
In the control method, the reverse rotation speed of the registration roller with respect to the first surface roughness is smaller than the reverse rotation speed of the registration roller with respect to the second surface roughness which is larger than the first surface roughness. The control method according to claim 9, wherein control is performed.

The invention according to claim 16 provides:
The control method is characterized in that when JAM occurs in the registration roller, control is performed so as not to reversely rotate the registration roller after releasing JAM or to reduce the time for performing reverse rotation. The control method according to any one of claims 9 to 15.

The invention according to claim 17 provides:
In a control program for an image forming apparatus that forms an image on a recording medium based on image data,
The image forming apparatus is configured to execute a step of controlling to change at least one of a reverse rotation speed and a reverse rotation time of a registration roller that can be rotated forward and backward provided in a recording medium conveyance path. It is a control program.

The invention according to claim 18
The step changes at least one of a reverse rotation speed and a reverse rotation time of the registration roller based on at least one of a basis weight, a type of the recording medium, and a loop amount formed by the registration portion. The control program according to claim 17, wherein the control program is controlled as follows.

The invention according to claim 19 is
In the step, at least one of a reverse rotation speed and a reverse rotation time of the registration roller is changed based on a set value indicating at least one of the basis weight, type, and loop amount. A control program according to claim 18.

The invention according to claim 20 provides
The step is controlled such that the reverse rotation time of the registration roller with respect to the first loop amount is smaller than the reverse rotation time of the registration roller with respect to the second loop amount that is larger than the first loop amount. The control program according to any one of claims 17 to 19, characterized in that:

The invention according to claim 21 is
The step is controlled so that the reverse rotation speed of the registration roller with respect to the first loop amount is smaller than the reverse rotation speed of the registration roller with respect to the second loop amount that is larger than the first loop amount. 21. The control program according to claim 17, wherein the control program is any one of claims 17 to 20.

The invention according to claim 22 is
The step is controlled such that the reverse rotation time of the registration roller with respect to the first surface roughness is smaller than the reverse rotation time of the registration roller with respect to the second surface roughness that is larger than the first surface roughness. A control program according to any one of claims 17 to 21, characterized in that:

The invention according to claim 23 is
The step is controlled so that the reverse rotation speed of the registration roller with respect to the first surface roughness is smaller than the reverse rotation speed of the registration roller with respect to the second surface roughness that is larger than the first surface roughness. The control program according to any one of claims 17 to 22, wherein the control program is executed.

The invention according to claim 24 provides
The step is characterized in that when JAM occurs in the registration roller, control is performed so as not to reversely rotate the registration roller or to reduce the time for reverse rotation after releasing JAM. A control program according to any one of claims 17 to 23.

  According to the present invention, recording on the conveyance path is performed by controlling at least one of the reverse rotation speed and the reverse rotation time of the registration roller provided on the recording medium conveyance path that can rotate forward and reverse. It is possible to correct the bending of the medium and reduce the occurrence of JAM.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention.

  In the figure, A is an image forming unit that forms an image on a recording medium by an electrophotographic method, B is an image reading unit that reads an image of a document and outputs image data, and C is an automatic document transport unit that transports the document to a reading position. D and D are post-processing devices that perform post-processing such as sorting, stapling and punching on the recording medium P discharged from the image forming unit A, and E is a large storage unit for storing the recording medium P supplied to the image forming unit A. It is a capacity feeding device.

  The image forming unit A includes a photoconductor 11, an image forming unit 12 that forms a toner image on the photoconductor 11 by a known charging unit, exposure unit, and developing unit, and a toner image on the photoconductor 11 as a recording medium. Transfer means 19 for transferring to the paper, paper feeding sections 13, 14, and 15 for storing the recording medium P on which an image is formed, a recording medium reversing and conveying section 17 for double-sided image formation, and a toner image formed on the recording medium P. A fixing device 40 for fixing and a control unit 30 are included. Reference numeral 18 denotes a registration roller, and 20 denotes a loop roller.

  The toner image formed on the photoconductor 11 by charging, exposure and development is transferred onto the recording medium P by the transfer means 19 and fixed by the fixing device 40.

  The fixing device 40 includes a heating roller and a pressure roller that rotates while being in pressure contact with the heating roller, and the surface temperature of the heating roller is detected by temperature detection means, and based on the detection information, A heating source built in the heating roller is ON / OFF controlled via the control unit 30 and is kept within a predetermined range.

  The paper feed unit 13 includes a paper feed unit 131 that operates in response to a paper feed start signal and separates and feeds the recording media P stored in the cassette 132 one by one. Similarly, the sheet feeding units 14 and 15 include a sheet feeding unit 141 and a cassette 142, and a sheet feeding unit 151 and a cassette 152, respectively. The large-capacity paper feeding device E includes a large-capacity recording medium storage unit 162, and feeds the recording medium P one by one from the top by the paper feeding unit 161.

  The control unit 30 compresses the read image data and temporarily stores it in the image memory, or decompresses the compressed image data and converts it into data for writing to the recording medium P. In addition, the connected devices are generally controlled.

  The image reading unit B includes an image sensor 24 that receives image light and converts it into an image signal, and a platen glass 25 on which a document is placed. The image reading unit B is placed on the document or platen glass 25 that is transported by the automatic document transport unit C. The placed original is read to generate image data.

  The automatic document conveying section C conveys the document placed on the document feeding table 21 from the platen roller 22 to the sheet discharge table 23, and image reading is performed below the platen roller 22.

  Here, the conveyance until the recording medium P is fed from the paper feeding units 13 to 15, the manual paper feeding unit 80 or the large-capacity paper feeding device E, is formed by the image forming unit A, and is discharged is described.

  The recording medium P stored from any one of the cassettes 132, 142, 152, the manual sheet feeding unit 80, or the large capacity sheet feeding device E selected by the sheet feeding start signal is fed one by one. 141, 151, 81 or 161 is taken out onto the transport path. The recording medium P is transported by a roller along a transport path to a resist section including a registration roller 18, a recording medium front end detection unit (181 in FIG. 4), a guide plate (182 in FIG. 4), and a loop roller 20. The registration unit corrects the bending in the conveyance direction of the recording medium P due to conveyance, and conveys the recording medium P so that the recording medium P is aligned with the toner image formed on the photoconductor 11 at the position of the transfer unit 19. Adjust the timing.

  The recording medium P on which the toner image is transferred by the transfer unit 19 is conveyed and the toner image is fixed by the fixing device 40. In the case of single-sided image formation, the recording medium P discharged from the fixing device 40 is discharged from the image forming unit A by the discharge roller 70. In the case of double-sided image formation, the recording medium P on which one side is fixed is reversed by the recording medium reversal conveyance unit 17 and then conveyed again to the registration unit, and after the toner image is transferred and fixed, the discharge roller Is discharged from the image forming unit A.

  FIG. 2 is an electrical block diagram relating to image data processing of the image forming apparatus.

  In the figure, a broken line connecting each unit indicates a serial communication line, and transmits and receives statuses and commands. Similarly, the thin solid line is a signal line that directly connects buses and units. Similarly, the double solid line transfers image data.

  The image forming unit A is provided with a recording unit 31, a control unit 32, and an adjustment value input unit 33.

  The recording unit 31 emits an LD based on the image data subjected to the writing process, exposes the image carrier, and records an image on a recording medium.

  In the control means 32, the overall control CPU performs serial communication with each control part such as the image reading part B, the recording means 31 and the adjustment value input means 33 in accordance with the program stored in the program memory while referring to the data in the system memory. The overall control is performed.

  Hereinafter, a flow of image formation of image data on a recording medium will be described.

<Scanning original>
The document is scanned with light from a light source (not shown). The scanning light of the document is photoelectrically converted by the CCD of the image reading unit B, and then transferred to the reading processing unit of the control unit 32 of the image generating unit A as an image signal. The reading processing unit performs processing such as A / D conversion and shading correction on the image signal, obtains image data, compresses it with the compression / decompression IC via the DRAM control IC, and stores it in the compression memory via the DRAM control IC. .

<Image writing>
The image data read from the compression memory is decompressed by the compression / decompression IC via the DRAM control IC and then transferred to the write processing unit via the DRAM control IC. The writing processing unit performs processing such as image arrangement, compression, and enlargement on the image data transferred based on the form to be printed, and transfers the processed image data to the LD of the recording unit 31.

  The adjustment value input unit 33 includes an LCD as a display and a button as an input unit, and is a setting unit that sets a type of a recording medium, a basis weight, and a loop amount for correcting the bending of the recording medium. . The input set value is stored in the nonvolatile memory of the control means 32.

  In this embodiment, the type of recording medium is classified according to the type of plain paper, high-quality paper, OHP sheet, and the like based on paper quality and surface roughness. The basis weight means the mass of one sheet of paper per square meter.

  A registration MT control means (not shown) in the printer control unit controls the rotation speed and rotation time of the registration MT 36 that drives the registration roller 18, and the forward / reverse rotation direction switching.

  In JAM detection, the arrival timing or passage time of the recording medium being conveyed is monitored by the sensor 37 arranged in the conveyance path of the recording medium, and the recording medium does not reach the sensor 37 within the specified time or does not pass the sensor. At this time, the overall control CPU determines that it is JAM. The JAM position information indicating the position where the JAM has occurred is transmitted from the overall control CPU to the adjustment value input means 33 and displayed as JAM information on the LCD as a display. If JAM is determined, the printing operation is stopped.

  FIG. 3 is a schematic diagram showing how the registration roller 18 rotates in the reverse direction due to the reverse rotation of the registration MT 36 in the registration unit, and the bending of the recording medium is corrected.

  The registration unit includes a registration roller 18, a recording medium front end detection unit (181 in FIG. 4), a guide plate (182 in FIG. 4), and a loop roller 20. When the toner image on the photoconductor 11 is transferred onto the recording medium P by the transfer unit 19, the recording medium P is temporarily stopped by the registration roller 18, and the leading edge position of the toner image on the photosensitive member 11 and the leading edge of the recording medium P are recorded. The registration rollers 18 are rotated again at the same timing so as to align the positions, and the conveyance is performed.

  3A shows a state in which the recording medium P is bent, and FIG. 3B shows a state in which the bending of the recording medium P is corrected.

  FIG. 4 is a schematic view of a state in which a loop is formed in the resist portion and the bending of the recording medium P is corrected as viewed from the side in time series.

  Information about the rotation speed, rotation direction, and rotation start timing of the registration roller is transmitted from the overall control CPU of the control unit 32 disposed in the image forming apparatus A to the printer control unit of the recording unit 31 via the serial communication line. The printer control unit determines a rotation pulse signal, a rotation / stop signal, and a forward / reverse signal for controlling the resist MT so as to achieve the received rotational speed, and outputs the determined signal to the resist MT.

  The rotation speed of the resist MT is determined by the frequency of the rotation pulse signal.

  When the rotation / stop signal is ON, the resist MT is rotated, and when it is OFF, the resist MT is stopped.

  The forward / reverse signal determines the rotation direction of the resist MT. When it is ON, it rotates in the forward direction, and when it is OFF, it rotates in the reverse direction.

  The registration roller 18 connected to the registration MT rotates according to the rotation of the registration MT.

  In FIG. 4A, the recording medium P is conveyed by the forward rotation of the loop roller 20 in the direction of arrow B, the leading end of the recording medium is detected by the recording medium leading end detection means 181, and the registration roller 18 is in the direction of arrow A. Start reverse rotation.

  In FIG. 4B, the recording medium P is further conveyed by the forward rotation of the loop roller 20, and the leading end reaches the registration roller 18. The state shown in FIG.

  In FIG. 4C, the recording medium P is further conveyed by the forward rotation of the loop roller 20, but the registration roller 18 is rotated in the reverse direction, so that it bends along the guide 182 and starts forming a loop.

  In FIG. 4D, the registration roller 18 stops rotating, but since the loop roller continues to rotate forward, the recording medium P is pressed against the registration roller 18 with its leading end pressed against the registration roller 18 by the strength of stiffness. Media bending is corrected.

  FIG. 4E shows a state in which the loop roller stops rotating and the bending of the recording medium is corrected. The state shown in FIG.

  Thereafter, the transfer unit 19 resumes normal rotation of the registration roller 18 and the loop roller 20 in the registration unit so that the toner image on the photoconductor 11 and the position of the recording medium P are aligned.

  5 and 6 are examples of a screen for setting the type of recording medium, the basis weight, and the registration loop amount that is the loop amount formed in the registration unit using the touch panel LCD as the adjustment value input means 33. FIG.

  In FIG. 5, when the machine state button 41 on the touch panel is touched and the recording medium setting button 42 is touched, FIG. 6A is displayed in the blank 43 in FIG. The size and the name indicating the size of the recording medium stored in the trays (for example, 51) displayed in black and white reversed of the trays 1 to 5 are displayed (for example, 52). When another tray number button is touched here, only the touched tray number is reversed in black and white, and the display changes to the display of the size, name and basis weight of the recording medium stored in the tray.

  Next, when changing the recording medium condition, if the recording medium condition selection button 53 is touched, the screen changes to the screen of FIG. Here, when the recording medium type button 54 is touched, the screen changes to FIG. Next, when the button of the recording medium type to be changed in FIG. 6C is touched and the OK button 55 is touched, the screen returns to FIG. 6B. The type of the recording medium is changed to the display of the recording medium touched in FIG.

  When it is desired to change the basis weight, when the basis weight button 56 is touched in FIG. 6B, the screen is changed to FIG. When the basis weight button to be changed is touched and the OK button 57 is touched, the screen returns to FIG. 6B, and the basis weight is changed to the basis weight display touched in FIG. 6D.

  When the recording medium type and the basis weight are determined, when the OK button 58 is touched in FIG. 6B, the determined recording medium type and the basis weight are stored in the non-volatile memory of the control means 32, and then the recording medium type and the basis weight are displayed. ), The display of the name and basis weight is changed, and the setting is completed.

  With the above operation, the recording medium type and basis weight for the tray number are set.

  Here, a procedure for setting the reverse rotation time of the resist MT 36 with respect to the type and basis weight of the recording medium set in FIGS. 5 and 6 will be described.

  Table 1 shows the reverse rotation time setting values of the resist MT 36 with respect to the recording medium and the basis weight.

  A table T1 showing the relationship between the preset type and basis weight of the recording medium shown in Table 1 and the reverse rotation time of the registration MT 36 is stored in the program memory of the control means 32, and the registration MT control means ( (Not shown) controls the reverse rotation time of the resist MT36 with reference to the table T1 based on the type and basis weight of the recording medium set when correcting the bending of the recording medium in the registration unit.

  Table 1 shows an example of the reverse rotation time of the resist MT 36 for each type of recording medium and basis weight. In Table 1, the type of the recording medium is classified according to the smoothness, and the reverse rotation time of the resist MT 36 is set according to the smoothness, that is, the surface roughness of the recording medium and the basis weight of the recording medium.

  For example, the reverse rotation time is set to 20 msec for rough paper with a basis weight of 80 g (5 ≦ smoothness <10 sec), and the reverse rotation time is set to 10 msec for plain paper with a basis weight of 80 g (20 ≦ smoothness <50 sec). Thus, it is possible to properly correct the bending of the recording medium.

  The smoothness in the present embodiment is the Beck smoothness described in JISP 8119.

  Returning to FIG. 6, FIG. 6E is a screen displayed on the LCD when the registration loop amount is set.

  As described above, when the machine state button (41 in FIG. 5) on the touch panel is touched and the loop amount adjustment button (44 in FIG. 5) is touched, FIG. 5 changes to FIG. 6 (e).

  Touching the +,-, or numeric button (61) displayed according to the registration loop amount to be set displays it in the registration loop amount adjustment column 62, and touches the setting button (61) to input the registration loop amount. . Input numbers in increments of -20 to +20. For example, if +13 is entered, the resist loop amount T is 13 mm. Since T = 13 is + 10 ≦ T <+15, referring to Table 2, the resist MT reverse rotation time is 30 msec at the maximum.

  Table 2 is a table T2 showing the relationship of the maximum value of the reverse rotation time of the resist MT with respect to the resist loop amount.

  The preset table 2 is stored in the program memory of the control means 32, and the registration MT control means (not shown) of the printer control unit is a registration set when correcting the bending of the recording medium with the registration rollers. The reverse rotation time of the resist MT is controlled with reference to the table T2 from the loop amount.

  In the present embodiment, the reverse rotation time of the resist MT is determined based on the type of recording medium and at least one of the basis weight and the resist loop amount. When the resist loop amount is set, Prior to the type and basis weight of the recording medium, the resist MT reverse rotation time is determined based on the resist loop amount. For example, in the case of a recording medium with rough paper 62 g ≦ basis weight <209 g, from Table 1, the resist MT reverse rotation time is 20 msec. However, when the resist loop amount is −5, the maximum value of the resist MT reverse rotation time is 15 msec from Table 2, so that the recording medium with rough paper 62 g ≦ basis weight <209 g is limited by the maximum value 15 msec. When the resist loop amount is −5, the resist MT reverse rotation time is 15 msec.

  In the above description, the operation unit of the image forming unit A is used as the adjustment value input unit 33. However, the PC (personal computer) is connected to the image forming unit A, and the type of the recording medium, the basis weight, and the like. It is also possible to input the resist loop amount.

  Further, in the present embodiment, the resist MT reverse rotation time is set based on at least one of the type and basis weight of the recording medium and the resist loop amount. Therefore, the reverse rotation of the resist MT according to at least one of the type and basis weight of the recording medium and the resist loop amount can be controlled, and the type, basis weight, and resist loop amount of the recording medium can be controlled. Since a corresponding loop can be formed, it is possible to properly correct the bending of the recording medium while reducing the occurrence of JAM in the recording medium.

  FIG. 7 is a flowchart of a process for correcting the bending of the recording medium by the reverse rotation of the resist MT36.

  The process for correcting the bending of the recording medium will be described with reference to the flowchart.

  The program for executing the flowchart of FIG. 7 is stored in the program memory and is executed by the overall control CPU.

  In step S1, it is confirmed whether the recording medium has been conveyed and the leading edge has reached the recording medium leading edge detection means. When the tip has arrived (step S1: YES), the process proceeds to step S2, and when it has not reached (step S1: NO), it waits for arrival.

  In step S2, a set value is set in timer 1. The timer 1 is the time from the end of correction of the recording medium due to the reverse rotation of the resist MT to the start of conveyance of the recording medium to the transfer means.

  In step S3, the basis weight of the recording medium is confirmed. If basis weight ≦ 50 g or 162 g ≦ basis weight (step S3: YES), the process proceeds to step S13. Otherwise (step S3: NO), the process proceeds to step S4.

  In step S4, the set registration loop amount is confirmed. If 0 ≦ registration loop amount (step S4: YES), the process proceeds to step S5. Otherwise (step S6: NO), the process proceeds to step S13.

  In step S5, the resist MT is switched to reverse rotation, and the rotation speed is set to low speed 1. The low speed 2 set in step S13 has a relation of low speed 1> low speed 2. The rotational speed of the resist MT is set under the conditions confirmed in steps S3 and S4. That is, when the basis weight of the recording medium is between 50 g and 162 g and the resist amount is equal to or greater than 0, the low speed is set to 1.

  In step S6, the reverse rotation time of the resist MT is set as the set value of the timer 2 based on the above-described Tables 1 and 2 based on the type, basis weight, and loop amount of the recording medium.

  In step S7, reverse rotation of the resist MT is started.

  In step S8, the timer 2 waits for time-up. Meanwhile, the resist MT continues to rotate backward. If the timer 2 has timed up (step S8: YES), the process proceeds to step S9. If the time has not expired (step S8: NO), the resist MT continues to rotate backward and waits in step S8.

  In step S9, the reverse rotation of the resist MT is stopped and switched to the normal rotation.

  In step S10, the timer 1 is confirmed to be up. If the time is up (step S10: YES), the process proceeds to step S11. If the time is not up (step S10: NO), the process waits at step S10.

  In step S11, normal rotation of the resist MT is started.

  In step S12, image formation is performed.

  In step S13, the resist MT is switched to reverse rotation, and the rotation speed is set to low speed 2.

  In step S14, the reverse rotation time of the resist MT is set as the set value of the timer 3 based on the above-described Tables 1 and 2 based on the type, basis weight, and loop amount of the recording medium.

  In step S15, reverse rotation of the resist MT is started.

  In step S16, the timer 3 waits for time-up. Meanwhile, the resist MT continues to rotate backward. If the timer 3 has timed up (step S16: YES), the process proceeds to step S9. If the timer 3 has not timed up (step S16: NO), the resist MT continues to rotate backward and waits in step S16.

  Next, a process in the case where JAM occurs in the conveyance of the resist portion after correcting the bending of the recording medium by the rotation control of the resist MT will be described with reference to FIG.

  Steps S21 to S31 are the same as steps S1 to S11 in FIG. 7, and steps S35 to S38 are the same as steps S13 to S16 in FIG.

  In step S32, it is determined by the control means (32 in FIG. 2) whether or not JAM has occurred in the conveyance of the registration unit. If JAM has occurred (step S32: YES), the process proceeds to step S34. If JAM has not occurred (step S32: NO), the process proceeds to step S33.

  In step S33, image formation is performed.

  In step S34, the registration unit transport JAM generation flag of the nonvolatile memory of the control means (32 in FIG. 2) is turned ON, and the printing operation is stopped.

  When the registration unit transport JAM occurs, the operator removes the recording medium on which the JAM has occurred and restarts the printing operation.

  FIG. 9 is a flowchart of processing when the printing operation is resumed after the registration unit conveyance JAM has occurred.

  Steps S51 to S52 are the same as steps S1 to S2 in FIG.

  In step S53, it is determined whether the registration unit transport JAM generation flag is ON. If it is ON (step S53: YES), the process proceeds to step S62. If it is OFF (step S53: NO), the process proceeds to step S54.

  In step S54, the resist MT is switched to the reverse rotation, and the rotation speed is set to the low speed 3. The low speed 3 is a reverse rotation speed of the resist MT when an image is formed before JAM occurs or a speed slower than the low speed 2.

  In step S55, the reverse rotation time of the resist MT is set in the timer 4. The timer 4 is the time of reverse rotation of the resist MT when an image is formed before the occurrence of JAM, or the time shorter than the time set by the timer 2, like the rotation speed.

  In step S56, reverse rotation of the resist MT is started.

  In step S57, the timer 4 waits for time-up. Meanwhile, the resist MT continues to rotate backward. If the timer 4 has expired (step S57: YES), the process proceeds to step S58. If the timer 4 has not expired (step S57: NO), the resist MT continues to reversely rotate and waits in step S57.

  In step S58, the reverse rotation of the resist MT is stopped and switched to the normal rotation.

  Steps S59 to S61 are the same as steps S10 to S12 in FIG.

  In step S62, the registration unit transport JAM flag is turned OFF, and the process proceeds to step S59. That is, the reverse rotation of the resist MT is not performed in the first image formation after the occurrence of JAM.

  In the present embodiment, a copying machine has been described as an example of the image forming apparatus, but the present invention can also be applied to a laser printer or the like.

  The detailed configuration and detailed operation of each configuration constituting the image forming apparatus can be changed as appropriate without departing from the spirit of the present invention.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is an electrical block diagram relating to image data processing of the image forming apparatus in the embodiment of the present invention. FIG. 6 is a schematic diagram illustrating a state in which a registration roller is rotated in reverse by rotation of a resist MT in the embodiment of the present invention, and the bending of a recording medium is corrected. 3A shows a state in which the recording medium is bent and is nipped by the registration rollers, and FIG. 3B shows a state in which the bending of the recording medium is corrected. FIG. 4 is a schematic diagram illustrating a state in which a loop is formed and the bending of a recording medium is corrected. FIG. 4A shows a state in which the recording medium is transported and the leading edge is detected by the recording medium leading edge detection means. FIG. 4B shows a state in which the recording medium is further conveyed and the leading end reaches the registration roller. FIG. 4C shows a state in which the recording medium is curved along the guide to form a loop. FIG. 4D shows a state where the registration roller is rotated in the reverse direction of the arrow and the nip is removed. FIG. 4E shows a state in which the recording medium is pushed by the registration roller with a firm strength and the bending of the recording medium is corrected. It is a schematic diagram which shows an example of the setting screen displayed on the touchscreen type LCD which is an adjustment value input means in embodiment of this invention. It is a schematic diagram which shows an example of the setting screen displayed on a part of touch panel type LCD of FIG. It is a flowchart of the process which correct | amends the curvature of a recording medium by reverse rotation of the resist MT in embodiment of this invention. It is a flowchart of a process in case JAM generate | occur | produces in conveyance of the registration part in embodiment of this invention. 6 is a flowchart of processing when a printing operation is resumed after cancellation of JAM in conveyance of a registration unit according to an embodiment of the present invention.

Explanation of symbols

18 Registration Roller 20 Loop Roller 31 Recording Unit 32 Control Unit 33 Adjustment Value Input Unit 36 Registration MT
A Image forming unit B Image reading unit C Automatic document conveying unit D Post-processing device E Large-capacity paper feeder

Claims (24)

In an image forming apparatus that forms an image on a recording medium based on image data,
A registration roller provided in the recording medium conveyance path and capable of rotating in the forward and reverse directions;
An image forming apparatus comprising: a control unit that changes at least one of a reverse rotation speed and a reverse rotation time of the registration roller. The control means changes at least one of a reverse rotation speed and a reverse rotation time of the registration roller based on at least one of a basis weight, a type of the recording medium, and a loop amount formed by the registration portion. The image forming apparatus according to claim 1. A setting unit configured to set at least one of the basis weight, type, and loop amount, and the control unit performs reverse rotation speed and reverse rotation time of the registration roller based on the setting by the setting unit; The image forming apparatus according to claim 2, wherein at least one of them is changed. The control unit controls the reverse rotation time of the registration roller with respect to the first loop amount to be shorter than the reverse rotation time of the registration roller with respect to the second loop amount that is larger than the first loop amount. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control means controls the reverse rotation speed of the registration roller with respect to the first loop amount to be smaller than the reverse rotation speed of the registration roller with respect to the second loop amount that is larger than the first loop amount. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control means is configured so that the reverse rotation time of the registration roller with respect to the first surface roughness is shorter than the reverse rotation time of the registration roller with respect to the second surface roughness that is larger than the first surface roughness. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled. The control means is configured so that the reverse rotation speed of the registration roller with respect to the first surface roughness is smaller than the reverse rotation speed of the registration roller with respect to the second surface roughness that is greater than the first surface roughness. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled. When the JAM is generated in the registration roller, the control means does not reversely rotate the registration roller after canceling the JAM, or reduces the time for reverse rotation of the registration roller or the reverse rotation speed. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled as follows. In a control method of an image forming apparatus for forming an image on a recording medium based on image data,
A control method comprising: controlling at least one of a reverse rotation speed and a reverse rotation time of a registration roller provided in a recording medium conveyance path and capable of rotating in the forward and reverse directions. The control method changes at least one of a reverse rotation speed and a reverse rotation time of the registration roller based on at least one of a basis weight of the recording medium, a type, and a loop amount formed by the registration portion. The control method according to claim 9, wherein control is performed so that the control is performed. Control is performed to change at least one of the reverse rotation speed and the reverse rotation time of the registration roller based on a setting value indicating at least one of the basis weight, type, and loop amount. The control method according to claim 10. The control method performs control so that the reverse rotation time of the registration roller with respect to the first loop amount is shorter than the reverse rotation time of the registration roller with respect to the second loop amount that is larger than the first loop amount. The control method according to any one of claims 9 to 11, wherein: The control method is controlled so that the reverse rotation speed of the registration roller with respect to the first loop amount is smaller than the reverse rotation speed of the registration roller with respect to the second loop amount that is larger than the first loop amount. The control method according to claim 9, wherein the control method is performed. The control method is such that the reverse rotation time of the registration roller with respect to the first surface roughness is smaller than the reverse rotation time of the registration roller with respect to the second surface roughness that is larger than the first surface roughness. The control method according to claim 9, wherein control is performed. In the control method, the reverse rotation speed of the registration roller with respect to the first surface roughness is smaller than the reverse rotation speed of the registration roller with respect to the second surface roughness which is larger than the first surface roughness. The control method according to claim 9, wherein control is performed. The control method is characterized in that when JAM occurs in the registration roller, control is performed so as not to reversely rotate the registration roller after releasing JAM or to reduce the time for performing reverse rotation. The control method according to any one of claims 9 to 15. In a control program for an image forming apparatus that forms an image on a recording medium based on image data,
The image forming apparatus is configured to execute a step of controlling to change at least one of a reverse rotation speed and a reverse rotation time of a registration roller that can be rotated forward and backward provided in a recording medium conveyance path. Control program. The step changes at least one of a reverse rotation speed and a reverse rotation time of the registration roller based on at least one of a basis weight, a type of the recording medium, and a loop amount formed by the registration portion. The control program according to claim 17, wherein control is performed as follows. In the step, at least one of a reverse rotation speed and a reverse rotation time of the registration roller is changed based on a set value indicating at least one of the basis weight, type, and loop amount. The control program according to claim 18. The step is controlled such that the reverse rotation time of the registration roller with respect to the first loop amount is smaller than the reverse rotation time of the registration roller with respect to the second loop amount that is larger than the first loop amount. The control program according to any one of claims 17 to 19, wherein: The step is controlled so that the reverse rotation speed of the registration roller with respect to the first loop amount is smaller than the reverse rotation speed of the registration roller with respect to the second loop amount that is larger than the first loop amount. The control program according to any one of claims 17 to 20, wherein The step is controlled such that the reverse rotation time of the registration roller with respect to the first surface roughness is smaller than the reverse rotation time of the registration roller with respect to the second surface roughness that is larger than the first surface roughness. The control program according to any one of claims 17 to 21, wherein: The step is controlled so that the reverse rotation speed of the registration roller with respect to the first surface roughness is smaller than the reverse rotation speed of the registration roller with respect to the second surface roughness that is larger than the first surface roughness. The control program according to any one of claims 17 to 22, characterized by: The step is characterized in that when JAM is generated in the registration roller, control is performed so as not to reversely rotate the registration roller or to reduce the time for reverse rotation after releasing JAM. The control program according to any one of claims 17 to 23.

Images