JP5109729B2 - Image forming apparatus, image forming apparatus control method, and image forming apparatus control program - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program, and more particularly to an image forming apparatus that performs sheet loop control, an image forming apparatus control method, and an image forming apparatus control program. About.

  In an electrophotographic image forming apparatus (MFP (Multi Function Peripheral), facsimile machine, copying machine, etc.), a transfer unit that transfers a toner image onto copy paper or OHP paper, and fixing that fixes the toner image on the paper Part.

  The sheet is conveyed by the transfer unit and the fixing unit. The conveyance speed of the paper may also change due to a change in the diameter of the heat roller (heat receiving roller). When the sheet conveyance speed changes, sheet pulling or excessive looping (deflection) occurs between the transfer unit and the fixing unit, causing image degradation.

  In order to solve such a problem, an image forming apparatus is known that controls the conveyance speed of each of a plurality of conveyance members so that a sheet forms a fixed loop between a transfer unit and a fixing unit. Yes.

  Patent Document 1 below describes an image forming apparatus that controls a loop with high accuracy by calculating a speed reference value of a conveyance member from a detection result of a loop detection unit and increasing or decreasing the conveyance speed with respect to the speed reference value. Has been. The loop sensor detects whether or not the loop amount has reached a certain amount, and updates the speed reference value as needed based on the result.

Patent Document 2 discloses an image forming apparatus that increases or decreases the fixing roller speed based on the fixing roller speed reference value so that the loop amount is constant.
JP 2005-181507 A JP 2006-313207 A

  An object of the present invention is to provide an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program capable of appropriately controlling the apparatus based on a loop detection result.

In order to achieve the above object, according to one aspect of the present invention, an image forming apparatus includes a first transport unit that is provided upstream of a transport path and transports a recording medium in a predetermined direction, and a downstream side of the transport path. A second conveyance unit that conveys the recording medium in a predetermined direction, and a loop that occurs in the recording medium between the first conveyance unit and the second conveyance unit when the recording medium is conveyed in the conveyance path; Storage means for storing information; and loop information acquisition means for acquiring information relating to a loop generated in the recording medium between the first conveying means and the second conveying means when the recording medium is actually conveyed in the conveying path; The recording medium being transported is based on the information stored in the storage means and the information about the loop obtained when the recording medium is actually transported, acquired by the loop information acquisition means. Judging means for judging whether or not a constant, and a control means for changing at least one of the driving speed of the first conveying means and second conveying means, the loop information obtaining means, resulting loop When the recording medium is in contact with both the first conveyance unit and the second conveyance unit, the control unit detects a difference in conveyance speed between the first conveyance unit and the second conveyance unit. The control unit performs control so that the loop amount, which is the deflection amount of the recording medium generated between the first transport unit and the second transport unit, is constant, and the control unit performs the first transport with reference to the speed reference value. Speed control means for increasing or decreasing the drive speed of at least one of the means and the second transport means, and change means for changing the speed reference value based on the detection result of the loop information acquisition means.
According to another aspect of the present invention, an image forming apparatus includes a first transport unit that transports a recording medium in a predetermined direction, provided on the upstream side of the transport path, and a recording medium that is provided on the downstream side of the transport path. A second transport unit that transports the recording medium in a predetermined direction, and a memory that stores information relating to a loop that occurs in the recording medium between the first transport unit and the second transport unit when the recording medium is transported in the transport path. Means, a loop information acquisition unit for acquiring information about a loop generated in the recording medium between the first transport unit and the second transport unit when the recording medium is actually transported in the transport path, and stored in the storage unit Whether the recording medium being transported is a predetermined one based on the information obtained and the information about the loop obtained when the recording medium is actually transported, acquired by the loop information acquisition means. And a determining means, by judging means, when the recording medium being conveyed is determined to be a predetermined one, the storage means stores information about the loop loop information acquisition means has acquired.

  Preferably, the determination unit determines that a media error has occurred when the recording medium being conveyed is not a predetermined one.

  Preferably, the image forming apparatus includes an image forming unit that forms an image, a transfer unit that transfers an image formed by the image forming unit onto a recording medium, and a fixing unit that fixes the image transferred onto the recording medium by the transfer unit. And a first driving unit for driving the transfer unit and a second driving unit for driving the fixing unit. The first conveying unit is a transferring unit, and the second conveying unit is a fixing unit. is there.

  Preferably, the image forming apparatus further includes an input unit that inputs information on a type of the recording medium conveyed in the conveyance path, and the storage unit stores information on a loop generated in the recording medium for each type of the recording medium. The determination means reads out information corresponding to the type of the recording medium input by the input means from the storage means and makes a determination.

  Preferably, the determination unit determines that the information regarding the type of the recording medium input by the input unit is incorrect when the recording medium being conveyed is not a predetermined one.

  Preferably, the storage unit stores information regarding the loop acquired by the loop information acquisition unit when the determination unit determines that the recording medium being conveyed is a predetermined one.

  Preferably, the storage unit does not store information regarding the loop acquired by the loop information acquisition unit when the determination unit determines that the recording medium being conveyed is not a predetermined one.

  Preferably, the image forming apparatus further includes a discharge unit that discharges the recording medium conveyed on the conveyance path when the determination unit determines that the recording medium being conveyed is not a predetermined one.

  Preferably, the discharging unit forcibly discharges the transported recording medium from the main body when it is determined that the transported recording medium is not a predetermined one when performing duplex printing.

According to still another aspect of the present invention, a control method for an image processing apparatus is provided on a downstream side of a conveyance path, a first conveyance unit that conveys a recording medium in a predetermined direction, provided on the upstream side of the conveyance path. Information on a loop generated in the recording medium between the first conveying means and the second conveying means when the recording medium is conveyed in the conveying path and the second conveying means for conveying the recording medium in a predetermined direction. A control method for an image forming apparatus including a storage unit for storing a loop generated in a recording medium between a first conveyance unit and a second conveyance unit when the recording medium is actually conveyed in a conveyance path Loop information acquisition step for acquiring information about the information, information stored in the storage means, and information about the loop obtained when the recording medium was actually transported, acquired by the loop information acquisition step Based on the absence determination step of determining whether the recording medium being conveyed is a predetermined and a control step of changing at least one of the driving speed of the first conveying means and second conveying means The loop information acquisition step detects the amount of the generated loop, and when the recording medium is in contact with both the first transport unit and the second transport unit in the control step, the first transport unit and Control is performed so that the loop amount, which is the deflection amount of the recording medium generated between the first conveying unit and the second conveying unit, is constant due to the difference in the conveying speed of the second conveying unit. Based on the detection result in the speed control step for increasing / decreasing the driving speed of at least one of the first transport unit and the second transport unit with reference to the speed reference value, and the loop information acquisition step. There are, and a changing step of changing the speed reference value.
According to still another aspect of the present invention, a control method for an image processing apparatus is provided on a downstream side of a conveyance path, a first conveyance unit that conveys a recording medium in a predetermined direction, provided on the upstream side of the conveyance path. Information on a loop generated in the recording medium between the first conveying means and the second conveying means when the recording medium is conveyed in the conveying path and the second conveying means for conveying the recording medium in a predetermined direction. A control method for an image forming apparatus including a storage unit for storing a loop generated in a recording medium between a first conveyance unit and a second conveyance unit when the recording medium is actually conveyed in a conveyance path Loop information acquisition step for acquiring information about the information, information stored in the storage means, and information about the loop obtained when the recording medium was actually transported, acquired by the loop information acquisition step And a determination step for determining whether or not the recording medium being transported is a predetermined one, and when it is determined in the determination step that the recording medium being transported is a predetermined one The storage means stores information related to the loop acquired in the loop information acquisition step.

According to still another aspect of the present invention, a control program for an image processing apparatus is provided on a downstream side of a conveyance path, a first conveyance unit that is provided on the upstream side of the conveyance path, and conveys a recording medium in a predetermined direction. Information on a loop generated in the recording medium between the first conveying means and the second conveying means when the recording medium is conveyed in the conveying path and the second conveying means for conveying the recording medium in a predetermined direction. A control program for an image forming apparatus including a storage unit for storing a loop generated in a recording medium between a first conveyance unit and a second conveyance unit when the recording medium is actually conveyed in a conveyance path Loop information acquisition step for acquiring information on the information, information stored in the storage means, and the loop obtained when the recording medium is actually transported acquired by the loop information acquisition step Based on the information about the control recording medium being conveyed to vary a determination step whether or not a predetermined, at least one of the driving speed of the first conveying means and second conveying means And the step of detecting the amount of generated loop in the loop information acquisition step, and in the control step, when the recording medium is in contact with both the first transport unit and the second transport unit, Control is performed so that the loop amount, which is the deflection amount of the recording medium generated between the first transport unit and the second transport unit, is constant due to the difference in transport speed between the first transport unit and the second transport unit. The control step includes a speed control step for increasing / decreasing a driving speed of at least one of the first transport unit and the second transport unit based on the speed reference value, a loop information Based on the detection result of the acquisition step, and a changing step of changing the speed reference value.
According to still another aspect of the present invention, a control program for an image processing apparatus is provided on a downstream side of a conveyance path, a first conveyance unit that is provided on the upstream side of the conveyance path, and conveys a recording medium in a predetermined direction. Information on a loop generated in the recording medium between the first conveying means and the second conveying means when the recording medium is conveyed in the conveying path and the second conveying means for conveying the recording medium in a predetermined direction. A control program for an image forming apparatus including a storage unit for storing a loop generated in a recording medium between a first conveyance unit and a second conveyance unit when the recording medium is actually conveyed in a conveyance path Loop information acquisition step for acquiring information on the information, information stored in the storage means, and the loop obtained when the recording medium is actually transported acquired by the loop information acquisition step And a determination step for determining whether or not the recording medium being transported is a predetermined one based on the information relating thereto, and the recording medium being transported is a predetermined one in the determination step When it is determined that, the storage unit stores information on the loop acquired in the loop information acquisition step.

  According to these inventions, it is possible to provide an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program capable of appropriately controlling the apparatus based on a loop detection result.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described.

  In a conventional image forming apparatus that does not have a paper basis weight detection mechanism, even if the media specified by the user and the transport media (media set in the paper feed unit) are different, the media is correct. It was judged that it was set. For example, even when the user sets thick paper in a certain paper feed slot and the user mistakenly sets the media in the paper feed slot as “plain paper”, the apparatus may detect the error. Can not.

  Therefore, in an image forming apparatus that records a loop detection result for each medium, there is a problem that if a user sets a medium by mistake, a past correct loop detection result stored for each medium is destroyed. If the correct loop detection result is broken, highly accurate loop control cannot be maintained.

  The image forming apparatus according to the present embodiment is configured such that when a user sets a medium by mistake, it can be detected without using a paper basis weight detection mechanism. Further, even when the user sets the medium by mistake, the loop control with high accuracy can be maintained.

  [First Embodiment]

  FIG. 1 is a diagram showing an outline of the central cross section of the image forming apparatus according to the first embodiment of the present invention.

  Here, it is assumed that the image forming apparatus is a tandem full-color printer.

  First, the configuration of the image forming unit of the image forming apparatus will be described. The image forming apparatus includes cartridges 28a, 28b, 28c, and 28d corresponding to YMCK (yellow, magenta, cyan, and black). Each cartridge 28a, 28b, 28c, 28d includes charging units 5a, 5b, 5c, 5d for charging the photoreceptors 3a, 3b, 3c, 3d, and exposure units 6a, 6b, 6c, 6d for exposing image patterns. In addition, developing units 4a, 4b, 4c, and 4d for developing toner are incorporated.

  The image forming apparatus includes an intermediate transfer belt 2 that forms an image by superimposing four color toner images formed on the photoreceptors 3a, 3b, 3c, and 3d, and a toner image formed on the intermediate transfer belt 2 as a recording medium. A secondary transfer roller 11 to be transferred onto the medium, an intermediate transfer belt cleaner (blade) 7 for separating the transfer residual toner from the intermediate transfer belt 2, a waste toner box 15 for storing the separated transfer residual toner, and a cartridge 28a. , 28b, 28c, and 28d, toner bottles 25a, 25b, 25c, and 25d that replenish toner by operating the stirring blades 26a, 26b, 26c, and 26d are provided.

  Next, the configuration of the recording medium transport unit will be described. The image forming apparatus includes a paper feed roller 8 that feeds a recording medium from the recording medium storage unit 16, a timing roller 10 that temporarily stops the fed recording medium, and a toner image that is image-formed on the intermediate transfer belt 2. A secondary transfer roller 11 for transfer onto the recording medium, a fixing roller 12 (consisting of a pressure roller 12a and a heating roller 12b) for fixing the toner image transferred onto the recording medium, and the recording medium after fixing are discharged. Alternatively, a paper discharge roller 13 that conveys to the double-sided conveyance path, and double-sided path conveyance rollers 14 a and 14 b that convey the recording medium to the timing roller 10 via the double-sided conveyance path are provided.

  Whether or not a loop formed on the sheet by the transfer portion adjacent to the secondary transfer roller 11 and the fixing roller 12 between the secondary transfer roller 11 and the fixing roller 12 on the sheet passing path has reached a certain level. A paper detection sensor (fixing loop sensor or loop detection sensor) 27 is provided.

  The paper feed roller 8 is a standard cassette paper feed roller, and a multi-manual paper feed roller 9 is also provided in the paper passing path.

  In the image forming apparatus, as a motor, a color PC motor 17, a main motor 18, a fixing motor 19, a color developing motor 20, a developing motor 21, a double-sided conveyance motor 22, and a toner replenishing motor (yellow, A magenta (for magenta) 23 and a toner supply motor (for cyan and black) 24 are provided.

  Further, paper detection sensors 29 to 31 and a paper material detection sensor 32 are provided in the paper passing path. The paper material detection sensor 32 may be omitted.

  FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus.

  The image forming apparatus includes a controller unit 100 and an engine control unit 200. The engine control unit 200 includes a CPU 203 that controls the image forming apparatus and controls the print head. The CPU 203 also controls various loads 205 such as a paper conveyance motor and a fixing heater.

  Further, in the engine control unit 200, an EEPROM (nonvolatile memory) 207 which is a storage medium and a CPU 203 are connected, and data measured by the CPU can be stored.

  In addition to the EEPROM 207, a CSIC (information storage unit) 201 is attached to the consumable unit, and information on the consumable can be stored.

  The engine unit 200 and the controller unit 100 are connected to exchange necessary information such as a dot counter.

  FIG. 3 is a diagram showing a mechanism for performing control so as to hold the loop at a constant amount.

  The motors M1 and M2 that are driving sources of the fixing roller 12 and the transfer roller 11 can be switched in driving speed by the CPU 203 via the motor drivers 205a and 205b.

  Further, the state of the loop detection sensor 27 for determining whether or not the loop amount has reached a predetermined amount is input to the CPU 203.

  FIG. 4 is a diagram illustrating the operating principle of the loop detection sensor.

  The loop detection sensor 27 includes a photo interrupter 27b and a mechanical actuator 27a.

  The mechanical actuator 27a rotates around the axis by contacting the transport sheet. When a loop is formed on the paper, the mechanical actuator 27a is pushed up as indicated by the dotted line, and the light shielding of the photo interrupter 27b is released accordingly. Thereby, the state of the loop can be detected.

  That is, if the photo interrupter 27b is in a light shielding state, there is no loop, and if the photo interrupter 27b is in a light transmitting state, there is a loop.

  The apparatus may be configured such that when the mechanical actuator 27a is pushed up, the photo interrupter 27b is shielded accordingly.

  FIG. 5 is a diagram illustrating a detailed configuration of the loop detection sensor.

  Referring to the drawing, a loop detection sensor composed of a photo interrupter 27 b and a mechanical actuator 27 a is provided in the vicinity of the secondary transfer roller 11. The secondary transfer roller 11 can be in pressure contact (indicated by a dotted line in the drawing) / separated (indicated by a solid line in the drawing) with respect to the intermediate transfer belt 2.

  FIG. 6 is a diagram illustrating a state of the loop detection sensor when the loop amount is small.

  A two-dot chain line in the figure indicates a loop state that the sheet can take. When the loop amount is small, the mechanical actuator 27a is rotated to the left, and the photo interrupter 27b is in a translucent state accordingly.

  FIG. 7 is a diagram illustrating a state of the loop detection sensor when the loop amount is medium (or large).

  A two-dot chain line in the figure indicates a loop state that the sheet can take. As the loop amount increases, the mechanical actuator 27a rotates to the right. When the loop amount becomes medium, the photo interrupter 27b becomes light-shielded accordingly.

  FIG. 8 is a flowchart showing a loop control process executed by the image forming apparatus.

  Referring to the drawing, in step S101, in response to receiving the print request transmitted from the controller, the printing operation is started in step S103. At this time, media information set by the user (paper material information such as whether the paper to be fed is plain paper, an OHP sheet, or cardboard) is also input to the apparatus.

  In step S105, when the leading end position of the paper reaches the loop control start position (for example, a point 5 mm before the fixing roller), in step S107, the speeds of various fixing drive motors are calculated and determined. Execute. In step S109, “loop control 2” is executed to switch the driving speed of the fixing motor.

  When the trailing edge position of the sheet reaches the loop control completion position (for example, a point beyond 5 mm downstream of the secondary transfer roller) in step S111, the loop control 2 is ended.

  Finally, in step S113, "loop control 3" which is a process of calculating the speed reference value of the fixing motor and Ron by calculation is executed, and the sheet is discharged in step S115 and the process is terminated. Note that Ron is a numerical value indicating the ratio of time when the speed of the fixing motor is set to be fast (the operation for eliminating the loop is performed) when one sheet is conveyed.

  FIG. 9 is a flowchart showing details of the loop control 1 (S107) of FIG.

  In step S201, the speed reference value Vref of the fixing motor that matches the paper material information is determined from the paper material information transmitted from the controller. In step S203, the fixing motor speeds Vu and Vd are calculated from the speed reference value. Each numerical value will be described below.

  The speed reference value Vref is a reference speed of the fixing motor, and a reference speed determined based on the result of the previous loop control is used. A detailed calculation method of Vref will be described with reference to a flowchart of loop control 3 in FIG.

  Vu is a speed setting on the loop cancellation side, and Vd is a speed setting on the loop forming side, and is calculated as follows.

  Vu = Gu * Vref (Gu> 1): Speed setting on the loop cancellation side

  Vd = Gd * Vref (Gd <1): Speed setting on the loop forming side

  FIG. 10 is a flowchart showing details of the loop control 2 (S109) of FIG.

  This is a control for switching the speed of the fixing drive motor in accordance with the ON / OFF switching of the loop detection sensor.

  If the output signal of the loop detection sensor is ON in step S301 (the state shown in FIG. 7 where the loop amount is medium or higher), the speed of the fixing drive motor is set to Vu in step S303. In step S305, “1” is added to the cumulative ON counter Con.

  If the output signal of the loop detection sensor is OFF in step S301 (the state of FIG. 6 where the loop amount is small), the speed of the fixing drive motor is set to Vd in step S307. In step S309, “1” is added to the cumulative OFF counter Coff.

  FIG. 11 is a flowchart showing details of the loop control 3 (S113) of FIG.

  This is to calculate the speed reference value from the value of the cumulative ON counter and the value of the cumulative OFF counter measured in the loop control 2.

  In step S401, the value of Ron and the speed reference value Vref are calculated. More specifically, the ratio Ron / Roff of the set time for each ON / OFF of the loop detection sensor is calculated based on the following formula.

  Ron = Con / (Con + Coff)

  Roff = 1-Ron

  Then, the speed reference value Vref, which is the center speed, is calculated from the ratio of Ron / Roff by the following formula.

  Vref = Vu * Ron + Vd * Roff

  When Ron is large, it means that the time during which the loop is formed is relatively long. Therefore, the speed reference value Vref is set earlier than the previous speed reference value. Conversely, when Roff is large, it means that the time during which no loop is formed is relatively long. Therefore, the speed reference value Vref is set slower than the previous speed reference value.

  Note that Vref may be calculated from the result of the last time (one sheet before), or the speed reference value may be calculated from the average value of a plurality of past sheets.

  In step S403, the paper material is determined.

  This is to calculate the rate of change of Ron from the result of Ron recorded in the paper material table corresponding to the paper material set by the user and Ron calculated this time. As a result, if it is determined that they are different by a predetermined ratio or more, “Media Abnormality” is set as the media error information in Step S405.

  If not, “media normal” is set as the media error information in step S409.

  If the types of paper are the same, the value of Ron becomes almost equal each time paper is passed. Therefore, if the Ron value recorded in the paper material table corresponding to the paper material set by the user differs from the measured Ron value by a predetermined amount or more (the Ron value has changed rapidly). The medium is determined to be different from the user setting (medium abnormality).

  For example, when the allowable ratio is set to 10%, it is assumed that the value of Ron recorded in the paper material table is 0.47, and the result Ron calculated this time is 0.45.

  First, the rate of change is calculated by the following equation.

  Rate of change = 100− (Ron of the current calculation result / Ron * 100 of the paper material table)

  = 100-0.45 / 0.47 * 100

  = -4.25

  In this example, since a predetermined ratio (10%) ≧ change ratio (absolute value) is established, it is determined that the medium is normal.

  Finally, in step S407, the calculated speed reference value and Ron are updated to a paper material table corresponding to the paper material set by the user.

  FIG. 12 is a diagram showing a specific example of the paper material table.

  Referring to the drawing, here, a paper material table corresponding to plain paper and a paper material table corresponding to thick paper are shown. In each table, the value of Ron and the value of Vref are recorded. Here, it is assumed that values for the past 10 sheets are recorded. The table is recorded in an EEPROM or the like.

  It is assumed that the user sets plain paper and actually passes plain paper. The average Ron of the past 10 plain papers is 42.6%, and the measurement result of this Ron is 43.0%.

  At this time, the difference of Ron is 0.4%, and since the difference is less than 10%, it is determined that the medium is correctly set, and “media normal” is set.

  In addition, when the user sets plain paper, it is assumed that thick paper is actually passed. The average Ron of the past 10 plain papers is 42.6%, and the measurement result of this Ron is 53.0%.

  At this time, the difference of Ron is 10.4%, and since the difference is 10% or more, it is determined that the medium is erroneously set, and “media abnormality” is set.

  FIG. 13 is a diagram illustrating an operation of the loop detection sensor when plain paper is actually passed in a state where plain paper is set.

  Here, the number of times the cumulative ON counter is added (the number of times the loop amount is determined to be medium or higher) is shown as the VH set number. Further, the ratio of the time when the fixing motor speed is set to Vu (VH ratio) and the ratio of the time set to Vd (VL ratio) are shown in percentage (the sum of the VH ratio and the VL ratio is 100). Become).

  The value of Vref is shown in the VC column. Here, the ratio of the speed to the system speed is shown as the value of VC. VC = 98.94 indicates that the fixing motor is operated at 98.94% of the system speed.

  In FIG. 13, the number of VH settings in the average of five measurements is 12.8, the VH ratio in the average of five measurements is 47.218, and the VL ratio in the average of five measurements is 52.782, five times. The VC in the average of the measurements is 99.158.

  FIG. 14 is a diagram illustrating the operation of the loop detection sensor when thick paper is actually passed in the state set as plain paper.

  In FIG. 14, the number of VH settings in the average of five measurements is 14.6, the VH ratio in the average of five measurements is 53.79, and the VL ratio in the average of five measurements is 46.21, five times. The VC in the average of the measurements is 99.906.

  Thus, since the detection value of the loop detection sensor is different between plain paper and thick paper, it can be seen that the type of media can be detected.

  FIG. 15 is a flowchart showing details of the paper discharge control (S115) of FIG.

  In this process, if “medium abnormality” is set as the media error information, discharge control of the main body is started regardless of the content of the instruction from the controller.

  Also, if “Media Normal” is set as the media error information, double-sided storage control starts if the controller's instruction is double-sided storage (double-sided printing), otherwise it is The paper discharge control is started.

  Referring to FIG. 15, in step S <b> 501, it is determined whether “media abnormality” is set as the media error information. If YES, the paper discharge control is performed in step S503 as an error.

  If “NO” in the step S501, it is determined whether or not the instruction from the controller is double-sided storage in a step S505. If YES, the double-sided storage control is started in step S507, and if NO, main body discharge control is started in step S509.

  According to this flowchart, when the user designates double-sided printing, if it is determined that the material of the recording medium specified by the user is different from the material of the actual recording medium to be conveyed, the recording medium to be conveyed is forced. Thus, the control is switched to the discharge from the main body.

  As a result, even when the user's media setting is incorrect, it is possible to prevent JAM when double-sided paper is passed by discharging the paper to the main body.

  [Second Embodiment]

  The difference between the image forming apparatus in the second embodiment and that in the first embodiment will be described below.

  FIG. 16 is a flowchart showing the contents of the loop control 3 process (S113 in FIG. 8) executed by the image forming apparatus according to the second embodiment.

  Since the processing in steps S601 to S605 and the processing in S609 and S611 are the same as the processing in steps S401 to S405 and the processing in S407 and S409 in FIG. 11, the description thereof will not be repeated here.

  After the processing in step S605 or S611, it is determined in step S607 whether “media normal” is set as the media error information. Only when the answer is YES, the current values of Ron and Vref are registered in the paper material table.

  As a result, the table corresponding to the paper material can be updated with the calculated speed reference value and Ron only when “medium normal” is set in the media error information by the paper material determination. That is, when the user's media setting is incorrect, the table is not updated with an incorrect value, and high-precision loop control can be maintained.

  [Effects of the embodiment]

  According to the above-described embodiment, the image forming apparatus includes: an image forming unit that forms an image; a transfer unit that transfers an image formed by the image forming unit onto a recording medium; and A fixing means for fixing the image transferred to the image forming apparatus; a first driving means for driving the transferring means; a second driving means for driving the fixing means; and the recording medium being both the transferring means and the fixing means. A loop amount, which is a deflection amount of the recording medium generated between the transfer unit and the fixing unit, is constant due to a difference in driving speed between the first driving unit and the second driving unit. The speed control means for increasing / decreasing the driving speed of the second driving means on the basis of the speed reference value of the second driving means, the loop detecting means for detecting the loop amount, and the loop detection Means detection Means for changing the speed reference value on the basis of the result, each recording media of different materials, and a detection result storing means for storing the detection result.

  The image forming apparatus switches the driving speed of the second driving unit with reference to the speed reference value of the second driving unit, and then stores the detection result and the detection of the conveyance storage medium by the loop detecting unit. When it is determined that the result is different from the predetermined value, it is determined that the material of the storage medium designated by the user is different from the material of the transport storage medium.

  According to this configuration, it is possible to determine the material of the storage medium using the loop detection means.

  The image forming apparatus does not store the detection result in the detection result storage unit when it is determined that the stored detection result and the detection result of the transport storage medium by the loop detection unit differ by a predetermined amount or more.

  According to such a configuration, even when the media setting of the user is incorrect, it is possible to maintain highly accurate loop control. That is, when a medium is detected using a fixing loop sensor and it is determined that a medium error has occurred, it is possible to maintain highly accurate loop control by not reflecting the loop control calculation result in the backup.

  Further, when the user designates double-sided printing and the user determines that the material of the storage medium specified by the user is different from the material of the transport storage medium, the image forming apparatus forcibly ejects the transport storage medium from the main body.

  According to such a configuration, even when the media setting of the user is wrong, it is possible to prevent JAM when the double-sided paper is passed by discharging the paper to the main body.

  With the above configuration, there is an effect that the fixing unit can be reliably controlled in an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer.

  [Others]

  In the above-described embodiment, the loop amount is adjusted by changing the sheet conveyance speed of the fixing roller. However, the speed of the secondary transfer roller is changed, or both the fixing roller and the secondary transfer roller are adjusted. The loop amount may be adjusted by changing the speed.

  Further, although the fixing roller and the secondary transfer roller are illustrated as examples of the member that conveys the sheet, the present invention can be applied even when a sheet conveyance mechanism such as other sheet conveyance rollers is used.

  The processing in the above-described embodiment may be performed by software or by using a hardware circuit.

  In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program may be downloaded to the apparatus via a communication line such as the Internet.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a diagram showing an outline of a central section of an image forming apparatus according to a first embodiment. 1 is a block diagram illustrating a configuration of an image forming apparatus. It is a figure which shows the mechanism which controls so that a loop may be hold | maintained to fixed amount. It is a figure which shows the principle of operation of a loop detection sensor. It is a figure which shows the detailed structure of a loop detection sensor. It is a figure which shows the state of a loop detection sensor when a loop amount is small. It is a figure which shows the state of a loop detection sensor when a loop amount is medium (or when it is large). 5 is a flowchart illustrating loop control processing executed by the image forming apparatus. It is a flowchart which shows the detail of the loop control 1 (S107) of FIG. It is a flowchart which shows the detail of the loop control 2 (S109) of FIG. It is a flowchart which shows the detail of the loop control 3 (S113) of FIG. It is a figure which shows the specific example of a paper material table. It is a figure which shows the operation | movement of a loop detection sensor when plain paper is actually passed in the state set as plain paper. It is a figure which shows operation | movement of a loop detection sensor at the time of actually passing thick paper in the state set as plain paper. It is a flowchart which shows the detail of sheet | seat discharge control (S115) of FIG. 10 is a flowchart showing the contents of loop control 3 processing (S113 in FIG. 8) executed by the image forming apparatus according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Full color image forming apparatus 2 Intermediate transfer belt 3a Photoconductor (yellow)
3b Photoconductor (Magenta)
3c photoreceptor (cyan)
3d photoconductor (black)
8 Standard Cassette Paper Feeding Roller 9 Multi Manual Feeding Roller 10 Timing Roller 11 Secondary Transfer Roller 12 Fixing Roller 12a Pressure Roller 12b Heating Roller 13 Paper Discharge Roller 14a Double-Sided Carrying Roller 14b Double-Sided Carrying Roller 16 Recording Medium Storage Unit 17 Color PC Motor 18 Main motor 19 Fixing motor 20 Color developing motor 22 Double-sided transport motor 27 Fixing loop sensor

Claims (13)

A first conveying means provided on the upstream side of the conveying path for conveying the recording medium in a predetermined direction;
A second conveying means for conveying the recording medium in a predetermined direction provided on the downstream side of the conveying path;
Storage means for storing information about a loop generated in the recording medium between the first conveying means and the second conveying means when the recording medium is conveyed in the conveying path;
A loop information acquisition unit that acquires information about a loop that occurs in the recording medium between the first conveyance unit and the second conveyance unit when the recording medium is actually conveyed in the conveyance path;
Whether the recording medium being transported is a predetermined one based on the information stored in the storage means and the information obtained by the loop information obtaining means regarding the loop when the recording medium is actually transported Determining means for determining whether or not ;
Control means for changing the drive speed of at least one of the first transport means and the second transport means;
The loop information acquisition means detects the amount of the generated loop,
When the recording medium is in contact with both the first transport unit and the second transport unit, the control unit may cause a difference in transport speed between the first transport unit and the second transport unit. Control is performed so that a loop amount, which is a deflection amount of the recording medium generated between the first transport unit and the second transport unit, becomes constant,
The control means includes
Speed control means for increasing or decreasing the drive speed of at least one of the first transport means and the second transport means with reference to a speed reference value;
An image forming apparatus comprising: a changing unit that changes the speed reference value based on a detection result of the loop information acquisition unit . A first conveying means provided on the upstream side of the conveying path for conveying the recording medium in a predetermined direction;
A second conveying means for conveying the recording medium in a predetermined direction provided on the downstream side of the conveying path;
Storage means for storing information about a loop generated in the recording medium between the first conveying means and the second conveying means when the recording medium is conveyed in the conveying path;
A loop information acquisition unit that acquires information about a loop that occurs in the recording medium between the first conveyance unit and the second conveyance unit when the recording medium is actually conveyed in the conveyance path;
Whether the recording medium being transported is a predetermined one based on the information stored in the storage means and the information obtained by the loop information obtaining means regarding the loop when the recording medium is actually transported Determination means for determining whether or not,
The image forming apparatus, wherein when the determination unit determines that the recording medium being conveyed is a predetermined recording medium, the storage unit stores information regarding the loop acquired by the loop information acquisition unit. 3. The image according to claim 2, wherein when the determination unit determines that the recording medium being conveyed is not a predetermined one, the storage unit does not store information regarding the loop acquired by the loop information acquisition unit. Forming equipment. The image forming apparatus according to claim 1, wherein the determination unit determines that a media error has occurred when the recording medium being conveyed is not a predetermined one. An image forming means for forming an image;
A transfer means for transferring an image formed by the image forming means onto a recording medium;
Fixing means for fixing the image transferred onto the recording medium by the transfer means;
First driving means for driving the transfer means;
Second driving means for driving the fixing means,
The first conveying means is the transfer means;
The image forming apparatus according to claim 1, wherein the second transport unit is the fixing unit. Further comprising input means for inputting information relating to the type of recording medium conveyed in the conveyance path;
For each type of recording medium, the storage means stores information about a loop that occurs in the recording medium,
The image forming apparatus according to claim 1, wherein the determination unit reads out information corresponding to the type of the recording medium input by the input unit from the storage unit and performs determination.   The image forming apparatus according to claim 6, wherein the determination unit determines that the information regarding the type of the recording medium input by the input unit is incorrect when the recording medium being conveyed is not a predetermined one. By the determination unit, when the recording medium being conveyed is determined to be not a predetermined one, further comprising a discharging means for discharging the recording medium being conveyed in the conveying path, one of claims 1-7 An image forming apparatus according to claim 1. Said discharge means, in the case of performing duplex printing, when the recording medium being conveyed is determined to be not a predetermined one, is forcibly discharged from the body of the recording medium being conveyed, according to claim 8 Image forming apparatus. A first conveying means provided on the upstream side of the conveying path for conveying the recording medium in a predetermined direction;
A second conveying means for conveying the recording medium in a predetermined direction provided on the downstream side of the conveying path;
A control method for an image forming apparatus, comprising: a storage unit that stores information relating to a loop generated in the recording medium between the first transport unit and the second transport unit when the recording medium is transported in the transport path. Because
A loop information acquisition step of acquiring information relating to a loop generated in the recording medium between the first transport unit and the second transport unit when the recording medium is actually transported in the transport path;
Whether the recording medium being transported is a predetermined one based on the information stored in the storage means and the information about the loop obtained when the recording medium is actually transported, acquired by the loop information acquisition step. A determination step for determining whether or not ;
A control step of changing a driving speed of at least one of the first transport unit and the second transport unit;
In the loop information acquisition step, the amount of generated loop is detected,
In the control step, when the recording medium is in contact with both the first transport unit and the second transport unit, due to the difference in transport speed between the first transport unit and the second transport unit, Control is performed so that a loop amount, which is a deflection amount of the recording medium generated between the first transport unit and the second transport unit, becomes constant,
The control step includes
A speed control step of increasing or decreasing the drive speed of at least one of the first transport means and the second transport means with reference to a speed reference value;
And a changing step of changing the speed reference value based on a detection result in the loop information acquisition step . A first conveying means provided on the upstream side of the conveying path for conveying the recording medium in a predetermined direction;
A second conveying means for conveying the recording medium in a predetermined direction provided on the downstream side of the conveying path;
A control method for an image forming apparatus, comprising: a storage unit that stores information relating to a loop generated in the recording medium between the first transport unit and the second transport unit when the recording medium is transported in the transport path. Because
A loop information acquisition step of acquiring information relating to a loop generated in the recording medium between the first transport unit and the second transport unit when the recording medium is actually transported in the transport path;
Whether the recording medium being transported is a predetermined one based on the information stored in the storage means and the information about the loop obtained when the recording medium is actually transported, acquired by the loop information acquisition step. A determination step for determining whether or not,
In the determination step, when it is determined that the recording medium being conveyed is a predetermined one, the storage unit stores information regarding the loop acquired in the loop information acquisition step. . A first conveying means provided on the upstream side of the conveying path for conveying the recording medium in a predetermined direction;
A second conveying means for conveying the recording medium in a predetermined direction provided on the downstream side of the conveying path;
A control program for an image forming apparatus, comprising: a storage unit that stores information about a loop generated in the recording medium between the first conveying unit and the second conveying unit when the recording medium is conveyed in the conveying path. Because
A loop information acquisition step of acquiring information relating to a loop generated in the recording medium between the first transport unit and the second transport unit when the recording medium is actually transported in the transport path;
Whether the recording medium being transported is a predetermined one based on the information stored in the storage means and the information about the loop obtained when the recording medium is actually transported, acquired by the loop information acquisition step. A determination step for determining whether or not ;
Causing the computer to execute a control step of changing a driving speed of at least one of the first transport unit and the second transport unit;
In the loop information acquisition step, the amount of generated loop is detected,
In the control step, when the recording medium is in contact with both the first transport unit and the second transport unit, due to the difference in transport speed between the first transport unit and the second transport unit, Control is performed so that a loop amount, which is a deflection amount of the recording medium generated between the first transport unit and the second transport unit, becomes constant,
The control step includes
A speed control step of increasing or decreasing the drive speed of at least one of the first transport means and the second transport means with reference to a speed reference value;
A control program for an image forming apparatus, comprising: a change step for changing the speed reference value based on a detection result in the loop information acquisition step . A first conveying means provided on the upstream side of the conveying path for conveying the recording medium in a predetermined direction;
A second conveying means for conveying the recording medium in a predetermined direction provided on the downstream side of the conveying path;
A control program for an image forming apparatus, comprising: a storage unit that stores information about a loop generated in the recording medium between the first conveying unit and the second conveying unit when the recording medium is conveyed in the conveying path. Because
A loop information acquisition step of acquiring information relating to a loop generated in the recording medium between the first transport unit and the second transport unit when the recording medium is actually transported in the transport path;
Whether the recording medium being transported is a predetermined one based on the information stored in the storage means and the information about the loop obtained when the recording medium is actually transported, acquired by the loop information acquisition step. And causing the computer to execute a determination step of determining whether or not
In the determination step, when it is determined that the recording medium being conveyed is a predetermined recording medium, the storage unit stores information regarding the loop acquired in the loop information acquisition step. .

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