JP6237666B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Conventionally, an image forming apparatus has a heating roller and a pressure roller, and includes a fixing unit that fixes a toner image. Various configurations for pressing and releasing the pressure roller with respect to the heating roller are known.

  For example, an image forming apparatus including a fixing pressure release lever is disclosed (see Patent Document 1). The fixing pressure release lever presses and releases the pressure roller with respect to the heating roller. In the image forming apparatus described in Patent Document 1, when a paper conveyance failure occurs, the user operates the fixing pressure release lever to open the pressure roller with respect to the heating roller and remove the paper.

  Patent Document 1 describes that according to the image forming apparatus, it is possible to easily remove a sheet that has been poorly conveyed.

JP-A-8-44125

  However, in order to arrange the fixing pressure release lever as in the image forming apparatus described in Patent Document 1, it is necessary to transmit the position of the fixing pressure release lever to a control unit that controls the operation of the image forming apparatus. For this purpose, it is necessary to arrange a sensor for detecting the position of the fixing pressure release lever, which increases the manufacturing cost of the image forming apparatus. Further, the control unit needs to perform control according to the position of the fixing pressure release lever. For example, if the cover of the image forming device housing is closed while the fixing pressure release lever is in the position to open the pressure roller, the pressure roller is pressed against the position of the fixing pressure release lever. The user needs to be prompted to return to the correct position. Therefore, the manufacturing cost of the image forming apparatus is further increased.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can quickly open a pressure roller with a simple configuration.

  An image forming apparatus of the present invention is an image forming apparatus that forms an image on a recording medium, and includes a fixing unit, a storage unit, and a rotation number recording unit. The fixing unit includes a heating roller, a pressure roller, and a driving mechanism, and fixes the toner image to the recording medium. The drive mechanism has a motor and causes the pressure roller to transition between the pressure-bonded state and the open state with respect to the heating roller by the driving force of the motor. The said memory | storage part memorize | stores the rotation speed of the said motor. The rotational speed recording unit records the open rotational speed, which is the rotational speed of the motor from the crimping state, in the storage unit when the rotation of the motor stops during the transition from the crimping state to the open state. To do.

  According to the image forming apparatus of the present invention, the pressure roller can be quickly opened with a simple configuration.

1 is a side view illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a side view illustrating configurations of an image forming unit and a transfer unit illustrated in FIG. 1. FIG. 2 is a side view illustrating a configuration of a driving mechanism of the fixing unit illustrated in FIG. 1. It is a block diagram which shows the functional structure of the control part and memory | storage part which are shown in FIG. It is a flowchart which shows the operation | movement of the crimping | release press release control part shown in FIG. It is a flowchart which shows operation | movement of the stop determination part and rotation speed recording part which are shown in FIG. It is a flowchart which shows operation | movement of the rotation speed setting part shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 7). In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof is not repeated.

  First, an image forming apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of an image forming apparatus 1 according to the present embodiment. In the present embodiment, the image forming apparatus 1 is a color copying machine.

  As shown in FIG. 1, the image forming apparatus 1 is an apparatus that forms an image on a recording paper P, and includes a housing 10, a paper feeding unit 2, a transport unit L, a toner supply unit 3, an image forming unit 4, A transfer unit 5, a fixing unit 7, and a discharge unit 8 are provided.

  The paper feed unit 2 is disposed at the lower part of the housing 10 and supplies the recording paper P to the transport unit L. The paper feed unit 2 can accommodate a plurality of recording papers P, and supplies the uppermost recording paper P to the transport unit L one by one. Hereinafter, the recording paper P is referred to as paper P for convenience.

  The transport unit L transports the paper P supplied by the paper feed unit 2 to the discharge unit 8 via the transfer unit 5 and the fixing unit 7.

  The toner supply unit 3 is a container that supplies toner to the image forming unit 4 and includes four toner cartridges 3c, 3m, 3y, and 3k. The toner cartridge 3c contains cyan toner. The toner cartridge 3m contains magenta toner. The toner cartridge 3y contains yellow toner. The toner cartridge 3k contains black toner.

  Hereinafter, the toner cartridges 3c, 3m, and 3y may be referred to as a color toner cartridge 31, and the toner cartridge 3k may be referred to as a black toner cartridge 32.

  The transfer unit 5 includes an intermediate transfer belt 54. The transfer unit 5 transfers the toner image formed on the intermediate transfer belt 54 onto the paper P by the image forming unit 4. The configuration of the transfer unit 5 will be described later with reference to FIG.

  The image forming unit 4 forms a toner image on the intermediate transfer belt 54. The image forming unit 4 is supplied with the color toner and the black toner from the color toner cartridge 31 and the black toner cartridge 32, respectively. Specifically, the image forming unit 4 includes four image forming units 4c, 4m, 4y, and 4k. Cyan toner is supplied from the toner cartridge 3c to the image forming unit 4c. Magenta toner is supplied from the toner cartridge 3m to the image forming unit 4m. Yellow toner is supplied from the toner cartridge 3y to the image forming unit 4y. Black toner is supplied to the image forming unit 4k from the toner cartridge 3k. The configuration of the image forming unit 4 will be described later with reference to FIG.

  The fixing unit 7 is a roller pair that fixes the toner image formed on the paper P by the transfer unit 5, and includes a heating roller 71 and a pressure roller 72. The paper P is heated and pressed by the heating roller 71 and the pressure roller 72. As a result, the fixing unit 7 fixes the unfixed toner image transferred to the paper P in the transfer unit 5.

  The discharge unit 8 discharges the paper P on which the toner image is fixed to the outside of the apparatus.

  Next, the configuration of the image forming unit 4 and the transfer unit 5 will be described with reference to FIG. FIG. 2 is a side view illustrating the configuration of the image forming unit 4 and the transfer unit 5. As shown in FIG. 2, the image forming unit 4 includes four image forming units 4c, 4m, 4y, and 4k.

  Each of the image forming units 4c, 4m, 4y, and 4k includes an exposure device 41, a photosensitive drum 42, a developing unit 43, a charging roller 44, and a cleaning blade 45. The configuration of the four image forming units 4c, 4m, 4y, and 4k is substantially the same except for the color of the supplied toner. Therefore, in this specification, the configuration of the image forming unit 4c to which cyan toner is supplied will be described, and the description of the configuration of the image forming units 4m, 4y, and 4k other than the image forming unit 4c will be omitted.

  The image forming unit 4c includes an exposure unit 41c (41), a photosensitive drum 42c (42), a developing unit 43c (43), a charging roller 44c (44), and a cleaning blade 45c (45).

  The charging roller 44c charges the photosensitive drum 42c to a predetermined potential. The exposure unit 41c irradiates the photosensitive drum 42c with laser light to form an electrostatic latent image on the photosensitive drum 42c. The developing unit 43c has a developing roller 431c. The developing roller 431c supplies cyan toner to the photosensitive drum 42c and develops the electrostatic latent image to form a toner image. In this way, a cyan toner image is formed on the peripheral surface of the photosensitive drum 42c.

  The tip (upper end in FIG. 2) of the cleaning blade 45c is in sliding contact with the peripheral surface of the photosensitive drum 42c. Cyan toner remaining on the peripheral surface of the photosensitive drum 42c is removed by the sliding contact between the peripheral surface of the photosensitive drum 42c and the tip of the cleaning blade 45c.

  The transfer unit 5 transfers the toner image onto the paper P (see FIG. 1). The transfer unit 5 includes four primary transfer rollers 51 (51c, 51m, 51y, 51k), a secondary transfer roller 52, a driving roller 53, an intermediate transfer belt 54, and a driven roller 55.

  The transfer unit 5 superimposes the toner images formed on the photosensitive drums 42 (42c, 42m, 42y, and 42k) of the image forming units 4c, 4m, 4y, and 4k on the intermediate transfer belt 54 after overlapping them. The toner image thus transferred is transferred from the intermediate transfer belt 54 to the paper P (see FIG. 1).

  The primary transfer roller 51c is disposed to face the photosensitive drum 42c with the intermediate transfer belt 54 interposed therebetween. The primary transfer roller 51c can be pressed against the photosensitive drum 42c via the intermediate transfer belt 54 or can be separated from the photosensitive drum 42c by a driving mechanism (not shown). The primary transfer roller 51 c is normally pressed against the photosensitive drum 42 c via the intermediate transfer belt 54. The other primary transfer rollers 51m, 51y, 51k are also in pressure contact with the corresponding photosensitive drums 42 (42m, 42y, or 42k) via the intermediate transfer belt 54, similarly to the primary transfer roller 51c.

  The drive roller 53 is disposed to face the secondary transfer roller 52 and drives the intermediate transfer belt 54.

  The intermediate transfer belt 54 is an endless belt that is stretched around four primary transfer rollers 51, a drive roller 53, and a driven roller 55. The intermediate transfer belt 54 is driven to rotate counterclockwise by the driving roller 53 as shown by arrows F1 and F2 in FIG. Further, the surface side of the intermediate transfer belt 54 is in contact with the peripheral surface of each photosensitive drum 42 (42c, 42m, 42y, 42k). A toner image is transferred from the photosensitive drum 42 (42c, 42m, 42y, 42k) to the surface of the intermediate transfer belt 54 by a primary transfer roller 51 (51c, 51m, 51y, 51k).

  Specifically, the intermediate transfer belt 54 is a seamless belt made of a resin such as polyimide, polycarbonate, and polyvinylidene fluoride.

  The driven roller 55 is driven to rotate as the intermediate transfer belt 54 rotates. A blade 56 is disposed at a position facing the driven roller 55 via the intermediate transfer belt 54. The blade 56 removes toner remaining on the surface of the intermediate transfer belt 54.

  The secondary transfer roller 52 is pressed against the drive roller 53. As a result, a nip N is formed between the secondary transfer roller 52 and the drive roller 53. The secondary transfer roller 52 and the driving roller 53 transfer the toner image on the intermediate transfer belt 54 to the paper P (see FIG. 1) when the paper P passes through the nip portion N.

  Next, the drive mechanism 70 will be described with reference to FIG. FIG. 3 is a side view showing the configuration of the drive mechanism 70 of the fixing unit 7 shown in FIG. The drive mechanism 70 presses and releases the pressure roller 72 against the heating roller 71 of the fixing unit 7. The drive mechanism 70 includes a support member 73, a spring 74, a roller 75, a cam 76, a pressure detection sensor 76 a, and a motor 77.

  Engaging members 721 that engage with the support member 73 are disposed at both ends of the pressure roller 72. The support member 73 supports both ends of the pressure roller 72 via the engagement member 721. The support member 73 is configured to be rotatable about a central axis 731 at one end (upper end in FIG. 3). A roller 75 and a fixing member 732 are disposed at the other end (the lower end in FIG. 3) of the support member 73.

  The roller 75 is configured to be rotatable with respect to the support member 73. The roller 75 is disposed in contact with the cam 76 and is urged by the cam 76. Since the roller 75 is urged by the cam 76, the support member 73 is rotated about the central axis 731.

  The spring 74 biases the support member 73 in a direction away from the heating roller 71 (rightward in FIG. 3). One end of the spring 74 (right end in FIG. 3) is fixed to a frame (not shown) that houses the heating roller 71 and the pressure roller 72, and the other end (left end in FIG. 3). Is fixed to the fixing member 732.

  The cam 76 abuts on the roller 75 and urges the roller 75 in a direction approaching the heating roller 71 (leftward in FIG. 3). For example, the cam 76 is formed in an elliptical shape with the rotation shaft 761 as the center. Since the support member 73 is biased by the spring 74 in a direction away from the pressure roller 72 (rightward in FIG. 3), the roller 75 is pressed against the cam 76. Therefore, the roller 75 moves in a direction approaching or separating from the pressure roller 72 in a state where the roller 75 is in contact with the outer peripheral surface of the cam 76 according to a change in the outer peripheral position of the cam 76.

  The pressure detection sensor 76 a detects that the pressure roller 72 is in pressure contact with the heating roller 71 (pressure contact state). Specifically, the crimp detection sensor 76a includes, for example, a photo interrupter, and detects the crimped state by detecting the rotation angle of the cam 76.

  The motor 77 rotates the cam 76. A reduction gear train (not shown) is disposed between the motor 77 and the cam 76.

  Next, the operation of the drive mechanism 70 will be described. The cam 76 is rotationally driven by the motor 77. When the cam 76 rotates, the outer peripheral position of the cam 76 changes, so that the roller 75 is moved in a direction close to the heating roller 71 (or away from the heating roller 71).

  For example, when the roller 75 is moved in a direction close to the heating roller 71 (leftward in FIG. 3), the support member 73 is rotated clockwise about the central axis 731. Then, the pressure roller 72 is moved in the direction approaching the heating roller 71 (leftward in FIG. 3) via the engaging member 721.

  Conversely, when the roller 75 is moved in a direction away from the heating roller 71 (rightward in FIG. 3), the support member 73 is rotated counterclockwise about the central axis 731. Then, the pressure roller 72 is moved in a direction away from the heating roller 71 (rightward in FIG. 3) via the engaging member 721.

  Thus, the cam 76 is rotated by the motor 77, whereby the pressure roller 72 is pressure-bonded (or released) to the heating roller 71.

  Next, functional configurations of the control unit 91 and the storage unit 92 will be described with reference to FIG. FIG. 4 is a block diagram showing functional configurations of the control unit 91 and the storage unit 92 shown in FIG. The controller 91 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The storage unit 92 includes a nonvolatile memory. The non-volatile memory is, for example, a memory such as a flash memory or an EEPROM (Electrically Erasable Programmable Read-Only Memory). A control program is stored in the ROM. The CPU functions as various functional units by reading and executing the control program stored in the ROM. The RAM is used as a work area when the CPU executes the control program.

  As shown in FIG. 4, in the control unit 91, the CPU reads and executes a control program stored in the ROM, so that the crimping release control unit 911, the stop determination unit 912, the rotation number recording unit 913, and the rotation It functions as various functional units including a number setting unit 914. Further, the CPU reads and executes the control program stored in the ROM, thereby causing the storage unit 92 (nonvolatile memory) to function as the rotation speed storage unit 921.

  The press release control unit 911 controls the operation of pressing and releasing the pressure roller 72 against the heating roller 71. Specifically, the pressure release control unit 911 causes the pressure roller 72 to transition to the open state when the power of the image forming apparatus 1 is turned on and when printing is completed. Further, the pressure release control unit 911 causes the pressure roller 72 to transition to the pressure-bonded state when a print request is issued to the image forming apparatus 1.

  The stop determination unit 912 determines whether a preset “stop condition” is satisfied. The “stop condition” is a condition for stopping the pressure bonding operation and the opening operation of the pressure roller 72 (in other words, stopping the driving of the motor 77). Specifically, the “stop condition” includes, for example, that a jam has occurred during printing, that the cover of the casing 10 (see FIG. 1) of the image forming apparatus 1 has been opened, and the main power supply of the image forming apparatus 1 Including being turned off.

  As described above, the motor 77 is stopped when a jam occurs during printing, when the cover of the casing 10 of the image forming apparatus 1 is opened, and when the main power of the image forming apparatus 1 is turned off. Is done. Therefore, the drive of the motor 77 can be stopped appropriately.

  The rotational speed recording unit 913 records the open rotational speed NP in the rotational speed storage unit 921. The open rotation speed NP is the rotation speed of the motor 77 that has moved the pressure roller 72 from the pressure-bonded state toward the open state. Specifically, the rotational speed recording unit 913 stores the open rotational speed NP in the rotational speed storage unit when the “stop condition” is satisfied during the transition of the pressure roller 72 from the press-bonded state to the open state. 921 is recorded. In the middle of the transition of the pressure roller 72 from the press-bonded state to the open state, in other words, the pressure roller 72 is moving in a direction away from the heating roller 71. Note that whether or not the pressure roller 72 is in the pressure-bonded state is determined based on the detection result of the pressure-bonding detection sensor 76a. Whether or not the “stop condition” is satisfied is determined by the stop determination unit 912.

  As described above, the rotational speed recording unit 913 records the open rotational speed NP in the rotational speed storage unit 921 when the motor 77 is stopped while the pressure roller 72 is changing from the press-bonded state to the open state. Is done. Therefore, since the open rotation speed NP, which is the rotation speed of the motor 77 that has moved the pressure roller 72 from the press-bonded state toward the open state, is recorded, the transition that is the rotation speed of the motor 77 for shifting to the open state. The rotation speed NQ can be obtained. Therefore, when the motor 77 is rotated at the transition rotational speed NQ, the state is changed to the open state, so that the pressure roller 72 can be quickly opened with a simple configuration.

  Further, since it is determined whether or not the pressure roller 72 is in a pressure-bonded state based on the detection result of the pressure-bonding detection sensor 76a, it can be accurately determined whether or not the pressure roller 72 is in a pressure-bonded state. .

  The rotational speed setting unit 914 sets a transition rotational speed NQ, which is the rotational speed of the motor 77 for transitioning to the open state, based on the open rotational speed NP when the pressure roller 72 is transitioned from the pressure-bonding state to the open state. . Specifically, the rotational speed setting unit 914 sets the transition rotational speed NQ based on the difference obtained by subtracting the open rotational speed NP from the preset maximum rotational speed NM. The maximum rotation speed NM is the rotation speed of the motor 77 when the pressure roller 72 is changed from the pressure-bonding state to the open state.

  As described above, since the transition rotational speed NQ is set based on the difference obtained by subtracting the open rotational speed NP from the maximum rotational speed NM, the transition rotational speed NQ can be set appropriately. Therefore, the pressure roller 72 can be opened more quickly.

  The rotation speed storage unit 921 stores the open rotation speed NP and the maximum rotation speed NM. The opening rotational speed NP is written into the rotational speed storage unit 921 by the rotational speed recording unit 913. The maximum rotational speed NM is written in the rotational speed storage unit 921 in advance. Further, the open rotation speed NP and the maximum rotation speed NM are read by the rotation speed setting unit 914.

  Next, referring to FIG. 5, control of the pressure roller 72 pressure bonding and opening operation performed by the pressure bonding release control unit 911 (hereinafter referred to as “pressure bonding release control”) will be described. FIG. 5 is a flowchart showing the operation of the crimping release control unit 911 shown in FIG. The following operations are all performed by the crimping release control unit 911.

  First, it is determined whether or not the main power supply is turned on (step S101). If it is determined that the main power supply is not turned on (NO in step S101), the process is set to a standby state. If it is determined that the main power source is turned on (YES in step S101), the process proceeds to step S103. Then, the pressure roller 72 is changed to an open state (step S103).

  Next, it is determined whether or not the pressure roller 72 has been changed to the open state (step S105). If it is determined that the pressure roller 72 has not been changed to the open state (NO in step S105), the process returns to step S103. If it is determined that the pressure roller 72 has been changed to the open state (YES in step S105), the process proceeds to step S107.

  Then, it is determined whether or not preparation for printing is completed (step S107). If it is determined that the preparation for printing has not been completed (NO in step S107), the process enters a standby state. If it is determined that the print preparation is completed (YES in step S107), the process proceeds to step S109. Next, it is determined whether or not there is a print request (step S109). If it is determined that there is no print request (NO in step S109), the process is in a standby state. If it is determined that there is a print request (YES in step S109), the process proceeds to step S111.

  Next, the pressure roller 72 is transitioned to the pressure-bonding state (step S111). Then, it is determined whether or not the pressure roller 72 has transitioned to the press-bonded state (step S113). If it is determined that the pressure roller 72 has not transitioned to the pressure-bonding state (NO in step S113), the process returns to step S111. If it is determined that the pressure roller 72 has transitioned to the press-bonded state (YES in step S113), the process proceeds to step S115.

  Then, a printing process is executed (step S115). Next, it is determined whether or not the printing process has been completed (step S117). If it is determined that the printing process has not been completed (NO in step S117), the process returns to step S115. If it is determined that the printing process has been completed (YES in step S117), the process returns to step S103.

  As described above, the press-bonding operation and the opening operation of the pressure roller 72 are appropriately controlled by the press-release control unit 911.

  Next, with reference to FIG. 6, a description will be given of control in which the rotation speed recording unit 913 records the open rotation speed NP in the rotation speed storage unit 921 (hereinafter referred to as “rotation speed recording control”). FIG. 6 is a flowchart showing operations of the stop determination unit 912 and the rotation speed recording unit 913 shown in FIG.

  First, the rotational speed recording unit 913 determines whether or not the pressure roller 72 is in a pressure-bonded state (step S201). When it is determined that the pressure roller 72 is not in the press-bonded state (NO in step S201), the process is set in a standby state. If it is determined that the pressure roller 72 is in the press-bonded state (YES in step S201), the process proceeds to step S203.

  Then, the rotational speed recording unit 913 determines whether or not the pressure roller 72 has started transition to the open state (step S203). If it is determined that the pressure roller 72 has not started transition to the open state (NO in step S203), the process is set to a standby state. If it is determined that the pressure roller 72 has started transition to the open state (YES in step S203), the process proceeds to step S205.

  Next, the rotation number recording unit 913 starts counting the rotation number of the motor 77 (step S205). Then, the stop determination unit 912 determines whether or not the “stop condition” is satisfied (step S207). If it is determined that the “stop condition” is not satisfied (NO in step S207), the process is set to a standby state. If it is determined that the “stop condition” is satisfied (YES in step S207), the process proceeds to step S209.

  Then, the rotation number recording unit 913 stops the rotation number of the motor 77 (step S209). Next, the rotational speed recording unit 913 records the open rotational speed NP in the rotational speed storage unit 921 (step S211), and the process ends. The opening speed NP is a count value of the speed when the count is stopped in step S209.

  As described above, the rotational speed recording unit 913 records the open rotational speed NP in the rotational speed storage unit 921.

  In the present embodiment, the case where the rotational speed recording unit 913 counts the rotational speed of the motor 77 will be described. However, a form including a counter that counts the rotational speed of the motor 77 may be used. In this case, the rotation speed recording unit 913 may instruct the counter to start, stop, and reset the count.

  Next, with reference to FIG. 7, opening control, which is control for causing the pressing roller 72 that has been stopped when the “stop condition” is satisfied, to transition to the opening state will be described. FIG. 7 is a flowchart showing the operation of the rotation speed setting unit 914 shown in FIG. The following processing is all performed by the rotation speed setting unit 914.

  First, it is determined whether or not the pressure roller 72 transitions to the open state (step S301). If it is determined that the pressure roller 72 does not transition to the open state (NO in step S301), the process is set to a standby state. If it is determined that the pressure roller 72 transitions to the open state (YES in step S301), the process proceeds to step S303.

  Then, it is determined whether or not the open rotation speed NP is stored in the rotation speed storage unit 921 (step S303). If it is determined that open speed NP is not stored in speed memory 921 (NO in step S303), the process proceeds to step S313. If it is determined that open rotation speed NP is stored in rotation speed storage unit 921 (YES in step S303), the process proceeds to step S305.

Next, the open rotation speed NP is read from the rotation speed storage unit 921 (step S305). Next, the maximum rotational speed NM is read from the rotational speed storage unit 921 (step S307). Then, the transition rotational speed NQ is obtained using the following equation (1) (step S309).
(Transition speed NQ) = (Maximum speed NM) − (Open speed NP) (1)
Next, the motor 77 is rotated at the transition rotational speed NQ, the pressure roller 72 is opened (step S311), and the process is terminated.

On the other hand, if NO in step S303, the maximum rotational speed NM is read from the rotational speed storage unit 921 (step S313). Then, the transition rotational speed NQ is obtained using the following equation (2) (step S315).
(Transition speed NQ) = (Maximum speed NM) (2)
Next, the motor 77 is rotated at the transition rotational speed NQ, the pressure roller 72 is opened (step S317), and the process is terminated.

  As described above, when the rotational speed storage unit 921 stores the open rotational speed NP, the motor 77 is rotated by the transition rotational speed NQ and the pressure roller 72 is opened, so that the configuration is simple. The pressure roller 72 can be quickly opened.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist thereof (for example, (1) to (2) shown below). For ease of understanding, the drawings schematically show each component as a main component, and the thickness, length, number, etc. of each component shown in the drawings are different from the actual for convenience of drawing. There is a case. Moreover, the shape, dimension, etc. of each component shown by said embodiment are an example, Comprising: It does not specifically limit, A various change is possible in the range which does not deviate substantially from the structure of this invention.

  (1) In the present embodiment, the case where the image forming apparatus is a color copying machine has been described. However, the image forming apparatus only needs to have a fixing unit. For example, the image forming apparatus may be a monochrome multifunction device.

  (2) In the present embodiment, the case has been described in which the opening rotational speed NP is recorded in the storage unit 92 when the motor 77 is stopped while the pressure roller 72 is changing from the pressure-bonding state to the opening state. A configuration in which the “compression rotation speed” is recorded in the storage unit 92 when the motor 77 is stopped while the pressure roller 72 is changing from the open state to the compression state. The “crimping rotation speed” is the rotation speed of the motor 77 that has moved the pressure roller 72 from the open state toward the crimping state.

  In this case, since the “rotation speed of the crimping” that is the rotation speed of the motor 77 that moves the pressure roller 72 from the open state toward the crimping state is recorded, the rotation of the motor 77 for shifting to the crimping state is recorded. It is possible to obtain the “transition rotational speed” that is a number. Therefore, if the motor 77 is rotated by “transition rotational speed”, the pressure state is changed to the pressure-bonding state, so that the pressure roller 72 can be quickly pressure-bonded with a simple configuration.

  In this case, it is preferable to provide a sensor for detecting the pressure-bonded state. This is because, when a sensor for detecting the pressure-bonded state is provided, the pressure-bonded state can be accurately detected, so that the pressure roller 72 can be pressure-bonded more quickly.

  The present invention is applicable to an image forming apparatus.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper feeding part 3 Toner replenishment unit 4 Image forming unit 5 Transfer part 7 Fixing part 70 Drive mechanism 71 Heating roller 72 Pressure roller 721 Engaging member 73 Supporting member 731 Center shaft 732 Fixing member 74 Spring 75 Roll 76 Cam 76a Crimp detection sensor 77 Motor 8 Discharge unit 91 Control unit 911 Crimp release control unit 912 Stop determination unit 913 Rotation number recording unit 914 Rotation number setting unit 92 Storage unit 921 Rotation number storage unit

Claims (6)

An image forming apparatus for forming an image on a recording medium,
A heating roller, a pressure roller, and a driving mechanism that causes the pressure roller to transition between a pressure-bonded state and an open state with respect to the heating roller by a driving force of a motor, and fix a toner image on the recording medium. A fixing unit;
A storage unit for storing the rotation speed of the motor;
A rotational speed recording unit that records in the storage unit an open rotational speed that is the rotational speed of the motor from the crimping state when the rotation of the motor is stopped during the transition from the crimping state to the open state. An image forming apparatus.   The image forming apparatus according to claim 1, further comprising a pressure detection sensor that detects that the pressure is in the pressed state.   The rotation of the motor is stopped when at least one of a main power supply is turned off, a jam occurs, and a housing cover is opened. Item 3. The image forming apparatus according to Item 2.   The rotation number setting part which sets the transition rotation speed which is the rotation speed of the said motor for making the said pressure roller change to the said open state based on the said open rotation speed is further provided in any one of Claims 1-3. The image forming apparatus according to claim 1. The storage unit stores in advance a maximum number of rotations that is the number of rotations of the motor when transitioning from the crimped state to the open state,
The image forming apparatus according to claim 4, wherein the rotation speed setting unit sets the transition rotation speed based on a difference obtained by subtracting the opening rotation speed from the maximum rotation speed. An image forming apparatus for forming an image on a recording medium,
A heating roller, a pressure roller, and a driving mechanism that causes the pressure roller to transition between a pressure-bonded state and an open state with respect to the heating roller by a driving force of a motor, and fix a toner image on the recording medium. A fixing unit;
A storage unit for storing the rotation speed of the motor;
A rotation speed recording unit that records in the storage unit a crimping rotation speed that is the rotation speed of the motor from the open state when the rotation of the motor stops during the transition from the open state to the crimping state. An image forming apparatus.

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