JP2007212541A - Image forming apparatus, and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and an image forming system, in which the changes in the circumferential length of an intermediate transfer body during image formation can be suppressed. <P>SOLUTION: The image forming apparatus includes the intermediate transfer body; a transfer roller which is movable between an abutment position where the roller abuts against the intermediate transfer body and a separation position, where the roller is separated from the intermediate transfer body, and which transfers a developer image to a medium, while being located at the abutment position; and a fixing device for fixing the developer image to the medium by a heat roller. In performing warm-up operation, the transfer roller is warmed by the heat roller, and the warmed transfer roller is moved to the abutting position, and also the intermediate transfer roller is rotated, so that the operation of warming up the intermediate transfer body is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming system.

  Image forming apparatuses such as laser beam printers are already well known. When such an image forming apparatus receives an image signal or the like from an external device such as a host computer, for example, the developing device is positioned at a developing position facing the photosensitive member, and the latent image carried on the photosensitive member is transferred to the developing device. To develop a developer image by transferring the developer image onto a medium, fix the developer image on the medium, and finally form an image on the medium. .

  In addition, in the image forming apparatus having the above function, a rotatable intermediate transfer member serving as an intermediate medium when the developer image is transferred to the medium, a contact position that contacts the intermediate transfer member, and the intermediate A transfer roller that is movable between a separation position separated from the transfer body, and that transfers the developer image to the medium in a state of being located at the corresponding contact position, and for fixing the developer image to the medium And a control unit for controlling the rotation operation of the intermediate transfer member and the separation contact operation of the transfer roller.

The fixing device includes a roller capable of contacting the developer image transferred to the medium, and a heating element for generating heat to warm the roller, and the roller heated by the heating element To fix the developer image on the medium. In order to appropriately fix the developer image on the medium by the roller provided in the fixing device, it is necessary to warm the roller to a predetermined temperature before image formation. Therefore, the control unit further performs a warm-up operation for generating heat in the heating element to warm the roller to a predetermined temperature.
Japanese Patent Laid-Open No. 11-30918

  By the way, the temperature of the intermediate transfer member may change as the temperature in the image forming apparatus changes. In such a case, the length of the intermediate transfer member in the rotation direction (that is, the intermediate transfer member expands or contracts). , Perimeter) may change. In order to suppress this change in circumference, a method of warming the intermediate transfer member to a high temperature may be employed.

  However, in some image forming apparatuses, image formation may be performed within a short time after the warm-up operation is completed. For this reason, in order to suppress such a change in the peripheral length of the intermediate transfer member during image formation, it is required to realize a technique that can quickly warm the intermediate transfer member to a high temperature.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus and an image forming system that can appropriately suppress a change in the circumference of an intermediate transfer member during image formation. There is.

  In order to solve the above-described problems, the main present invention is: (a) a rotatable intermediate transfer member serving as an intermediate medium when transferring a developer image to a medium; and (b) a contact contacting the intermediate transfer member. A transfer roller that is movable between a position and a separation position that is separated from the intermediate transfer body, and that transfers the developer image to the medium in a state of being located at the corresponding contact position; A roller capable of contacting the developer image transferred to the medium; and a heating element for generating heat to warm the roller, and the developer image is transferred to the medium by the roller heated by the heating element. A fixing device for fixing the heat to the heat transfer member; and (d) a control unit for controlling the rotation operation of the intermediate transfer member and the separation / contact operation of the transfer roller by generating heat to the heat generating member. Warm-up operation can be performed to warm the And (e) an image forming apparatus comprising: (f) the control unit configured to transfer the transfer roller in a state where the transfer roller is positioned at the separated position when the warm-up operation is performed. The roller is heated by the heating element, and the transfer roller heated by the heating element is moved to the contact position during execution of the warm-up operation or immediately after the end of the warm-up operation, and the transfer In the image forming apparatus, the intermediate transfer member is rotated in a state where the roller is located at the corresponding contact position, and a warming operation for warming the intermediate transfer member is executed.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  At least the following will be made clear by the description of the present specification and the accompanying drawings.

(A) a rotatable intermediate transfer member serving as an intermediate medium when transferring the developer image to the medium; (b) a contact position contacting the intermediate transfer member; and a separation position separating from the intermediate transfer member. , A transfer roller for transferring the developer image to the medium in a state of being located at a corresponding contact position, and (c) a roller capable of contacting the developer image transferred to the medium And a heating device for generating heat to warm the roller, and (d) the fixing device for fixing the developer image onto the medium by the roller warmed by the heating device. A control unit for controlling the rotation operation of the intermediate transfer member and the separation / contact operation of the transfer roller, and is capable of executing a warm-up operation for generating heat to the heating element to warm the roller to a predetermined temperature. And an image forming apparatus comprising (e) (F) When the warm-up operation is performed, the control unit warms the transfer roller to the heating element in a state where the transfer roller is positioned at the separated position, and executes the warm-up operation. In the middle or immediately after the end of the warm-up operation, the transfer roller heated by the heating element is moved to the contact position, and the intermediate transfer body is moved with the transfer roller positioned at the contact position. An image forming apparatus that performs a warming operation of rotating and warming the intermediate transfer member.
According to such an image forming apparatus, the intermediate transfer member is warmed by moving the transfer roller warmed by the heat source to the contact position during the warm-up operation or immediately after the warm-up operation is completed. The body can be warmed quickly to high temperatures. Further, by warming the intermediate transfer body to a high temperature, it is possible to suppress the temperature of the intermediate transfer body from changing even if the temperature in the image forming apparatus changes. For this reason, even when the image formation is executed within a short time after the warm-up operation is completed, it is possible to appropriately suppress the change in the peripheral length of the intermediate transfer member during the image formation.

In the image forming apparatus, the controller may rotate the intermediate transfer member one or more times with the transfer roller positioned at a corresponding contact position to execute the warming operation.
In such a case, the entire intermediate transfer member can be warmed by a single warming operation.

Further, in this image forming apparatus, the fixing device has an opening for allowing the medium having the developer image transferred thereon to pass toward the roller, and the transfer roller is located at the separation position. In this case, the transfer roller may block the opening.
When the transfer roller closes the opening when the transfer roller is located at the separated position, the heat generated by the heating element tends to stay in the fixing device, so that the roller can be appropriately heated. Therefore, the warm-up operation can be performed effectively.

Further, in this image forming apparatus, the control unit moves the transfer roller heated by the heating element to the contact position immediately after the end of the warm-up operation, and the transfer roller The intermediate transfer member may be rotated while being in the contact position, and a warming operation for warming the intermediate transfer member may be executed.
In such a case, it is possible to prevent the time required for the warm-up operation from becoming long, and to appropriately warm the intermediate transfer member.

In addition, the image forming apparatus includes a moving member that moves between a first position and a second position, the moving member closing the opening when positioned at the first position, The control unit is capable of controlling the movement operation of the moving member, and moves the transfer roller warmed by the heating element to the contact position during execution of the warm-up operation, and the transfer roller Rotating the intermediate transfer member in a state where the intermediate transfer member is positioned at the corresponding contact position, performing a warming operation for warming the intermediate transfer member, and moving the moving member located at the second position to the first position, The opening may be blocked by the moving member.
If the moving member closes the opening when the transfer roller moves from the separated position to the contact position during the warm-up operation by providing the moving member, the heat generated by the heating element is generated. Since it becomes easy to stay in the fixing device, the roller can be appropriately warmed, so that the warm-up operation can be effectively performed.

In the image forming apparatus, the control unit may perform the warming operation a plurality of times by reciprocating the transfer roller a plurality of times between the separation position and the contact position. .
In such a case, the transfer roller warmed by the heating element is brought into contact with the intermediate transfer member every time the warming operation is executed, so that the intermediate transfer member can be immediately heated to a high temperature.

Further, in this image forming apparatus, when the transfer roller reciprocates a plurality of times, the position at which the transfer roller contacts the intermediate transfer member at the contact position is a plurality of different positions. It is good as well.
In such a case, since only a part of the intermediate transfer member can be prevented from being excessively warmed, the entire intermediate transfer member can be uniformly heated.

Further, in this image forming apparatus, the control unit performs a plurality of times of the warming operation at a time T1 during which the transfer roller is continuously positioned at the separation position at an initial stage of performing the warming operation a plurality of times. It is possible to make the transfer roller longer than the time T2 during which the transfer roller is continuously positioned at the separation position in the latter half of the period for which the rotation is executed.
Since the transfer roller at the beginning of the period is more likely to be deprived of heat by the intermediate transfer body when the intermediate transfer body is warmed than at the later stage of the period, the temperature of the transfer roller at the initial stage is higher than that at the later stage. Easy to fall. In this case, when the time T1 is made longer than the time T2, the temperature of the transfer roller that is heated by the heating element and moves to the contact position can be kept high during the period. Become.

Further, in this image forming apparatus, the control unit performs the warming operation for a time T3 during which the transfer roller is continuously positioned at the contact position in a later stage of the period in which the warming operation is performed a plurality of times. It may be set longer than the time T4 during which the transfer roller is continuously positioned at the contact position at the beginning of the period of execution multiple times.
In order to effectively suppress the change in the peripheral length of the intermediate transfer member during image formation, it is desirable that the temperature of the entire intermediate transfer member is uniform in the later stage than in the initial period. Therefore, when the time T3 is longer than the time T4, the temperature of the intermediate transfer member can be made uniform by warming the intermediate transfer member for a long time by the transfer roller in the latter period. .

Further, (a) a rotatable intermediate transfer member serving as an intermediate medium when the developer image is transferred to the medium, (b) a contact position that contacts the intermediate transfer member, and a spacing away from the intermediate transfer member. A transfer roller for transferring the developer image to the medium in a state where the developer image is transferred to the medium, and (c) being able to contact the developer image transferred to the medium. A fixing device for fixing the developer image onto the medium by the roller heated by the heating element, and a heating device for heating the roller by generating heat (d) ) A control unit for controlling the rotation operation of the intermediate transfer member and the separation / contact operation of the transfer roller, and performing a warm-up operation for generating heat to the heating element to warm the roller to a predetermined temperature. An image provided with a control unit executable and (e) (F) The control unit, when executing the warm-up operation, warms the transfer roller to the heating element in a state where the transfer roller is positioned at the separation position, and performs the warm-up operation. The transfer roller heated by the heating element is moved to the contact position, and the intermediate transfer body is rotated with the transfer roller positioned at the contact position. (G) The control unit rotates the intermediate transfer member at least once in a state where the transfer roller is located at the corresponding contact position, and executes the warming operation. ) The fixing device has an opening for allowing the medium onto which the developer image has been transferred to pass toward the roller. When the transfer roller is located at the separated position, the transfer roller is Plug the opening (I) a moving member that moves between a first position and a second position, the moving member closing the opening when positioned at the first position, wherein the control unit includes the moving member The transfer roller heated by the heating element is moved to the contact position and the transfer roller is positioned at the corresponding contact position during execution of the warm-up operation. In this state, the intermediate transfer member is rotated to perform a warming operation for warming the intermediate transfer member, the moving member located at the second position is moved to the first position, and the opening is formed in the moving member. (J) the controller reciprocally moves the transfer roller between the separation position and the contact position a plurality of times to execute the warming operation a plurality of times, and (k) the transfer roller During the reciprocating movement a plurality of times, the intermediate transfer The position where the transfer roller contacts the body at the contact position is a plurality of different positions. (L) The control unit moves the transfer roller at the beginning of a period in which the warming operation is performed a plurality of times. The time T1 that is continuously positioned at the separation position is set to be longer than the time T2 that the transfer roller is continuously positioned at the separation position in the latter period of the period in which the warming operation is performed a plurality of times. The control unit, at a later stage of the period in which the warming operation is performed a plurality of times, has a time T3 for continuously positioning the transfer roller at the contact position, at an initial stage of the period in which the warming operation is performed a plurality of times. An image forming apparatus characterized in that the transfer roller is made longer than a time T4 for continuously positioning the transfer roller at the contact position.
According to such an image forming apparatus, an effect capable of appropriately suppressing a change in the peripheral length of the intermediate transfer member during image formation is most effectively achieved.

Further, (A) a computer, and (B) an image forming apparatus connectable to the computer, (a) a rotatable intermediate transfer member serving as an intermediate medium when a developer image is transferred to the medium; (B) The developer image can be moved between a contact position that contacts the intermediate transfer member and a separation position that is separated from the intermediate transfer member, and the developer image is placed on the medium in a state of being positioned at the contact position. A transfer roller for transferring; (c) a roller capable of contacting the developer image transferred to the medium; and a heating element for generating heat to warm the roller. A fixing device for fixing the developer image onto a medium by the heated roller; and (d) a control unit for controlling the rotation operation of the intermediate transfer member and the separation contact operation of the transfer roller. , Heat is generated in the heating element, and the roller is A control unit capable of performing a warm-up operation for warming up to a temperature, an image forming apparatus including (e), and an image forming system including (C), wherein (D) the control unit includes the warming operation When the warm-up operation is performed, the heat-generating body is warmed while the warm-up operation is being performed or immediately after the warm-up operation is performed. The transfer roller warmed by the movement is moved to the contact position, and the intermediate transfer body is rotated while the transfer roller is positioned at the corresponding contact position, and the intermediate transfer body is warmed. An image forming system.
According to such an image forming system, it is possible to appropriately suppress a change in the circumference of the intermediate transfer member during image formation.

=== Example of Overall Configuration of Image Forming System ===
The outline of the image forming system 700 will be described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory diagram showing an external configuration of the image forming system 700. FIG. 2 is a block diagram showing a part of the configuration of the image forming system 700 shown in FIG. The image forming system 700 includes a laser beam printer (hereinafter also referred to as a printer) 10 as an “image forming apparatus” and a computer 702 capable of communicating with the printer 10.

  The computer 702 includes a display device 704 for displaying information such as a cathode ray tube (CRT), a liquid crystal display device, a plasma display, an input device 708 such as a keyboard 708A and a mouse 708B, and an FD (flexible drive). Reading device 710 such as device 710A, CD-ROM drive device 710B, MO (Magneto Optical) disk drive device (not shown), DVD (Digital Versatile Disk) device (not shown), and internal memory such as RAM (not shown) And an external memory (not shown) such as a hard disk drive unit. The computer 702 is housed in a mini-tower type housing in this embodiment, but is not limited to this.

  The computer 702 includes an operating system, an application program 795 that operates under the operating system, and a printer driver 796 that is an example of a control program. The printer driver 796 includes an image processing unit 797, a display interface unit 801, an input interface unit 803, and a user interface processing unit 805.

  The application program 795 is a program on the computer 702 for causing the printer 10 to perform image formation. Image data AD on the application program is sent to the printer driver 796 in accordance with an image formation execution command from the application program 795.

  The image processing unit 797 receives the image data AD that can be interpreted by the application program 795, converts the image data AD into image data PD that can be interpreted by the printer 10, and sends the converted image data PD to the printer 10 together with various control signals COM. It has a function to do. That is, the image processing unit 797 of the printer driver 796 instructs the printer 10 to execute image formation after performing the above-described image processing. In order to realize the function, the image processing unit 797 performs resolution conversion, color component conversion, and the like, for example.

  The display interface unit 801 has a function of displaying various user interface windows related to image formation on the display device 704. The input interface unit 803 has a function of receiving input information input by the user using the input device 708 on the user interface window.

  The user interface processing unit 805 has a function of providing an interface between the display interface unit 801 or the input interface unit 803 and the printer 10. For example, the user interface processing unit 805 receives the input information from the input interface unit 803 and interprets the input information. Then, various control signals COM are sent to the printer 10 and the image processing unit 797. Further, it interprets various control signals COM received from the printer 10 and sends information related to display to the display interface unit 801.

  Note that the printer driver 796 included in the computer 702 is supplied in a form recorded on a computer-readable recording medium. Such recording media include flexible disks, CD-ROMs, magneto-optical disks, IC cards, ROM cartridges, punch cards, printed matter on which codes such as bar codes are printed, computer internal storage devices (such as RAM and ROM). A variety of computer-readable media such as a memory) and an external storage device can be used. It is also possible to download such a computer program to the computer 702 via the Internet.

=== Example of Overall Configuration of Image Forming Apparatus ===
Next, an outline of a laser beam printer (hereinafter also referred to as a printer) 10 will be described with reference to FIGS. FIG. 3 is a diagram showing main components constituting the printer 10. FIG. 4 is a block diagram illustrating the configuration of the control unit 100 of the printer 10. FIG. 5 is a perspective view showing the primary transfer unit 60. In FIG. 3, the up and down directions are indicated by arrows. For example, the paper feed tray 92 is disposed below the printer 10, and the fixing unit 90, which is an example of a “fixing device”, is Is located at the top of the.

  The printer 10 according to the present embodiment forms an image based on an image formation command from the image processing unit 797 of the printer driver 796 of the computer 702. As shown in FIG. 3, the printer 10 includes a charging unit 30, an exposure unit 40, a YMCK developing unit 50, a primary transfer unit 60, an intermediate transfer body 62, and a secondary transfer unit 80 along the rotation direction of the photoreceptor 20. , A photosensitive member cleaning unit 82, an intermediate transfer member cleaning unit 85, a fixing unit 90, a display unit 95 having a liquid crystal panel as a means for notifying a user, and controlling these units and the like to control the operation as a printer. The control unit 100 that is an example of the “unit” is included.

  The photoreceptor 20 has a cylindrical conductive substrate and a photosensitive layer formed on the outer peripheral surface thereof, and is for carrying a latent image on the surface of the photosensitive layer. The photoconductor 20 is rotatable about a central axis, and in the present embodiment, rotates in the clockwise direction as indicated by an arrow in FIG.

  The charging unit 30 is a device for charging the photoconductor 20, and the exposure unit 40 is a device for forming a latent image on the photoconductor 20 charged by irradiating a laser. The exposure unit 40 includes a semiconductor laser, a polygon mirror, an F-θ lens, and the like, and irradiates a modulated laser onto the charged photoconductor 20 based on an image signal input from the computer 702. .

  The YMCK developing unit 50 stores the latent image formed on the photoconductor 20 with toner stored in four developing devices, that is, black (K) toner stored in the black developing device 51, and magenta developing device 52. This is a device for developing using the magenta (M) toner, the cyan (C) toner accommodated in the cyan developing device 53, and the yellow (Y) toner accommodated in the yellow developing device 54.

  The YMCK developing unit 50 can move the positions of the four developing devices 51, 52, 53, 54 by rotating with the four developing devices 51, 52, 53, 54 mounted. Yes. That is, the YMCK developing unit 50 holds the four developing devices 51, 52, 53, and 54 by the four developing device holding portions 55a, 55b, 55c, and 55d, and the four developing devices 51, 52, 53 and 54 are rotatable around the central axis 50a while maintaining their relative positions. Each time image formation for one page is completed, the photosensitive member 20 is selectively opposed to the photosensitive member 20, and each of the four color toners accommodated in the developing devices 51, 52, 53, and 54 is used. The carried latent image is visualized as a toner image which is an example of a “developer image”. Each of the four developing devices 51, 52, 53, 54 described above can be attached to and detached from the printer main body, more specifically, the developing device holding portions 55a, 55b, 55c, 55d of the YMCK developing unit 50. It has become.

  The primary transfer unit 60 is a device for transferring a single color toner image formed on the photoconductor 20 to an intermediate transfer body 62 described later. The primary transfer unit 60 sequentially superimposes and transfers the four color toner images visualized by the four developing devices onto the intermediate transfer body 62, thereby forming a full color toner image on the intermediate transfer body 62.

  The intermediate transfer body 62 is an intermediate medium when transferring the toner image on the photoconductor 20 to a recording medium (paper, film, cloth, etc.) as an example of “medium”, and the toner (toner image) is used as the recording medium. In order to transfer the toner (toner image), the toner (toner image) is rotated while being carried and moved. The intermediate transfer member 62 is formed by providing a tin vapor deposition layer on the surface of a PET film, and forming a semiconductive paint on the surface layer (hereinafter, the semiconductive paint layer is also referred to as a resistance layer 62a (FIG. 5)), and laminating it. It is a belt.

  A driving roller 71, a driven roller 72, and the like are provided inside the intermediate transfer body 62. The drive roller 71 is in contact with the inner peripheral surface of the intermediate transfer body 62 and has a function of rotating the intermediate transfer body 62 at substantially the same peripheral speed as that of the photoconductor 20. The driven roller 72 is in contact with the inner peripheral surface of the transfer belt and stretches the intermediate transfer member 62 in a rotatable manner.

  The intermediate transfer member 62 is in contact with the photosensitive member 20, and a toner image on the photosensitive member 20 is transferred to the intermediate transfer member 62 at a contact portion between the intermediate transfer member 62 and the photosensitive member 20. A transfer portion is formed. When the primary transfer bias is applied from the transfer bias applying unit 121 to the primary transfer unit 60, an electric field is formed between the intermediate transfer body 62 and the photoconductor 20 in the primary transfer unit, and the toner image formed on the photoconductor 20. Is transferred to the intermediate transfer member 62. When the four color toner images are sequentially transferred, a full color toner image is formed on the intermediate transfer body 62.

  Further, in the vicinity of the intermediate transfer member 62, a pulse signal generator 75 (FIG. 4) including a synchronization reading sensor RS is disposed. The synchronization reading sensor RS is a sensor for detecting the reference position of the intermediate transfer body 62, and is a vertical synchronization reading sensor for obtaining a synchronization signal in the sub-scanning direction substantially perpendicular to the main scanning direction, that is, a vertical synchronization signal Vsync. Function as. More specifically, the reading sensor RS for synchronization has a light emitting part for emitting light and a light receiving part for receiving light, and the hole formed at a predetermined position of the intermediate transfer body 62 is When the light emitted from the light emitting unit passes, the light receiving unit receives the light. At this time, the pulse signal generator 75 generates a pulse signal. Here, the pulse signal is a reference signal serving as a reference for the rotation operation of the intermediate transfer body 62 and the separation / contact operation of the secondary transfer roller 301 described later. The pulse signal generation unit 75 generates a pulse signal every predetermined time (every time the intermediate transfer body 62 rotates once).

  Further, as shown in FIG. 3, a temperature sensor 65 for detecting the temperature of the intermediate transfer body 62 is disposed in the vicinity of the intermediate transfer body 62.

  The secondary transfer unit 80 is a device for transferring (secondary transfer) a single color toner image or a full color toner image formed on the intermediate transfer body 62 to a recording medium. Details of the secondary transfer unit 80 will be described later.

  The fixing unit 90 is a device for fixing a toner image on a recording medium to the medium, and includes a fixing roller 501 that is an example of a “roller” and a pressure roller 502 that presses the fixing roller 501. Yes. Details of the fixing unit 90 will be described later.

  In addition, a paper feed tray 92 is provided below the printer 10, and the paper feed tray 92 stores a recording medium and supplies the recording medium to the recording medium conveyance path 400. The recording medium conveyance path 400 is provided from the paper feed tray 92 to the paper discharge tray 226. The recording medium conveyance path 400 is formed by a guide portion for guiding the recording medium from the paper feed tray 92 to the paper discharge tray 226, and the guide portion includes a large number of guide members (for example, FIG. 6). The fixing unit upstream guide member 401) shown in FIG. The secondary transfer unit 80 and the fixing unit 90 described above are provided along the recording medium conveyance path 400, and a plurality of rollers for conveying the recording medium (for example, a paper feed roller 94, a registration roller 96, A paper discharge roller 97) is also provided.

  The photoconductor cleaning unit 82 is provided between the primary transfer unit 60 and the charging unit 30 and has a rubber photoconductor cleaning blade 84 that is in contact with the surface of the photoconductor 20. After the toner image is transferred onto the transfer member 62, the toner remaining on the photosensitive member 20 is scraped off and removed by the photosensitive member cleaning blade 84.

  The intermediate transfer body cleaning unit 85 is an apparatus that is provided above the YMCK developing unit 50 and collects toner that is not transferred to the recording medium but remains on the intermediate transfer body 62. The intermediate transfer body cleaning unit 85 includes an intermediate transfer body cleaning blade 86 that can be brought into and out of contact with the intermediate transfer body 62, and the intermediate transfer body cleaning blade 86 is brought into contact with the intermediate transfer body 62 to be placed on the intermediate transfer body 62. Scrape off any toner.

  As shown in FIG. 4, the control unit 100 includes a main controller 101 and a unit controller 102. An image signal and a control signal are input to the main controller 101, and a command based on the image signal and the control signal is received. A unit controller 102 controls each of the units and forms an image.

  Next, an image forming operation of the printer 10 configured as described above will be described. Various operations of the printer 10 described below are mainly realized by the main controller 101 or the unit controller 102 in the printer 10. In particular, in the present embodiment, it is realized by the CPU processing a program stored in the program ROM. And this program is comprised from the code | cord | chord for performing the various operation | movement demonstrated below.

  First, when an image signal and a control signal from the computer 702 are input to the main controller 101 of the printer 10 via an interface (denoted as I / F in FIG. 4) 112, a unit based on a command from the main controller 101 is entered. The photoconductor 20 and the intermediate transfer body 62 are rotated under the control of the controller 102. The photoconductor 20 is sequentially charged by the charging unit 30 at the charging position while rotating.

  The charged area of the photoconductor 20 reaches an exposure position as the photoconductor 20 rotates, and a latent image corresponding to image information of the first color, for example, yellow Y, is formed in the area by the exposure unit 40. . In the YMCK developing unit 50, a yellow developing device 54 that contains yellow (Y) toner is located at a developing position facing the photoconductor 20.

  The latent image formed on the photoconductor 20 reaches the development position as the photoconductor 20 rotates, and is developed with yellow toner by the yellow developing device 54. As a result, a yellow toner image is formed on the photoreceptor 20.

  The yellow toner image formed on the photoconductor 20 reaches the primary transfer position as the photoconductor 20 rotates, and is transferred to the intermediate transfer body 62 by the primary transfer unit 60. At this time, a primary transfer bias having a polarity opposite to the charging polarity of the toner is applied to the primary transfer unit 60. During this time, the photosensitive member 20 and the intermediate transfer member 62 are in contact with each other, and the secondary transfer unit 80 is in a standby state with being separated from the intermediate transfer member 62.

  The above processing is sequentially executed for each developing device for the second color, the third color, and the fourth color, so that four color toner images corresponding to the respective image signals are transferred to the intermediate transfer body 62. It is transcribed and superimposed. As a result, a full-color toner image (hereinafter simply referred to as a toner image) is formed on the intermediate transfer member 62.

  The toner image formed on the intermediate transfer body 62 reaches the secondary transfer position as the intermediate transfer body 62 rotates, and is transferred to the recording medium by the secondary transfer unit 80. In the transfer, the recording medium is conveyed from the paper feed tray 92 to the secondary transfer unit 80 via the paper feed roller 94 and the registration roller 96. Further, when performing the transfer operation, the secondary transfer unit 80 cooperates with the intermediate transfer body 62 to sandwich the recording medium and to apply the secondary transfer bias described above. Further, the toner remaining on the intermediate transfer member 62 without being transferred to the recording medium is collected by the intermediate transfer member cleaning unit 85.

When the recording medium to which the toner image has been transferred is introduced into the fixing unit 90, the space between the fixing roller 501 heated to a predetermined temperature by the internal heater 501c and the pressure roller 502 is set to both rollers. Passes in a pinched state. At this time, the fixing roller 501 and the pressure roller 502 heat and press the toner image on the recording medium, so that the toner image is fused to the recording medium.
The recording medium on which the toner image is fused is conveyed to the paper discharge tray 226 via the paper discharge roller 97.

  On the other hand, after the primary transfer position has passed, the photosensitive member 20 is scraped off by the photosensitive member cleaning blade 84 supported by the photosensitive member cleaning unit 82 to form the next latent image. Prepare for charging. The toner that has been scraped off is collected in a residual toner collecting section provided in the photoconductor cleaning unit 82.

=== Overview of Control Unit ===
Next, the configuration of the control unit 100 will be described with reference to FIG. The main controller 101 of the control unit 100 is connected to a computer 702 via an interface 112 and includes an image memory 113 for storing an image signal input from the computer 702. The unit controller 102 includes units of the apparatus main body (charging unit 30, exposure unit 40, YMCK developing unit 50, primary transfer unit 60, secondary transfer unit 80, photoconductor cleaning unit 82, intermediate transfer body cleaning unit 85, fixing unit. 90), each unit is controlled based on a signal input from the main controller 101 while detecting a state of each unit by receiving a signal from a sensor included therein.

=== Configuration Example of Fixing Unit 90 ===
Next, a configuration example of the fixing unit 90 will be described with reference to FIGS. 6 and 7. FIG. 6 is a schematic cross-sectional view showing main components of the secondary transfer unit 80, the intermediate transfer body 62, and the fixing unit 90 installed in the printer 10, and the secondary transfer roller 301 is in the middle. A state in which the transfer body 62 is in contact is shown. FIG. 7 is a schematic perspective view of the fixing unit 90. 6, as in FIG. 3, the vertical direction is indicated by an arrow. For example, the central axis of the driving roller 71 is below the introduction port 505 of the fixing unit 90.

  In FIG. 6, the recording medium conveyance path 400 is indicated by a broken line, and the recording medium moves along the recording medium conveyance path 400 in the direction indicated by the symbol P in the drawing. On the other hand, the vertical direction indicated by the arrow in FIG. 7 indicates the vertical direction of the fixing unit 90 when installed in the printer 10. Further, the fixing unit 90 shown in FIG. 6 is mounted such that one end surface 504a in the longitudinal direction of the fixing unit 90 shown in FIG. 7 faces the back side in the direction penetrating the paper surface in FIG. is there.

  As described above, the fixing unit 90 heats and presses the toner image on the recording medium to fix it on the medium. The fixing unit 90 includes a fixing roller 501, a pressure roller 502 that presses the fixing roller 501, and a fixing roller. A temperature sensor 503 that measures the surface temperature of 501 and a housing 504 that accommodates the above-described members are included therein.

  The fixing roller 501 is a roller that can come into contact with the toner image transferred to the recording medium. The fixing roller 501 heats the toner image on the recording medium and fuses the toner image to the recording medium. The fixing roller 501 is provided in the fixing unit 90 so that the longitudinal direction thereof is along the longitudinal direction of the fixing unit 90 (the direction passing through the paper surface in FIG. 6). The fixing roller 501 has a metal small diameter portion 501a and a rubber large diameter portion 501b, and is rotatable around the rotation axis of the fixing roller 501 (that is, the central axis of the small diameter portion 501a). .

  Further, inside the fixing roller 501, an internal heater 501 c that is an example of a “heating element” for generating heat to heat (heat) the fixing roller 501 (in this embodiment, a halogen heater is used). The toner image on the recording medium is heated and fused to the recording medium by the fixing roller 501 heated (heated) by the internal heater 501c. The internal heater 501c is energized when the printer 10 is in an operating state (this generates heat in the internal heater 501c), and the fixing roller 501 is set to a set temperature (in this embodiment, about 180). (Warm-up operation) is performed to warm up to (℃).

  The pressure roller 502 cooperates with the fixing roller 501 to press the toner image on the recording medium. The pressure roller 502 is provided at a position adjacent to the fixing roller 501 so that the longitudinal direction thereof is along the longitudinal direction of the fixing unit 90. Similarly to the fixing roller 501, the pressure roller 502 has a metal small diameter portion 502a and a rubber large diameter portion 502b, and the rotation shaft of the pressure roller 502 (that is, the center of the small diameter portion 502a). It can be rotated around the axis.

  The pressure roller 502 is configured to be able to press the fixing roller 501. When the fixing unit 90 fixes the toner image on the recording medium onto the recording medium, the pressure roller 502 is pressed against the fixing roller 501 via the recording medium by a pressing member (not shown), and the fixing roller 501. And the pressure roller 502, the toner image on the recording medium is pressed by these two rollers.

  The temperature sensor 503 contacts the peripheral surface of the fixing roller 501 and measures the surface temperature of the fixing roller 501. The temperature sensor 503 in the present embodiment is a thermistor, and FIG. 6 shows a contact portion 503a and a lead wire portion 503b as main components of the temperature sensor. The temperature sensor 503 measures the surface temperature of the fixing roller 501 in a state where the contact portion 503 a is pressed against the fixing roller 501. When the measured value of the temperature sensor 503 exceeds the set temperature, the above-described warm-up operation for heating the fixing roller 501 ends.

  The housing 504 is for housing the fixing roller 501, the pressure roller 502, the temperature sensor 503, and the like. The housing 504 is a member made of heat-resistant resin, and as shown in FIG. 6, the recording medium having the toner image transferred to the outer surface thereof is passed toward the fixing roller 501 (in other words, the recording medium is removed). An introduction port 505, which is an example of an “opening” for introduction into the fixing unit 90, and a discharge port 506 for discharging the recording medium to the outside of the fixing unit 90 are provided. Further, as shown in FIG. 6, the housing 504 has recording medium guide portions 507 a and 507 b at one end in the short-side direction of the introduction port 505 and the discharge port 506. That is, the recording medium guide portions 507a and 507b are one member among many guide members that form the above-described guide portion.

  In the fixing unit 90 according to the present embodiment, the length of the introduction port 505 in the short direction is equal to or less than the outer diameter of the large diameter portion 301b of the secondary transfer roller 301, and the length of the introduction port 505 in the longitudinal direction. The length is equal to or shorter than the length of the large diameter portion 301b in the axial direction. In such a case, a secondary transfer roller 301 described later moves to a position intersecting with a virtual plane (portion indicated by a broken line in FIG. 8) that closes the introduction port 505 of the fixing unit 90 and comes into contact with the fixing unit 90. At this time, the inlet 505 can be closed (see FIG. 8). This operation will be described in detail in the configuration example and operation section of the secondary transfer unit 80 described later.

=== Configuration Example and Operation of Secondary Transfer Unit 80 ===
Next, a configuration example of the secondary transfer unit 80 will be described with reference to FIGS. 6 and 8. FIG. 8 is a schematic cross-sectional view showing the main constituent members of the secondary transfer unit 80, the intermediate transfer body 62, and the fixing unit 90 installed in the printer 10 as in FIG. A state is shown in which the transfer roller 301 is separated from the intermediate transfer body 62 toward the fixing unit 90 and is on standby.

  The secondary transfer unit 80 includes a secondary transfer roller 301 which is an example of a “transfer roller”, a secondary transfer roller support member 302, and the like.

  The secondary transfer roller 301 is for transferring the toner image on the intermediate transfer body 62 to a recording medium. The secondary transfer roller 301 can be separated from and brought into contact with the intermediate transfer body 62. It is possible to move between a separation position separated from 62 (position of the secondary transfer roller 301 shown in FIG. 8). Then, the secondary transfer roller 301 transfers the toner image transferred to the intermediate transfer body 62 by the primary transfer unit 60 to the recording medium while being located at the corresponding contact position. More specifically, the secondary transfer roller 301 transfers the toner image transferred to the intermediate transfer body 62 by the primary transfer unit 60 and moved to the secondary transfer position as the intermediate transfer body 62 rotates. The image is transferred to the recording medium in the state of being in the contact position.

  The secondary transfer roller 301 is provided such that its longitudinal direction is along the longitudinal direction of the drive roller 71 (that is, the direction penetrating the paper surface of FIG. 6), and is composed of a rotating shaft portion 301a made of metal and urethane sponge. A large-diameter portion 301b. Further, the rotating shaft portion 301a of the secondary transfer roller 301 is rotatably supported by a secondary transfer roller support member 302 described later.

  When the secondary transfer roller 301 performs a transfer operation, a secondary transfer bias is applied to the secondary transfer roller 301 as described above. When the recording medium passes through the position sandwiched between the drive roller 71 and the secondary transfer roller 301, the toner image on the intermediate transfer body 62 also passes over the recording medium and is generated by applying the secondary transfer bias. The toner image is transferred to the recording medium by the transferred electric field. The magnitude of the secondary transfer bias is adjusted by constant current control.

  At the abutting position, as shown in FIG. 6, the secondary transfer roller 301 is adjacent to the driving roller 71 in a rotating state, and the recording medium passes between the driving roller 71 and the secondary transfer roller 301. In addition, it abuts against the intermediate transfer member 62 via the recording medium. At this time, since the intermediate transfer member 62 is rotated by the rotation of the drive roller 71, the secondary transfer roller 301 that is in contact with the intermediate transfer member 62 rotates together with the drive roller 71 and the intermediate transfer member 62. It becomes. Note that the rotation direction of the secondary transfer roller 301 is opposite to the rotation direction of the drive roller 71.

  On the other hand, as shown in FIG. 8, at the separation position, the secondary transfer roller 301 intersects with a virtual plane (portion indicated by a wavy line in FIG. 8) that closes the introduction port 505 of the fixing unit 90 and is fixed. It is in contact with the unit 90. Further, the inlet 505 is in contact with the fixing unit 90 so as to close the inlet 505 when the secondary transfer roller 301 is separated (in this embodiment, as described above, the longitudinal direction of the inlet 505 And the length in the edge direction is a length that can be closed by the secondary transfer roller 301).

  As described above, the fixing unit 90 is provided with the internal heater 501c, and the distance between the secondary transfer roller 301 located at the separated position and the internal heater 501c is the same as the secondary transfer roller 301 located at the contact position. It is smaller than the distance from the internal heater 501c. Then, the secondary transfer roller 301 located at the separated position is heated by the internal heater 501c. For this reason, the internal heater 501c has not only a function of heating the fixing roller 501 but also a function of heating the secondary transfer roller 301 located at the separation position.

  The secondary transfer roller support member 302 is for supporting the secondary transfer roller 301. One secondary transfer roller support member 302 is provided at each end of the secondary transfer roller 301. The secondary transfer roller support member 302 is fixed to a shaft 302a provided along the longitudinal direction of the secondary transfer roller 301 (that is, the axial direction of the secondary transfer roller 301), and rotates around the shaft 302a. Is supported so that you can. Further, the secondary transfer roller support member 302 has a first rotation position (a position of the secondary transfer roller support member 302 shown in FIG. 6) and a first rotation with the shaft 302a as a rotation fulcrum by the action of a cam mechanism (not shown). It reciprocates between two rotation positions (the position of the secondary transfer roller support member 302 shown in FIG. 8). Then, when the secondary transfer roller support member 302 rotates, the secondary transfer roller 301 moves integrally with the secondary transfer roller support member 302. That is, when the secondary transfer roller support member 302 is in the first rotation position, the secondary transfer roller 301 is in the contact position, and when the secondary transfer roller support member 302 is in the second rotation position, the secondary transfer roller support member 302 is in the second rotation position. The next transfer roller 301 is positioned at the separation position.

  The cam mechanism has not only a function of moving the secondary transfer roller 301 and the secondary transfer roller support member 302 but also a function of maintaining the position of the secondary transfer roller 301 at the contact position or the separation position. ing.

  Next, the operation of the secondary transfer unit 80 configured as described above will be described. The secondary transfer roller 301 moves to the contact position when the toner image is transferred to the recording medium or when the intermediate transfer body 62 is warmed (warming operation of the intermediate transfer body 62) as will be described later. Is controlled to stand by at the standby position.

  Here, the operation of the secondary transfer unit 80 when the toner image is transferred to the recording medium (that is, when the transfer operation is executed) will be described (the operation of the secondary transfer unit 80 when the warming operation is executed, etc.) Will be described later). The secondary transfer roller 301 stands by at a separated position until the secondary transfer unit 80 receives a transfer operation start signal from the secondary transfer unit drive control circuit (see FIG. 4). At this time, as described above, the secondary transfer roller 301 contacts the fixing unit 90 and closes the introduction port 505 in a state where it intersects with a virtual plane that closes the introduction port 505 of the fixing unit 90. .

  When the secondary transfer unit 80 receives the transfer operation start signal, the secondary transfer roller support member 302 is rotated from the second rotation position to the first rotation position by the cam mechanism described above. Accordingly, the secondary transfer roller 301 moves in a direction approaching the intermediate transfer member 62 and reaches the contact position. Thereafter, as described above, when the recording medium reaches between the driving roller 71 and the secondary transfer roller 301 at the contact position, the secondary transfer roller 301 contacts the intermediate transfer member 62 via the recording medium. The secondary transfer roller 301 is rotated with the driving roller 71 and the intermediate transfer body 62 to transfer the toner image on the intermediate transfer body 62 to the recording medium, and the recording medium is moved along the recording medium conveyance path 400. Then, it is conveyed in the direction toward the fixing unit 90. Further, while the transfer is continued, the secondary transfer roller support member 302 is maintained at the first rotation position and the secondary transfer roller 301 is maintained at the contact position.

  When the secondary transfer roller 301 finishes transferring, the secondary transfer roller support member 302 is rotated from the first rotation position to the second rotation position by the cam mechanism. Accordingly, the secondary transfer roller 301 is separated from the intermediate transfer body 62 so as to approach the fixing unit 90. When the secondary transfer roller 301 reaches the separation position, the secondary transfer roller 301 is maintained at the separation position until the next transfer operation.

=== Regarding the warming operation of the intermediate transfer member 62 ===
As described in the section “Problems to be Solved by the Invention”, the temperature of the intermediate transfer body 62 may change as the temperature in the printer 10 changes. In such a case, the intermediate transfer body 62 expands and contracts. As a result, the length (that is, the circumferential length) of the intermediate transfer body 62 in the rotation direction may change. If the peripheral length of the intermediate transfer body 62 changes during image formation after the warm-up operation, the toner image may be held at a position shifted from a predetermined position of the intermediate transfer body 62. The quality of the product may be reduced.

  In particular, when a color image is formed by superimposing four color toner images, the position of the four color toner image fluctuates due to the expansion and contraction of the circumference of the intermediate transfer body 62, thereby reducing the quality of the color image. The possibility to do increases.

  Therefore, in the printer 10 according to the present embodiment, a warming operation for warming the intermediate transfer body 62 during non-image formation is performed in order to suppress expansion and contraction of the intermediate transfer body 62 during image formation. Hereinafter, an example of the warming operation of the intermediate transfer member 62 will be described.

<<< Example of warming operation >>>
Hereinafter, the warming operation of the intermediate transfer body 62 immediately after the warm-up operation is finished will be described with reference to FIG. FIG. 9 is a flowchart for explaining the warming operation of the intermediate transfer member 62.

  In the printer 10 according to the present embodiment, the warm-up operation is performed immediately after the printer 10 is turned on or when the surface temperature of the fixing roller 501 does not exceed 180 (° C.) when an image forming command is received. Executed. Hereinafter, a warm-up operation that is executed when the surface temperature of the fixing roller 501 does not exceed 180 (° C.) when an image forming command is received will be described as an example.

  It should be noted that various operations of the printer 10 when the warming operation is executed (for example, warm-up operation, rotation operation of the intermediate transfer body 62, separation contact operation of the secondary transfer roller 301, etc.) are mainly controlled. This is realized by the unit 100 (FIG. 4). In particular, in the present embodiment, it is realized by the CPU processing a program stored in the ROM. And this program is comprised from the code | cord | chord for performing the various operation | movement demonstrated below.

  In this embodiment, the printer 10 is in a state (standby state) before receiving an image forming command from the computer 702, the internal heater 501c is not energized, and the secondary transfer roller 301 is in the separated position shown in FIG. It starts from the state located at. As described above, the secondary transfer roller 301 located at the separation position contacts the fixing unit 90 and closes the introduction port 505 in a state where it intersects the virtual plane that closes the introduction port 505 of the fixing unit 90. It is out.

  When the printer 10 receives the image forming command (step s102), the temperature sensor 503 measures the surface temperature of the fixing roller 501 (step s104). If the measured value of the temperature sensor 503 exceeds the set temperature of 180 (° C.) (step s106: Yes), the above-described image forming operation is executed (step s116). On the other hand, when the measured value of the temperature sensor 503 does not exceed 180 (° C.) (step s106: No), the control unit 100 energizes the internal heater 501c to perform fixing before executing the image forming operation. The warm-up operation of the roller 501 is executed (step s108). That is, the control unit 100 heats the fixing roller 501 by generating heat in the internal heater 501c.

  Even when the warm-up operation is performed, the secondary transfer roller 301 is in contact with the fixing unit 90 in a state where it intersects the virtual plane that closes the introduction port 505 of the fixing unit 90, and the introduction port 505 is blocked. For this reason, the secondary transfer roller 301 located at the separated position and closing the inlet 505 is heated by the internal heater 501 c of the fixing unit 90. As described above, the control unit 100 warms the secondary transfer roller 301 to the internal heater 501c in a state where the secondary transfer roller 301 is positioned at the separation position while the warm-up operation is being performed.

  Next, when the measured value of the temperature sensor 503 exceeds 180 (° C.) during heating of the fixing roller 501, the control unit 100 ends the execution of the warm-up operation (step s110: Yes) ( Step s112). Note that the time from the start of the warm-up operation until the surface temperature of the fixing roller 501 exceeds the set temperature is approximately 60 (seconds) in the printer 10 according to the present embodiment. ) Warm-up operation ends when it elapses.

  Then, immediately after the warm-up operation is finished, the control unit 100 moves the secondary transfer roller 301 warmed by the internal heater 501c to the contact position, and the secondary transfer roller 301 is brought to the corresponding contact position. The intermediate transfer body 62 is rotated in the positioned state, and a warming operation for warming the intermediate transfer body 62 is executed (step s114). Note that the control unit 100 causes the secondary transfer roller 301 to reciprocate a plurality of times between the separation position and the contact position, and performs the warming operation a plurality of times (four times in the present embodiment). .

  Here, the operation of the secondary transfer unit 80 when the warming operation is executed four times will be described with reference to FIG. FIG. 10 is a time chart showing the operation of the secondary transfer roller 301 when the warming operation is executed a plurality of times. FIG. 10 shows the position of the secondary transfer roller 301 when the warming operation is executed four times. For example, the secondary transfer roller 301 is located at the separation position until 63 (seconds) has elapsed since the start of the warm-up operation, and the secondary transfer roller from 63 (second) to 67 (second). 301 is located in the contact position. In FIG. 10, the change in the surface temperature of the fixing roller 501 when the warm-up operation is executed is indicated by a broken line. Specifically, the surface temperature of the fixing roller 501 at the start of the warm-up operation is about 20 (° C.), and the surface of the fixing roller 501 until 60 (seconds) elapses after the start of the warm-up operation. After the temperature rises and 60 (seconds) elapses, the surface temperature of the fixing roller 501 is maintained at 180 (° C.).

  First, the control unit 100 is positioned at a separated position and is heated by the internal heater 501c when 63 (seconds) has elapsed from the start of the warm-up operation (that is, immediately after the end of the warm-up operation). Is moved to the contact position, and the intermediate transfer body 62 is rotated in a state where the secondary transfer roller 301 is positioned at the corresponding contact position, and the first warming operation (D1 in FIG. 10) is executed. .

  That is, the secondary transfer roller support member 302 is rotated from the second rotation position to the first rotation position by the cam mechanism described above, so that the secondary transfer roller 301 located at the separation position is moved to the contact position. Will move. As shown in FIG. 10, the time for which the secondary transfer roller 301 is located at the contact position during the first warming operation D1 is 4 (seconds). This time is longer than the time for which the intermediate transfer body 62 rotates once (in this embodiment, 3 (seconds)). For this reason, the control unit 100 rotates the intermediate transfer body 62 one or more times in a state where the secondary transfer roller 301 is positioned at the corresponding contact position, and executes the first warming operation D1.

  When the first warming operation D1 ends (67 seconds after the start of the warm-up operation), the control unit 100 moves the secondary transfer roller 301 located at the contact position to the separation position. That is, as the secondary transfer roller support member 302 rotates from the first rotation position to the second rotation position, the secondary transfer roller 301 positioned at the contact position moves to the separation position. Then, the secondary transfer roller 301 that has moved to the separation position is warmed again by the heat in the fixing unit 90. Note that the control unit 100 positions the secondary transfer roller 301 at the separation position for 10 (seconds) until the second warming operation (D2 in FIG. 10) is executed.

  When 77 (seconds) elapses from the start of the warm-up operation, the control unit 100 causes the second warming operation D2 to be executed in the same manner as the first warming operation D1. The time for which the secondary transfer roller 301 is located at the contact position during the second warming operation D2 is 4 (seconds), as in the first warming operation D1. When the second warming operation D2 ends (81 (seconds) after the start of the warm-up operation), the control unit 100 moves the secondary transfer roller 301 located at the contact position to the separation position. Then, the secondary transfer roller 301 that has moved to the separation position is warmed again by the heat in the fixing unit 90. Note that the control unit 100 keeps the secondary transfer roller 301 at the separation position for 7 (seconds) until the third warming operation (D3 in FIG. 10) is executed.

  When 88 (seconds) has elapsed from the start of the warm-up operation, the control unit 100 causes the third warming operation D3 to be executed in the same manner as the first warming operation D1. The time for which the secondary transfer roller 301 is located at the contact position during the third warming operation D3 is 4 (seconds), as in the first warming operation D1. When the third warming operation D3 is completed (when 92 seconds have elapsed since the start of the warm-up operation), the control unit 100 moves the secondary transfer roller 301 located at the contact position to the separation position. Then, the secondary transfer roller 301 that has moved to the separation position is warmed again by the heat in the fixing unit 90. Note that the control unit 100 keeps the secondary transfer roller 301 in the separated position for 4.5 (seconds) until the fourth warming operation (D4 in FIG. 10) is executed.

  When 96.5 (seconds) have elapsed from the start of the warm-up operation, the control unit 100 causes the fourth warming operation D4 to be executed in the same manner as the first warming operation D1. As shown in FIG. 10, the time for which the secondary transfer roller 301 is located at the contact position during the fourth warming operation D4 is 4 (seconds), as in the first warming operation D1. When the fourth warming operation D4 ends (when 100.5 (seconds) has elapsed from the start of the warm-up operation), the control unit 100 moves the secondary transfer roller 301 located at the contact position to the separation position, The state where the secondary transfer roller 301 is located at the separation position is maintained. Thereby, the four warming operations D4 are completed.

  As described above, the secondary transfer roller 301 moves to the intermediate transfer member 62 when 63 (seconds), 77 (seconds), 88 (seconds), and 96.5 (seconds) have elapsed since the start of the warm-up operation. By the contact, four warming operations are executed. Further, as described above, since the time for which the intermediate transfer member 62 rotates once is 3 (seconds), when the warming operation is performed four times (in other words, the secondary transfer roller 301 is rotated four times. When reciprocating, the position of the intermediate transfer body 62 where the secondary transfer roller 301 contacts at the contact position is a plurality of different positions. In other words, when the warming operation is executed four times, the position of the intermediate transfer body 62 where the secondary transfer roller 301 comes into contact at the contact position is different.

  Further, as described above, the time during which the secondary transfer roller 301 is continuously located in the separated position between the first warming operation D1 and the second warming operation D2 is 10 (seconds), and the second time The time during which the secondary transfer roller 301 continues to be in the separated position between the second warming operation D2 and the third warming operation D3 is 7 (seconds), and the third warming operation D3 and the fourth warming operation D3. The time for which the secondary transfer roller 301 continues to be in the separated position during the operation D4 is 4.5 (seconds). As described above, the control unit 100 starts the time T1 (that is, 10 (seconds)) for continuously positioning the secondary transfer roller 301 at the separation position in the initial period of executing the warming operation a plurality of times (four times). ) Is made longer than the time T2 (that is, 4.5 (seconds)) during which the secondary transfer roller 301 is continuously positioned at the separated position in the latter period of the period in which the warming operation is performed four times.

  Returning to the flowchart, the description of the warming operation of the intermediate transfer member 62 will be continued. After the warming operation is executed four times (when 108 (seconds) has elapsed since the start of the warm-up operation), the control unit 100 performs the above-described image forming operation based on the image forming command received in step s102. Execute (step s116). At this time, the control unit 100 executes the image forming operation using the intermediate transfer body 62 that has become high temperature by the above-described warming operation.

  In the above description, as shown in FIG. 10, the control unit 100 sets the time for which the secondary transfer roller 301 is continuously located at the contact position during a period in which the warming operation is performed four times, that is, a predetermined time (that is, 4 (seconds)), but is not limited to this. For example, as shown in FIG. 11, the control unit 100 determines that the time T3 during which the secondary transfer roller 301 is continuously positioned at the contact position in the latter half of the period in which the warming operation is executed four times [specifically, , 16 (seconds), which is the time of the third warming operation D3 in FIG. 11, at the initial stage of executing the warming operation a plurality of times, the secondary transfer roller 301 is continuously positioned at the contact position. It may be longer than the time T4 [specifically, 4 (seconds), which is the time of the first warming operation D1 in FIG. 11]. In FIG. 11, unlike FIG. 10, in the period in which the warming operation is executed a plurality of times, the time during which the secondary transfer roller 301 is continuously located in the separated position is a fixed time (that is, 6 (seconds)). It has become.

  Furthermore, the control unit 100 may make the time T1 longer than the time T2 and make the time T3 longer than the time T4 when the warming operation is executed a plurality of times. FIG. 11 is a time chart showing the operation of the secondary transfer roller 301 when the warming operation is executed a plurality of times, as in FIG.

=== Regarding the Printer 10 According to the Second Embodiment ===
The printer 10 according to the second embodiment, which is different from the printer 10 described above (hereinafter also referred to as the printer 10 according to the first embodiment), will be described.

<<< Configuration Example of Printer 10 >>>
Among the configurations of the printer 10 according to the second embodiment, the configurations of the secondary transfer unit 80 and the fixing unit 90 are different from the configurations of the secondary transfer unit 80 and the fixing unit 90 of the printer 10 according to the first embodiment. Therefore, in the following, configurations of the secondary transfer unit 80 and the fixing unit 90 will be described. In the following, the configuration of the printer 10 according to the second embodiment other than the secondary transfer unit 80 and the fixing unit 90 is the same as the configuration of the printer 10 according to the first embodiment. Omit the explanation.

  FIG. 12 is a diagram showing the intermediate transfer body 62, the secondary transfer unit 80, and the fixing unit 90 when the secondary transfer roller 301 is located at the contact position. FIG. 13 is a diagram illustrating the intermediate transfer body 62, the secondary transfer unit 80, and the fixing unit 90 when the secondary transfer roller 301 is positioned between the contact position and the separation position. FIG. 14 is a diagram showing the intermediate transfer body 62, the secondary transfer unit 80, and the fixing unit 90 when the secondary transfer roller 301 is located at the separation position. In FIGS. 12 to 14, the vertical direction is indicated by arrows as in FIG.

<Configuration of Fixing Unit 90>
First, the configuration of the fixing unit 90 will be described. Similar to the fixing unit 90 according to the first embodiment, the fixing unit 90 according to the second embodiment includes a fixing roller 501, a pressure roller 502, a temperature sensor 503, a housing 504, and the like. The configurations of the fixing roller 501, the pressure roller 502, and the temperature sensor 503 are the same as those in the first embodiment.

  On the other hand, unlike the first embodiment, the housing 504 has a shutter 521 which is an example of a “moving member” in the lower part thereof. The introduction port 505 is formed between one end 521a in the short direction of the shutter 521 and the recording medium guide 507a. Since the shutter 521 in the present embodiment can move (slide) between the first position (position shown in FIG. 12) and the second position (position shown in FIG. 14), the shutter 521 is moving (sliding). The length of the introduction port 505 in the short direction changes. When the shutter 521 is located at the second position as shown in FIG. 14, the length in the short direction of the introduction port 505 is the largest. When the shutter 521 is located at the first position as shown in FIG. The length of the introduction port 505 in the short direction is the smallest. For this reason, when the shutter 521 is located at the first position, the shutter 521 closes the introduction port 505 compared to when the shutter is located at the second position.

  A tension spring 523 is provided on the other end side of the shutter 521 in the short direction. The tension spring 523 has hooks 523a and 523b at both ends thereof, the hook 523a on the one end side (right side in FIG. 12) is the shutter 521, and the hook 523b on the other end side (left side in FIG. 12) is the connecting portion. 522, respectively. The tension spring 523 pulls the shutter 521 toward the connecting portion 522 by the tension force.

<Configuration of secondary transfer unit 80>
Next, the configuration of the secondary transfer unit 80 will be described. Similar to the secondary transfer unit 80 according to the first embodiment, the secondary transfer unit 80 according to the second embodiment includes a secondary transfer roller 301 and a secondary transfer roller support member 302. The configuration of the secondary transfer roller 301 is the same as that in the first embodiment.

  On the other hand, unlike the first embodiment, the secondary transfer roller support member 302 has a U-shape, and the secondary transfer roller support member 302 has a support portion 302b that supports the secondary transfer roller 301 and a secondary when viewed from the shaft 302a. And an extension part 302c extending to the opposite side to the transfer roller 301 side. The secondary transfer roller support member 302 has a first rotation position (the position of the secondary transfer roller support member 302 shown in FIG. 12) with the shaft 302a as a rotation fulcrum by the action of the cam mechanism described above. It reciprocates between the second rotation position (the position of the secondary transfer roller support member 302 shown in FIG. 14). Then, when the secondary transfer roller support member 302 rotates, the secondary transfer roller 301 moves integrally with the secondary transfer roller support member 302. That is, when the secondary transfer roller support member 302 is in the first rotation position, the secondary transfer roller 301 is in the contact position, and when the secondary transfer roller support member 302 is in the second rotation position, the secondary transfer roller support member 302 is in the second rotation position. The next transfer roller 301 is positioned at the separation position.

  In addition, a contact portion 302 d that can come into contact with the shutter 521 is formed in the extended portion 302 c as the secondary transfer roller support member 302 rotates. The contact portion 302d is disposed on the front side of the tension spring 523 in FIG. Then, when the secondary transfer roller support member 302 is further rotated in a state where the contact portion 302d is in contact (the state shown in FIG. 13), the shutter 521 that is pulled to the connecting portion 522 side by the tension spring 523 is the first. It moves between one position and the second position. That is, when the secondary transfer roller support member 302 moves from the first rotation position to the second rotation position, the contact portion 302d that contacts the shutter 521 resists the pulling force of the tension spring 523, and the shutter 521 is moved from the second position to the first position. On the other hand, when the secondary transfer roller support member 302 moves from the second rotation position to the first rotation position, the shutter 521 moves from the first position to the second position by the pulling force of the tension spring 523.

<<< Example of warming operation >>>
As described above, in the printer 10 according to the first embodiment, the warming operation of the intermediate transfer body 62 is performed immediately after the end of the warm-up operation. However, in the printer 10 according to the second embodiment, the intermediate transfer body 62 The warming operation of the body 62 is executed during the execution of the warm-up operation. Therefore, a warming operation performed during the warm-up operation will be described with reference to FIGS. 15 and 16. FIG. 15 is a flowchart for explaining the warming operation of the intermediate transfer member 62. FIG. 16 is a time chart showing the operation of the secondary transfer roller 301 when the warming operation is executed a plurality of times.

  In the printer 10 according to the present embodiment, the warm-up operation is performed immediately after the printer 10 is turned on or when the surface temperature of the fixing roller 501 does not exceed 180 (° C.) when an image forming command is received. Executed. Hereinafter, a warm-up operation that is executed when the surface temperature of the fixing roller 501 does not exceed 180 (° C.) when an image forming command is received will be described as an example.

  Various operations of the printer 10 when the warming operation is executed (for example, warm-up operation, rotation operation of the intermediate transfer body 62, separation contact operation of the secondary transfer roller 301, movement operation of the shutter 521, etc.) This is mainly realized by the control unit 100 (FIG. 4). In particular, in the present embodiment, it is realized by the CPU processing a program stored in the ROM. And this program is comprised from the code | cord | chord for performing the various operation | movement demonstrated below.

  In this embodiment, the printer 10 is in a state (standby state) before receiving an image forming command from the computer 702, the internal heater 501c is not energized, and the secondary transfer roller 301 is in the separated position shown in FIG. It starts from the state located at. As described above, the secondary transfer roller 301 located at the separation position closes the introduction port 505 in a state where it intersects the virtual plane that closes the introduction port 505 of the fixing unit 90.

  When the printer 10 receives the image forming command (step s202), the temperature sensor 503 measures the surface temperature of the fixing roller 501 (step s204). If the measured value of the temperature sensor 503 exceeds the set temperature of 180 (° C.) (step s206: Yes), the above-described image forming operation is executed (step s222). On the other hand, when the measured value of the temperature sensor 503 does not exceed 180 (° C.) (step s206: No), the control unit 100 energizes the internal heater 501c to perform fixing before executing the image forming operation. The warm-up operation of the roller 501 is executed (step s208). That is, the control unit 100 heats the fixing roller 501 by generating heat in the internal heater 501c.

  Even when the warm-up operation is started, the secondary transfer roller 301 closes the introduction port 505 while intersecting the virtual plane that closes the introduction port 505 of the fixing unit 90. The secondary transfer roller 301 is heated by the internal heater 501c of the fixing unit 90 when it is positioned at the separated position during the warm-up operation.

  In the present embodiment, the warming operation (first warming operation, D1 in FIG. 16) is executed when 21 (seconds) has elapsed since the start of warm-up. When the measured value of the temperature sensor 503 exceeds 180 (° C.) (step s210: Yes), the warm-up operation is terminated (step s220). On the other hand, as shown in FIG. 16, when the measured value of the temperature sensor 503 does not exceed 180 (° C.) (step s210: No), the warm-up operation is continued while the temperature is warmed by the internal heater 501c. The secondary transfer roller 301 is moved to the contact position, and the intermediate transfer body 62 is rotated in a state where the secondary transfer roller 301 is positioned at the corresponding contact position, so that the intermediate transfer body 62 is warmed. It is executed (step s212). At this time, the control unit 100 moves the shutter 521 located at the second position (position shown in FIG. 14) to the first position (position shown in FIG. 12), and introduces the inlet to the shutter 521. Block 505.

  That is, the secondary transfer roller support member 302 is rotated from the second rotation position to the first rotation position by the cam mechanism described above, so that the secondary transfer roller 301 located at the separation position is moved to the contact position. Moving. Then, when the secondary transfer roller 301 and the intermediate transfer body 62 located at the contact position rotate, the first warming operation is executed. Further, as the secondary transfer roller support member 302 rotates from the second rotation position to the first rotation position, the contact portion 302 d of the secondary transfer roller support member 302 resists the tensile force of the tension spring 523. By moving (sliding) the shutter 521 from the second position to the first position, the shutter 521 closes the inlet 505.

  As shown in FIG. 16, the control unit 100 executes the first warming operation for 4 (seconds), and when the measured value of the temperature sensor 503 exceeds 180 (° C.) during this 4 (seconds). (Step s214: Yes), the secondary transfer roller 301 located at the contact position is forcibly moved to the separation position, and the warming operation is ended (Step s218). Then, the control unit 100 ends the warm-up operation (step s220).

  On the other hand, as shown in FIG. 16, when the measured value of the temperature sensor 503 does not exceed 180 (° C.) during the 4 (seconds) (step s214: No), the control unit 100 is in the contact position. The secondary transfer roller 301 that is positioned is moved to the separation position when 4 seconds have elapsed (step s216). That is, as the secondary transfer roller support member 302 rotates from the first rotation position to the second rotation position, the secondary transfer roller 301 positioned at the contact position moves to the separation position. Further, as the secondary transfer roller support member 302 rotates from the first rotation position to the second rotation position, the shutter 521 moves (slides) from the first position to the second position by the pulling force of the tension spring 523. To do. Thus, the first warming operation D1 is completed.

  After the completion of the first warming operation D1, the control unit 100 repeats the operations of steps s210 to 216 described above while the warm-up operation is continued. In the present embodiment, as shown in FIG. 16, during the warm-up operation, four warming operations (that is, the first warming operation D1, the second warming operation D2, the third warming operation D3, the fourth warming operation) are performed. The warming operation D4) is executed.

  Here, four warming operations will be described. As shown in FIG. 16, the secondary transfer roller 301 moves to the intermediate transfer body 62 when 21 (seconds), 35 (seconds), 46 (seconds), and 54.5 (seconds) have elapsed since the start of the warm-up operation. By abutting for 4 (seconds), four warming operations are executed. This 4 (seconds) is longer than the time for which the intermediate transfer body 62 rotates once (in this embodiment, 3 (seconds)). Therefore, the control unit 100 rotates the intermediate transfer body 62 one or more times in a state where the secondary transfer roller 301 is located at the corresponding contact position, and executes the first warming operation. Further, as described above, since the time for which the intermediate transfer member 62 rotates once is 3 (seconds), when the warming operation is performed four times (in other words, the secondary transfer roller 301 is rotated four times. When reciprocating, the position of the intermediate transfer body 62 where the secondary transfer roller 301 contacts at the contact position is a plurality of different positions. In other words, when the warming operation is executed four times, the position of the intermediate transfer body 62 where the secondary transfer roller 301 comes into contact at the contact position is different.

  Further, as shown in FIG. 16, the time during which the secondary transfer roller 301 is continuously located in the separated position between the first warming operation D1 and the second operation D2 is 10 (seconds). The time during which the secondary transfer roller 301 continues to be in the separated position between the third warming operation D2 and the third warming operation D3 is 7 (seconds), and the third warming operation D3 and the fourth warming operation D3. The time during which the secondary transfer roller 301 continues to be in the separated position between the warming operation D4 is 4.5 (seconds). As described above, the control unit 100 starts the time T1 (that is, 10 (seconds)) for continuously positioning the secondary transfer roller 301 at the separation position in the initial period of executing the warming operation a plurality of times (four times). ) Is made longer than the time T2 (that is, 4.5 (seconds)) during which the secondary transfer roller 301 is continuously positioned at the separated position in the latter period of the period in which the warming operation is performed four times.

  Returning to the flowchart, the description of the warming operation of the intermediate transfer member 62 will be continued. In this embodiment, since the measured value of the temperature sensor 503 exceeds 180 (° C.) after the fourth warming operation is finished (step s210: Yes), the secondary transfer roller 301 is located at the separation position. In the state, the warm-up operation is finished (step s220). Then, after finishing the warm-up operation (69 seconds after the start of the warm-up operation), the control unit 100 executes the above-described image forming operation based on the image formation command received in step s102. (Step s222).

  In the above description, as shown in FIG. 16, the control unit 100 sets the time for which the secondary transfer roller 301 is continuously located at the contact position during a period in which the warming operation is performed four times, that is, a predetermined time (that is, 4 (seconds)), but is not limited to this. For example, as shown in FIG. 17, the control unit 100 determines that the time T3 during which the secondary transfer roller 301 is continuously positioned at the contact position in the latter part of the period in which the warming operation is executed a plurality of times [specifically, , 16 (seconds), which is the time of the third warming operation D3 in FIG. 17, in the initial period of executing the warming operation a plurality of times, the secondary transfer roller 301 is continuously positioned at the contact position. It is also possible to make it longer than the time T4 [specifically, 4 (seconds), which is the time of the first warming operation D1 in FIG. 17]. In FIG. 17, unlike FIG. 16, in the period in which the warming operation is executed a plurality of times, the time during which the secondary transfer roller 301 is continuously located in the separated position is a certain time (that is, 6 (seconds)). It has become.

  Furthermore, the control unit 100 may make the time T1 longer than the time T2 and make the time T3 longer than the time T4 when the warming operation is executed a plurality of times. FIG. 17 is a time chart showing the operation of the secondary transfer roller 301 when the warming operation is executed a plurality of times, as in FIG.

=== Effectiveness of Printer 10 described above ===
As described above, the “image forming apparatus” (printer 10) has a rotatable “intermediate” that is an intermediate medium when (a) “developer image” (toner image) is transferred to “medium” (recording medium). Transfer body ”(intermediate transfer body 62), and (b) a contact position that contacts the intermediate transfer body 62 and a separation position that is separated from the intermediate transfer body 62. A “transfer roller” (secondary transfer roller 301) for transferring the toner image to the recording medium in a state of being positioned at (2), and (c) a “roller” (fixing roller 501) that can contact the toner image transferred to the recording medium. ) And a “heating element” (internal heater 501c) for generating heat to warm the fixing roller 501, and fixing the toner image onto the recording medium by the fixing roller 501 heated by the internal heater 501c. "Fixing device" (fixing) Knit 90) and (d) a “control unit” (control unit 100) for controlling the rotation operation of the intermediate transfer body 62 and the separation / contact operation of the secondary transfer roller 301, and heats the internal heater 501c. And a control unit 100 capable of executing a warm-up operation for generating and heating the fixing roller 501 to a predetermined temperature. Then, as shown in FIGS. 9 and 15, the control unit 100 moves the secondary transfer roller 301 to the internal heater 501c in a state where the secondary transfer roller 301 is positioned at the separated position when the warm-up operation is performed. The secondary transfer roller 301 warmed by the internal heater 501c is moved to the contact position while the warm-up operation is being performed or immediately after the warm-up operation is completed, and the secondary transfer roller 301 is moved. The intermediate transfer member 62 is rotated in a state where the intermediate transfer member 62 is positioned at the corresponding contact position, and a warming operation for warming the intermediate transfer member 62 is executed.

  According to such a printer 10, the intermediate transfer body 62 is moved by moving the secondary transfer roller 301 warmed by the internal heater 501c to the contact position during execution of the warm-up operation or immediately after the end of the warm-up operation. Since it warms, the intermediate transfer body 62 can be quickly warmed to a high temperature. The intermediate transfer body 62 is warmed to a high temperature, so that the temperature of the intermediate transfer body 62 can be prevented from changing even if the temperature in the printer 10 changes. For this reason, even when image formation is executed within a short time after the warm-up operation is completed, it is possible to appropriately suppress a change in the peripheral length of the intermediate transfer body 62 during image formation.

=== Other Embodiments ===
As mentioned above, although the printer etc. which concern on this invention were demonstrated based on the said embodiment, embodiment mentioned above is for making an understanding of this invention easy, and does not limit this invention. . The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.

  In the above embodiment, an intermediate transfer type full color laser beam printer has been described as an example of the image forming apparatus. However, the present invention is not limited to the intermediate transfer type, such as a full color laser beam printer, a monochrome laser beam printer, a copying machine, and a facsimile. The present invention can be applied to various image forming apparatuses.

Furthermore, in the above embodiment, as shown in FIG. 10 and the like, the control unit 100 rotates the intermediate transfer body 62 one or more times with the secondary transfer roller 301 positioned at the corresponding contact position, and performs the warming operation. However, the present invention is not limited to this. For example, the control unit 100 may execute the warming operation by rotating the intermediate transfer body 62 less than one turn while the secondary transfer roller 301 is located at the corresponding contact position.
However, when the control unit 100 rotates the intermediate transfer body 62 one or more times with the secondary transfer roller 301 positioned at the corresponding contact position to execute the warming operation, the intermediate transfer is performed by a single warming operation. It becomes possible to warm the whole body 62. Therefore, the above embodiment is more desirable.

Further, in the above embodiment, as shown in FIG. 6, the fixing unit 90 has an “opening” (introduction port 505) for allowing the recording medium on which the toner image is transferred to pass to the fixing roller 501. It was decided. As shown in FIG. 8, when the secondary transfer roller 301 is located at the separation position, the secondary transfer roller 301 blocks the introduction port 505. However, it is not limited to the above. For example, the secondary transfer roller 301 may not block the inlet 505 when the secondary transfer roller 301 is positioned at the separation position.
However, if the secondary transfer roller 301 closes the introduction port 505 when the secondary transfer roller 301 is positioned at the separation position, the heat generated by the internal heater 501c tends to stay in the fixing unit 90. As a result, the fixing roller 501 can be appropriately heated, so that the warm-up operation can be effectively performed. Therefore, the above embodiment is more desirable.

Furthermore, in the above embodiment, as shown in FIGS. 12 to 14, the printer 10 is a “moving member” (shutter 521) that moves between the first position and the second position, The shutter 521 that closes the inlet 505 is provided when positioned. The control unit 100 can control the moving operation of the shutter 521, and during the execution of the warm-up operation, moves the secondary transfer roller 301 heated by the internal heater 501c to the contact position, and The intermediate transfer body 62 is rotated in a state where the secondary transfer roller 301 is positioned at the corresponding contact position, and a warming operation for warming the intermediate transfer body 62 is executed, and the shutter 521 positioned at the second position is moved to the first position. The inlet 505 is blocked by the shutter 521 by moving to the position. However, it is not limited to the above. For example, the shutter 521 that closes the introduction port 505 may not be provided.
However, when the shutter 521 is provided and the shutter 521 closes the inlet 505 when the secondary transfer roller 301 moves from the separated position to the contact position during the warm-up operation, the internal heater 501c is used. Since the heat generated by the heat tends to stay in the fixing unit 90, the fixing roller 501 can be appropriately warmed, so that the warm-up operation can be effectively performed. Therefore, the above embodiment is more desirable.

Further, in the above embodiment, as shown in FIG. 10 and the like, the control unit 100 reciprocates the secondary transfer roller 301 between the separation position and the contact position a plurality of times to perform the warming operation. Although it is determined to be executed a plurality of times, the present invention is not limited to this. For example, the control unit 100 may move the secondary transfer roller 301 from the separation position to the contact position only once and execute the warming operation only once.
However, when the secondary transfer roller 301 moves a plurality of times between the separation position and the contact position and the warming operation is performed a plurality of times, the internal heater 501c performs each time the warming operation is performed. Since the warmed secondary transfer roller 301 is brought into contact with the intermediate transfer member 62, the intermediate transfer member 62 can be immediately heated to a high temperature. Therefore, the above embodiment is more desirable.

Further, in the above embodiment, when the secondary transfer roller 301 reciprocates a plurality of times, the position of the intermediate transfer body 62 where the secondary transfer roller 301 comes into contact at the contact position is a plurality of different positions. However, the present invention is not limited to this. For example, when the secondary transfer roller 301 reciprocates a plurality of times, the position of the intermediate transfer body 62 that the secondary transfer roller 301 contacts at the contact position may always be the same position.
However, when the secondary transfer roller 301 reciprocates a plurality of times, the position of the intermediate transfer body 62 where the secondary transfer roller 301 contacts at the contact position is a plurality of different positions. Since only a part of the intermediate transfer member 62 can be prevented from being overheated, the entire intermediate transfer member 62 can be uniformly heated. Therefore, the above embodiment is more desirable.

Further, in the above embodiment, as shown in FIG. 10 and FIG. 16, the control unit 100 continues to position the secondary transfer roller 301 at the separation position at the beginning of the period in which the warming operation is executed a plurality of times. The time T1 is set to be longer than the time T2 during which the secondary transfer roller 301 is continuously positioned at the separation position in the latter period during which the warming operation is performed a plurality of times. However, the present invention is not limited to this. It is not a thing. For example, the control unit 100 may make the length of the time T1 the same as the length of the time T2.
Since the secondary transfer roller 301 in the initial period in which the warming operation is performed a plurality of times is more likely to be deprived of heat by the intermediate transfer body 62 when the intermediate transfer body 62 is warmed than in the latter period of the period, Compared to the latter stage, the temperature of the secondary transfer roller 301 tends to decrease. At this time, the time T1 for continuously positioning the secondary transfer roller 301 at the separation position at the initial stage is set longer than the time T2 for continuously positioning the secondary transfer roller 301 at the separation position at the latter stage. In this case, the temperature of the secondary transfer roller 301 that is heated by the internal heater 501c and moves to the contact position can be kept high during the period. Therefore, the above embodiment is more desirable.

Further, in the above embodiment, as shown in FIG. 11 and FIG. 17, the control unit 100 continues the secondary transfer roller 301 to the contact position in the latter stage of the period in which the warming operation is executed a plurality of times. The time T3 to be positioned is set to be longer than the time T4 in which the secondary transfer roller 301 is continuously positioned at the contact position at the beginning of the period in which the warming operation is performed a plurality of times. Is not to be done. For example, the control unit 100 may make the length of the time T3 the same as the length of the time T4.
In order to effectively suppress a change in the peripheral length of the intermediate transfer body 62 during image formation, it is desirable that the temperature of the entire intermediate transfer body 62 be uniform in the later stage than in the initial period. Therefore, when the time T3 is longer than the time T4, the temperature of the intermediate transfer body 62 is made uniform by warming the intermediate transfer body 62 for a long time by the secondary transfer roller 301 in the latter stage. Is possible. Therefore, the above embodiment is more desirable.

1 is an explanatory diagram showing an external configuration of an image forming system 700. FIG. FIG. 2 is a block diagram illustrating a part of the configuration of the image forming system 700 illustrated in FIG. 1. FIG. 2 is a diagram illustrating main components constituting the printer. 2 is a block diagram illustrating a configuration of a control unit 100 of the printer 10. FIG. FIG. 3 is a perspective view showing a primary transfer unit 60. FIG. 2 is a schematic cross-sectional view illustrating main components of the secondary transfer unit 80, the intermediate transfer body 62, and the fixing unit 90 installed in the printer 10, and the secondary transfer roller 301 is attached to the intermediate transfer body 62. A state of contact is shown. 2 is a schematic perspective view of a fixing unit 90. FIG. FIG. 2 is a schematic cross-sectional view showing main components of the secondary transfer unit 80, the intermediate transfer body 62, and the fixing unit 90 installed in the printer 10, and the secondary transfer roller 301 is separated from the intermediate transfer body 62. A state in which the apparatus is waiting in the direction of the fixing unit 90 is shown. 6 is a flowchart for explaining a warming operation of the intermediate transfer member 62. 6 is a time chart showing the operation of the secondary transfer roller 301 when a warming operation is executed a plurality of times. 6 is a time chart showing the operation of the secondary transfer roller 301 when a warming operation is executed a plurality of times. FIG. 4 is a diagram illustrating the intermediate transfer body 62, the secondary transfer unit 80, and the fixing unit 90 when the secondary transfer roller 301 is located at the contact position. FIG. 6 is a diagram illustrating the intermediate transfer body 62, the secondary transfer unit 80, and the fixing unit 90 when the secondary transfer roller 301 is positioned between the contact position and the separation position. FIG. 6 is a diagram illustrating the intermediate transfer body 62, the secondary transfer unit 80, and the fixing unit 90 when the secondary transfer roller 301 is positioned at a separation position. 6 is a flowchart for explaining a warming operation of the intermediate transfer member 62. 6 is a time chart showing the operation of the secondary transfer roller 301 when a warming operation is executed a plurality of times. 6 is a time chart showing the operation of the secondary transfer roller 301 when a warming operation is executed a plurality of times.

Explanation of symbols

10 printer, 20 photoconductor, 30 charging unit, 40 exposure unit,
50 YMCK developing unit, 50a central axis, 51 black developing device,
52 magenta developing device, 53 cyan developing device, 54 yellow developing device,
55a, 55b, 55c, 55d Developing device holder, 60 Primary transfer unit,
62 intermediate transfer member, 65 temperature sensor, 71 driving roller, 72 driven roller,
75 pulse signal generator, 80 secondary transfer unit,
82 photoconductor cleaning unit, 84 photoconductor cleaning blade,
85 Intermediate transfer member cleaning unit, 86 Intermediate transfer member cleaning blade,
90 fixing unit, 92 paper feed tray, 94 paper feed roller, 96 registration roller,
97 Paper discharge roller,
100 control unit, 101 main controller,
102 unit controller, 112 interface, 113 image memory,
226 discharge tray, 301 secondary transfer roller, 301a rotating shaft,
301b Large diameter portion, 302 Secondary transfer roller support member, 302a Shaft,
302b support part, 302c extension part, 302d contact part,
400 recording medium conveyance path, 401 fixing unit upstream guide member,
501 fixing roller, 501a small diameter part, 501b large diameter part,
501c Internal heater, 502 pressure roller, 502a small diameter part,
502b Large diameter part, 503 Temperature sensor, 503a Contact part,
503b Lead wire portion, 504 housing, 504a One longitudinal end surface,
505 inlet, 506 outlet, 507a, 507b recording medium guide,
521 shutter, 521a one end, 522 connecting portion,
523 tension spring, 523a, 523b hook,
700 image forming system, 702 computer, 704 display device,
708 input device, 708A keyboard, 708B mouse,
710 reading device, 710A FD device, 710B CD-ROM drive device,
795 application program, 796 printer driver,
797 Image processing unit, 801 Display interface unit,
803 input interface unit, 805 user interface processing unit,
AD image data, COM control signal, PD image data,
T Toner

Claims (11)

(A) a rotatable intermediate transfer member serving as an intermediate medium when transferring the developer image to the medium;
(B) The developer image can be moved between a contact position that contacts the intermediate transfer member and a separation position that is separated from the intermediate transfer member, and the developer image is placed on the medium in a state of being positioned at the contact position. A transfer roller for transferring;
(C) a roller capable of contacting the developer image transferred to the medium; and a heating element for generating heat to warm the roller, and the development by the roller heated by the heating element. A fixing device for fixing the agent image on the medium;
(D) A control unit for controlling the rotation operation of the intermediate transfer member and the separation / contact operation of the transfer roller, and generating warming to heat the heating member to a predetermined temperature. A control unit capable of executing an operation;
An image forming apparatus comprising (e),
(F) The control unit
When the warm-up operation is performed, the transfer roller is warmed to the heating element in a state where the transfer roller is positioned at the separation position.
During execution of the warm-up operation or immediately after the end of the warm-up operation,
Moving the transfer roller warmed by the heating element to the contact position; and
An image forming apparatus, wherein the intermediate transfer member is rotated in a state where the transfer roller is located at a corresponding contact position to perform a warming operation for warming the intermediate transfer member. The image forming apparatus according to claim 1,
The controller is
With the transfer roller positioned at the corresponding contact position, rotate the intermediate transfer member one or more times,
An image forming apparatus that performs the warming operation. The image forming apparatus according to claim 1, wherein:
The fixing device has an opening for allowing the medium having the developer image transferred thereon to pass toward the roller;
The image forming apparatus, wherein the transfer roller closes the opening when the transfer roller is located at the separation position. The image forming apparatus according to any one of claims 1 to 3,
The controller is
Immediately after the end of the warm-up operation,
Moving the transfer roller warmed by the heating element to the contact position; and
An image forming apparatus, wherein the intermediate transfer member is rotated in a state where the transfer roller is located at a corresponding contact position to perform a warming operation for warming the intermediate transfer member. The image forming apparatus according to claim 3, wherein
A moving member that moves between a first position and a second position, the moving member closing the opening when located at the first position,
The controller is
The movement of the moving member can be controlled;
During execution of the warm-up operation,
Moving the transfer roller warmed by the heating element to the contact position; and
Rotating the intermediate transfer member in a state where the transfer roller is located at the corresponding contact position, and performing a warming operation to warm the intermediate transfer member,
An image forming apparatus, wherein the moving member located at the second position is moved to the first position to block the opening. An image forming apparatus according to any one of claims 1 to 5,
The controller is
The transfer roller is reciprocated a plurality of times between the separation position and the contact position,
An image forming apparatus, wherein the warming operation is executed a plurality of times. The image forming apparatus according to claim 6,
When the transfer roller reciprocates a plurality of times,
The image forming apparatus according to claim 1, wherein the position where the transfer roller contacts the intermediate transfer member at the contact position is a plurality of different positions. The image forming apparatus according to claim 6 or 7, wherein
The controller is
At the beginning of a period in which the warming operation is performed a plurality of times, a time T1 for continuously positioning the transfer roller at the separation position is set.
An image forming apparatus characterized in that, in the latter part of a period in which the warming operation is executed a plurality of times, the transfer roller is made longer than a time T2 in which the transfer roller is continuously positioned at the separation position. The image forming apparatus according to claim 6, wherein:
The controller is
At a later stage of the period in which the warming operation is performed a plurality of times, a time T3 for continuously positioning the transfer roller at the contact position,
2. An image forming apparatus according to claim 1, wherein, at the beginning of a period in which the warming operation is performed a plurality of times, the transfer roller is made longer than a time T4 for continuously positioning the transfer roller at the contact position. (A) a rotatable intermediate transfer member serving as an intermediate medium when transferring the developer image to the medium;
(B) The developer image can be moved between a contact position that contacts the intermediate transfer member and a separation position that is separated from the intermediate transfer member, and the developer image is placed on the medium in a state of being positioned at the contact position. A transfer roller for transferring;
(C) a roller capable of contacting the developer image transferred to the medium; and a heating element for generating heat to warm the roller, and the development by the roller heated by the heating element. A fixing device for fixing the agent image on the medium;
(D) A control unit for controlling the rotation operation of the intermediate transfer member and the separation / contact operation of the transfer roller, and generating warming to heat the heating member to a predetermined temperature. A control unit capable of executing an operation;
An image forming apparatus comprising (e),
(F) The control unit
When the warm-up operation is performed, the transfer roller is warmed to the heating element in a state where the transfer roller is positioned at the separation position.
During execution of the warm-up operation,
Moving the transfer roller warmed by the heating element to the contact position; and
Rotating the intermediate transfer member in a state where the transfer roller is located at the corresponding contact position, and performing a warming operation to warm the intermediate transfer member,
(G) The control unit
With the transfer roller positioned at the corresponding contact position, rotate the intermediate transfer member one or more times,
Performing the warming operation;
(H) the fixing device has an opening for allowing the medium having the developer image transferred thereon to pass toward the roller;
When the transfer roller is located at the separation position, the transfer roller closes the opening,
(I) a moving member that moves between a first position and a second position, the moving member closing the opening when positioned at the first position;
The controller is
The movement of the moving member can be controlled;
During execution of the warm-up operation,
Moving the transfer roller warmed by the heating element to the contact position; and
Rotating the intermediate transfer member in a state where the transfer roller is located at the corresponding contact position, and performing a warming operation to warm the intermediate transfer member,
Moving the moving member located in the second position to the first position, closing the opening in the moving member;
(J) The control unit
The transfer roller is reciprocated a plurality of times between the separation position and the contact position,
The warming operation is executed a plurality of times,
(K) When the transfer roller reciprocates a plurality of times,
The position where the transfer roller contacts the intermediate transfer member at the contact position is a plurality of different positions.
(L) The control unit
At the beginning of a period in which the warming operation is performed a plurality of times, a time T1 for continuously positioning the transfer roller at the separation position is set.
In the latter part of the period in which the warming operation is executed a plurality of times, the transfer roller is made longer than the time T2 in which the transfer roller is continuously positioned in the separated position,
(M) The control unit
At a later stage of the period in which the warming operation is performed a plurality of times, a time T3 for continuously positioning the transfer roller at the contact position,
2. An image forming apparatus according to claim 1, wherein, at the beginning of a period in which the warming operation is performed a plurality of times, the transfer roller is made longer than a time T4 for continuously positioning the transfer roller at the contact position. (A) a computer, and
(B) An image forming apparatus connectable to the computer,
(A) a rotatable intermediate transfer member serving as an intermediate medium when transferring the developer image to the medium;
(B) The developer image can be moved between a contact position that contacts the intermediate transfer member and a separation position that is separated from the intermediate transfer member, and the developer image is placed on the medium in a state of being positioned at the contact position. A transfer roller for transferring;
(C) a roller capable of contacting the developer image transferred to the medium; and a heating element for generating heat to warm the roller, and the development by the roller heated by the heating element. A fixing device for fixing the agent image on the medium;
(D) A control unit for controlling the rotation operation of the intermediate transfer member and the separation / contact operation of the transfer roller, and generating warming to heat the heating member to a predetermined temperature. A control unit capable of executing an operation;
(E) an image forming apparatus,
An image forming system comprising (C),
(D) The control unit
When the warm-up operation is performed, the transfer roller is warmed to the heating element in a state where the transfer roller is positioned at the separation position.
During execution of the warm-up operation or immediately after the end of the warm-up operation,
Moving the transfer roller warmed by the heating element to the contact position; and
An image forming system, wherein the intermediate transfer member is rotated in a state where the transfer roller is located at a corresponding contact position to perform a warming operation for warming the intermediate transfer member.

Images