JP5141464B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 discloses an image forming apparatus that shifts the pressure-bonding state between an image carrier and an intermediate transfer body to a black mode or a color mode during standby for an image forming operation according to an image forming mode frequently used by a user. Have been described.

In this way, the time until image formation on the first recording medium is started by setting the pressure-bonding state between the image carrier and the intermediate transfer member to the image forming mode frequently used by the user during standby for the image forming operation. Can be shortened.
JP 2002-196560 A

  An object of the present invention is to improve the detachability of an image carrier that is supported so as to be detachable while shortening the time until the start of image formation.

  According to a first aspect of the present invention, a black toner image is formed on the surface of the image forming apparatus, and a black image holding member that is detachably supported on the main body of the image forming apparatus, and a black image holding member adjacent to the black image holding member. A color toner image is formed on the surface, and is formed on the color image carrier, the black image carrier, and the color image carrier that are detachably supported by the apparatus main body. An intermediate transfer member to which a toner image is transferred, and the black image holding member and the color image holding member are provided so as to face each other with the intermediate transfer member interposed therebetween. And a transfer member that is pressed against the color image holding member to transfer the toner image formed on the black image holding member and the color image holding member to the intermediate transfer member, and the transfer member is moved to move the black image holding member. Only in front of the image carrier A black mode for pressing the intermediate transfer member, a switching means for switching to the color mode for pressing the intermediate transfer member against the black image holding member and the color image holding member, and a black image or a color image when waiting for an image forming operation. The switching means is controlled in accordance with the use ratio to switch the pressure-bonding state of the black image holding body, the color image holding body and the intermediate transfer body to the black mode or the color mode, and the black image holding Control means for always shifting to the black mode when waiting for an image forming operation when it is time to replace at least one of the color image holding body and the color image holding body, and the black image holding body and the color image holding body The intermediate transfer member is separated from the intermediate transfer member, and the black image carrier and the color image carrier are transferred to a detachable mode in which the detachable mode can be detached from the apparatus main body. Characterized in that it comprises a means.

  An image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect, wherein when the image forming operation is on standby, the control unit controls the switching unit to invalidate the transition to the black mode at all times. The present invention is characterized in that a conversion means is provided.

  An image forming apparatus according to a third aspect of the present invention is the image forming apparatus according to the second aspect, wherein when the transition to the black mode by the control unit is invalidated by the invalidating unit, the switching unit is operated, It is characterized in that there is provided a transition means for shifting the pressure contact state of the black image carrier, the color image carrier and the intermediate transfer member to a black mode or a color mode.

  According to the configuration of the first aspect of the present invention, when waiting for the image forming operation, the control means controls the switching means according to the use ratio of the black image or the color image to control the black image carrier and the color image. The pressure bonding state between the holding member and the intermediate transfer member is shifted to the black mode or the color mode. Further, when it is time to replace at least one of the black image carrier and the color image carrier, the control unit controls the switching unit to wait for the image forming operation to control the black image carrier and the color image. The pressure-bonding state between the holding body and the intermediate transfer body is always shifted to the black mode. Then, when waiting for the image forming operation, the intermediate transfer member is pressed only to the black image holding member.

  Thus, when the black image carrier and the color image carrier are exchanged, the black image carrier, the color image carrier and the intermediate transfer member are separated by operating the desorption means. The operating force for shifting the holding body and the color image holding body to a detachable mode that can be detachably attached to the apparatus main body can be reduced as compared with the case where the image forming operation is on standby in the color mode. That is, it is possible to improve the detachability of the image carrier that is supported so as to be detachable while shortening the time until the start of image formation.

  According to the configuration of the second aspect of the present invention, the invalidating unit invalidates the control unit that controls the switching unit to always shift to the black mode when waiting for the image forming operation. For this reason, for example, in the case of a user who uses only the color mode, the time until the start of image formation on the first sheet member P can be shortened as compared with the case where this configuration is not provided.

  According to the configuration of the third aspect of the present invention, when the invalidation means invalidates the transition to the black mode at all times by the control means, the transition means activates the switching means, and the black image carrier and color The pressure-bonding state between the image carrier and the intermediate transfer member is shifted to the black mode or the color mode. In other words, the user can select the standby mode of the image forming operation by operating the transition unit. When the user selects an appropriate mode, the time until the start of image formation on the first recording medium can always be shortened as compared with the case where this configuration is not provided.

  Hereinafter, an example of an image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS.

(overall structure)
As shown in FIG. 6, an endless belt as an intermediate transfer member that is stretched around a plurality of rollers 12 and conveyed in the direction of arrow A by driving a motor (not shown) is provided in the apparatus main body 10A of the image forming apparatus 10. An intermediate transfer belt 14 is provided.

  The image forming apparatus 10 corresponds to the formation of a color image, and forms an image forming unit that forms toner images corresponding to four colors of yellow (Y), magenta (M), cyan (C), and black (K). 28Y, 28M, 28C, and 28K are arranged along the longitudinal direction of the intermediate transfer body belt 14, and are detachably supported by the apparatus main body 10A.

  In addition, about the member provided for each color, it adds and shows the alphabet (Y / M / C / K) which shows each color at the end of a code | symbol, but when it demonstrates without distinguishing especially a color, The description will be made by omitting the alphabet at the end of the code.

  The image forming unit 28 includes a photosensitive drum 16 as an image holding member that is rotated clockwise by a driving unit including a motor and a gear (not shown). The photosensitive drum 16 includes a black photosensitive drum 16K for black on which a black toner image is formed and a photosensitive drum 16Y, 16M, and 16C for color on which a color toner image is formed on the surface. And divided.

  Further, a charging roller 18 for uniformly charging the surface of the photosensitive drum 16 to a predetermined potential is disposed on the peripheral surface of the photosensitive drum 16. The charging roller 18 is a conductive roller, and its circumferential surface is in contact with the circumferential surface of the photosensitive drum 16, and is arranged so that the axial direction of the charging roller 18 coincides with the axial direction of the photosensitive drum 16. ing.

  Further, on the peripheral surface on the downstream side of the charging roller 18 in the rotation direction of the photosensitive drum 16, light emission using an LED (light emitting diode) as a light emitting element for forming a latent image on the photosensitive drum 16 as a light source. An LED print head (LPH) 20 as a container extends in the axial direction of the photosensitive drum 16. Hereinafter, the LED print head 20 is referred to as LPH 20. The LPH 20 forms a latent image on the photosensitive drum 16 by irradiating the photosensitive drum 16 with a light beam according to image data.

  Further, a latent image formed on the photosensitive drum 16 is developed with toner of a predetermined color (yellow / magenta / cyan / black) on the peripheral surface downstream of the LPH 20 in the rotation direction of each photosensitive drum 16. A developing device 22 for forming a toner image is disposed.

  The developing device 22 has a cylindrical developing roller 24 that is disposed in proximity to the photosensitive drum 16 and is rotatably provided. A developing bias is applied to the developing roller 24, and the toner loaded in the developing device 22 is attached to the peripheral surface. As the developing roller 24 rotates, the toner attached to the developing roller 24 is conveyed to the surface of the photoconductive drum 16, and the toner is rubbed against the photoconductive drum 16 to form a latent image formed on the photoconductive drum 16. It is configured to be developed as a donor image.

  A transfer roller 30 serving as a transfer member for transferring the toner image on each photoconductive drum 16 to the intermediate transfer belt 14 is disposed on the peripheral surface downstream of the developing device 22 in the rotation direction of each photoconductive drum 16. Is provided. The transfer roller 30 is charged at a predetermined potential and rotates counterclockwise to convey the intermediate transfer belt 14 at a predetermined speed, and the intermediate transfer belt 14 is pressed against the photosensitive drum 16 and sequentially opposed. As a result, the transfer roller 30 transfers the toner image on the photosensitive drum 16 onto the intermediate transfer belt 14.

  Further, when the image forming unit 28 including the photosensitive drum 16 is detachable from the apparatus main body 10A, the transfer roller 30 is moved by a detachable member 54 described later, so The transfer belt 14 is separated (see FIG. 2), and the image forming unit 28 is shifted to a detachable mode in which the image forming unit 28 can be detached from the apparatus main body 10A. Details of the detachable member 54 and the like will be described later.

  Further, a cleaning blade 26 that collects residual toner such as transfer residual toner and retransfer toner on the photosensitive drum 16 is disposed downstream of the transfer roller 30 on the peripheral surface of the photosensitive drum 16. The cleaning blade 26 is arranged so that one side is in contact with the photosensitive drum 16, and toner remaining on the photosensitive drum 16 without being transferred to the intermediate transfer belt 14, or on the photosensitive drum 16 at the time of transfer. The toner of other colors that have adhered to the toner is scraped off and collected.

  Here, the toner images of different colors formed by the image forming units 28 are transferred on the belt surface of the intermediate transfer belt 14 so as to overlap each other. As a result, a color toner image is formed on the intermediate transfer belt 14. In this embodiment, the toner image in which the four color toner images are transferred in a superimposed manner is referred to as a final toner image.

  On the downstream side of the four image forming units 28 in the transport direction of the intermediate transfer belt 14, a transfer device 34 including two rollers 34A and 34B facing each other is disposed. The final toner image formed on the intermediate transfer belt 14 is sent between the rollers 34A and 34B, taken out from the paper tray 36 provided at the bottom of the image forming apparatus 10, and between the rollers 34A and 34B. It is transferred to the sheet member P that has been conveyed to.

  In addition, a fixing device 40 including a heating roller 40A and a pressure roller 40B is disposed in the conveyance path of the sheet member P to which the final toner image has been transferred. The sheet member P conveyed to the fixing device 40 is nipped and conveyed by the heating roller 40A and the pressure roller 40B, whereby the toner on the sheet member P melts and is pressed against the sheet member P to be fixed. .

  On the other hand, a cleaner 42 that collects toner remaining on the intermediate transfer belt 14 without being transferred to the sheet member P by the transfer device 34 is disposed downstream of the transfer device 34 in the conveyance direction of the intermediate transfer belt 14. Has been. The cleaner 42 is provided with a blade 44 so as to be in contact with the intermediate transfer body belt 14, and collects residual toner by rubbing it.

  In the image forming apparatus 10 configured as described above, an image is formed as follows.

  First, the charging roller 18 uniformly negatively charges the surface of the photosensitive drum 16 with a predetermined charging portion potential. Further, exposure is performed by the LHP 20 so that the image portion on the charged photosensitive drum 16 becomes a predetermined exposure portion potential, and a latent image is formed on the photosensitive drum 16.

  Further, when the latent image on the rotating photosensitive drum 16 passes through the developing roller 24 provided in the developing device 22, the toner of the developer G adheres to the latent image by electric force, and the latent image is visualized as a toner image. The

  The visualized toner images of the respective colors are sequentially transferred to the intermediate transfer belt 14 by the electric force of the transfer roller 30, and a color final toner image is formed on the intermediate transfer belt 14.

  The final toner image is fed between rollers 34A and 34B provided in the transfer device 34, taken out from the paper tray 36, and transferred to the sheet member P that is also conveyed between the rollers 34A and 34B. .

  Further, the toner image transferred to the sheet member P is fixed by the fixing device 40, and the sheet member P is discharged out of the device.

  When a black image is formed, the pressure-bonding state between the photosensitive drum 16 and the intermediate transfer belt 14 is set to a black mode (see FIG. 1), and when a color image is formed, the photosensitive drum 16 and the intermediate transfer member. The pressure contact state with the belt 14 is a color mode (see FIG. 3). Details of the black mode and the color mode will be described later.

(Main part configuration)
As described above, when a black image is formed by the image forming apparatus 10 according to the present embodiment, as shown in FIG. 1, the pressure-bonded state between the photosensitive drum 16 and the intermediate transfer belt 14 is shifted to the black mode. Let

  More specifically, the transfer roller 30, which includes a drive motor, a clutch, a cam, a link mechanism, and the like, is disposed opposite to the color photosensitive drums 16Y, 16M, and 16C, and is opposed to the color photosensitive drums 16Y, 16M, and 16C. A retractor mechanism 50 is provided as switching means that moves so as to approach or separate.

  In order to prevent the surface of the photoconductor drum 16 from being scraped, in the black mode, the retractor mechanism 50 is operated to move the transfer roller 30, and the intermediate transfer from the color photoconductor drums 16Y, 16M, and 16C is performed. The body belt 14 is separated. That is, in the black mode, in order to prevent the surface of the photoconductor drum 16 from being scraped, only the transfer roller 30 disposed opposite to the black photoconductor drum 16K causes the intermediate transfer belt 14 to move to the black photoconductor drum. Press to 16K.

  On the other hand, as shown in FIG. 3, in the color mode, the retractor mechanism 50 is operated to move the transfer roller 30 to the color photosensitive drums 16Y, 16M, and 16C. Is configured to press. That is, in the color mode, the transfer roller 30 disposed so as to face all the photosensitive drums 16 presses the intermediate transfer belt 14 against all the photosensitive drums 16.

  Further, a control unit 52 is provided as a control means for controlling the retractor mechanism 50. When the image forming operation is on standby, the retractor mechanism 50 is controlled in accordance with the use ratio of the black image or the color image, so The pressure-bonding state between the photosensitive drum 16K and the color photosensitive drums 16Y, 16M, and 16C and the intermediate transfer belt 14 is switched to a black mode (see FIG. 1) or a color mode (see FIG. 3).

  Specifically, as shown in FIG. 4, when the image forming operation is completed, it is predicted whether a black image or a color image will be used in the next JOB. Specifically, the past total use ratio, calendar use ratio (previous use ratio on that day), and most recent use ratio are averaged to the sum of squares, and the mode is shifted to a higher ratio mode. In this embodiment, since the ratio of the black image is higher than that of the color image, the mode is shifted to the black mode.

  As described above, by selecting the mode during the standby of the image forming operation, the time until the start of image formation on the first sheet member P is shortened at the next image formation.

  Further, when it is time to replace at least one of the photosensitive drums 16, the control unit 52 controls the retractor mechanism 50 to always shift to the black mode when waiting for the image forming operation.

  The time to replace the photosensitive drum 16 of the first embodiment is the time when the preset Warning number or Warning rotation speed is reached, and when the Warning number or Warning rotation speed is reached, the control unit 52 is reached. However, a warning display is performed on a display panel (not shown), and when the image forming operation is on standby, the retractor mechanism 50 is controlled to always shift to the black mode.

  That is, as shown in FIG. 5A, assuming that the lifetime of the photosensitive drum 16 is 100 and the Warningpoint is reached (range A in the figure), the control unit 52 waits for the image forming operation to wait for a black image or The retractor mechanism 50 is controlled in accordance with the color image usage ratio. On the other hand, after reaching Warpingpoint (range B in the figure), the control unit 52 controls the retractor mechanism 50 to always shift to the black mode when waiting for the image forming operation.

  On the other hand, as shown in FIG. 3, the transfer roller 30 disposed opposite to the photosensitive drum 16 is moved to separate the black photosensitive drum 16K and the color photosensitive drums 16Y, 16M, and 16C from the intermediate transfer belt 14. A demounting member 54 is provided as demounting means for shifting the image forming unit 28 including the photosensitive drum 16 to a demounting mode in which the image forming unit 28 is demountable from the apparatus main body 10A.

  Specifically, the detachable member 54 is rotatably attached to the support portion 56 that supports each transfer roller 30, and is rotated in the direction of arrow B to move the support portion 56 to move the photosensitive drum 16. The intermediate transfer belt 14 is separated from the intermediate transfer belt 14 so as to shift to the detaching mode (see FIG. 2).

  That is, when the user replaces the image forming unit 28 provided with the photosensitive drum 16, the lever portion 58 is rotated to separate the photosensitive drum 16 and the intermediate transfer belt 14 and then replace the image forming unit 28. It is supposed to be.

  Here, the operating force required to rotate the lever portion 58 is 8N when the pressure-bonding state between the photosensitive drum 16 and the intermediate transfer belt 14 is in the black mode. On the other hand, when the pressure-bonding state between the photosensitive drum 16 and the intermediate transfer belt 14 is the color mode, the intermediate transfer belt 14 is pressed against all the photosensitive drums 16, and thus the operation force is 15N. .

  Therefore, as described above, when it is time to replace at least one of the photosensitive drums 16, the control unit 52 controls the retractor mechanism 50 to always shift to the black mode when waiting for the image forming operation. ing. In other words, by rotating the lever portion 58 with an operating force of 8N, all the photosensitive drums and the intermediate transfer belt 14 are separated from each other, and the image forming unit 28 including the photosensitive drum 16 can be detached from the apparatus main body 10A. It is configured to shift to the mode.

  An image forming apparatus according to a second embodiment of the present invention will be described with reference to FIG. In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the second embodiment, unlike the first embodiment, an invalid portion 60 is provided as an invalidating means for invalidating the control unit 52 from controlling the retractor mechanism 50 to always shift to the black mode.

  Further, when the transition to the black mode is always invalidated by the invalid portion 60, the retractor mechanism 50 is operated, and the black photosensitive drum 16K and the color photosensitive drums 16Y, 16M, 16C and the intermediate transfer belt 14 are operated. A transition portion 62 is provided as a transition means for shifting the pressure-bonding state to the black mode or the color mode.

  The user can always disable the black mode by operating the invalidation unit 60 on the display panel provided in the image forming apparatus 10 or the monitor of his / her personal computer, and can select the standby mode of the image forming operation. That is, the user can select an appropriate mode.

  Note that the mode set by one user can be confirmed on the monitor of another user's personal computer, and the current mode is set on all personal computer monitors.

  An image forming apparatus according to a third embodiment of the present invention will be described with reference to FIG. In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the third embodiment, the time when the photosensitive drum 16 is replaced is not the time when the preset number of Warning sheets or the Warning rotation speed is reached as in the first embodiment, but the performance of the photosensitive drum 16 is determined. It is time to reach the guaranteed life end.

  That is, as shown in FIG. 5B, assuming that the life of the photosensitive drum 16 is 100, the control unit 52 waits for the image forming operation until the life 100 (life end) is reached (range C in the figure). At times, the retractor mechanism 50 is controlled in accordance with the usage ratio of the black image or the color image. On the other hand, when reaching the life end (D in the figure), the control unit 52 controls the retractor mechanism 50 to shift to the black mode when waiting for the image forming operation.

1 is a configuration diagram illustrating an image forming unit including an intermediate transfer belt, a transfer roller, and a photosensitive drum of an image forming apparatus according to a first embodiment of the present invention. 1 is a configuration diagram illustrating an image forming unit including an intermediate transfer belt, a transfer roller, and a photosensitive drum of an image forming apparatus according to a first embodiment of the present invention. 1 is a configuration diagram illustrating an image forming unit including an intermediate transfer belt, a transfer roller, and a photosensitive drum of an image forming apparatus according to a first embodiment of the present invention. FIG. 3 is a flowchart illustrating a control flow of a control unit employed in the image forming apparatus according to the first embodiment of the present invention. FIG. 3A is a timing diagram illustrating control timing of a control unit employed in the image forming apparatus according to the first embodiment of the present invention. (B) is a timing diagram showing control timing of a control unit employed in an image forming apparatus according to a third embodiment of the present invention. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention. FIG. 5 is a configuration diagram illustrating an image forming unit including an intermediate transfer belt, a transfer roller, and a photosensitive drum of an image forming apparatus according to a second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 10A Apparatus main body 14 Intermediate transfer body belt (intermediate transfer body)
16Y color photoconductor drum (color image carrier)
16M photoconductor drum for color (color image carrier)
16C color photosensitive drum (color image carrier)
16K black photosensitive drum (black image carrier)
28 Image forming unit 30 Transfer roller (transfer member)
50 Retractor mechanism (switching means)
52 Control unit (control means)
54 Desorption member (desorption means)
60 Invalid part (invalidation means)
62 Transfer part (transfer means)

Claims (3)

A black toner image is formed on the surface, and a black image carrier that is detachably supported by the apparatus main body,
A color image holding body provided adjacent to the black image holding body, on which a color toner image is formed and supported detachably on the apparatus body;
An intermediate transfer member to which a toner image formed on the black image carrier and the color image carrier is transferred;
The intermediate transfer member is provided so as to face the black image holding member and the color image holding member, and the intermediate transfer member is pressed against the black image holding member and the color image holding member. A transfer member for transferring the toner image formed on the black image carrier and the color image carrier to the intermediate transfer member;
Switching between a black mode in which the transfer member is moved and the intermediate transfer member is pressed only to the black image holding member, and a color mode in which the intermediate transfer member is pressed against the black image holding member and the color image holding member. Means,
When the image forming operation is on standby, the switching means is controlled in accordance with the use ratio of the black image or the color image, and the black image holding body and the color image holding body and the intermediate transfer body are pressed against each other. A control unit that switches to the black mode or the color mode, and always shifts to the black mode when waiting for an image forming operation when it is time to replace at least one of the black image holding body and the color image holding body.
Desorption means for separating the black image carrier and the color image carrier from the intermediate transfer member to shift the black image carrier and the color image carrier to a desorption mode in which the black image carrier and the color image carrier can be detached from the apparatus main body. When,
An image forming apparatus comprising:   The image forming apparatus according to claim 1, further comprising: a disabling unit that disables the control unit from controlling the switching unit to always shift to the black mode when waiting for an image forming operation.   When the transition to the always black mode by the control means is invalidated by the invalidating means, the switching means is operated to switch between the black image holding body, the color image holding body, and the intermediate transfer body. The image forming apparatus according to claim 2, further comprising a transition unit that shifts the pressure-bonded state to a black mode or a color mode.

Images