JP2007086182A - 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 capable of appropriately preventing uneven density while suppressing the consumption of developer. <P>SOLUTION: The image forming apparatus includes: an image carrier for carrying a latent image; a developing device including a storing part having an opening, and for storing the developer and a rotatable developer carrier arranged facing the opening so as to carry the developer; and a controller for carrying out the rotating operation of the developer carrier as a pre-developing operation in order to prevent the uneven density when the latent image is developed by the developing device, and also, for forming the latent image on the image carrier and shifting only the below-mentioned developer to the image carrier in the case of rotating the developer carrier, that is, only the developer carried in a certain area in the circumferential direction of the developer carrier, and also, carried in the area including all the non-exposed part not exposed on the opening before starting the rotating operation of the developer carrier among the developer carried by the developer carrier. <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. Such an image forming apparatus includes, for example, an image carrier for carrying a latent image and a rotatable developer carrier for carrying a developer, and an image is formed by the developer carried on the developer carrier. A developing device that develops the latent image carried on the carrier, and when an image signal or the like is transmitted from an external device such as a host computer, the developing device is positioned at a development position facing the image carrier. The latent image carried on the image carrier is developed with the developer carried on the developer carrier to form a developer image, and the developer image is transferred to the medium, and finally onto the medium. Form an image.

  By the way, when the developing device develops a latent image in a state where development by the developing device has not been performed for a long time (in other words, in a state where the developer carrier has not rotated for a long time), the latent image is obtained by the development. It is known that density unevenness occurs in a developer image (finally an image), and this phenomenon (or density unevenness itself) is called neglected banding.

In the case of neglected banding, when the state where the developer carrier does not rotate (does not move) continues, the charge amount of the developer carried on the developer carrier becomes uneven in the circumferential direction of the developer carrier. Caused by. Then, in order to prevent the occurrence of the neglected banding, a measure is proposed in which the developer carrying member is rotated as the pre-preparation operation for the development so that the charge amount of the developer is made uniform before the development. ing. For example, when the power of the image forming apparatus is turned on, or when the time when the developer carrying body is not continuously rotated while the power of the image forming apparatus is turned on exceeds a predetermined time, the developer carrying body By rotating, it is possible to appropriately prevent the occurrence of neglected bunting during development.
JP 2004-126089 A

  The following two different types of control are known as the control related to the rotation operation of the developer carrier described above that is executed to prevent the occurrence of neglected banding. There are pros and cons.

  First, as a control relating to the rotation operation, a developer carried on the developer carrier is always formed when the developer carrier is rotating by forming a latent image on the image carrier. Is known to move the image to the image carrier. In this control, the developer carrying member is rotated while constantly moving the developer on the developer carrying member to the image carrying member. Therefore, the uniform charge amount of the developer is further promoted, and the development is facilitated. It is possible to more appropriately prevent the occurrence of neglected bunting. However, this control has a demerit that a lot of developer is consumed wastefully.

  On the other hand, when executing the rotation operation, a control is known in which a latent image is not formed on the image carrier and the developer carried on the developer carrier is not moved to the image carrier. Although this control is superior in terms of saving developer, when the control is executed, the charge amount of the developer is more uniform than the above-described control that constantly moves the developer. There is a possibility that the occurrence of neglected bunting cannot be prevented appropriately.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an image forming apparatus and an image forming apparatus that can appropriately prevent the occurrence of uneven density while suppressing the consumption of the developer. To realize the system.

  The main aspect of the present invention is an image carrier for carrying a latent image, a housing part having an opening for housing a developer, and a rotation provided to face the opening for carrying the developer. A developing device for developing the latent image carried on the image carrier by the developer carried on the developer carrier, and development of the latent image by the developing device. A controller that executes a rotation operation of the developer carrier as a pre-preparation operation of the development in order to prevent occurrence of density unevenness at the time, and the developer carrying when the rotation operation is executed Of the developer carried on the body, all the unexposed portions that are part of the circumferential direction of the developer carrying body and that have not been exposed from the opening before the start of the rotation operation are removed. Only the developer carried on the containing area, An image forming apparatus characterized by having a controller for moving the image bearing member to form a latent image on the image bearing member.

  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.

An image carrier for carrying a latent image, a container having an opening for containing the developer, and a rotatable developer carrier for carrying the developer provided facing the opening A developing device for developing the latent image carried on the image carrier by the developer carried on the developer carrier, and unevenness in density when developing the latent image by the developing device. A controller for executing a rotation operation of the developer carrier as a pre-preparation operation of the development in order to prevent the occurrence of the occurrence, and when the rotation operation is executed, the controller carries the developer carrier. Of the developer, carried in a partial region in the circumferential direction of the developer carrying member and including all unexposed portions that were not exposed from the opening before the start of the rotation operation. Only the developed developer is applied to the image carrier. Image forming apparatus characterized by having a controller which moves to form an image to said image bearing member.
According to such an image forming apparatus, it is possible to appropriately prevent the occurrence of uneven density while suppressing the consumption of the developer.

Further, the controller causes the developer carrier to carry out the rotation operation at a plurality of types of timing, and to execute the rotation operation at only a part of the plurality of types of timings. Among the developed developers, a partial region in the circumferential direction of the developer carrier, the region including all of the unexposed portions that were not exposed from the opening before the start of the rotation operation, Only the developer carried on the substrate may be moved to the image carrier after forming a latent image on the image carrier.
In such a case, the rotation operation according to the situation can be executed.

Further, the controller is carried by the developer carrier when the rotation operation is executed based on a period during which the developer carrier has not been rotated immediately before the rotation operation is started. Among the developer, a partial region in the circumferential direction of the developer carrier, and a region including all of the non-exposed portions that were not exposed from the opening before the start of the rotation operation. It may be determined whether or not only the carried developer forms a latent image on the image carrier and is moved to the image carrier.
In such a case, the rotation operation according to the situation can be executed.

Further, the controller rotates the developer carrying member a plurality of times when the rotation operation is executed, and the developer carrying member only during a part of the plurality of rotations of the developer carrying member. Of the developer carried on the body, all the unexposed portions that are part of the circumferential direction of the developer carrying body and that have not been exposed from the opening before the start of the rotation operation are removed. Only the developer carried in the containing region may be moved to the image carrier after forming a latent image on the image carrier.
In such a case, the developer is carried in a partial area in the circumferential direction of the developer carrying body and including all the unexposed portions, and the image is carried when the rotation operation is performed. The amount of the developer moved to the body can be finely adjusted.

Further, the controller causes the rotation operation to be executed at a plurality of types of timing, and depending on which type of timing the rotation operation is executed, in a partial region in the circumferential direction of the developer carrier. And a developer carried in an area including all of the non-exposed portions that were not exposed from the opening before the execution of the rotation operation, and the image carrier when the rotation operation is performed. It is good also as changing the quantity of the developer moved to a body.
In such a case, the rotation operation according to the situation can be executed.

Further, the controller is a partial region in the circumferential direction of the developer carrier according to a period during which the developer carrier has not been rotated immediately before the start of the rotation operation, A developer carried in an area including all the non-exposed portions that were not exposed from the opening before the start of the rotation operation, and moves to the image carrier when the rotation operation is performed The amount of the developer to be changed may be changed.
In such a case, the rotation operation according to the situation can be executed.

  Further, the controller may change the amount of developer moved to the image carrier by changing a latent image carried on the image carrier. In addition, the controller rotates the developer carrying member a plurality of times when executing the rotating operation, and among the developers carried on the developer carrying member, one of the developers in the circumferential direction of the developer carrying member. Only the developer carried in the area including all of the unexposed parts that have not been exposed from the opening before the execution of the rotation operation is performed. By changing the number of rotations out of a plurality of rotations of the developer carrier, the control of forming and moving the image carrier to the image carrier is performed. The amount may be changed. The controller may change the amount of developer moved to the image carrier by changing a developing bias applied to the developer carrier.

In addition, the controller may include a developer carried on a boundary region between the non-exposed portion and the exposed portion exposed from the opening before the execution of the rotation operation in the region. When moving to the image carrier, the amount of developer moved to the image carrier may be gradually changed by changing the latent image carried on the image carrier.
In such a case, as a result of more emphasis on the latter of the two objectives of preventing occurrence of density unevenness and saving developer, the density unevenness may occur even if the density unevenness occurs. Less noticeable.

  Further, the developing device is provided in the opening, and has a layer thickness regulating member for regulating the layer thickness of the developer by contacting the contacted portion of the developer carrying member with a width, and the opening. And a seal member for contacting the contacted portion of the developer carrying member with a width to prevent leakage of the developer, and the non-exposed portion includes the contacted portion and The contacted part may be included.

An image bearing member for carrying a latent image; a housing portion having an opening for housing the developer; and a rotatable development for carrying the developer provided facing the opening. A developing device for developing the latent image carried on the image carrier by the developer carried on the developer carrier, and the density of the latent image when the latent image is developed by the developing device. In order to prevent the occurrence of unevenness, the controller executes a rotation operation of the developer carrying member as a pre-preparation operation of the development, and is carried on the developer carrying member when the rotating operation is executed. Among the developed developers, a partial region in the circumferential direction of the developer carrier, the region including all of the unexposed portions that were not exposed from the opening before the start of the rotation operation, Only the developer carried on the image carrier A controller that forms a latent image on the body and moves the latent image to the image carrier, the controller executing the rotation operation at a plurality of types of timing, and a part of the plurality of types of timings. When the rotation operation is executed only at the timing, a part of the developer carried on the developer carrying body in the circumferential direction of the developer carrying body, and the execution of the rotation operation starts. Only the developer carried in the area including all of the non-exposed portions that were not exposed from the opening before, forms a latent image on the image carrier and moves the image carrier to the image carrier, and the controller Is based on a period during which the developer carrier has not been rotated immediately before the start of the rotation operation, when the rotation operation is performed, the developer carried on the developer carrier Of which, the developer Only the developer carried in a partial region in the circumferential direction of the holder, the region including all of the unexposed portions that were not exposed from the opening before the start of the rotation operation. The controller determines whether to form a latent image on the image carrier and move the image carrier to the image carrier, and the controller rotates the developer carrier a plurality of times when the rotation operation is performed. Of the developer carried on the developer carrier only in some rotations of the plurality of rotations of the developer carrier, it is a partial region in the circumferential direction of the developer carrier, and A latent image is formed on the image carrier only by the developer carried in the region including all the unexposed portions that were not exposed from the opening before the start of the rotation operation. The controller moves the controller at any kind of timing. Depending on whether or not a part of the developer carrying member in the circumferential direction of the developer carrying member is included, and includes all unexposed parts that are not exposed from the opening before the start of the rotation operation. The amount of the developer carried in the region, which is moved to the image carrier when the rotation operation is executed, is changed, and the controller performs the development immediately before the start of the rotation operation. Depending on the period during which the agent carrier was not continuously rotated, it was a partial region in the circumferential direction of the developer carrier, and was not exposed from the opening before the start of the rotation operation The controller is configured to change an amount of developer carried on an area including all of the non-exposed portion, and moved to the image carrier when the rotation operation is performed. Changing the latent image carried on the carrier The amount of the developer moved to the image carrier is changed by the controller, and the controller is a partial region in the circumferential direction of the developer carrier among the developers carried on the developer carrier. Then, a latent image is formed on the image carrier only by the developer carried on the region including all the non-exposed portions that were not exposed from the opening before the start of the rotation operation. By changing the number of rotations of the plurality of rotations of the developer carrier, the amount of developer moved to the image carrier is changed by changing the control of moving the carrier to the carrier, The controller moves, to the image carrier, a developer carried on the boundary area between the non-exposed part and the exposed part exposed from the opening before the start of the rotation operation. When carrying out, it is carried on the image carrier. By changing the latent image, the amount of developer moved to the image carrier is gradually changed, and the developing device is provided in the opening and has a width at the contacted portion of the developer carrier. And a layer thickness regulating member for regulating the layer thickness of the developer by contacting the developer and the opening, and contacting the contacted portion of the developer carrying member with a width to prevent the developer from leaking. It is also possible to realize an image forming apparatus characterized in that the non-exposed portion includes the contacted portion and the contacted portion.
In this way, the object of the present invention can be achieved more effectively because most of the effects described above can be achieved.

A computer and an image forming apparatus that can be connected to the computer, an image carrier for carrying a latent image, a container having an opening for containing a developer, and the opening A rotatable developer carrying member that is provided so as to carry the developer, and for developing the latent image carried on the image carrier by the developer carried on the developer carrying member. A developing device, and a controller that executes a rotation operation of the developer carrying member as a pre-preparation operation of the development in order to prevent occurrence of density unevenness when the latent image is developed by the developing device. A part of the developer carried in the circumferential direction of the developer carrying member of the developer carried by the developer carrying member when the rotating operation is performed, and before the execution of the rotating operation is started Exposed from the opening An image forming apparatus having a controller that forms a latent image on the image carrier and moves only the developer carried on the region including all of the non-exposed portions that have not been present to the image carrier. An image forming system characterized by this can also be realized.
According to such an image forming system, it is possible to appropriately prevent the occurrence of uneven density while suppressing the consumption of the developer.

=== Example of Overall Configuration of Image Forming Apparatus ===
Next, an outline of a laser beam printer (hereinafter also referred to as a printer) 10 as an example of the image forming apparatus will be described with reference to FIG. FIG. 1 is a diagram illustrating main components constituting the printer 10. In FIG. 1, the vertical direction is indicated by arrows. For example, the paper feed tray 92 is disposed at the lower part of the printer 10, and the fixing unit 90 is disposed at the upper part of the printer 10.

  As shown in FIG. 1, the printer 10 according to the present embodiment includes a charging unit 30, an exposure unit 40, and a YMCK along the rotation direction of a photoconductor 20 as an example of an image carrier for carrying a latent image. The developing device 50, the primary transfer unit 60, the intermediate transfer member 70, and the cleaning blade 76 are provided. Further, the secondary transfer unit 80, the fixing unit 90, the operation panel 95, and these units are controlled to operate the printer 10. 2 has a control unit 100 (FIG. 2) as an example of a controller for controlling.

  The photoreceptor 20 has a cylindrical conductive substrate and a photosensitive layer formed on the outer peripheral surface thereof, and is rotatable around a central axis. In the present embodiment, the photoreceptor 20 is indicated by an arrow in FIG. Rotate clockwise.

  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 charges the modulated laser based on an image signal input from a host computer (not shown) such as a personal computer or a word processor. The irradiated photoconductor 20 is irradiated.

  The YMCK developing device 50 has a rotary 55 as a rotating body and four developing devices attached to the rotary 55. The rotary 55 is rotatable and includes four attachment / detachment portions 55b, 55c, 55d, and 55e to which each of the four developing devices 51, 52, 53, and 54 can be attached and detached. The black developing device 51 containing black (K) toner is detachable with respect to the attaching / detaching portion 55b, and the magenta developing device 52 containing magenta (M) toner is attachable / detachable with respect to the attaching / detaching portion 55c. The cyan developing device 53 containing cyan (C) toner is detachable from the attaching / detaching portion 55d, and the yellow developing device 54 containing yellow (Y) toner is attachable / detachable to / from the attaching / detaching portion 55e.

  The rotary 55 rotates to move the four developing devices 51, 52, 53, and 54 mounted on the attachment / detachment portions 55b, 55c, 55d, and 55e, respectively. That is, the rotary 55 rotates the four developing devices 51, 52, 53, and 54 that are mounted while maintaining the relative positions around the central axis 55a. The developing devices 51, 52, 53, and 54 are selectively opposed to the latent image formed on the photoconductor 20 as an example of the developer contained in each of the developing devices 51, 52, 53, and 54. The latent image on the photoconductor 20 is developed with toner. Details of each developing device will be described later.

The primary transfer unit 60 is a device for transferring a single color toner image formed on the photoconductor 20 to the intermediate transfer body 70. When four color toners are sequentially transferred in a superimposed manner, the full color toner is transferred to the intermediate transfer body 70. An image is formed.
This intermediate transfer body 70 is an endless belt in which a tin vapor deposition layer is provided on the surface of a PET film and a semiconductive paint is formed on the surface layer and laminated. The intermediate transfer body 70 is driven to rotate at substantially the same peripheral speed as the photoconductor 20. A synchronization reading sensor RS is provided in the vicinity of the intermediate transfer member 70. The synchronization reading sensor RS is a sensor for detecting the reference position of the intermediate transfer body 70, and obtains a synchronization signal Vsync in the sub-scanning direction orthogonal to the main scanning direction. The reading sensor RS for synchronization has a light emitting unit for emitting light and a light receiving unit for receiving light. When the light emitted from the light emitting unit passes through a hole formed at a predetermined position of the intermediate transfer body 70 and is received by the light receiving unit, the synchronization reading sensor RS generates a pulse signal. One pulse signal is generated every time the intermediate transfer member 70 rotates once.

The secondary transfer unit 80 is a device for transferring a single color toner image or a full color toner image formed on the intermediate transfer body 70 to a recording medium such as paper, film, or cloth.
The fixing unit 90 is a device for fusing a single color toner image or a full color toner image transferred onto a recording medium onto a recording medium such as paper to form a permanent image.

  The cleaning unit 75 is provided between the primary transfer unit 60 and the charging unit 30 and has a rubber cleaning blade 76 that is in contact with the surface of the photoconductor 20. The cleaning unit 75 is disposed on the intermediate transfer body 70 by the primary transfer unit 60. After the toner image is transferred, the toner T remaining on the photoconductor 20 is scraped off and removed by the cleaning blade 76.

  The operation panel 95 is a part serving as an interface with the user, and exhibits a function as an input receiving unit for receiving an instruction input from the user and an information output unit for giving various information to the user. In order to perform these functions, the operation panel 95 includes operation buttons, a liquid crystal panel, and the like.

  As shown in FIG. 2, 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 in response to a command based on the image signal and the control signal. 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.
First, when a control signal including an image signal from a host computer (not shown) and a signal indicating an image formation execution command is input to the main controller 101 of the printer 10 via the interface (I / F) 112, the main controller 101 The photosensitive member 20 and the intermediate transfer member 70 are rotated by the control of the unit controller 102 based on the command from the unit. Thereafter, the reference position of the intermediate transfer body 70 is detected by the synchronization reading sensor RS, and a pulse signal is output. This pulse signal is sent to the unit controller 102 via the serial interface 121. The unit controller 102 controls the following operations based on the received pulse signal.

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. .
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 70 by the primary transfer unit 60. At this time, a primary transfer voltage 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 70 are in contact with each other, and the secondary transfer unit 80 is separated from the intermediate transfer member 70.

By repeating the above process for the second color, the third color, and the fourth color, the toner images of the respective colors corresponding to the respective image signals are transferred to the intermediate transfer member 70 in an overlapping manner. As a result, a full color toner image is formed on the intermediate transfer member 70.
The full-color toner image formed on the intermediate transfer body 70 reaches the secondary transfer position as the intermediate transfer body 70 rotates, and is transferred to the recording medium by the secondary transfer unit 80. 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. When performing the transfer operation, the secondary transfer unit 80 is pressed against the intermediate transfer body 70 and a secondary transfer voltage is applied.
The full color toner image transferred to the recording medium is heated and pressurized by the fixing unit 90 and fused to the recording medium.

  On the other hand, after the primary transfer position has elapsed, the toner adhering to the surface of the photoconductor 20 is scraped off by the cleaning blade 76 to prepare for charging for forming the next latent image. The toner that has been scraped off is collected by a residual toner collecting unit provided in the cleaning unit 75.

=== Overview of Control Unit ===
Next, the configuration of the control unit 100 will be described with reference to FIG. FIG. 2 is a block diagram showing the control unit 100 provided in the printer 10.
The main controller 101 of the control unit 100 is connected to a host computer via an interface 112 and includes an image memory 113 for storing image signals input from the host computer.
The unit controller 102 of the control unit 100 is electrically connected to each unit (charging unit 30, exposure unit 40, primary transfer unit 60, secondary transfer unit 80, fixing unit 90, operation panel 95) and the YMCK developing device 50. The units and the YMCK developing device 50 are controlled based on the signals input from the main controller 101 while detecting the states of the units and the YMCK developing device 50 by receiving signals from the sensors included in the units. .

=== Overview of Developing Device ===
Next, an outline of the developing device will be described with reference to FIGS. 3 and 4. FIG. 3 is a cross-sectional view showing main components of the black developing device 51. FIG. 4 is a perspective view of the black developing device 51 as viewed from the developing roller 510 side. The cross-sectional view shown in FIG. 3 represents a cross-section obtained by cutting the black developing device 51 along a plane perpendicular to the longitudinal direction shown in FIG. In FIG. 3, the vertical direction is indicated by an arrow. For example, the central axis of the developing roller 510 is lower than the central axis of the photoconductor 20. Further, in FIG. 3, the black developing device 51 is shown in a state where the black developing device 51 is located at a developing position facing the photoconductor 20.

  The rotary 55 includes a black developing device 51 containing black (K) toner, a magenta developing device 52 containing magenta (M) toner, a cyan developing device 53 containing cyan (C) toner, and yellow (Y) toner. Although the housed yellow developing device 54 is provided, the configuration of each developing device is the same, so the black developing device 51 will be described below.

  As shown in FIGS. 3 and 4, the black developing device 51 includes a housing 540, a toner container 530 as an example of a container, a developing roller 510 as an example of a developer carrier, a toner supply roller 550, a layer thickness regulation. A regulating blade 560 as an example of a member, a seal member 520, and the like are provided.

  The housing 540 is manufactured by welding an upper housing and a lower housing which are integrally formed, and a toner container 530 for containing the toner T is formed therein. The toner containing body 530 has two toner containing portions, that is, a first toner containing portion 530a and a second toner, by a regulating wall 545 for partitioning the toner T projected inwardly (in the vertical direction in FIG. 3) from the inner wall. It is divided into the accommodating portion 530b. The upper portions of the first toner storage portion 530a and the second toner storage portion 530b communicate with each other, and the movement of the toner T is restricted by the restriction wall 545.

  An opening 541 that communicates with the outside of the housing 540 (toner container 530) is provided in the lower portion of the first toner container 530a. A toner supply roller 550 is provided in the first toner storage portion 530 a so that its peripheral surface faces the opening 541 and is rotatably supported by the housing 540. Further, a developing roller 510 is provided from the outside of the housing 540 so that the circumferential surface faces the opening 541, and the developing roller 510 is in contact with the toner supply roller 550.

  The developing roller 510 carries the toner T and conveys it to a developing position facing the photoconductor 20. The developing roller 510 is made of aluminum, stainless steel, iron, or the like, and is subjected to nickel plating, chrome plating, or the like as necessary. Further, as shown in FIG. 4, the developing roller 510 is provided so that its longitudinal direction is along the longitudinal direction of the black developing device 51. Further, the developing roller 510 is rotatable about the central axis, and as shown in FIG. 3, the developing roller 510 is rotated in a direction (counterclockwise in FIG. 3) opposite to the rotation direction of the photoconductor 20 (clockwise in FIG. 3). Rotate. The central axis is below the central axis of the photoconductor 20. As shown in FIG. 3, there is a gap between the developing roller 510 and the photoconductor 20 when the black developing device 51 faces the photoconductor 20. That is, the black developing device 51 develops the latent image formed on the photoconductor 20 in a non-contact state. When developing the latent image formed on the photoconductor 20, a developing bias in which a DC voltage and an AC voltage are superimposed is applied to the developing roller 510, and alternating between the developing roller 510 and the photoconductor 20. An electric field is formed.

  The toner supply roller 550 supplies the toner T to the developing roller 510. The toner supply roller 550 is made of polyurethane foam or the like, and is in contact with the developing roller 510 in an elastically deformed state. The toner supply roller 550 is disposed below the first toner storage unit 530a, and the toner T stored in the first toner storage unit 530a and the second toner storage unit 530b is positioned below the first toner storage unit 530a. Then, the toner is supplied to the developing roller 510 by the toner supply roller 550. The toner supply roller 550 is rotatable about a central axis, and the central axis is below the rotation central axis of the developing roller 510. Further, the toner supply roller 550 rotates in a direction (clockwise in FIG. 3) opposite to the rotation direction of the developing roller 510 (counterclockwise in FIG. 3). The toner supply roller 550 has a function of supplying the toner T to the developing roller 510 and rotates while being in contact with the developing roller 510 to develop the toner T remaining on the developing roller 510 after development. It also has a function of scraping from the roller 510.

  The regulating blade 560 is provided in the opening 541 and abuts against the contacted portion 510 a of the developing roller 510 to regulate the layer thickness of the toner T carried on the developing roller 510 and is carried on the developing roller 510. The toner T is charged. The regulation blade 560 has a rubber part 560a and a rubber support part 560b. The rubber part 560a is made of silicon rubber, urethane rubber or the like, and the rubber support part 560b is a thin plate having spring properties such as phosphor bronze or stainless steel. The rubber part 560a is supported by the rubber support part 560b, and one end of the rubber support part 560b is fixed to the blade support metal plate 562. In this state, the rubber part 560a is pressed against the developing roller 510 by the elastic force due to the bending of the rubber support part 560b.

  Further, a blade back member 570 made of malt plane or the like is provided on the side opposite to the developing roller 510 side of the regulating blade 560. The blade back member 570 prevents the toner T from entering between the rubber support portion 560b and the housing 540, stabilizes the elastic force due to the bending of the rubber support portion 560b, and from the back of the rubber portion 560a to the rubber portion 560a. The rubber portion 560a is pressed against the developing roller 510 by urging the developing roller 510 toward the developing roller 510. Therefore, the blade back member 570 improves the uniform contact property and the sealing property of the rubber portion 560a to the developing roller 510.

  The end of the regulating blade 560 opposite to the side supported by the blade support metal plate 562, that is, the tip is not in contact with the developing roller 510, and a portion away from the tip by a predetermined distance is the developing roller. 510 abuts with a width. That is, the regulating blade 560 is not in contact with the developing roller 510 at the edge, but is in contact with the belly. The regulating blade 560 is disposed so that the tip thereof faces the upstream side in the rotation direction of the developing roller 510, and is in a so-called counter contact. The contact position where the regulating blade 560 contacts the developing roller 510 is below the central axis of the developing roller 510 and below the central axis of the toner supply roller 550.

  The seal member 520 contacts the contacted portion 510b of the developing roller 510 with a width to prevent the toner T in the black developing device 51 from leaking out of the unit, and on the developing roller 510 that has passed the developing position. The toner T is collected in the developing device without being scraped off. The seal member 520 is a seal made of a polyethylene film or the like. The seal member 520 is provided in the opening 541 and is supported by a seal support sheet metal 522. Further, a seal urging member 524 made of malt plain or the like is provided on the opposite side of the seal member 520 from the developing roller 510 side. The seal member 520 is developed by the elastic force of the seal urging member 524. 510 is pressed. The contact position where the seal member 520 contacts the developing roller 510 is above the central axis of the developing roller 510.

  In the black developing device 51 configured as described above, the toner supply roller 550 supplies the toner T stored in the toner container 530 to the developing roller 510. The toner T supplied to the developing roller 510 reaches the contact position of the regulating blade 560 as the developing roller 510 rotates, and the layer thickness is regulated and electric charge is applied when passing through the contact position. Is done. The toner T on the developing roller 510 whose layer thickness is regulated reaches the developing position facing the photoconductor 20 by further rotation of the developing roller 510, and is formed on the photoconductor 20 under an alternating electric field at the developing position. Used for developing the latent image. The toner T on the developing roller 510 that has passed the developing position by further rotation of the developing roller 510 passes through the seal member 520 and is collected in the developing device without being scraped off by the seal member 520. Further, the toner T still remaining on the developing roller 510 can be peeled off by the toner supply roller 550.

=== Regarding the Standing Banding and the Preparatory Rotating Operation of the Developing Roller 510 to Prevent the Generation of the Standing Banding ===
As described in the background art section, when the developing device develops a latent image in a state where development by the developing device has not been performed for a long time (in other words, the state where the developing roller 510 has not rotated for a long time). As a result, shading unevenness (so-called neglected banding) occurs. In order to prevent the occurrence of the neglected banding, there is known a method for executing a rotation operation of the developing roller 510 (the rotation operation is also referred to as a preparation rotation operation for convenience) as the advance preparation operation for the development. The measure is also implemented in the embodiment.

  Here, first, the neglected banding will be described with reference to FIGS. 3 and 5, and subsequently, the preparatory rotation operation of the developing roller 510 according to the present embodiment will be described with reference to FIGS. 6 and 7. FIG. 5 is a schematic diagram for explaining the exposed portion 510c and the non-exposed portion 510d on the developing roller 510. 6 and 7 will be described later.

<<< About neglected banding >>>
The neglected banding is caused by the fact that the state of the small particle size toner (fine toner) adhering to a partial region in the circumferential direction of the developing roller 510 continues for a long time when the developing roller 510 does not rotate (does not move). This is considered to be the main factor.

  The region in the circumferential direction of the developing roller 510 is an exposed portion 510c exposed from the opening 541 (the right side portion when the contacted portion 510a and the contacted portion 510b are the boundary in FIGS. 3 and 5). The contact portion 510a and the contacted portion 510b are not included), and the non-exposed portion 510d that is not exposed from the opening 541 (in FIG. 3 and FIG. 5, the contacted portion 510a and the contacted portion 510b are bounded). The fine toner adheres to both the exposed portion 510c and the non-exposed portion 510d, but is not exposed to the left portion of the contact portion 510a and the contacted portion 510b. Unlike the toner adhering to the exposed portion 510c, the fine powder toner adhering to the portion 510d is subjected to a large pressure because the toner is present in the vicinity thereof. Further, the fine powder toner adhering to the non-exposed portion 510d is placed in a sealed space (that is, inside the toner container 530), unlike the toner adhering to the exposed portion 510c. If the state in which the developing roller 510 does not rotate (does not move) continues for a long time, the environment around the fine toner described above affects the fine toner, and the state of the fine toner is changed.

  Therefore, if the developing roller 510 does not rotate (does not move) for a long time, the state of the fine toner adhering to the exposed portion 510c and the state of the fine toner adhering to the non-exposed portion 510d are greatly different. It becomes. The difference in the state of the fine toner is that the toner charge amount is nonuniform in the circumferential direction of the developing roller 510 (between the exposed portion 510c and the non-exposed portion 510d) when the developing device develops the latent image. In the end, the non-uniformity of the charge amount causes non-uniformity in toner flight from the developing device to the photoconductor 20, and the toner image (finally, the image) obtained by development is shaded. Unevenness (so-called left banding) occurs (actually, the toner image by the toner carried on the exposed portion 510c is thin, and the toner image by the toner carried on the non-exposed portion 510d is dark).

<<< Regarding Preparatory Rotation Operation of Developing Roller 510 >>>
Next, the preparatory rotation operation of the developing roller 510 according to the present embodiment will be described with reference to FIGS. FIG. 6 is a flowchart relating to the preparatory rotation operation of the developing roller 510 according to the present embodiment. FIG. 7 is a comparison table showing differences between the first preparation rotation operation to the fifth preparation rotation operation.

  Various operations of the printer 10 when the preparation rotation operation is executed are mainly realized by the control unit 100 (FIG. 2). 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.

  The control unit 100 performs the preparatory rotation operation at a plurality of types (three types in the present embodiment). That is, in this embodiment, three types of preparatory rotation operation start conditions are determined in advance, and the control unit 100 starts the preparatory rotation operation of the developing roller 510 when the preparatory rotation operation start conditions are satisfied. . Here, the preparation rotation operation start condition is such that the preparation rotation operation is started in a state where the developing roller 510 has not rotated for a long time or in a state where there is a high possibility that the developing roller 510 has not rotated for a long time. In the printer 10 according to the present embodiment, when the printer 10 is turned on (first start condition), the image signal and the signal indicating the image formation execution command are included. A period during which the control signal is input to the printer 10 and the developing roller 510 has not been rotated immediately before (the period is referred to as a continuous non-rotating period for convenience) is a predetermined period (a so-called threshold value). In this embodiment, when it is 3 hours or more (second start condition) and when the developing device is attached to the attachment / detachment portion of the printer main body (third start condition), the preparatory rotation Work is adapted to be started.

  Although the printer 10 includes four developing devices, whether or not the second start condition is satisfied is determined for each developing device. That is, the control unit 100 stores, for each developing device, the time when the rotation operation of the developing roller 510 (rotation operation when image formation is performed, the preparation rotation operation, etc.) is completed, and the image signal and the image formation execution command are stored. When a control signal including a signal indicating the above is input to the printer 10, it is determined for each developing device whether or not the continuous non-rotation period is equal to or longer than a predetermined period using a timer in the printer 10. Further, when the third start condition is satisfied, only the preparatory rotation operation of the developing roller 510 provided in the mounted developing device is executed, and when the first start condition is satisfied, all The preparatory rotation operation of the developing roller 510 provided in the developing device is executed.

  Moreover, about the preparatory rotation operation | movement which concerns on this Embodiment, as shown in FIG. 7, the following 5 types of preparatory rotation operation | movement (1st, 2nd, 3rd, 4th, and 4) from which control by the control unit 100 differs mutually. And the fifth preparatory rotation operation) is prepared, and one of the five preparatory rotation operations is performed depending on which timing of the three types of timing described above is executed. Is to be selected. The control unit 100 rotates the developing roller 510 a plurality of times when executing the preparatory rotation operation. However, the number of rotations of the developing roller 510 in the preparatory rotation operation is constant regardless of the type of the preparatory rotation operation. In the embodiment, the rotation number is 11 rotations.

  The first preparation rotation operation is a preparation rotation operation that is executed when the first start condition is satisfied (step S2: yes, step S10). The control unit 100 controls the developing roller 510 and the like provided in the developing device to execute the first preparatory rotation operation of the developing roller 510. During the first preparatory rotation operation, the control unit 100 performs the development. Of the toner carried on the roller 510, all of the non-exposed portion 510d that is a partial region in the circumferential direction of the developing roller 510 and has not been exposed from the opening 541 before the execution of the first preparation rotation operation is started. Only the toner carried in an area including the above (for convenience, this area is referred to as a toner consumption area; see FIG. 5) forms a latent image on the photoconductor 20 and moves it to the photoconductor 20.

  The second preparation rotation operation is a preparation rotation operation that is executed when the second start condition is satisfied (step S4: yes). In the present embodiment, as shown in step S8 of FIG. 6, when the second start condition is satisfied, among the second preparation rotation operation, the third preparation rotation operation, and the fourth preparation rotation operation Is selected based on the continuous non-rotation period. The second preparatory rotation operation is executed when the continuous non-rotation period is 4 hours or longer (step S8: 4 hours or longer, step S12).

  During the second preparatory rotation operation, the control unit 100 causes only the toner carried in the toner consumption area of the toner carried on the developing roller 510 to be a latent image on the photoreceptor 20 as in the first preparatory rotation operation. The latent image formed on the photoconductor 20 is different from the latent image formed on the photoconductor 20 when the first preparatory rotation operation is executed. More specifically, when the first preparatory rotation operation is performed, a latent image corresponding to the solid image is formed on the photoconductor 20, whereas when the second preparatory rotation operation is performed. A latent image corresponding to the halftone image is formed on the photoreceptor 20. Therefore, the amount of toner that moves to the photoconductor 20 when the second preparatory rotation operation is executed is smaller than the amount of toner that moves to the photoconductor 20 when the first preparatory rotation operation is executed.

  The third preparation rotation operation is a preparation rotation operation that is executed when the second start condition is satisfied and the continuous non-rotation period is 3.5 hours or more and less than 4 hours (step S4: yes, Step S8: 3.5-4 hours, step S14). During the third preparatory rotation operation, the control unit 100 removes only the toner carried in the toner consumption area out of the toner carried on the developing roller 510, as in the first preparatory rotation operation and the second preparatory rotation operation. A latent image is formed on the photosensitive member 20 and moved to the photosensitive member 20, and the latent image corresponding to the halftone image is formed on the photosensitive member 20 in the same manner as the second preparation rotation operation. However, unlike the first preparatory rotation operation and the second preparatory rotation operation, the toner carried on the developing roller 510 is carried in the toner consumption area only by a part of the plural rotations of the developing roller 510. Only the applied toner forms a latent image on the photoconductor 20 and moves to the photoconductor 20. That is, when the first preparatory rotation operation or the second preparatory rotation operation is executed, every time the developing roller 510 rotates 11 times, the toner carried on the developing roller 510 is carried in the toner consumption area. In the case where only the toner is moved to the photoconductor 20 by forming a latent image on the photoconductor 20, when the third preparatory rotation operation is executed, an odd number is generated when the developing roller 510 rotates 11 times. At the rotation (first, third, fifth, seventh, ninth and eleventh rotations), only the toner carried in the toner consumption area among the toner carried on the developing roller 510 is transferred to the photosensitive member 20 as a latent image (halftone image). A latent image corresponding to the above is formed and moved to the photosensitive member 20. Then, at the even-numbered rotations (2, 4, 6, 8, and 10th rotations), a latent image is not formed on the photoconductor 20, and control for moving the toner carried on the developing roller 510 to the photoconductor 20 is executed. Not. Therefore, the amount of toner that moves to the photoconductor 20 when the third preparatory rotation operation is executed is smaller than the amount of toner that moves to the photoconductor 20 when the second preparatory rotation operation is executed.

  The fourth preparatory rotation operation is a preparatory rotation operation that is executed when the second start condition is satisfied and the continuous non-rotation period is 3 hours or more and less than 3.5 hours (step S4: yes, Step S8: 3 to 3.5 hours, step S16). During the fourth preparatory rotation operation, the control unit 100 differs from the first preparatory rotation operation to the third preparatory rotation operation, and does not form a latent image on the photoconductor 20 but uses the toner carried on the developing roller 510. Control that does not move to the photoconductor 20 (that is, control described in the section of the problem to be solved by the invention) is executed. Such control is executed in all of the 11 rotations of the developing roller 510.

  The fifth preparatory rotation operation is a preparatory rotation operation that is executed when the third start condition is satisfied (step S6: yes, step S18). In the fifth preparatory rotation operation, the control unit 100 does not move only the toner carried in the toner consumption area out of the toner carried on the developing roller 510 to the photoconductor 20 (first preparatory rotation). (Unlike the operation to the third preparatory rotation operation), the toner carried in all the areas in the circumferential direction of the developing roller 510 forms a latent image on the photoconductor 20 and moves to the photoconductor 20 (ie, the invention). The control described in the section of the problem to be solved is executed. Such control is executed in all of the 11 rotations of the developing roller 510.

  As described above, in the printer 10 according to the present embodiment, the developing roller 510 is used as the pre-development operation for the development in order to prevent the occurrence of uneven density (unbanded banding) when developing the latent image by the developing device. Of the toner carried on the developing roller 510 in the circumferential direction of the developing roller 510 when the rotating operation is executed. In this case, only the toner carried in the area (that is, the toner consumption area) including all of the non-exposed portion 510d that has not been exposed from the opening 541 before the execution of the rotation operation is performed is the photoconductor 20. And a controller (control unit 100) for forming a latent image and moving it to the photoconductor 20. As a result, it is possible to realize the printer 10 and the like that can appropriately prevent the occurrence of uneven density (left banding) while suppressing toner consumption.

  That is, as described in the section of the problem to be solved by the invention, the following two types of control are provided as the control related to the above-described preparation rotation operation that is executed to prevent the occurrence of uneven shading (left banding). As is known, each of both controls has advantages and disadvantages.

  First, as a control related to the preparatory rotation operation, the toner carried on the developing roller 510 is always moved to the photosensitive member 20 when the developing roller 510 is rotating by forming a latent image on the photosensitive member 20. There is known a control for making it (referred to as a first comparative example). In such a case, a control is executed to form a latent image on the photosensitive member 20 and move the toner carried on all areas in the circumferential direction of the developing roller 510 to the photosensitive member 20, and the toner on the developing roller 510 is moved. Since the developing roller 510 is rotated while being constantly moved to the photoconductor 20, the uniform charge amount of the toner is further promoted, and it is more appropriate that density unevenness (left banding) occurs during development. It becomes possible to prevent. However, this control has a demerit that a lot of toner is wasted.

  On the other hand, there is known a control in which a latent image is not formed on the photoconductor 20 and toner carried on the developing roller 510 is not moved to the photoconductor 20 when the preparation rotation operation is executed (second comparative example). ). The control is excellent in terms of toner saving, but when the control is executed, the charge amount of the toner is not sufficiently uniformed as compared with the above-described control for constantly moving the toner. The occurrence of neglected bunting may not be properly prevented.

  On the other hand, when the preparatory rotation operation is executed, the toner carried on the developing roller 510 is a partial region in the circumferential direction of the developing roller 510, and the opening before the start of the preparatory rotation operation is started. Control for moving only the toner carried on the area (that is, the toner consumption area) including all of the non-exposed portion 510d that has not been exposed from 541 to the photosensitive body 20 by forming a latent image on the photosensitive body 20. Is executed, only the toner carried in a partial area in the circumferential direction of the developing roller 510 moves to the photoconductor 20, so that the toner carried in all the areas in the circumferential direction of the developing roller 510 is photosensitive. Compared to the first comparative example that moves to the body 20, toner consumption is suppressed.

  Further, since the partial region in the circumferential direction of the developing roller 510 includes all of the non-exposed portions 510d that are not exposed from the opening 541 before the start of the preparatory rotation operation, the non-exposed portions are included. It is possible to surely remove the fine powder toner which is attached to 510d and whose state has changed and which is the main cause of density unevenness (leaving banding). ) Can be appropriately prevented (the fine powder toner that has adhered to the non-exposed portion 510d and whose state has been mutated, which is the main cause of neglected banding, can be removed reliably. Then, since it is the same as the second comparative example, the ability to prevent neglected banding is ensured compared to the second comparative example).

<<< Method for Moving Only Toner Carried in Toner Consumption Area to Photosensitive Member 20 >>>
Here, a method of moving only the toner carried in the toner consumption area to the photoconductor 20 will be described. As described above, when the first preparation rotation operation to the third preparation rotation operation are executed, the control unit 100 sensitizes only the toner carried in the toner consumption area among the toner carried on the developing roller 510. A latent image is formed on the body 20 and moved to the photoconductor 20, and in order to realize this, it is necessary to appropriately control the timing of the latent image formation by the exposure unit 40 described above. That is, when the toner carried in the toner consumption area reaches the developing position facing the photoreceptor 20 by the rotation of the developing roller 510, the control unit 100 has a latent image on the photoreceptor 20 facing the toner. On the other hand, when the toner carried in the region other than the toner consumption region reaches the developing position facing the photoconductor 20 due to the rotation of the developing roller 510, a latent image exists on the photoconductor 20 facing the toner. Therefore, it is necessary to control the timing of latent image formation by the exposure unit 40.

  In the printer 10 according to the present embodiment, the timing is calculated in advance, and information related to the timing is described in a program stored in the ROM in the control unit 100. Then, the control unit 100 refers to the information and controls the timing of latent image formation by the exposure unit 40. Below, the calculation principle of the said timing is demonstrated.

  As described above, the operations of the various units provided in the printer 10 are controlled based on the pulse signal output from the synchronization reading sensor RS. That is, the operation timing of the unit based on the pulse signal (in other words, the time from when the pulse signal is output until the operation is executed) is determined in advance.

  First, the developing roller 510 will be described. Since the period from when the pulse signal is output until the developing roller 510 starts rotating for execution of the preparatory rotation operation is known, the following time based on the pulse signal is described. That is, the time until the non-exposed portion 510d (toner carried on the non-exposed portion) reaches the developing position can be calculated based on the rotation speed of the developing roller 510.

  In order for the latent image to exist at a position on the photosensitive member 20 facing the developing roller 510 during the time when the non-exposed portion 510d (toner carried on the non-exposed portion) reaches the developing position, at what timing the latent image is displayed. Whether it must be formed can be calculated based on the rotational speed of the photoreceptor 20.

  In the present embodiment, for example, when a latent image is formed after a pulse signal is output from 380 to 450 msec, 570 to 640 msec,... During the time to reach the position, a latent image exists at a position on the photoconductor 20 facing the developing roller 510. In the present embodiment, the toner consumption area includes the non-exposed part 510d and is wider than the non-exposed part 510d. For example, after the pulse signal is output, 375 to 455 msec, 565 ˜645 msec,..., If a latent image is to be formed later, when the toner carried in the toner consumption area reaches the development position, the latent image is present on the photoreceptor 20 facing the toner. To be able to.

=== Other Embodiments ===
The image forming apparatus and the like according to the present invention have been described above based on the above embodiment. However, the above embodiment of the present invention is for facilitating understanding of the present invention and limits the present invention. is not. 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.

  Moreover, in the said embodiment, the control unit 100 is only a part of timings (namely, when 1st start conditions are satisfy | filled) among 2 types of timing (namely, 3 types timing), and 2nd start. (Only when the condition is satisfied), when the preparatory rotation operation is executed, only the toner carried in the toner consumption area among the toner carried on the developing roller 510 is formed on the photosensitive member 20 as a latent image. However, the present invention is not limited to this. For example, when the preparatory rotation operation is executed at all timings among a plurality of timings, the photosensitive drum 20 is carried by the developing roller 510. Only the toner carried in the toner consumption area among the toners may be moved to the photoconductor 20 by forming a latent image on the photoconductor 20.

  Of the three types of timing described above, when the printer 10 is turned on (when the first start condition is satisfied) and when the developing device is attached to the attachment / detachment portion of the printer body (when the third start condition is When satisfied, since the continuous non-rotation period of the developing roller 510 is not detected, it is necessary to place more emphasis on the former purpose of the two purposes of preventing neglected banding and saving toner. In addition, when the first start condition and the third start condition are compared, the frequency at which the third start condition is satisfied is expected to be much less than the frequency at which the first start condition is satisfied. When is satisfied, the latter of the two purposes may be more neglected than when the first start condition is satisfied. From this point of view, in the printer 10 according to the present embodiment, when the third start condition is satisfied, the toner carried in all the areas in the circumferential direction of the developing roller 510 is transferred to the photoreceptor 20 as a latent image. Control of forming and moving to the photoconductor 20 is executed.

  As described above, only the toner carried in the toner consumption region among the toners carried on the developing roller 510 when the preparation rotation operation is executed only at some timings among the plurality of types of timings. When a latent image is formed on the photoconductor 20 and moved to the photoconductor 20, a preparatory rotation operation corresponding to the situation can be executed. In this respect, the above embodiment is more desirable.

  Further, in the above embodiment, the control unit 100 performs the developing roller 510 when performing the preparing rotation operation based on the period during which the developing roller 510 has not been rotated immediately before the execution of the preparing rotation operation. Whether only the toner carried in the toner consumption area among the toners carried on the toner is formed on the photoconductor 20 and moved to the photoconductor 20 (that is, the second preparatory rotation operation or the third preparatory rotation). Execution of the operation or execution of the fourth preparatory rotation operation), but is not limited to this. For example, when the preparatory rotation operation is performed regardless of the period, the developing roller Only the toner carried in the toner consumption area among the toners carried on 510 may be moved to the photoreceptor 20 by forming a latent image on the photoreceptor 20.

  When the second start condition is satisfied, the longer the continuous non-rotation period is, the more important is the former purpose of the two purposes of preventing neglected banding and saving toner, On the other hand, the shorter the continuous non-rotation period, the more important should be the latter of the two purposes. From this point of view, in the printer 10 according to the present embodiment, when the continuous non-rotation period is 3.5 hours or more, only the toner carried in the toner consumption area among the toner carried on the developing roller 510 is used. Are controlled to form a latent image on the photoconductor 20 and move the photoconductor 20 to the photoconductor 20. On the other hand, if the continuous non-rotation period is less than 3.5 hours, a latent image is formed on the photoconductor 20. Thus, control is performed so that the toner carried on the developing roller 510 is not moved to the photosensitive member 20.

  As described above, when the preparatory rotation operation is executed based on the period during which the developing roller 510 has not been rotated immediately before the start of the preparatory rotation operation, the toner consumption of the toner carried on the developing roller 510 is reduced. In the case where it is determined whether or not only the toner carried in the region is to be moved to the photoconductor 20 by forming a latent image on the photoconductor 20, a preparatory rotation operation can be executed according to the situation. In this respect, the above embodiment is more desirable.

In the above-described embodiment, the control unit 100 only performs the toner carried on the developing roller 510 among the toner carried on the developing roller 510 by only a part of the plurality of rotations of the developing roller 510. , A latent image is formed on the photoconductor 20 and moved to the photoconductor 20, but the present invention is not limited to this, and such control may not be executed.
However, the above embodiment is more preferable in that the amount of toner carried in the toner consumption area and moved to the photoconductor 20 when the preparation rotation operation is executed can be finely adjusted.

  Further, in the above-described embodiment, the control unit 100 performs the photosensitive rotation when the preparatory rotation operation is performed on the toner carried in the toner consumption area, depending on the timing at which the preparatory rotation operation is performed. The amount of toner moved to the body 20 was changed. That is, the toner amount when the first start condition is satisfied (when the first preparatory rotation operation is executed) and when the second start condition is satisfied (for example, the second preparatory rotation operation is executed). However, the present invention is not limited to this. For example, the toner amount may be controlled to be constant regardless of the type of timing at which the preparatory rotation operation is executed.

  As described above, when the power of the printer 10 is turned on (when the first start condition is satisfied), the continuous non-rotation period of the developing roller 510 is detected unlike when the second start condition is satisfied. Therefore, it is necessary to give more importance to the former purpose of the two purposes of preventing neglected banding and saving toner. From this point of view, in the printer 10 according to the present embodiment, the amount of toner when the first start condition is satisfied (when the first preparatory rotation operation is executed) satisfies the second start condition. The amount of the toner is set to be larger than the amount of toner when the second preparation rotation operation is performed (for example, when the second preparatory rotation operation is performed).

  As described above, the amount of toner carried in the toner consumption area and moved to the photoconductor 20 when the preparation rotation operation is executed, depending on the timing at which the preparation rotation operation is executed. When changing the value, it is possible to execute a preparatory rotation operation corresponding to the situation. In this respect, the above embodiment is more desirable.

  In the above embodiment, the control unit 100 determines that the toner amount when the first start condition is satisfied (when the first preparation rotation operation is executed) and the second start condition are satisfied. The amount of the toner (for example, when the second preparatory rotation operation is executed) is changed to the latent image carried on the photoconductor 20 (the latent image corresponding to the solid image or the latent image corresponding to the halftone image). However, the present invention is not limited to this.

  For example, the control of moving only the toner carried on the toner consumption area out of the toner carried on the developing roller 510 to the photosensitive member 20 by forming a latent image on the photosensitive member 20 is performed by rotating the developing roller 510 a plurality of times. By changing the number of rotations among the rotations, the amount of toner when the first start condition is satisfied and the amount of toner when the second start condition is satisfied are changed. It may be.

  Further, by changing the developing bias applied to the developing roller 510, the amount of the toner when the first start condition is satisfied and the amount of the toner when the second start condition is satisfied are changed. (For example, when the preparatory rotation operation is executed when the first start condition is satisfied, the value of the developing bias applied to the developing roller 510 is set to the value of the developing bias when normal image formation is performed. When the preparatory rotation operation is executed when the second start condition is satisfied, the value of the developing bias applied to the developing roller 510 is set to the value of the developing bias when normal image formation is performed. Value).

  Further, in the above embodiment, the control unit 100 prepares the toner carried in the toner consumption area according to the period during which the developing roller 510 has not been continuously rotated immediately before the start of the preparation rotation operation. The amount of toner moved to the photoconductor 20 when the rotation operation is executed is changed. That is, the amount of toner when the continuous non-rotation period is 4 hours or more and the amount of toner when the continuous non-rotation period is 3.5 hours or more and less than 4 hours are different from each other. It is not limited. For example, the toner amount may be controlled to be constant regardless of the period during which the developing roller 510 has not been rotated immediately before the start of the preparation rotation operation.

  As described above, when the second start condition is satisfied, the longer the continuous non-rotation period, the more important is the former purpose of the two purposes of preventing neglected banding and saving toner. On the other hand, the shorter the continuous non-rotation period, the more important should be the latter purpose of the two purposes. From this point of view, in the printer 10 according to the present embodiment, the toner amount when the continuous non-rotation period is 4 hours or more is the toner amount when the continuous non-rotation period is 3.5 hours or more and less than 4 hours. Try to be more than the amount.

  As described above, when the developing roller 510 is not continuously rotated immediately before the start of the preparatory rotation operation, the photosensitive member 20 is used when the preparatory rotation operation is performed for the toner carried in the toner consumption region. When the amount of toner to be moved to is changed, a preparatory rotation operation corresponding to the situation can be executed. In this respect, the above embodiment is more desirable.

Further, in the above embodiment, the control unit 100 forms only a toner carried on the toner consumption area of the toner carried on the developing roller 510 by forming a latent image on the photoreceptor 20 and moves it to the photoreceptor 20. By changing the number of rotations of the plurality of rotations of the developing roller 510, the toner amount and the continuous non-rotation period when the continuous non-rotation period is 4 hours or more are 3 The amount of the toner when the time is 5 hours or more and less than 4 hours is changed, but the present invention is not limited to this.
For example, the latent image carried on the photoconductor 20 includes the amount of the toner when the continuous non-rotation period is 4 hours or more and the amount of the toner when the continuous non-rotation period is 3.5 hours or more and less than 4 hours. You may make it change by changing.

  Further, by changing the developing bias applied to the developing roller 510, the toner amount when the continuous non-rotation period is 4 hours or more and the above-described toner amount when the continuous non-rotation period is 3.5 hours or more and less than 4 hours. The amount of toner may be changed (for example, when the continuous non-rotation period is 4 hours or more, the value of the developing bias applied to the developing roller 510 is set to the developing bias when normal image formation is performed. When the continuous non-rotation period is 3.5 hours or more and less than 4 hours, the value of the developing bias applied to the developing roller 510 is set to the value of the developing bias when normal image formation is performed. Value).

  Further, the control unit 100 includes boundary areas 510e and 510f (the boundary areas 510e) between the non-exposed portion 510d and the exposed portion 510c exposed from the opening 541 before the start of the preparatory rotation operation. , 510f (shown in FIG. 5), when the toner carried on the photoconductor 20 is moved, the latent image carried on the photoconductor 20 is changed to change the toner to be moved to the photoconductor 20. The amount may be gradually changed.

  For example, one of the first preparation rotation operation to the third preparation rotation operation is executed, and the control unit 100 removes only the toner carried in the toner consumption area among the toner carried on the developing roller 510. When the latent image is formed on the toner 20 and moved to the photosensitive member 20, the control unit 100 does not make the amount of toner moved to the photosensitive member 20 constant over the entire toner consumption region, but instead consumes the toner. Only when the toner carried in the boundary areas 510e and 510f of the area is moved to the photoconductor 20, the amount of toner moved to the photoconductor 20 is gradually changed (more specifically, carried in the boundary area 510e). When the transferred toner is moved to the photoconductor 20, the amount of toner moved to the photoconductor 20 is gradually decreased, and the toner carried in the boundary area 510f is removed from the photoconductor 2. When moving to gradually increase the amount of toner moved to the photosensitive member 20).

  In this way, even if abandoned banding occurs as a result of more emphasis on the latter of the two purposes of preventing abandoned banding and saving toner, Abandoned banding with a gentle change in density occurs at the boundary between the dark part and the thin part, and therefore the abandoned banding is less noticeable.

=== Configuration of Image Forming System etc. ===
Next, an image forming system according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 8 is an explanatory diagram showing an external configuration of the image forming system. The image forming system 700 includes a computer 702, a display device 704, a printer 706, an input device 708, and a reading device 710. In this embodiment, the computer 702 is housed in a mini-tower type housing, but is not limited thereto. The display device 704 is generally a CRT (Cathode Ray Tube), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 706, the printer described above is used. In this embodiment, the input device 708 uses a keyboard 708A and a mouse 708B, but is not limited thereto. In this embodiment, the reading device 710 uses a flexible disk drive device 710A and a CD-ROM drive device 710B, but is not limited to this. For example, an MO (Magneto Optical) disk drive device or a DVD (Digital Versatile) is used. Disk) etc. may be used.

  FIG. 9 is a block diagram showing a configuration of the image forming system shown in FIG. An internal memory 802 such as a RAM and an external memory such as a hard disk drive unit 804 are further provided in a housing in which the computer 702 is housed.

  In the above description, the example in which the printer 706 is connected to the computer 702, the display device 704, the input device 708, and the reading device 710 to configure the image forming system has been described. However, the present invention is not limited to this. Absent. For example, the image forming system may include a computer 702 and a printer 706, and the image forming system may not include any of the display device 704, the input device 708, and the reading device 710.

  For example, the printer 706 may have a part of the functions or mechanisms of the computer 702, the display device 704, the input device 708, and the reading device 710. As an example, the printer 706 includes an image processing unit that performs image processing, a display unit that performs various displays, a recording medium attachment / detachment unit for attaching / detaching a recording medium that records image data captured by a digital camera or the like. It is good also as a structure to have.

  The image forming system realized in this way is a system superior to the conventional system as a whole system.

FIG. 2 is a diagram illustrating main components constituting the printer. 2 is a block diagram showing a control unit 100 provided in the printer 10. FIG. FIG. 2 is a cross-sectional view showing main components of a black developing device 51. FIG. 4 is a perspective view of the black developing device 51 as viewed from the developing roller 510 side. It is a schematic diagram for explaining an exposed portion 510c and a non-exposed portion 510d on the developing roller 510. 5 is a flowchart relating to a preparatory rotation operation of the developing roller 510 according to the present embodiment. It is the comparison table which showed the difference between 1st preparatory rotation operation thru / or 5th preparatory rotation operation. 1 is an explanatory diagram showing an external configuration of an image forming system. It is a block diagram which shows the structure of the image forming system shown in FIG.

Explanation of symbols

10 printer, 20 photoconductor, 30 charging unit, 40 exposure unit,
50 YMCK development device, 51 Black development device, 52 Magenta development device,
53 Cyan developing device, 54 Yellow developing device, 55 Rotary,
55a central axis, 55b, 55c, 55d, 55e detachable part,
60 primary transfer unit, 70 intermediate transfer member, 75 cleaning unit,
76 Cleaning blade, 80 Secondary transfer unit, 90 Fixing unit,
92 paper feed tray, 94 paper feed roller, 95 operation panel, 96 registration roller,
100 control unit, 101 main controller,
102 unit controller, 112 interface,
113 image memory, 121 serial interface,
510 developing roller, 510a contacted part, 510b contacted part,
510c exposed area, 510d non-exposed area, 510e boundary area, 510f boundary area,
520 seal member, 522 seal support sheet metal, 524 seal urging member,
530 toner container, 530a first toner container, 530b second toner container,
540 housing, 541 opening, 545 restriction wall, 550 toner supply roller,
560 regulating blade, 560a rubber part, 560b rubber support part,
562 blade support sheet metal, 570 blade backing member,
700 image forming system, 702 computer, 704 display device,
706 printer, 708 input device, 708A keyboard, 708B mouse,
710 reader,
710A flexible disk drive device, 710B CD-ROM drive device,
802 internal memory, 804 hard disk drive unit, T toner,
RS synchronization reading sensor

Claims (13)

An image carrier for carrying a latent image;
A container having an opening for accommodating the developer; and a rotatable developer carrying member provided to face the opening for carrying the developer, and carried by the developer carrying member. A developing device for developing the latent image carried on the image carrier by the developer,
A controller that executes a rotation operation of the developer carrier as a pre-preparation operation of the development in order to prevent occurrence of uneven density when developing the latent image by the developing device;
When performing the rotation operation,
Of the developer carried on the developer carrying member, it is a partial region in the circumferential direction of the developer carrying member that has not been exposed from the opening before the start of the rotation operation. Only the developer carried in the area including all of the
A controller that forms a latent image on the image carrier and moves it to the image carrier;
An image forming apparatus comprising: The image forming apparatus according to claim 1.
The controller is
The rotation operation is executed at a plurality of types of timing,
In only a part of the plurality of types of timings,
Of the developer carried on the developer carrying member when the rotating operation is performed, it is a partial region in the circumferential direction of the developer carrying member, and the opening is opened before the execution of the rotating operation is started. Forming only a developer carried on an area including all of the non-exposed portions that have not been exposed from the toner image, forming a latent image on the image carrier and moving the image carrier to the image carrier. apparatus. The image forming apparatus according to claim 1, wherein:
The controller is
Based on a period during which the developer carrier has not been rotated immediately before the start of the rotation operation,
When the rotation operation is performed, a part of the developer carried on the developer carrier in the circumferential direction of the developer carrier, and the opening before the start of the rotation operation is performed. Determining whether or not only the developer carried on the area including all of the non-exposed portions that were not exposed from the toner image is formed on the image carrier and moved to the image carrier. An image forming apparatus. The image forming apparatus according to any one of claims 1 to 3,
The controller is
When performing the rotation operation, the developer carrier is rotated a plurality of times,
In only a part of the plurality of rotations of the developer carrier,
Of the developer carried on the developer carrying member, it is a partial region in the circumferential direction of the developer carrying member that has not been exposed from the opening before the start of the rotation operation. An image forming apparatus, wherein only the developer carried in the region including all of the above is formed on the image carrier to form a latent image and is moved to the image carrier. 5. The image forming apparatus according to claim 1, wherein:
The controller is
The rotation operation is executed at a plurality of types of timing,
Depending on what kind of timing the rotation is performed,
A developer carried in a partial region in the circumferential direction of the developer carrying member and including all unexposed portions that were not exposed from the opening before the start of the rotation operation; A developer that moves to the image carrier when the rotation operation is performed;
An image forming apparatus characterized by changing the amount of. The image forming apparatus according to any one of claims 1 to 5,
The controller is
According to the period during which the developer carrier has not been rotated immediately before the start of the rotation operation,
A developer carried in a partial region in the circumferential direction of the developer carrying member and including all unexposed portions that were not exposed from the opening before the start of the rotation operation; A developer that moves to the image carrier when the rotation operation is performed;
An image forming apparatus characterized by changing the amount of. The image forming apparatus according to claim 5 or 6, wherein:
The image forming apparatus, wherein the controller changes the amount of developer moved to the image carrier by changing a latent image carried on the image carrier. The image forming apparatus according to claim 5 or 6, wherein:
The controller is
When performing the rotation operation, the developer carrier is rotated a plurality of times,
Of the developer carried on the developer carrying member, it is a partial region in the circumferential direction of the developer carrying member that has not been exposed from the opening before the start of the rotation operation. Only the developer carried in the area including all of the above, a control for forming a latent image on the image carrier and moving it to the image carrier,
An image forming apparatus, wherein the amount of developer moved to the image carrier is changed by changing how many rotations of the plurality of rotations of the developer carrier are executed. The image forming apparatus according to claim 5 or 6, wherein:
The image forming apparatus, wherein the controller changes the amount of developer moved to the image carrier by changing a developing bias applied to the developer carrier. The image forming apparatus according to any one of claims 1 to 9,
The controller is
When the developer carried in the boundary area between the non-exposed part and the exposed part exposed from the opening before the start of the rotation operation is moved to the image carrier. An image forming apparatus characterized by gradually changing the amount of developer moved to the image carrier by changing a latent image carried on the image carrier. The image forming apparatus according to claim 1,
The developing device includes:
A layer thickness regulating member provided in the opening and configured to abut against the contacted portion of the developer carrying member with a width to regulate the layer thickness of the developer;
A seal member provided in the opening, for contacting the contacted portion of the developer carrying member with a width to prevent leakage of the developer,
The image forming apparatus according to claim 1, wherein the non-exposed portion includes the contacted portion and the contacted portion. An image carrier for carrying a latent image;
A container having an opening for accommodating the developer; and a rotatable developer carrying member provided to face the opening for carrying the developer, and carried by the developer carrying member. A developing device for developing the latent image carried on the image carrier by the developer,
A controller that executes a rotation operation of the developer carrier as a pre-preparation operation of the development in order to prevent occurrence of uneven density when developing the latent image by the developing device;
When performing the rotation operation,
Of the developer carried on the developer carrying member, it is a partial region in the circumferential direction of the developer carrying member that has not been exposed from the opening before the start of the rotation operation. Only the developer carried in the area including all of the
A controller that forms a latent image on the image carrier and moves it to the image carrier;
Have
The controller is
The rotation operation is executed at a plurality of types of timing,
In only a part of the plurality of types of timings,
Of the developer carried on the developer carrying member when the rotating operation is performed, it is a partial region in the circumferential direction of the developer carrying member, and the opening is opened before the execution of the rotating operation is started. Only the developer carried on the area including all of the non-exposed portions that were not exposed from the image forming member, forming a latent image on the image carrier and moving the image carrier to the image carrier,
The controller is
Based on a period during which the developer carrier has not been rotated immediately before the start of the rotation operation,
When the rotation operation is performed, a part of the developer carried on the developer carrier in the circumferential direction of the developer carrier, and the opening before the start of the rotation operation is performed. Determining whether or not to move only the developer carried on the area including all of the non-exposed portions that were not exposed from the image carrier to form a latent image on the image carrier,
The controller is
When performing the rotation operation, the developer carrier is rotated a plurality of times,
In only a part of the plurality of rotations of the developer carrier,
Of the developer carried on the developer carrying member, it is a partial region in the circumferential direction of the developer carrying member that has not been exposed from the opening before the start of the rotation operation. Only the developer carried in the region including all of the above, and forming a latent image on the image carrier to move to the image carrier,
The controller is
Depending on what kind of timing the rotation is performed,
A developer carried in a partial region in the circumferential direction of the developer carrying member and including all unexposed portions that were not exposed from the opening before the start of the rotation operation; A developer that moves to the image carrier when the rotation operation is performed;
Change the amount of
The controller is
According to the period during which the developer carrier has not been rotated immediately before the start of the rotation operation,
A developer carried in a partial region in the circumferential direction of the developer carrying member and including all unexposed portions that were not exposed from the opening before the start of the rotation operation; A developer that moves to the image carrier when the rotation operation is performed;
Change the amount of
The controller changes the amount of developer moved to the image carrier by changing the latent image carried on the image carrier,
The controller is
Of the developer carried on the developer carrying member, it is a partial region in the circumferential direction of the developer carrying member that has not been exposed from the opening before the start of the rotation operation. Only the developer carried in the area including all of the above, a control for forming a latent image on the image carrier and moving it to the image carrier,
By changing the number of rotations of a plurality of rotations of the developer carrier, the amount of developer moved to the image carrier is changed,
The controller is
When the developer carried in the boundary area between the non-exposed part and the exposed part exposed from the opening before the start of the rotation operation is moved to the image carrier. By changing the latent image carried on the image carrier, the amount of developer moved to the image carrier is gradually changed,
The developing device includes:
A layer thickness regulating member provided in the opening and configured to abut against the contacted portion of the developer carrying member with a width to regulate the layer thickness of the developer;
A seal member provided in the opening, for contacting the contacted portion of the developer carrying member with a width to prevent leakage of the developer,
The image forming apparatus according to claim 1, wherein the non-exposed portion includes the contacted portion and the contacted portion. Computer and
An image forming apparatus connectable to the computer, comprising: an image carrier for carrying a latent image; a housing portion having an opening for housing a developer; and the opening facing the opening. A developing device for developing a latent image carried on the image carrier by the developer carried on the developer carrier, and a developing device comprising a rotatable developer carrier for carrying the developer; A controller that executes a rotation operation of the developer carrier as a preliminary operation for the development in order to prevent occurrence of density unevenness when the latent image is developed by the apparatus, and executes the rotation operation; Of the developer carried on the developer carrying member in a partial region in the circumferential direction of the developer carrying member and not exposed from the opening before the start of the rotation operation. All the unexposed parts An image forming apparatus including a controller for moving non-region, the developer carried only, to form a latent image of the image bearing member to the image bearing member to a,
An image forming system comprising:

Images