JP2011215561A - Optical writing device and image forming apparatus - Google Patents

Abstract

In an optical writing apparatus provided with a shutter member, a light exit window can be opened and closed quickly.
An optical housing (25) has light exit windows (25y, 25c, 25m, 25k) for emitting a light beam generated by a light beam generating means, and an image is carried by the light beam transmitted through the light exit window and emitted. An optical writing device that performs optical writing on the body, is provided with a shutter plate 30 that can be moved between a position where the light exit window 25y and the like are opened and a position where it is shielded. The shutter sensor 7 detects the passage of a plurality of light shielding members 6 having different circumferential lengths provided at intervals around the worm wheel 64 and moved by a shutter driving mechanism having a shutter 66. By detecting the passage of a specific light shielding member among the plurality of light shielding members 6 in advance, the initial position of the shutter plate 30 is recognized and stored. The actual detection information of the light blocking member 6 by the position information and the shutter sensor 7, and controls the opening and closing of such light exit window 25y by the shutter plate 30.
[Selection] Figure 5

Description

  The present invention is mounted on an electrophotographic image forming apparatus such as a copying machine, a facsimile machine, a printer, a printing machine, a digital multi-function peripheral (MFP), etc., and scans and emits a light beam to expose a photoconductor. The present invention relates to a writing device (optical scanning device) and monochrome and color image forming apparatuses including the writing device.

  In the electrophotographic image forming apparatus as described above, the surface of a photoreceptor is generally charged, and then the surface is exposed according to image data by a light beam emitted from an optical writing device (optical scanning device). An electrostatic latent image is formed, the latent image is visualized with toner by a developing device, and the toner image is transferred onto a recording sheet to form an image. In such an image forming apparatus, when forming an electrostatic latent image by scanning a photosensitive member with a laser beam by an optical writing device, the optical element of the scanning optical system is placed in an optical housing, and scanning optical In order to maintain the optical characteristics of the system, the optical housing is sealed, and the optical system is isolated from the image forming system of the image forming apparatus.

In this case, the scanning laser light from the optical housing irradiates the photosensitive member through the exit window of the optical housing. Therefore, if the exit window is soiled by dust such as scattered toner, the electrostatic latent image is not correctly formed, adversely affects the formed image, and the image quality is degraded.
Therefore, conventionally, in order to prevent the exit window of the optical housing from being soiled, a cover member such as a shutter that can be opened and closed is provided outside the exit window, and the exit window is covered by the cover member at times other than during image formation. In order to prevent contamination by scattered toner or the like.

  For example, in the optical writing device described in Patent Document 1, a shutter member integrated with a shutter plate is slidably mounted within a predetermined range on a member formed with a light exit window provided with dustproof glass of an optical housing, and is normally used. At that time (during image formation), the shutter plate is in a position to open the light exit window, and the surface of the photoreceptor can be exposed by irradiating laser light through the light exit window. On the other hand, when not in use or during maintenance, the shutter member is moved to a position where the light exit window is closed (covered) to prevent dust such as scattered toner from adhering to the dust-proof glass.

In an optical writing apparatus having such a shutter member, a motor, a gear mechanism that transmits the rotation of the shutter member to the shutter plate, a cam, a link mechanism, and the like are used as means for moving the shutter member so as to open and close the light emission window. Has been.
However, the current position of the shutter plate must be accurately known in order to control the shutter member so as to always open and close the light exit window correctly according to the state of the image forming apparatus. Therefore, in the conventional apparatus, the position of the shutter member is defined every time the shutter control is performed. For this reason, there is a problem that the control process takes time and the opening and closing of the light exit window is delayed.

  The present invention has been made to solve such a conventional problem, and once the position of the shutter member is defined, it is not necessary to define the position of the shutter member in the subsequent shutter control. The purpose of the present invention is to shorten the control processing time and to quickly open and close the light exit window.

  The optical writing apparatus according to the present invention has a light exit window for emitting a light beam generated by the light beam generating means in an optical housing having a light beam generating means therein, and transmits the light through the light exit window. In an optical writing apparatus that performs optical writing on an image carrier with a light beam to be moved, the optical housing can be moved between a position where the light exit window is opened and a position where the light exit window is shielded with respect to the optical housing. A shutter driving means having a rotating cam member for moving the shutter member, and a plurality of light shielding members having different circumferential lengths provided at intervals along the periphery of the rotating cam member; A photosensor that detects the passage of each of the light shielding members when the rotating cam member rotates, and the photosensor is configured to detect a specific light shielding member of the plurality of light shielding members in advance. By detecting the excess, the initial position of the shutter member is recognized and stored, and thereafter, the shutter driving means is controlled based on the stored initial position information and the actual detection information of the light shielding member by the photosensor. Then, a shutter control means for controlling opening and closing of the light exit window by the shutter member is provided.

  In the optical writing device, the light beam generating means is means for generating a light beam for each of a plurality of image forming colors, and the optical housing is a light beam for each image forming color generated by the light beam generating means. Is an optical writing device that has a plurality of light exit windows that respectively emit light, and performs optical writing on the image carrier for each image forming color by each light beam that passes through and exits each light exit window. In this case, a plurality of the shutter members are provided so as to be movable between a position where each of the plurality of light exit windows of the optical housing is opened and a position where it is shielded. A shutter driving unit having a member, a plurality of light shielding members, and a photosensor; and the shutter control unit controls the shutter driving unit for each of the plurality of image forming colors. The above plurality of the shutter members may be adapted to control the opening and closing of each of the plurality of light exit window.

As a result, the shutter control means emits a light beam of an image forming color that is not used when light writing by a part of the image forming colors of the plurality of image forming colors is selected. The shutter member that opens and shields the light can be controlled so that the light exit window is always shielded.
In addition, when the monochrome light writing is selected, the shutter control means includes a shutter member that opens and blocks a light emission window that emits a light beam of an image forming color used only for color light writing. It is also possible to control so that the light exit window is always shielded.

  The shutter control unit is configured to determine whether the photosensor has previously detected the passage of the specific light shielding member among the plurality of light shielding members, and whether the photosensor has continuously detected the passage of the light shielding member. It is good to have a means to judge by whether it is more than preset time.

The shutter control means also determines the detection state of the photosensor when the shutter driving means is stopped when performing an opening operation or a shielding operation for shielding the shutter member to open the light exit window. If the determination result is not in a required state, means for repeatedly executing the opening operation or shielding operation until the determination result is in the required state or the determination result that is not in the required state reaches a predetermined number of times. Is desirable.
The shutter control means may further include means for notifying abnormality when the result of the determination is not in a required state even when the opening operation or the shielding operation is performed a predetermined number of times.
In these, it is possible to have means for allowing the user to designate and store the predetermined number of times.

  Further, when the shutter control means detects the initial position of the shutter member and stores it, if the passage of the specific light shielding member cannot be detected, the shutter control means passes the specific light shielding member. It is desirable to have means for repeatedly executing the process of recognizing and storing the initial position of the shutter member until a predetermined number of times that it is possible to detect or not be detected.

The shutter control means further notifies an abnormality when the passage of the specific light shielding member cannot be detected even after performing the process of recognizing and storing the initial position of the shutter member a predetermined number of times. It is good to have a means.
Also in these, it is possible to have means for storing the specified number of times by the user.

An image forming apparatus according to the present invention includes any one of the above optical writing devices. When the image forming apparatus includes an interlock unit that releases the interlock when either the openable door or the cover is opened and shuts off the power other than the power necessary for the control, The shutter control unit of the optical writing device does not perform an opening operation or a shielding operation for blocking the light emission window on the shutter member when the interlock unit releases the interlock. desirable.
The shutter control means of the optical writing device preferably includes means for initializing stored information of the initial position of the shutter member when the interlock means releases the interlock.

  An image forming apparatus including the above-described optical writing device capable of writing with a plurality of image forming colors and an automatic color selection unit, wherein the shutter control unit is configured to perform each of the plurality of the above-described items when performing color printing. When performing monochrome printing by controlling the plurality of light exit windows to be opened only during image formation by a shutter member, the light exit windows for emitting a light beam used for monochrome light writing are opened and shielded. The shutter member that controls the light emission window to be opened only at the time of image formation by the shutter member, and opens and blocks the light emission window that emits a light beam of an image forming color used only for color light writing. There is also provided an optical writing device for controlling the member so that its light exit window is always shielded.

  The optical writing device according to the present invention can perform shutter opening / closing control by a shutter member that can be moved between a position where the light exit window of the optical housing is opened and a position where it is shielded, in a shorter time than in the past. Further, only one sensor is required for detecting the position of the shutter member.

1 is a diagram showing a schematic configuration of an engine unit in an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing a part related to the present invention of a control system of the image forming apparatus shown in FIG. 1. It is a layout figure which simplifies and shows an operation panel.

1 is a schematic longitudinal sectional view showing an internal configuration of a first embodiment of an optical writing device according to the present invention. FIG. 6 is a perspective view showing the optical housing, the shutter plate, and the drive mechanism portion of the optical writing device separately. It is a perspective view which expands and shows typically the principal part of the shutter drive mechanism. It is a bottom view which shows typically the positional relationship of the sensor shielding member provided in the worm wheel in FIG. 6, and a cam roller.

It is a flowchart of the main routine of the write control with respect to 1st Example of the optical writing apparatus by this invention. It is a flowchart which shows the process at the time of jam generation | occurrence | production or a door opening. It is a flowchart which shows the process at the time of interlock cancellation | release. It is a flowchart which shows the process of the subroutine of shutter release operation | movement in FIG. It is a flowchart which shows the process of the subroutine of the shutter shielding operation | movement in FIG. FIG. 13 is a flowchart showing processing of a subroutine of initialization operations in FIGS. 11 and 12. FIG. 5 is a timing chart showing related operations of a polygon motor, a shutter motor, and a shutter sensor in the first embodiment of the optical writing device according to the present invention.

FIG. 5 is a perspective view including a shutter plate and a driving mechanism portion thereof in a second embodiment of the optical writing device according to the present invention. It is a flowchart of the main routine of the write control with respect to 2nd Example of the optical writing apparatus by this invention. FIG. 16 is a flowchart showing processing of a subroutine for shutter release operation in FIG. 15. FIG. 16 is a flowchart showing a subroutine of a shutter shielding operation in FIG. 15. FIG. 20 is a flowchart showing processing of a subroutine of initialization operations in FIGS. 18 and 19.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
[Example of image forming apparatus]
First, an embodiment of an image forming apparatus according to the present invention will be described with reference to FIGS. This image forming apparatus is equipped with an optical writing device according to the present invention.
FIG. 1 is a diagram showing a schematic configuration of an engine unit of a color printer as the image forming apparatus.

This color printer includes each mechanism for configuring an engine unit and a control unit (described later) that performs control related to printing (image formation) process processing by each mechanism.
As shown in FIG. 1, the engine unit is an image carrier for generating toner images of yellow (Y), cyan (C), magenta (M), and black (K) that are a plurality of image forming colors. Four photosensitive drums 1Y, 1C, 1M, and 1K are arranged at predetermined intervals along the intermediate transfer belt 11 that is an intermediate transfer member. The intermediate transfer belt 11 is always in contact with the black photosensitive drum 1K, and is in contact with the other color photosensitive drums 1Y, 1C, and 1M.

  Around each of the photosensitive drums 1Y, 1C, 1M, and 1K, a charger, a developing device, a cleaning device, and the like are provided in a case. 10Y, 10C, 10M, and 10K are configured. However, only the image forming process unit 10K for black illustrates them, but is not given a reference because of space. The other image forming process units 10Y, 10C, and 10M show only the photosensitive drums 1Y, 1C, and 1M, and the peripheral parts and case are not shown in the drawing, and detailed descriptions thereof are omitted.

  The intermediate transfer belt 11 is provided in the intermediate transfer unit 16 and is stretched by a drive roller 19 that also serves as a secondary transfer backup roller, a driven roller 20 that also serves as a cleaning backup roller, and a tension roller 21. 19 is driven endlessly counterclockwise in FIG. Primary transfer bias rollers 17Y, 17C, 17M, and 17K are disposed to face the respective 1Y, 1C, 1M, and 1K with the intermediate transfer belt 11 interposed therebetween. A cleaning device 18 is provided so as to face the driven roller 20.

Above the intermediate transfer belt 11, yellow (Y), cyan (C), magenta (M), and black (K) toners are supplied to the developing devices of the image forming process units 10Y, 10C, 10M, and 10K, respectively. Toner bottles 26Y, 26C, 26M, and 26K are disposed.
A secondary transfer roller 22 is provided so as to face the intermediate transfer belt 11 with the drive roller 19 interposed therebetween.

  An optical writing device (unit) 2 according to the present invention is disposed below the image forming process units 10Y, 10C, 10M, and 10K. The optical writing device 2 will be described later in more detail. Lasers that are light beams generated by light emission of four laser diodes (not shown) that are light sources for respective colors provided in the optical housing 25. The beam is reflected on each side of each of the two-stage polygon mirrors 12a and 12b, which are rotary polygon mirrors, to scan a predetermined angle range, and each laser beam is deflected by a folding mirror and formed on the upper surface of the optical housing 25. Each of the photosensitive drums 1Y, 1C, 1M, and 1K is exposed upward in the main scanning direction (direction perpendicular to the paper surface).

  Each light exit window of the optical housing 25 is sealed with dust-proof glass at 25y, 25c and the like. A shutter plate 30 as a shutter member is mounted on the surface of the optical housing 25 on which the light exit windows 25y and 25c are formed so as to be slidable within a predetermined range obliquely in the left-right direction in FIG. In this way, each light exit window 25y, 25c, etc. is in a position to be opened. At the time of non-image formation, maintenance, etc., the shutter plate 30 moves in the direction of the arrow and closes the light exit windows 25y, 25c and the like. In FIG. 1, the shutter driving means for moving the shutter plate 30 is not shown, and the shutter driving means will be described in detail later.

A paper feed cassette (also referred to as a paper feed tray) 13 that stores transfer paper as recording paper is disposed below the optical writing device 2, and paper feed that feeds and transports the transfer paper. A paper transport device including a roller 14, a transport roller pair 8, a registration roller pair 15 and the like is provided.
A fixing device 23 and a paper discharge roller pair 24 are provided on the downstream side in the paper conveyance direction (upward in FIG. 1), and a stack portion 27 is formed on the upper surface of the printer main body.

When a full color image is formed by this color printer, the surface of the photosensitive drums 1Y, 1C, 1M, and 1K that rotate clockwise in FIG. 1 is charged by the image forming process units 10Y, 10C, 10M, and 10K, respectively. The photosensitive drum 1Y, 1C, 1M, and 1K is exposed to static electricity corresponding to the image data of each color. An electrostatic latent image is formed. This is developed with each color toner of Y, C, M, and K by a developing device to form a toner image of each color.
The toner images of the respective colors are transferred onto the surface of the intermediate transfer belt 11 in the order of Y, C, M, and K at the primary transfer positions facing the primary transfer bias rollers 17Y, 17C, 17M, and 17K. A toner image is formed.

On the other hand, the uppermost transfer paper in the paper feed cassette 13 is fed by the paper feed roller 14, and the transfer paper is conveyed by the conveyance roller pair 8 until the leading end abuts against the registration roller pair 15 and waits. Then, the registration roller pair 15 is rotated at a predetermined timing to convey the transfer paper to the nip portion between the intermediate transfer belt 11 and the secondary transfer roller 22, where the full color toner image on the intermediate transfer belt 11 is transferred to the transfer paper. Batch transfer.
After the transfer paper is passed through the fixing device 23 and the toner image is fixed by heat and pressure, the transfer paper on which the full color image is printed is discharged to the stack section 27 by the discharge roller pair 24.

Here, the configuration of the portion related to the present invention in the control system of the image forming apparatus (color printer) of this embodiment will be described with reference to FIGS.
This image forming apparatus includes a controller unit 4 and an engine unit 5 as shown in the block diagram of FIG. The controller unit 4 includes a control unit 40, an operation unit 41 connected thereto, and a panel display unit 42. The control unit 40 receives image data from a host device (not shown), temporarily stores it, converts it into print data, and sequentially sends it to the engine unit 5. Various parameters and the like are changed or selected according to the input information, and control such as causing the panel display unit 42 to perform various displays including “abnormality” to be described later is also executed.

The control unit 40 includes a microcomputer including a CPU, a ROM, a RAM, and the like, and can also serve as an engine control unit that controls each unit of the engine unit 5.
FIG. 3 shows a simplified operation panel in which an operation unit 41 having a plurality of operation keys and a panel display unit 42 such as a liquid crystal display panel are laid out.

The engine unit 5 is provided with a write control unit 50, and an NVRAM control unit 51, a motor control unit 52, a sensor detection unit 53, and an interlock switch 54 connected thereto.
The writing control unit 50 controls the optical writing device 2 shown in FIG. 1 to execute control for performing main scanning exposure on the photosensitive drums 1Y, 1C, 1M, and 1K of each image forming process unit at a required timing. In addition to this, in cooperation with each part shown in the drawing, it also functions as shutter control means for controlling operations such as shutter opening and closing according to the present invention by software as will be described later. Although other parts relating to the control of the engine unit 5 are not shown, an engine control unit having a microcomputer for controlling the entire engine unit 5 may be provided, or the control unit 40 of the controller unit 4 may provide it. You may also serve.

  The NVRAM control unit 51 is a control unit that stores and reads information in and from the NVRAM that is a nonvolatile memory, and stores each time information, position information, and the like used for shutter opening / closing control described later in the NVRAM. The motor control unit 52 controls driving of a shutter motor for moving the shutter plate 30. The sensor detection unit 53 operates a shutter sensor that detects a sensor shielding member that rotates integrally with a cam roller, which will be described later, that moves the shutter plate 30.

  The interlock switch 54 is a switch for interlock means, and is provided individually or in combination with a cover or wall portion that can be opened and closed, such as a front cover of the main body of the image forming apparatus and left and right doors. When the switch is turned off and any one of the cover and the wall is opened, the interlock is released, and the switch for turning off the power supply of the apparatus except for the power supply necessary for the control is used. Since this is a safety switch conventionally provided in an image forming apparatus such as a general copying machine or printer, detailed description thereof is omitted.

[Structure of First Embodiment of Optical Writing Apparatus]
Next, the structure of the first embodiment of the optical writing apparatus according to the present invention will be described in detail. First, the structure of the optical writing apparatus will be described with reference to FIGS.
FIG. 4 is a schematic longitudinal sectional view showing the internal configuration of the optical writing device, which is similar to the optical writing device 2 shown in FIG. FIG. 5 is a perspective view showing the optical housing of the optical writing device, the shutter plate, and the driving mechanism portion thereof separately.

  The optical writing apparatus 2 shown in FIG. 4 is simply described with reference to FIG. 1, but two stages of polygon mirrors 12 a and 12 b rotated by the polygon motor 12 are installed at the center of the optical housing 25, The fθ lenses 28 are arranged in two stages on both sides, and are not shown because they are in the overlapping positions on the far side, but laser diodes (not shown) that are light sources for each color are two on the left and right sides. It is arranged one by one. These constitute light beam generating means.

  Then, a laser beam, which is a light beam generated by each light emission of each laser diode, is reflected on each side surface of the two-stage polygon mirrors 12a and 12b to scan a predetermined angle range, and each image color Each laser beam Ly, Lc, Lm, Lk is condensed through the fθ lens 28 and then reflected once or twice by the folding mirrors M1 to M8, respectively, and each light formed on the upper surface plate 25a of the optical housing 25. The light is emitted upward from the emission windows 25y, 25c, 25m, and 25k, and the surfaces of the photosensitive drums 1Y, 1C, 1M, and 1K for each image forming color are exposed in the main scanning direction (direction perpendicular to the paper surface).

The upper surface plate 25a is a light emission window forming member. As shown in FIG. 5, the light emission windows 25y, 25c, 25m, and 25k that are elongated along the main scanning direction are spaced apart in the longitudinal direction of the upper surface plate 25a. The protrusion 25b is formed so as to prevent the intrusion of dust so as to surround the periphery of each light emission window. Each of the light exit windows 25y, 25c, 25m, and 25k is sealed with a dust-proof glass so that toner powder and other dusts are prevented from entering the optical housing 25.
Engagement pieces 25d are provided so as to protrude from both sides of the upper surface plate 25a in the longitudinal direction so as to face each other, and the upper end portions thereof are bent inward.

  A shutter plate 30 as a shutter member is disposed on the upper surface plate 25a of the optical housing 25, and the arrows A and B in FIG. 5 are provided between the protrusions 25b and the engagement pieces 25d of the upper surface plate 25a. It is slidably held in the B direction. The shutter plate 30 is formed with an opening 31 larger than the light exit window and a closing portion 32 adjacent thereto at positions corresponding to the light exit windows 25y, 25c, 25m, and 25k. When the shutter plate 30 moves in the direction indicated by the arrow A, each opening 31 is positioned on each light exit window 25y, 25c, 25m, 25k (position where the light exit window is opened), and the shutter is opened. When the state moves and moves in the direction indicated by the arrow B, the shutters 32 are closed at the positions where the closed portions 32 overlap the light exit windows 25y, 25c, 25m, and 25k (positions that shield the light exit windows). .

On both side portions of the shutter plate 30, locked portions 33 bulging outward along the longitudinal direction are formed at positions corresponding to the engagement pieces 25 d of the upper surface plate 25 a, respectively. A slot 33a having a predetermined length that is sufficiently longer than the longitudinal dimension of the joining piece 25d is formed. By inserting the engagement pieces 25d of the upper surface plate 25a of the optical housing 25 into the slots 33a, the shutter plate 30 is supported so as to be slidable with a predetermined stroke in the directions indicated by arrows A and B. A spring (not shown) is engaged between 25d and the shutter plate 30 and is always urged in the direction indicated by the arrow B in FIG. 5 (the direction in which the shutter is closed).
Further, a cam follower 34 having an arcuate concave curved surface is provided at the center of the end of the shutter plate 30 in the arrow B direction.

  The shutter driving mechanism for moving the shutter plate 30 is shutter driving means, and as shown in FIGS. 4 and 5, the worm gear 62 fixed to the rotating shaft of the shutter motor 61 and the shaft 63 are engaged with the worm gear 62 and rotated about the shaft 63. A worm wheel 64 and a cam roller 66 rotatably supported by a pin 65 erected on an eccentric position on the worm wheel 64, and the cam roller 66 is formed on a concave curved surface formed on the cam follower 34 of the shutter plate 30. It is in contact. The worm wheel 64 and the cam roller 66 constitute a rotating cam member. The cam follower 34 and the cam roller 66 are always in contact with each other by the urging force of the shutter plate 30 in the direction indicated by the arrow B. As the shutter motor 61, a DC motor may be used.

  By driving the shutter motor 61, the worm wheel 64 is rotated by the rotation of the worm gear 62. As the worm wheel 64 rotates, the position of the cam roller 66 rotatably supported on the upper portion thereof changes. When the position of the cam roller 66 moves to the worm gear 62 side, the cam follower 34 follows the urging force of a spring (not shown), and the shutter plate 30 slides in the arrow B direction. Thereby, each closing part 32 comes to a position that shields each light exit window 25y, 25c, 25m, 25k, and closes the shutter.

  When the position of the cam roller 66 moves to the side opposite to the worm gear 62 (side closer to the optical housing 25), the cam follower 34 pushes back against the urging force, and the shutter plate 30 slides in the direction of arrow A. As a result, each opening 31 is positioned to open each light exit window 25y, 25c, 25m, 25k, and the shutter is opened.

  Further, in order to grasp the position of the rotating cam member, that is, the position of the cam roller 66 (corresponding to the position of the shutter plate 30), as clearly shown in FIGS. A plurality of thin plate-like sensor shielding members 6A, 6C, and 6E having different lengths in the direction are provided in a suspended manner, which are detected by using one shutter sensor 7, and the shielding state is monitored. As the shutter sensor 7, for example, a transmissive photosensor in which a light emitting element and a light receiving element are arranged to face each other is used. If the shielding members 6A, 6C, 6E are reflective members, a reflective photosensor may be used.

The positions A to E shown in FIG. 7 are used for control processing described below. The length of the sensor shielding members 6A, 6C, and 6E is the shortest for the sensor shielding member 6E, the sensor shielding member 6A is about twice that length, and the sensor shielding member 6C is about three times the sensor shielding member 6A. These are collectively referred to as a sensor shielding member 6.
6 is a perspective view schematically showing an enlarged main part of the shutter drive mechanism. FIG. 7 is a view showing the positions of the sensor shielding members 6A, 6C, 6E provided on the worm wheel 64 and the cam rollers 66. It is a bottom view which shows a relationship typically. The positions A, C, and E in FIG. 7 are positions at which the shutter sensor 7 is turned on by being shielded by the sensor shielding member 6A, the sensor shielding member 6C, and the sensor shielding member 6E, respectively. In these drawings, the worm wheel 64 is shown in a simplified disk shape.

[Write Control and Shutter Control Operation of First Embodiment]
Next, in the image forming apparatus according to the present invention, the writing executed by the writing control unit 50 of the engine unit 5 shown in FIG. 2 in cooperation with the other units with respect to the optical writing device 2 of the first embodiment described above. The control and shutter control operation (function of the shutter control means) will be described with reference to the flowcharts of FIGS.
First, referring to FIG. 8, the processing of the main routine of write control for the optical writing device 2 according to the present invention will be described. When the writing control unit 50 of the engine unit 5 shown in FIG. 2 is instructed to start printing from the control unit 40 of the controller unit 4, this writing control process is started and steps S1 to S5 are sequentially executed.

At the start of print control or print adjustment of the image forming apparatus shown in FIGS. 1 and 2, the process of FIG. 8 is started. First, in step S1, the polygon motor 12 is turned on and driven to prepare the writing device. Next, after the shutter opening operation is performed in step S2, the writing process is executed in step S3. After the end of the writing process, the polygon motor 12 is turned off and stopped in step S4, and the shutter shielding operation is performed in step S5, and the process ends.
The shutter opening operation subroutine will be described in detail with reference to FIG. 11, and the shutter shielding operation subroutine with reference to FIG.
The writing process is a process for forming an image on a recording sheet by an electrophotographic process as described with reference to FIG.

The write controller 50 monitors the jam sensor and the interlock switch 54 described above even during the processing of the main routine. Although a jam sensor has not been described, it is a known sensor that detects when a recording paper cannot be conveyed during a writing process and a jam occurs, and is provided at each important point of the conveyance path.
When a jam occurs or the door or cover to which the interlock is connected is opened (referred to as interlock release), it is detected by a signal from the jam sensor or the interlock switch, and the jam door opening shown in FIG. The time process is started, and a subroutine for shutter shielding operation (described with reference to FIG. 12) is executed.

When the interlock is released, the interlock release processing shown in FIG. 10 is started and the sensor position information stored in the NVRAM is initialized.
In this process, since the current does not flow to the shutter motor 61 due to the release of the interlock and the excitation is cut off, the shutter position cannot be grasped, and there is a difference between the held shutter position information and the actual shutter position. This is because it may occur. For this reason, when the interlock is released, the shutter position information held in the NVRAM is initialized to make the shutter position information unknown. Thereafter, an initialization operation is performed when the shutter is opened or closed after the interlock is not released, and the shutter position is redefined.

  The process of the subroutine for the shutter opening operation shown in FIG. 11 starts as soon as the polygon motor 12 is turned on. First, in step S11, it is checked whether or not the interlock is released. When either the openable / closable door or the cover is opened, the interlock is released. In this case, the process is terminated without performing the shutter opening operation. If the interlock is not released (all doors and covers are closed), the shutter motor 61 is turned on and the worm wheel 64 is rotated in step S12.

In step S13, it is checked whether or not the C position has been recognized. This is confirmation of whether or not the information on the C position shown in FIG. 7 is stored in the NVRAM. If the C position has been recognized, the process proceeds to step 15 without performing the initialization process in step S14.
If the C position has not been recognized (the C position information is not stored in the NVRAM), the process proceeds to step S15 after performing the initialization process (described with reference to FIG. 13) in step S14.

  In step S15, the detection signal of the shutter sensor 7 is checked and the detection of the A position by detecting the sensor shielding member 6A shown in FIG. 7 is awaited. When the A position is detected, the process proceeds to step S16 and the opening process delay time. After waiting (waiting) for Xt time, the shutter motor 61 is turned off in step S17. That is, the shutter motor 61 is stopped after the opening process delay time after the A position is detected.

  Then, after waiting (waiting) for a Wt time that is a reaction confirmation time in step S18, the detection state of the shutter sensor 7 is confirmed in step S19, and the shutter is shielded (the sensor shielding member 6 is interposed between the light emitting element and the light receiving element). If it is determined that the cam roller 66 has come to the worm gear 62 side and is in the shutter open position, the process ends.

  However, if it is determined that the shutter sensor 7 is exposed (the sensor shielding member 6 is not interposed between the light emitting element and the light receiving element: it is not in a required state), the process proceeds to step S20, and this process is performed a certain number of times or more. It is checked whether or not a step has been passed, and if it has not passed a certain number of times, the number of passes is counted, and it is determined whether or not the position C has been passed in step S21. If it has passed the position C, the processing from step S12 is repeated with the time obtained by subtracting the Xa time as the opening adjustment time from the Xt time as a new Xt time in step S22. On the other hand, if the position C has not been passed, the process from step S12 is repeated with the time obtained by adding the Xa time to the Xt time in step S23 as a new Xt time.

  Note that the Xa time can be arbitrarily specified by the user. When the user sets this time Xa from the operation unit 41 of the operation panel shown in FIG. 3, the time Xa is stored in the NVRAM by the NVRAM control unit 51 from the panel display unit 42 via the write control unit 50 of FIG. .

If it is determined that the detection result of the shutter sensor 7 in step S19 is exposed even after the shutter opening operation described above has been performed a certain number of times (the number of shutter opening operation retries) or more, hardware such as a shutter plate drive mechanism It is determined that there is an abnormality, and the process proceeds from step S20 to step S24 to notify the panel display unit 42 shown in FIG. 3 of the abnormality and display it. Note that the number of shutter opening operation retries can also be set by the user from the operation unit 41 of the operation panel shown in FIG.
In this way, the shutter plate 30 can be moved to a position where the light exit windows 25y, 25c, 25m, and 25k are reliably opened.

In order to end the writing process at the end of printing control or printing adjustment, the writing control unit shown in FIG. Simultaneously with the stop of the polygon motor 12, the processing of the subroutine for the shutter shielding operation shown in FIG. 12 is started.
In steps S31 to S35, the same processing as the shutter opening operation described in FIG. 11 is performed.
In step S35, the detection signal of the shutter sensor 7 is checked, and the detection of the C position by detecting the sensor shielding member 6C shown in FIG. 7 is awaited. If the C position is detected, the process proceeds to step S36 and the shielding process is performed. After waiting (waiting) for the delay time Yt, the shutter motor 61 is turned off in step S37. That is, the shutter motor 61 is stopped after the shielding processing delay time as a C position detection trigger.

  Then, after waiting (waiting) for Wt time, which is the reaction confirmation time, in step S38, the detection state of the shutter sensor 7 is confirmed in step S39 and exposed (the sensor shielding member 6 is between the light emitting element and the light receiving element). If it is determined that the cam roller 66 is on the side opposite to the worm gear 62 (side closer to the optical housing 25) and is in the shutter shielding position, the process ends. .

  However, if it is determined that the shutter sensor 7 is shielding (the sensor shielding member 6 is interposed between the light-emitting element and the light-receiving element: not in a required state), the process proceeds to step S40, and this process is performed a certain number of times or more. It is checked whether or not a step has been passed, and if it has not passed a certain number of times, the number of passes is counted and it is determined whether or not the position C has been passed in step S41. If it has passed the C position, the process from step S32 is repeated by setting the time obtained by subtracting the Ya time as the shielding adjustment time from the Yt time in step S42 as a new Yt time. On the other hand, if the position does not pass through the F position, the process from step S32 is repeated with the time obtained by adding the Ya time to the Yt time in step S43 as a new Yt time.

  Note that the Ya time can be arbitrarily designated by the user. When the user sets this time Ya from the operation unit 41 of the operation panel shown in FIG. 3, the time Ya is stored in the NVRAM by the NVRAM control unit 51 from the panel display unit 42 via the write control unit 50 of FIG. .

If it is determined that the detection result of the shutter sensor 7 in step S39 is shielded even if the shutter shielding operation described above is performed a predetermined number of times (the number of times of shutter shielding operation retry), hardware such as a shutter plate drive mechanism It is determined that there is an abnormality, and the process proceeds from step S40 to step S44 to notify the panel display unit 42 shown in FIG. 3 of the abnormality and display it. Note that the number of shutter shielding operation retries can also be set by the user from the operation unit 41 of the operation panel shown in FIG.
In this way, the shutter plate 30 can be moved to a position where the light exit windows 25y, 25c, 25m, and 25k are reliably shielded.

Next, the subroutine of the initialization operation executed in step S14 in FIG. 11 and step S34 in FIG. 13 will be described with reference to FIG.
Since the position of the cam roller 66 is unknown when the optical writing device is turned on, the initial position of the cam roller 66 is grasped and moved to the initial position by this initialization operation.

When the initialization shown in FIG. 13 is started, the shutter motor 61 is turned on in step S12 of FIG. 11 or step S32 of FIG. 12, so that the worm wheel 64, which is a gear provided with a cam roller 66 at an eccentric position. Is rotating.
Therefore, it waits for the shutter sensor 7 to be turned ON by being shielded by the sensor light shielding member 6 in step S51, and when it is turned ON, counting of the sensor ON time is started in step S52. Thereafter, counting of the sensor ON (shielding) time is continued until the shutter sensor 7 is exposed and turned OFF in step S53. When the shutter sensor 7 is turned OFF in step S53, the counting of the sensor ON time is ended in step S54. .

  In step S55, it is determined whether or not the counted time is 120 ms or longer. If the counted time is 120 ms or longer, the sensor light-shielding portion that shields the shutter sensor 7 during the counting is a specific light-shielding member. It is recognized that it is the sensor light shielding member 6C at the C position shown in FIG. This C position means that the cam roller 66 is positioned on the side close to the optical housing 25 as shown in FIGS. 4 and 5, that is, the shutter plate 30 opens the light emission windows 25y, 25c, 25m, and 25k. It is defined as the positional relationship. Therefore, in step S56, the C position is recognized from the count value at that time, the C position information is stored in NVRAM, and the process is terminated.

The time of 120 ms is a time corresponding to the time required for the sensor light-shielding member 6C, which is a specific light-shielding member, to pass through the shutter sensor 7 and is obtained in advance by calculation or actual measurement and stored in a memory such as NVRAM. .
Therefore, the time from when the shutter sensor 7 is shielded by the sensor shading member 6 and turned ON until the sensor shading member 6 passes and turns OFF is counted, and the sensor shading unit 6C passes through the shutter sensor 7. If it is more than the time required for this (120 ms in this example), it is recognized as the sensor light shielding member 6C, and the C position time and C position information are stored.

  However, in step S55, if the counted time is not 120 ms or more, it is determined in step S57 whether or not this step has been passed a certain number of times. The above process is repeated up to the number of times. If the time counted in step S55 is not 120 ms or more indicating the C position even if the above processing is repeated a certain number of times or more, it is recognized in step S57 that there is a hardware abnormality in the shutter plate drive mechanism, etc., and the process proceeds to step S58. Then, the panel display unit 42 shown in FIG. 3 is notified of the abnormality and displayed. The fixed number of times is the number of retries for the initialization operation, and can be set by the user.

FIG. 14 is a timing chart showing related operations of the polygon motor 12, the shutter motor 61, and the shutter sensor 7 under the control of the above-described embodiment.
By controlling the shutter of the optical writing device in this way, it is possible to realize faster control using a single sensor compared to the conventional control using a plurality of sensors.

According to the above-described embodiment, when the interlock means releases the interlock, the power supply other than the power supply necessary for the control is cut off, and the current to the shutter motor is cut off, the shutter opening operation and the shutter shielding operation are performed. Therefore, it is possible to prevent the shutter from being incompletely opened / closed when the interlock is released.
Also, when the interlock is released, the stored information on the initial position of the shutter member is initialized, so that the shutter is controlled in a state where the stored initial position information and the actual initial position of the shutter member are inconsistent. Can not be.

  If a desired result is not obtained even if the shutter opening operation, the shutter shielding operation, or the initial position detection operation of the shutter member is performed a predetermined number of times, an abnormality is notified, and this is displayed on the display panel to notify the user. it can. Since the user can arbitrarily set the fixed number of times (number of tries), the waiting time can be made to correspond to the user's desire.

[Second Embodiment of Optical Writing Device]
Next, a second embodiment of the optical writing device according to the present invention will be described. FIG. 15 is a perspective view showing the appearance of the optical writing apparatus, and the same reference numerals are given to the same parts as those in FIGS.
In the optical writing device 2 'of the second embodiment, the configuration on the optical housing 25 side is the same as the configuration on the optical housing 25 side of the optical writing device 2 of the first embodiment described with reference to FIGS. is there. That is, the light beams for the respective image forming colors are emitted from the four light emission windows 25y, 25c, 25m, and 25k elongated in the main scanning direction provided on the upper surface plate 25a of the optical housing 25, and are shown in FIG. Optical writing is performed on the image carriers 1Y, 1C, 1M, and 1K for each image forming color.

On the upper surface plate 25a of the optical housing 25, four shutter plates (shutter members) having different lengths for individually opening and closing the light exit windows 25y, 25c, 25m, and 25k.
30y, 30c, 30m, and 30k are sequentially overlapped so as to be slidable with a predetermined stroke in the directions indicated by arrows A and B. Between the upper surface plate 25a and the shutter plates 30y, 30c, 30m, and 30k, there is provided means for guiding movement in the directions indicated by arrows A and B, such as the engagement piece 25d and the slit 33 shown in FIG. However, the illustration is omitted.

  Each of the shutter plates 30y, 30c, 30m, and 30k has an opening 31 that is larger than each of the light exit windows at positions corresponding to the light exit windows 25y, 25c, 25m, and 25k, and a closing portion 32 adjacent thereto. And are formed respectively. When the shutter plates 30y, 30c, 30m, and 30k move in the direction indicated by the arrow A, the positions of the openings 31 on the light exit windows 25y, 25c, 25m, and 25k (positions that open the light exit windows). ) And the shutter is opened, and when it moves in the direction of arrow B, the position where each closing portion 32 overlaps each light exit window 25y, 25c, 25m, 25k (position where the light exit window is shielded). Thus, the shutter is closed.

Although not visible in FIG. 15, openings that always open the light exit windows 25 c, 25 m, and 25 k are provided in portions where other shutter plates overlap the shutter plates 30 y, 30 c, and 30 m.
Further, tension springs 35 are respectively engaged between both end portions in the width direction of the shutter plates 30y, 30c, 30m, and 30k and the upper surface plate 25a, so that the shutter plates 30y, 30c, 30m, and 30k are always indicated by arrows. It is energized in the B direction (direction in which the shutter is closed).

Further, cam followers 34y, 34c, 34m, and 34k each having an arcuate concave curved surface formed at the end in the arrow B direction of each of the shutter plates 30y, 30c, 30m, and 30k are sequentially extended in the width direction. ing.
Then, shutter driving means 70y, 70c, 70m, and 70k for driving the shutter plates 30y, 30c, 30m, and 30k are provided for each image forming color.

  Each of the shutter driving means 70y, 70c, 70m, and 70k includes a shutter motor 61, a pinion gear 72 fixed to the rotation shaft thereof, a spur gear 74 that meshes with the spur gear 74 and rotates about the shaft 73, and the spur gear 74. The cam roller 66 is rotatably supported by a pin erected at the upper eccentric position. The cam rollers 66 are in contact with the concave curved surfaces formed on the cam followers 34y, 34c, 34m, and 34k of the shutter plates 30y, 30c, 30m, and 30k, respectively. Since the shutter driving units 70y, 70c, 70m, and 70k have the same configuration, some symbols are omitted in FIG. 15 due to space.

  The spur gear 74 and the cam roller 66 constitute a rotating cam member. The cam followers 34y, 34c, 34m, 34k and the cam rollers 66 are always in contact with each other by the urging force of the shutter plates 30y, 30c, 30m, 30k in the arrow B direction. As the shutter motor 61, a DC motor may be used.

  In each of the shutter driving means 70y, 70c, 70m, and 70k, the spur gear 74 is rotated by the rotation of the pinion gear 72 by driving the shutter motor 61. The rotation of the spur gear 74 changes the position of the cam roller 66 that is rotatably supported on the upper portion thereof. When the position of the cam roller 66 moves to the pinion gear 72 side, the cam followers 34y, 34c, 34m, and 34k move following the urging force of the tension spring 35, and the shutter plates 30y, 30c, 30m, and 30k slide in the arrow B direction. Moving. Thereby, each closing part 32 comes to a position that shields each light exit window 25y, 25c, 25m, 25k, and closes the shutter.

  When the position of the cam roller 66 moves to the side opposite to the pinion gear 72 (side closer to the optical housing 25), the cam followers 34y, 34c, 34m, 34k are pushed back against the biasing force by the cam roller 66, and the shutter plates 30y, 30c, 30m and 30k slide in the direction of arrow A. As a result, each opening 31 is positioned to open each light exit window 25y, 25c, 25m, 25k, and the shutter is opened.

  Further, in order to grasp the position of the rotating cam member, that is, the position of the cam roller 66 (corresponding to the positions of the shutter plates 30y, 30c, 30m, and 30k), each of them is replaced with the worm wheel 64 shown in FIGS. A plurality of thin plate-shaped sensor shielding members 6A, 6C, and 6E (collectively referred to as sensor shielding members 6) having different circumferential lengths are provided along the outer periphery of the spur gear 74, one of which is provided. The shutter sensor 7 is used for detection and the shielding situation is monitored. These sensor shielding members 6A, 6C, 6E and the shutter sensor 7 are the same as those in the first embodiment described above, but are provided for the spur gears 74 of the shutter driving means 70y, 70c, 70m, 70k.

In this embodiment, the shutter driving means 70y, 70c, 70m, and 70k are controlled for each of a plurality of (four colors in this example) image forming colors, and a plurality of shutter members 30y, 30c, and 30m that are shutter members. , 30k can individually control the opening and closing of the plurality of light exit windows 25y, 25c, 25m, 25k.
If space is allowed, instead of the pinion gear 72 and the spur gear 74 of each shutter driving means 70y, 70c, 70m, 70k in FIG. 15, a worm gear and a worm wheel that meshes with and rotates in the same manner as in the first embodiment. Use it. In that case, each shutter motor 61 becomes sideways.

Write control and shutter control operation (function of shutter control means) executed by the write control unit 50 of the engine unit 5 shown in FIG. 2 in cooperation with other units will be described with reference to the flowcharts of FIGS.
FIG. 16 shows the processing of the main routine of the writing control for the optical writing device 2 ′ of the second embodiment, which is processing in place of the processing of the main routine explained with reference to FIG. 8 in the first embodiment.

When the write control unit 50 of the engine unit 5 shown in FIG. 2 is instructed to start printing from the control unit 40 of the controller unit 4, the write control process shown in FIG. 16 is started and steps S61 to S74 are sequentially executed. To do.
When this processing is started, first, after the polygon motor 12 is turned on in step S61, the write control unit 50 checks the print color mode obtained in step S62 before driving the shutter motor 61 shown in FIG. To do. In the case of printing by automatic color selection, the automatically selected print color mode is confirmed.

  If it is full-color mode printing, the shutters for all the colors of YCMK are set as opening targets in step S63, and the shutter opening operation for all the light exit windows 25y, 25c, 25m, and 25k is executed in step S65.

If full-color mode printing is not performed in step S62, that is, printing that does not use all colors, such as single-color (monochrome) mode printing or two-color mode printing, the shutter corresponding to the requested image forming color in step S64. Is set as the release target. In step S65, a shutter opening operation is performed on the shutter set as the opening target (for example, only the shutter that opens the light exit window 25k). Therefore, a shutter that is not set as an object to be opened (a shutter plate that shields a light exit window that emits a laser beam of an unused image color that is not used) is not opened and remains in a shielded state.
The subroutine for the shutter opening operation will be described later with reference to FIG.

When the shutter release operation is completed, the writing process is executed in step S66. In step S67, it is determined whether or not the process is the final process. If not, the next requested print color mode is confirmed in step S68. It is determined whether or not the image forming colors in the next print request and the next print request are different.
If the image forming colors are the same, the process returns to step S66 while the shutter state is kept as it is, and the processes from the writing process are repeated. If the image forming colors are different, a shutter other than the image forming color requested in step S69 is set as a shielding object, and a shutter of the newly requested image forming color is set as an opening object in step S70.

Then, after performing the shutter shielding operation for the shutter set as the shielding target in step S71 and the shutter opening operation for the shutter set as the opening target in step S72, respectively, the process returns to step S66 to perform the processing from the writing process. repeat.
If it is the final process in step S67, the process proceeds to step S73, the polygon motor 12 is turned off, the shutter shielding operation is performed for the shutter that is opened in step S74, and this writing control process is ended.
The shutter shielding subroutine will also be described later with reference to FIG.

  In the shutter opening operation subroutine, the processing shown in FIG. 17 is performed in parallel with each shutter driving unit (all or any of 70y, 70c, 70m, and 70k) related to the shutter set as the opening target. Run sequentially. The processing shown in FIG. 17 is the same as the shutter opening operation subroutine shown in FIG. 11 except step S24B. Therefore, the same step numbers as those in FIG.

  If the shutter sensor 7 is exposed (OFF) in step S19 and has passed the predetermined number of times in step S20, the corresponding shutter malfunction (hardware such as the shutter plate to open the light exit window and its shutter driving means) 3), the process proceeds to step S24B to notify the panel display unit 42 shown in FIG. 3 of the corresponding shutter abnormality and display it.

  In the shutter shielding subroutine, the processing shown in FIG. 18 is performed in parallel with each shutter driving means (all or any of 70y, 70c, 70m, and 70k) related to the shutter set as the shielding target. Run sequentially. The process shown in FIG. 18 is the same as the shutter shielding subroutine shown in FIG. 12 except for step S24B. Therefore, the same step numbers as those in FIG.

  If the shutter sensor 7 is in the shielding state (ON) in step S39 and has passed step S40 a certain number of times, the corresponding shutter abnormality (the shutter plate that should shield the light exit window and the hardware such as the shutter driving means) The process proceeds to step S44B, and the corresponding shutter abnormality is notified to the panel display unit 42 shown in FIG. 3 and displayed.

FIG. 19 shows the subroutine of the initialization operation in step S14 in FIG. 17 and step S34 in FIG. Since this flowchart is also the same except for the initialization operation subroutine shown in FIG. 13 and step S58B, each step is given the same step number as in FIG. 13, and the description thereof is omitted.
In this initializing operation, if the ON time of step S55 does not become 120 ms or more exceeds a certain number of times, it is determined that there is a hardware error in the shutter opening / closing mechanism, etc., and the process proceeds to step S58B. The panel display unit 42 is notified and displayed.

  Note that the user can arbitrarily set whether or not to perform such individual control for each image forming color of the shutter. When the user sets the execution failure, the shutter control is executed simultaneously for all the colors regardless of whether the full color mode is set. Furthermore, when each hardware abnormality described above occurs, the writing control unit 50 shown in FIG. 2 notifies the panel display unit 42 in FIG. 3 and displays the color information of the shutter member in which the hardware abnormality has occurred. Let

  According to this embodiment, the writing control unit 50, which is a shutter control means, controls the shutter drive means 70y, 70c, 70m, 70k for each of a plurality of image forming colors, and a shutter which is a plurality of shutter members. The plates 30y, 30c, 30m, and 30k can control the opening and closing of the plurality of light exit windows 25c, 25m, and 25k.

When light writing with a part of the plurality of image colors (monochrome mode, single color mode, two-color mode, etc.) is selected, a light beam with an unused image color is emitted. The shutter member that opens and shields the light emission windows to be controlled can be controlled so that the light emission windows are always shielded so that scattered toner and dust do not adhere to the light emission windows.
When monochrome optical writing is selected, a shutter member that opens and shields a light exit window that emits a light beam of an image forming color that is used only for color optical writing is always shielded. It can also be controlled.

In monochrome mode or monochrome mode printing, the user can specify whether to open only the shutter member corresponding to the image forming color used in those modes from the operation unit 41 shown in FIGS. .
The operation unit shown in FIGS. 2 and 3 determines whether or not to close the shutter member that opens and closes the light emission window of the image forming color that is not used in printing that uses a plurality of colors but not all colors, such as color printing. 41 can be specified.
In such a shutter control operation for each image forming color, when the shutter control fails, if it is displayed as an abnormality relating to the shutter of the corresponding image forming color, the user can determine which color the shutter control has occurred abnormally. It is easy to know.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope defined by the claims, and it is needless to say that it is not necessary to have all the configurations described in the embodiments. For example, the rotating cam member of the shutter driving means is not limited to the worm wheel or the spur gear and the cam roller described in the above embodiment, and various rotating cam members can be used. Although an example in which the image forming colors are four colors has been described, the present invention is not limited to this, and the present invention can be implemented even in the case of two colors, three colors, or five colors or more.

  INDUSTRIAL APPLICABILITY The present invention can be used for electrophotographic monochrome and color image forming apparatuses such as copying machines, facsimile machines, printers, printing machines, digital multi-function peripherals (MFPs), etc., and opens and shields light exit windows for emitting light beams. It is effective when applied to an optical writing device provided with a shutter member.

1Y, 1C, 1M, 1K: photosensitive drum (image carrier)
2, 2 ': Optical writing device 4: Controller part 5: Engine part
6, 6A, 6C, 6E: Sensor shielding member 7: Shutter sensor
8: Pair of conveyance rollers 10Y, 10C, 10M, 10K: Image forming process section
11: Intermediate transfer belt 12a, 12b: Polygon mirror 13: Paper feed cassette 14: Paper feed roller 15: Registration roller pair 16: Intermediate transfer unit
17Y, 17C, 17M, 17K: primary transfer bias roller
18: Cleaning device 19: Drive roller (secondary transfer backup roller)

20: driven roller (cleaning backup roller) 21: tension roller 22: secondary transfer roller 23: fixing device 24: discharge roller pair
25: Optical housing 25y, 25c, 25m, 25k: Light exit window 25a: Top plate 25b: Projection 25d: Engagement pieces 26Y, 26C, 26M, 26K: Toner bottle
27: Stack portion 28: fθ lens
30, 30y, 30c, 30m, 30k: shutter plate (shutter member)
31: Opening portion 32: Closing portion 33: Locked portion 33a: Slots 34, 34y, 34c, 34m, 34k: Cam follower 34a: Concave surface 35: Tension spring

40: Control unit 41: Operation unit 42: Panel display unit 50: Write control unit 51: NVRAM control unit 52: Motor control unit 52
53: Sensor detection unit, 54: Interlock switch 61: Shutter motor 62: Worm gear 63: Shaft
64: Worm wheel 65: Pin 66: Cam roller 70y, 70c, 70m, 70k: Shutter driving means 72: Pinion gear 73: Spur gear

JP 2007-245480 A

Claims (15)

An optical housing having a light beam generating means inside has a light exit window for emitting the light beam generated by the light beam generating means, and the light beam transmitted through the light exit window is emitted onto the image carrier. In an optical writing device that performs optical writing,
With respect to the optical housing, provided with a shutter member movable to a position for opening and shielding the light exit window,
Shutter driving means having a rotating cam member for moving the shutter member;
A plurality of light shielding members having different circumferential lengths provided at intervals along the periphery of the rotating cam member;
A photosensor that detects the passage of each light shielding member when the rotating cam member rotates;
The photo sensor detects the initial position of the shutter member by detecting the passage of a specific light shielding member among the plurality of light shielding members in advance, and thereafter stores the information on the stored initial position and the photo. An optical writing apparatus comprising: shutter control means for controlling the shutter driving means based on actual detection information of the light shielding member by a sensor to control opening and closing of the light emission window by the shutter member. . The optical writing device according to claim 1,
The light beam generating means is a means for generating a light beam for each of the plurality of image forming colors, and the optical housing emits a plurality of light beams for each of the image forming colors generated by the light beam generating means. An optical writing device that has an emission window and performs optical writing on an image carrier for each image forming color by each light beam that is transmitted through and emitted from each light emission window,
A plurality of the shutter members are provided so as to be movable between a position where each of the plurality of light exit windows of the optical housing is opened and a position where it is shielded.
For each of the plurality of shutter members, a shutter driving unit having the rotating cam member, the plurality of light shielding members, and the photosensor are provided, respectively.
The shutter control unit controls the shutter driving unit for each of the plurality of image forming colors, and controls the opening and closing of the plurality of light emission windows by the plurality of shutter members. Writing device.   The shutter control means opens the light emission window for emitting a light beam of an unused image forming color when light writing with a part of the plurality of image forming colors is selected. 3. The optical writing device according to claim 2, wherein the shutter member to be shielded is controlled so as to always shield the light exit window.   When the monochrome light writing is selected, the shutter control means opens and blocks the light emitting window that emits a light beam of an image forming color that is used only for color light writing. The optical writing device according to claim 2, wherein the optical writing window is controlled so as to be always shielded.   The shutter control unit is configured to determine whether the photosensor has previously detected the passage of the specific light shielding member among the plurality of light shielding members, and whether the photosensor has continuously detected the passage of the light shielding member. 5. The optical writing device according to claim 1, further comprising means for determining whether or not a predetermined time is exceeded.   The shutter control unit determines a detection state of the photosensor when the shutter driving unit is stopped when the shutter member performs an opening operation for opening the light emission window or a shielding operation for blocking the light emission window. If the result is not in the required state, it has means for repeatedly executing the opening operation or the shielding operation until the predetermined state is reached or the determination result that is not in the required state reaches a predetermined number of times. The optical writing device according to claim 1, wherein:   The shutter control means includes means for notifying an abnormality when the result of the determination is not a required state even when the opening operation or the shielding operation is performed a predetermined number of times. Item 7. The optical writing device according to Item 6.   8. The optical writing apparatus according to claim 6, further comprising means for storing the specified number of times by a user.   The shutter control means detects the passage of the specific light shielding member when the passage of the specific light shielding member cannot be detected during the process of recognizing and storing the initial position of the shutter member. 6. The apparatus according to claim 1, further comprising means for repeatedly executing a process of recognizing and storing the initial position of the shutter member until a predetermined number of times that it can be detected or cannot be detected. The optical writing device according to Item.   The shutter control means is means for notifying abnormality when the passage of the specific light-shielding member is not detected even after performing processing for recognizing and storing the initial position of the shutter member a predetermined number of times. The optical writing device according to claim 9, further comprising:   11. The optical writing apparatus according to claim 9, further comprising means for storing the specified number of times by a user.   An image forming apparatus comprising the optical writing device according to claim 1. The image forming apparatus according to claim 12, further comprising an interlock unit that releases the interlock when any of the openable door and the cover is opened, and shuts off a power source other than the power source necessary for the control.
The shutter control means of the optical writing device does not perform an opening operation or a shielding operation for shielding the shutter member to open the light exit window when the interlock means releases the interlock. An image forming apparatus.   14. The shutter control means of the optical writing device has means for initializing stored information of an initial position of the shutter member when the interlock means releases the interlock. Image forming apparatus. An image forming apparatus comprising the optical writing device according to claim 2 and automatic color selection means,
When performing color printing, the shutter control means controls the plurality of light exit windows to be opened only during image formation by the plurality of shutter members, and when performing monochrome printing, the shutter control means Image formation that is used only for color light writing by controlling the light emission window to be opened only during image formation by the shutter member that opens and shields the light emission window that emits the light beam used for light writing. An optical writing apparatus, wherein the shutter member that opens and shields the light exit window that emits a color light beam is controlled so as to always shield each light exit window.

Images