JP2006018150A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To clean an image carrier without lowering productivity in image formation. <P>SOLUTION: Respective four-line state developer images 122 and 124 are formed on both sides in a main scanning direction of a transferable image area 120 where the developer image to be transferred to a recording medium is formed on the image carrier 44. A developer image in accordance with image data is formed in the transferable image area 120, and the developer image formed in the transferable image area 120 is transferred to the recording medium. The developer images 122 and 124 are the line state developer images whose width in a subscanning direction is from one dot to ten dots, for example. The developer images 122 and 124 are removed by a cleaning blade 62 without being transferred to the recording medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a printer, a copying machine, or a facsimile.

2. Description of the Related Art An image forming apparatus is known in which a latent image written on a photoconductor is developed with toner, the developed image is transferred to a recording medium, and then toner remaining on the photoconductor is cleaned with a cleaning blade.
In this type of image forming apparatus, if images are continuously formed on a recording medium having a narrow width relative to an image-forming area on the photoreceptor, toner is not supplied to an area outside the recording medium width on the photoreceptor. In addition, the frictional force between the photoconductor and the cleaning blade may be increased to damage the cleaning blade, or the area outside the recording medium width on the photoconductor may be insufficiently cleaned. Therefore, when the width of the recording medium passed this time is smaller than the width of the recording medium passed last time, a black belt as a toner image is formed in a portion corresponding to the difference between the previous recording medium width and the current recording medium width, It is known to form an image by supplying toner to the cleaning blade to prevent an increase in frictional force between the photosensitive member and the cleaning blade (see Patent Document 1). Further, when the width of the recording medium in the supply direction is narrower than a predetermined determination reference width, at least a region that does not face the recording medium in the transferable region of the intermediate transfer belt and from a side end in the recording medium supply direction It is known to form a belt-like toner image on the outside and supply the toner to the cleaning blade (see Patent Document 2).

JP-A-7-20726 JP 2001-175090 A

  However, in the above conventional example, there is a problem that productivity of image formation decreases because a toner image is formed in an area between recording media and the toner is supplied to the cleaning blade.

  An object of the present invention is to provide an image forming apparatus capable of cleaning an image carrier without reducing image forming productivity.

  In order to achieve the above object, the first feature of the present invention is that an image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and the optical writing means Developing means for developing a latent image with a developer to form a developer image, transfer means for transferring the developer image formed on the image carrier, cleaning means for cleaning the remaining developer, and recording medium And an image forming apparatus having a control means for controlling the optical writing means so as to form a cleaning latent image outside the width in the main scanning direction of the recording medium. That is, since the cleaning latent image is not formed in the area between the recording media of the image carrier, a process of cleaning the area between the recording media of the image carrier is not necessary. Therefore, it is possible to supply the developer to the cleaning means without deteriorating the image forming productivity and clean the image carrier. In addition, when a cleaning latent image is formed in the area between the recording mediums of the image carrier, the site where the cleaning unit functions when cleaning the remaining developer is located in the main scanning direction of the recording medium. Since it changes outside the scanning direction, that is, when it functions within the main scanning direction of the recording medium, there is almost no remaining developer outside the main scanning direction of the recording medium, and the main scanning of the recording medium. When functioning outside the direction, there is almost no remaining developer in the main scanning direction of the recording medium, and the load received by the cleaning unit in the longitudinal direction of the cleaning unit is partially and alternately changed. The tip of the cleaning means is likely to be damaged, but according to the first feature of the present invention, the developer is present within the width of the recording medium in the sub-scanning direction and outside the width of the recording medium in the main scanning direction. Image carrier recording In the area between the media, there is almost no remaining developer, so that damage to the tip of the cleaning means can be reduced.

  The second feature of the present invention is that an image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and a latent image written by the optical writing means are developed by a developer. A developing unit that forms a developer image by developing the toner, a transfer unit that transfers the developer image formed on the image carrier, a cleaning unit that cleans the remaining developer, and the optical writing unit. A first scanning light control means for controlling the optical writing means to generate scanning light corresponding to an image signal, and scanning light for writing a cleaning latent image. The image forming apparatus includes a second scanning light control unit that controls the optical writing unit. Therefore, since the scanning light for writing the cleaning latent image can be generated without complicating the configuration and processing of the first scanning light control means, the developer can be used without reducing the image forming productivity. The image carrier can be cleaned by supplying the cleaning means.

  Preferably, the control means controls the optical writing means so as to form a cleaning latent image having a width in the sub-scanning direction of 10 dots or less. Therefore, the image carrier can be cleaned while suppressing the amount of developer supplied to the cleaning means.

  Preferably, the control means controls the cleaning latent image according to the width of the recording medium in the main scanning direction. That is, since the developer is supplied to the cleaning unit by the cleaning latent image corresponding to the width in the main scanning direction of the recording medium, the developer can be effectively supplied to the cleaning unit.

  Preferably, the image forming apparatus further includes a setting receiving unit that receives a setting of the number of times the transfer unit continuously transfers the developer image, and the control unit performs cleaning based on the setting received by the setting receiving unit. The optical writing means is controlled to change the frequency of forming the latent image for use. That is, since the cleaning latent image is formed based on the number of times the developer image is continuously transferred, the developer can be effectively supplied to the cleaning unit.

  The third feature of the present invention is that an image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and a latent image written by the optical writing means are developed by a developer. A developing unit that forms a developer image by developing the toner, a transfer unit that transfers the developer image formed on the image carrier, a cleaning unit that cleans the remaining developer, and the optical writing unit. And an image forming apparatus that controls the optical writing unit to change the frequency of forming a cleaning latent image in accordance with the number of rotations of the image carrier. Accordingly, even when an image is formed on a recording medium having a different width in the sub-scanning direction, the developer can be effectively supplied to the cleaning unit.

  The fourth feature of the present invention is that an image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and a latent image written by the optical writing means are developed by a developer. A developing unit that forms a developer image by developing the toner, a transfer unit that transfers the developer image formed on the image carrier, a cleaning unit that cleans the remaining developer, and the optical writing unit. An image forming unit configured to control the optical writing unit to change a width of the cleaning latent image in the sub-scanning direction according to the resolution of the developer image formed by the developing unit. In the device. That is, it is possible to prevent the amount of the developer supplied to the cleaning unit from being excessive or insufficient depending on the resolution of the developer image.

  The fifth feature of the present invention is that an image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and a latent image written by the optical writing means are developed by a developer. A developing unit that forms a developer image by developing the toner, a transfer unit that transfers the developer image formed on the image carrier, a cleaning unit that cleans the remaining developer, and the optical writing unit. And an image forming apparatus that controls the optical writing unit so as to change a frequency of forming a cleaning latent image according to a transfer speed of the transfer unit. That is, even if the stress on the cleaning unit due to the frictional force between the image carrier and the cleaning unit changes according to the transfer speed of the transfer unit, the developer can be effectively supplied to the cleaning unit.

  Preferably, the control unit further includes an environmental condition detection unit that detects an environmental condition, and the control unit changes the frequency of forming a cleaning latent image according to a detection result of the environmental condition detection unit. Controls the optical writing means. Therefore, even if the environmental conditions change, the developer can be effectively supplied to the cleaning means.

  Preferably, the transfer means has a transfer roll for transferring a developer image formed on the image carrier by being pressed against the image carrier, and the environmental condition detection means is the transfer roll. An environmental condition is detected based on a change in resistance value. That is, the developer can be effectively supplied to the cleaning unit according to the environmental conditions without providing a member that detects only the environmental conditions.

  Preferably, the apparatus further includes an environmental condition detecting unit that detects an environmental condition, and a setting receiving unit that receives a setting of the number of times that the transfer unit continuously transfers the developer image. When it is detected that the temperature and humidity are high, and the setting receiving unit receives a plurality of settings, the control unit controls the cleaning latent image according to the width of the recording medium in the main scanning direction. In other words, the developer is supplied to the cleaning unit when the cleaning by the cleaning unit tends to be insufficient, so that the developer can be effectively supplied to the cleaning unit.

  According to the present invention, the image carrier can be cleaned without reducing the productivity of image formation.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, an image forming unit 14 is mounted in the image forming apparatus main body 12, and a discharge unit 16, which will be described later, is provided above the image forming apparatus main body 12. In addition, for example, two-stage sheet feeding units 18 a and 18 b are disposed below the image forming apparatus main body 12. Further, below the image forming apparatus main body 12, two-stage sheet feeding units 18c and 18d that are detachably mounted as options are disposed. The image forming apparatus 10 may include a personal computer (PC) and other terminal devices connected via a network as a system.

  Each of the paper feed units 18a to 18d includes a paper feed unit main body 20 and a paper feed cassette 22 in which a recording medium is stored. The paper feed cassette 22 is slidably attached to the paper feed unit main body 20 and is pulled out in the front direction (right direction in FIG. 1). In addition, a paper feed roll 24 is disposed in the upper part near the rear end of the paper feed cassette 22, and a retard roll 26 and a nudger roll 28 are disposed in front of the paper feed roll 24. Further, the optional paper feed units 18c and 18d are provided with a pair of feed rolls 30 respectively.

  The conveyance path 32 is a recording medium path from the feed roll 30 to the discharge port 34 of the lowermost sheet feeding unit 18d. This conveyance path 32 is near the back surface (left side surface in FIG. 1) of the image forming apparatus main body 12. In addition, it has a portion that is formed substantially vertically from the feed roll 30 of the lowermost paper feed unit 18d to the fixing device 36 described later. A transfer roll 42 and an image carrier 44 described later are arranged on the upstream side of the fixing device 36 in the conveyance path 32, and a resist roll 38 is arranged on the upstream side of the transfer roll 42 and the image carrier 44. Further, a discharge roll 40 is disposed in the vicinity of the discharge port 34 of the conveyance path 32.

  Accordingly, the recording medium fed from the paper feed cassette 22 of the paper feed units 18a to 18d by the feed roll 24 is wound by the retard roll 26 and the nudger roll 28 and guided to the transport path 32, and is temporarily stopped by the registration roll 38. The developer image is transferred between a transfer roll 42 and an image carrier 44, which will be described later, at a timing, and the transferred developer image is fixed by the fixing device 36, and is discharged by the discharge roll 40. 34 is discharged to the discharge unit 16.

  However, in the case of duplex printing, it is returned to the reverse path. That is, the front side of the discharge roll 40 in the transport path 32 is divided into two forks, and a switching claw 46 is provided at the divided portion, and a reversing path 48 is formed from the divided portion to the registration roll 38. The reversing path 48 is provided with transport rolls 50a to 50c. In the case of double-sided printing, the switching claw 46 is switched to the side that opens the reversing path 48, and the discharge roll 40 is in front of the rear end of the recording medium. At that time, the discharge roll 40 is reversed, the recording medium is guided to the reverse path 48, and is discharged from the discharge port 34 to the discharge unit 16 through the registration roll 38, the transfer roll 42, the image carrier 44 and the fixing device 36. It is.

  The discharge unit 16 includes an inclined part 52 that is rotatable with respect to the image forming apparatus main body. The inclined portion 52 has a lower discharge port portion and is inclined so as to gradually increase in the front direction (right direction in FIG. 1), with the discharge port portion as a lower end and a higher tip as an upper end. The inclined portion 52 is supported by the image forming apparatus main body 12 so as to be rotatable around the lower end. As shown by a two-dot chain line in FIG. 1, when the inclined portion 52 is rotated upward and opened, an opening portion 54 is formed, and a process cartridge 64 described later can be attached and detached through the opening portion 54. .

  The image forming unit 14 is of, for example, an electrophotographic system, and includes, for example, an image carrier 44 made of a photosensitive member, a charging device 56 made of, for example, a charging roll that uniformly charges the image carrier 44, and charged by the charging device 56. An optical writing device 58 for writing a latent image on the image carrier 44 with a laser beam, a developing device 60 for visualizing the latent image of the image carrier 44 formed by the optical writing device 58 with a developer, and this development A transfer roll 42 that transfers the developer image visualized by the apparatus 60 to the image carrier 44 by being pressed against the image carrier 44, a cleaning blade 62 that cleans the developer remaining on the image carrier 44, and a transfer roll 42. It comprises a fixing device 36 comprising, for example, a pressure roll and a heating roll, for fixing the developer image on the transferred recording medium to the recording medium. . The cleaning blade 62 is configured to be able to clean the image carrier 44 by being in sliding contact with the entire image formable area where the image can be formed on the image carrier 44.

  The process cartridge 64 is obtained by integrating the image carrier 44, the charging device 56, the developing device 60, and the cleaning blade 62. The process cartridge 64 is disposed immediately below the inclined portion 52 of the discharge portion 16 and is attached and detached through the opening portion 54 formed when the inclined portion 52 is opened as described above.

  The optical writing device 58 has a laser optical scanning unit 88 to be described later, and is arranged in the vicinity of the front surface of the image forming apparatus main body 12 in parallel with the paper feeding units 18a to 18d described above. To expose. The exposure position of the image carrier 44 is the latent image writing position P.

  A user interface (UI) 70 and a control unit 72 are disposed on the upper part of the image forming apparatus 10. The UI 70 includes a display unit on which various control information and settings are displayed, and an input unit such as a touch panel for inputting settings and the like. That is, the user sets the UI 70 with the size of the recording medium on which the image forming apparatus 10 forms an image, the type of the recording medium, the number of times of continuous image formation, the resolution of the formed image, the image forming process speed, and the like. Can be set. The control unit 72 includes a laser diode (LD) control unit 92 which will be described later, and controls each unit constituting the image forming apparatus 10 according to the setting input via the UI 70. In addition, the control unit 72 can count the number of rotations of the image carrier 44.

Next, control of the transfer roll 42 by the control unit 72 will be described.
FIG. 2 shows details of the transfer roll 42, the image carrier 44, and the periphery thereof. In the image carrier 44, a photosensitive layer 76 is formed around the drum base 74. The drum base 74 is made of a conductor such as aluminum and is grounded. The photosensitive layer 76 is composed of an inorganic or organic photoconductor. The charging device 56 is pressed against the image carrier 44 with a predetermined pressing force, and is driven to rotate as the image carrier 44 rotates. When a predetermined charging bias is applied to the charging device 56, the peripheral surface of the rotating image carrier 44 is uniformly charged to a predetermined polarity and potential. The image carrier 44 is irradiated with the laser beam from the optical writing device 58 at the latent image writing position P on the photosensitive layer 76. The developing roller 78 is provided in the developing device 60 described above, and rotates with a developer layer formed thereon. When a predetermined bias is applied, the developing roller 78 is transferred to the image carrier 44, and the image carrier. A developer image is formed on 44.

  The transfer roll 42 includes a conductive rotary shaft 80 and a conductive rubber layer 82 formed on the outer periphery thereof. The rubber layer 82 is adjusted such that conductive particles are dispersed in a relatively soft rubber material such as EPDM, urethane, silicon, etc., and the volume resistivity is about 105 to 1010 Ω · m. A rotary shaft 80 of the transfer roll 42 is connected to a high voltage power source 86 via a current detector 84. The high voltage power supply 86 is configured such that the output voltage changes under the control of the control unit 72 including the LD control unit 100 described later, and outputs a constant voltage according to the voltage setting by the control unit 72. The current detector 84 detects a current supplied from the high voltage power source 86 to the transfer roll 42 and outputs a detected current value to the control unit 72.

  A predetermined constant voltage is applied to the transfer roll 42 by the controller 72 setting a predetermined voltage for the high-voltage power supply 86. On the other hand, the resistance value of the rubber layer 82 changes greatly when environmental conditions such as temperature and humidity change. Therefore, even if the high voltage power supply 86 applies a constant voltage to the transfer roll 42, if the temperature and humidity change, the current supplied from the high voltage power supply 86 to the transfer roll 42 changes. For example, when the temperature and humidity increase, the resistance value of the rubber layer 82 decreases, and the detected current value detected by the current detector 84 increases. The control unit 72 controls the voltage setting for the high-voltage power supply 86 according to the detected current value received from the current detector 84. That is, the control unit 72 detects an environmental condition via the current detector 84 and controls the high voltage power supply 86.

Next, control of the optical writing device 58 by the control unit 72 will be described.
In FIG. 3, a laser optical scanning unit 88 included in the optical writing device 58 and its periphery are shown. The laser optical scanning unit 88 includes, for example, a laser diode (LD) 90, a collimator lens 92, a rotary polygon mirror 94, and an fθ lens 96. The LD 90 generates laser light under the control of the LD control unit 100 described later and irradiates the collimator lens 92. The collimator lens 92 collimates the laser light generated by the LD 90 and outputs it to the rotating polygon mirror 94. The rotary polygon mirror 94 has, for example, six mirror surfaces, and reflects the laser light that has passed through the collimator lens 92 toward the fθ lens 96 while rotating at a constant angular velocity under the control of the control unit 72. The fθ lens 96 converts the laser beam reflected by the rotating polygon mirror 94 while rotating at a constant angular velocity into a laser beam scanned at a constant velocity in the main scanning direction of the image carrier 44.

  A scanning start sensor 98 is disposed in the vicinity of the scanning start position of the image carrier 44. The scanning start sensor 98 detects that the laser beam reflected by the rotary polygon mirror 94 has been applied to the position where the scanning start sensor 98 is disposed, and outputs it to the LD control unit 100.

  FIG. 4 shows the configuration of the LD control unit 100. As described above, the LD control unit 100 is included in the control unit 72, and includes an image processing circuit 102, an MCU (microcontroller unit) circuit 104, an output setting circuit 106, and a laser diode (LD) lighting circuit 108. The image processing circuit 102 includes a video signal generator 110 that operates under the control of the MCU circuit 104. The video signal generator 110 receives image data from, for example, a PC, generates a video signal by modulating the image data, and the output setting circuit 106 will be described later after a scanning start position setting time to be described later elapses. Output to the AND circuit 118.

  The MCU circuit 104 includes a laser diode (LD) control signal generator 104, a memory 114, and the like. Based on information input from the current detector 84, the UI 70, and the scan start sensor 98, an image processing circuit 102, an output setting, and the like. The circuit 106 and the high-voltage power supply 86 are controlled. The LD control signal generator 112 generates an LD control signal according to information input from each of the current detector 84, UI 70, and scanning start sensor 98, and outputs the LD control signal to an output adjustment circuit 116 described later of the output setting circuit 106. To do. The memory 114 stores settings for the LD control signal generator 112 and the like.

  The output setting circuit 106 includes an output adjustment circuit 116 that operates under the control of the MCU circuit 104, and an AND circuit 118. The output adjustment circuit 116 adjusts the output level of the LD control signal generated by the LD control signal generator 112 and outputs it to the AND circuit 118. The AND circuit 118 is L level when at least one of the adjusted LD control signal input from the output adjustment circuit 116 and the video signal input from the video signal generator 110 is L level (low level). A scanning signal is output to the LD lighting circuit 108, and in other cases, an H level (high level) scanning signal is output to the LD lighting circuit 108.

  The LD lighting circuit 108 lights the LD 90 according to the scanning signal input from the AND circuit 118. Note that the LD lighting circuit 108 lights (active low) the LD 90 when an L level scanning signal is received. That is, when at least one of the LD control signal generator 112 and the video signal generator 110 outputs an L level signal, the LD lighting circuit 108 receives the L level scanning signal and the laser beam is directed to the image carrier 44. The latent image is written on the image carrier 44.

Next, the operation of the LD control unit 100 will be described.
FIG. 5 is a timing chart showing an example of a scanning signal in the main scanning direction input to the LD lighting circuit 108.
In the timing chart shown in FIG. 5, the width in the main scanning direction of the recording medium is narrower than the main scanning direction width of the image formable region of the image carrier 44, and the central portion of the image formable region of the image carrier 44 is shown. A scanning signal in the case where the developer image formed in (1) is transferred to a recording medium (center registration) is taken as an example.

  When the video signal generator 110 receives image data from a PC or the like, the video signal generator 110 starts modulation of the image data and waits until a scan start position setting time described later elapses. When the MCU circuit 104 receives a signal indicating that the video signal generator 110 has received image data from the image processing circuit 102, the MCU circuit 104 outputs a main scanning start position detection signal A from the LD control signal generator 112.

  When the LD control signal generator 112 outputs the L level LD control signal A (main scanning start position detection signal A), the scanning start sensor 98 is irradiated with laser light via the laser optical scanning unit 88. When the scan start sensor 98 is irradiated with laser light, the MCU circuit 104 receives a signal indicating that the scan start sensor 98 has been irradiated with laser light from the scan start sensor 98 and starts measuring the scan start position setting time. To do. The scan start position setting time is irradiated by the video signal B output from the video signal generator 110 after the laser beam irradiated by the LD control signal A output from the LD control signal generator 112 is detected by the scanning start sensor 98. This is a delay time for aligning the scanning start position of the laser beam to the transfer position of the developer image with respect to the recording medium.

  The MCU circuit 104 is within the scan start position setting time, and the rotary polygon mirror 94 is so irradiated that the laser beam irradiated through the laser optical scanning unit 88 is irradiated into the image formable region of the image carrier 44. The LD control signal generator 112 outputs the L level LD control signal C within the time during which the motor is rotating.

  When the video signal generator 110 receives from the MCU circuit 104 a signal indicating that the scan start position setting time has elapsed after the LD control signal C is output from the LD control signal generator 112, the video signal generator 110 outputs the video signal B. .

  Further, the MCU circuit 104 is after the video signal B is output from the video signal generator 110 and the laser beam irradiated through the laser optical scanning unit 88 is within the image formable region of the image carrier 44. The LD control signal generator 112 outputs an L level LD control signal D within the time during which the rotary polygon mirror 94 is rotated so that the laser beam is irradiated.

  Therefore, the scanning signal in the main scanning direction input to the LD lighting circuit 108 is an L level signal having a length corresponding to the LD control signals A, C, and D, and a length and level signal corresponding to the video signal B. Including. Further, as described above, the LD lighting circuit 108 lights the LD 90 when an L level scanning signal is received. That is, the laser beam corresponding to the LD control signal A is irradiated outside the image formable region of the image carrier 44, and the laser light corresponding to the LD control signals C and D and the video signal B can be formed on the image carrier 44. Since the irradiation is performed in the region, linear cleaning latent images are written on the image carrier 44 on both sides of the latent image corresponding to the video signal B in the main scanning direction. The scanning width in the main scanning direction of the laser light scanned on the image carrier 44 corresponding to the video signal B may be equal to or smaller than the width of the recording medium.

FIG. 6 is a schematic view illustrating a state in which the latent image written on the image carrier 44 is developed with the developer in accordance with the scanning signal input to the LD lighting circuit 108.
The image carrier 44 has, for example, four linear lines on both sides in the main scanning direction of the transferable image area 120 on which a developer image to be transferred to the recording medium is formed under the control of the LD control unit 100. Developer images 122 and 124 are formed. The transferable image area 120 is an area corresponding to the recording medium. In this transferable image area 120, a developer image corresponding to the image data input to the video signal generator 110 is formed. The developer image thus formed is transferred to a recording medium. The developer images 122 and 124 have widths in the main scanning direction corresponding to the LD control signals C and D, respectively. Further, the developer images 122 and 124 are linear developer images having a width in the sub-scanning direction of, for example, 1 to 10 dots. That is, the developer images 122 and 124 are linear developer images with a width (line width) in the sub-scanning direction of 10 dots or less, and the developer images 122 and 124 are formed at predetermined intervals in the sub-scanning direction. In addition, the MCU circuit 104 outputs an LD control signal from the LD control signal generator 112. The LD control unit 100 changes the width in the sub-scanning direction of the developer images 122 and 124 according to, for example, the resolution of the image formed on the recording medium set by the user via the UI 70. For example, the LD control unit 100 sets the width of the developer images 122 and 124 in the sub-scanning direction to 1 dot when the image resolution is 600 dpi and to 2 dots when the image resolution is 1200 dpi. For the developer images 122 and 124, initial settings such as the main scanning direction width and the sub-scanning direction width are stored in the memory 114.

  When the main scanning direction width of the image formable area of the image carrier 44 and the main scanning direction width of the recording medium (or transferable image area 120) are the same, the LD control unit 100 outputs LD control signals C and D. Therefore, the developer images 122 and 124 are not formed. The LD controller 100 also changes the width (line length) of the developer images 122 and 124 in accordance with the width of the recording medium in the main scanning direction. Further, the LD control unit 100 changes the frequency of outputting the LD control signals C and D according to the number of images continuously formed on the recording medium by the image forming apparatus 10. For example, when the same image is continuously formed on 10 recording media (continuous image formation) by the user setting or the like via the UI 70, the LD control unit 100 displays the first and 10th recording media. The developer images 122 and 124 are formed only when the developer image to be transferred is formed, and when one image is formed on only one recording medium (intermittent image formation), it is transferred to the recording medium. The developer images 122 and 124 may be formed when the developer image is formed.

  Further, the LD control unit 100 determines that the developer images 122 and 124 correspond to the width of the recording medium in the main scanning direction, the number of times of continuous printing, the number of rotations of the image carrier 44, and the process speed (transfer speed or the like) for forming an image. Change the frequency of formation. The process speed of the image forming apparatus 10 is set according to the type of recording medium such as cardboard or OHO sheet. In addition, the LD control unit 100 may form the developer images 122 and 124 according to the detection result of the current detector 84. For example, the LD control unit 100 is a recording in which the environment in which the image forming apparatus 10 is disposed is high temperature and high humidity and the width in the main scanning direction is narrower than the width in the main scanning direction of the image formable area of the image carrier 44. When continuous images are formed on the medium, the developer images 122 and 124 may be formed.

Next, processing for changing settings relating to the developer images 122 and 124 will be described.
FIG. 7 is a flowchart illustrating a first processing example (S10) in which the LD control unit 100 changes the settings relating to the developer images 122 and 124.

  As shown in FIG. 7, in step 100 (S100), the MCU circuit 104 determines that the main scanning direction width of the recording medium set via the UI 70 is the maximum main scanning direction width (image forming apparatus 10 can form an image). It is determined whether or not it is the same as the maximum recording medium width. If the width of the recording medium in the main scanning direction is the same as the maximum recording medium width, the process proceeds to S116, and otherwise the process proceeds to S102.

  In step 102 (S102), the MCU circuit 104 determines whether the main scanning direction width (recording medium width) of the recording medium set via the UI 70 has been changed, for example. If the recording medium width has been changed, the process proceeds to S104. Otherwise, the process proceeds to S106.

  In step 104 (S104), the MCU circuit 104 causes the LD control signals C and D generated by the LD control signal generator 112 to change the widths of the developer images 122 and 124 in the main scanning direction and the sub scanning direction. Are changed and stored in the memory 114. The frequency of forming the developer images 122 and 124 in the sub-scanning direction includes a case where the developer images 122 and 124 are formed a plurality of times within the width of the recording medium in the sub-scanning direction and a case where the developer images 122 and 124 are not formed.

  In step 106 (S106), the MCU circuit 104 determines whether or not the number of times of continuous printing (number of sheets) set via the UI 70 is a predetermined value or more, for example. If the number of continuous prints is equal to or greater than the predetermined value, the process proceeds to S110. Otherwise, the process proceeds to S108.

  In step 108 (S108), the MCU circuit 104 determines whether or not the transfer speed is equal to or higher than a predetermined value. If the transfer speed is equal to or higher than the predetermined value, the process proceeds to S110. Otherwise, the process proceeds to S112. The transfer speed is set according to the type of the recording medium as described above, and the MCU circuit 104 determines the transfer speed based on the type of the recording medium set via the UI 70, for example.

  In step 110 (S110), the MCU circuit 104 changes the settings of the LD control signals C and D generated by the LD control signal generator 112 so as to change the formation frequency of the developer images 122 and 124 in the sub-scanning direction. And stored in the memory 114. The frequency of forming the developer images 122 and 124 in the sub-scanning direction includes a case where the developer images 122 and 124 are formed a plurality of times within the width of the recording medium in the sub-scanning direction and a case where the developer images 122 and 124 are not formed.

  In step 112 (S112), the MCU circuit 104 determines whether the resolution of the image set through the UI 70 is equal to or higher than a predetermined value, for example. If the resolution is greater than or equal to the predetermined value, the process proceeds to S114. Otherwise, the process ends.

  In step 114 (S114), the MCU circuit 104 changes the settings of the LD control signals C and D generated by the LD control signal generator 112 so as to change the sub-scanning direction width of the developer images 122 and 124, and the memory. 114.

  In step 116 (S116), the MCU circuit 104 sets the LD control signals C and D generated by the LD control signal generator 112 to the H level and stores them in the memory 114. That is, the MCU circuit 104 prevents the developer images 122 and 124 from being formed.

Next, a second processing example in which the LD control unit 100 changes settings related to the developer images 122 and 124 will be described.
FIG. 8 is a flowchart illustrating a second processing example (S20) in which the LD control unit 100 changes the settings relating to the developer images 122 and 124.

  As shown in FIG. 8, in step 200 (S200), the MCU circuit 104 determines that the main scanning direction width of the recording medium set via, for example, the UI 70 is the maximum main scanning direction width (image forming apparatus 10 can form an image). It is determined whether or not it is the same as the maximum recording medium width. If the width of the recording medium in the main scanning direction is the same as the maximum recording medium width, the process proceeds to S208. Otherwise, the process proceeds to S202.

  In step 202 (S202), the MCU circuit 104 determines whether or not the number of continuous printing (number of sheets) set through the UI 70 is equal to or greater than a predetermined value, for example. If the number of continuous printing is greater than or equal to the predetermined value, the process proceeds to S204. Otherwise, the process proceeds to S208.

  In step 204 (S204), the MCU circuit 104 determines whether or not the detected current value received via the current detector 84 is greater than or equal to a predetermined value. If the detected current value is greater than or equal to the predetermined value, the temperature and humidity of the environment in which the image forming apparatus 10 is installed are considered to be greater than or equal to the predetermined value, and the process proceeds to S206. Otherwise, the process proceeds to S208.

  In step 206 (S206), the MCU circuit 104 changes the settings of the LD control signals C and D generated by the LD control signal generator 112 so as to change the formation frequency of the developer images 122 and 124 in the sub-scanning direction. And stored in the memory 114. Note that the frequency of forming the developer images 122 and 124 in the sub-scanning direction includes a case where the developer images 122 and 124 are formed a plurality of times within the width of the recording medium in the sub-scanning direction.

  In step 208 (S208), the MCU circuit 104 sets the LD control signals C and D generated by the LD control signal generator 112 to the H level and stores them in the memory 114. That is, the MCU circuit 104 prevents the developer images 122 and 124 from being formed.

Next, a processing example for forming the developer images 122 and 124 under the control of the control unit 72 will be described.
FIG. 9 is a flowchart illustrating a processing example (S30) for forming the developer images 122 and 124 under the control of the control unit 72.

  As shown in FIG. 9, in step 300 (S300), the control unit 72 counts the number of rotations of the image carrier 44 when the image forming unit 14 forms an image.

  In step 302 (S302), the controller 72 determines whether or not the number of rotations of the image carrier 44 has reached a predetermined number. If the number of rotations of the image carrier 44 has reached a predetermined number, the process proceeds to S304, and otherwise the process ends.

  In step 304 (S304), the control unit 72 controls the optical writing device 58 to form predetermined developer images 122 and 124 on the image carrier 44.

  Note that the image forming apparatus 10 of the present embodiment has been described as an example of an image forming apparatus that has a single image carrier 44 and forms a black and white image. However, the present invention is not limited thereto. It may be a tandem color image forming apparatus having a body, or a rotary color image forming apparatus having one image carrier and an intermediate transfer member.

1 is a cross-sectional view illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a detailed view showing details of a transfer roll, an image carrier, and the periphery thereof. It is a schematic diagram which shows the laser optical scanning part contained in an optical writing device, and its periphery. It is a block diagram which shows the structure of LD control part. It is a timing chart which shows an example of the scanning signal of the main scanning direction input into LD lighting circuit. FIG. 4 is a schematic view illustrating a state in which a latent image written on an image carrier in response to a scanning signal input to an LD lighting circuit is developed with a developer. It is a flowchart which shows the 1st process example (S10) in which the LD control part changes the setting regarding a developer image. It is a flowchart which shows the 2nd process example (S20) in which the LD control part changes the setting regarding a developer image. It is a flowchart which shows the process example (S30) which forms a developer image by control of a control part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 42 Transfer roll 44 Image carrier 56 Charging apparatus 58 Optical writing apparatus 60 Developing apparatus 62 Cleaning blade 64 Process cartridge 70 User interface (UI)
72 Control unit 74 Drum base 76 Photosensitive layer 80 Rotating shaft 82 Rubber layer 84 Current detector 86 High voltage power supply 88 Laser optical scanning unit 98 Scan start sensor 100 LD (laser diode) control unit 102 Image processing circuit 104 MCU circuit 106 Output setting circuit 108 LD lighting circuit 110 Video signal generator 112 LD control signal generator 114 Memory 120 Transferable image areas 122 and 124 Developer image

Claims (11)

  An image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and developing means for developing a latent image written by the optical writing means with a developer to form a developer image; Transfer means for transferring the developer image formed on the image carrier, cleaning means for cleaning the remaining developer, and cleaning within the width of the recording medium in the sub-scanning direction and outside the width of the recording medium in the main scanning direction An image forming apparatus comprising: control means for controlling the optical writing means so as to form a latent image for use.   An image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and developing means for developing a latent image written by the optical writing means with a developer to form a developer image; A transfer unit that transfers the developer image formed on the image carrier; a cleaning unit that cleans the remaining developer; and a control unit that controls the optical writing unit. A first scanning light control means for controlling the optical writing means to generate scanning light corresponding to the second scanning light, and a second scanning light for controlling the optical writing means to generate scanning light for writing a cleaning latent image. And an image forming apparatus.   3. The image forming apparatus according to claim 1, wherein the control unit controls the optical writing unit to form a cleaning latent image having a width in the sub-scanning direction of 10 dots or less.   The image forming apparatus according to claim 1, wherein the control unit controls the latent image for cleaning according to a width in a main scanning direction of the recording medium.   The image forming apparatus further includes a setting receiving unit that receives a setting of the number of times that the transfer unit continuously transfers the developer image, and the control unit forms a cleaning latent image based on the setting received by the setting receiving unit. The image forming apparatus according to claim 1, wherein the optical writing unit is controlled to change the frequency.   An image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and developing means for developing a latent image written by the optical writing means with a developer to form a developer image; A transfer unit that transfers the developer image formed on the image carrier; a cleaning unit that cleans the remaining developer; and a control unit that controls the optical writing unit. An image forming apparatus, wherein the optical writing unit is controlled to change a frequency of forming a cleaning latent image in accordance with the number of rotations of the carrier.   An image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and developing means for developing a latent image written by the optical writing means with a developer to form a developer image; A transfer unit that transfers the developer image formed on the image carrier; a cleaning unit that cleans the remaining developer; and a control unit that controls the optical writing unit. An image forming apparatus, wherein the optical writing unit is controlled to change a width of the cleaning latent image in the sub-scanning direction according to a resolution of a developer image formed by the unit.   An image carrier, optical writing means for writing a latent image on the image carrier by scanning light, and developing means for developing a latent image written by the optical writing means with a developer to form a developer image; A transfer unit that transfers the developer image formed on the image carrier; a cleaning unit that cleans the remaining developer; and a control unit that controls the optical writing unit. An image forming apparatus, wherein the optical writing unit is controlled to change a frequency of forming a cleaning latent image in accordance with a transfer speed of the unit.   An environmental condition detection unit that detects an environmental condition is further included, and the control unit controls the optical writing unit to change a frequency of forming a cleaning latent image in accordance with a detection result of the environmental condition detection unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The transfer unit includes a transfer roll that transfers a developer image formed on the image carrier by being pressed against the image carrier, and the environmental condition detection unit is adapted to change a resistance value of the transfer roller. The image forming apparatus according to claim 9, wherein environmental conditions are detected based on the environmental conditions.   An environmental condition detecting means for detecting an environmental condition; and a setting receiving means for receiving a setting of the number of times that the transfer means continuously transfers the developer image; and the environmental condition detecting means is at high temperature and high humidity. The control means controls the latent image for cleaning according to the width of the recording medium in the main scanning direction when the setting acceptance means accepts the setting a plurality of times. Any one of the image forming apparatuses.

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