JP2016051119A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the life of a photoreceptor and stabilize image quality by uniformly using an exposure area of the photoreceptor.SOLUTION: There is provided an image forming apparatus including an optical scanner that deflects a laser beam from a laser emitting part with a deflector into a scanning beam, and writes an electrostatic latent image on a photoreceptor with the scanning beam, the image forming apparatus further including: an exposure history storage part 52a that stores exposure positions on the photoreceptor and a history of the amounts of exposure; and a control part 50 that changes the direction of an image to be exposed so that a distribution of the amounts of exposure on the photoreceptor is made uniform on the basis of the exposure positions and the amounts of exposure stored in the exposure history storage part 52a.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming apparatus having a copy function, a scanner function, and the like.

  Conventionally, the life of a photoconductor of an optical scanning unit mounted on an image forming apparatus is managed by the rotation time or the number of printed sheets. Therefore, even if the usage of the photoconductor is uneven, a predetermined rotation time or When a predetermined number of printed sheets arrives, the life is uniformly reached. In addition, when the usage pattern by the user is a usage pattern in which only one side of the photoconductor is extremely used, an adverse effect on the stability of the image quality (that is, local cleaning failure, etc.) has occurred. .

  Therefore, in order to solve such a problem, Patent Document 1 includes an optical writing position changing unit, and an optical writing position perpendicular to the paper feed direction is provided for optical writing on the surface of the photosensitive member by a scanning beam. An image forming apparatus that can be changed for each print is disclosed.

JP-A-5-162376

  The image forming apparatus described in Patent Document 1 is configured to change the exposure start position according to a preset setting value sent from a counter or a controller. For this reason, the user cannot grasp the exact damage of the photoreceptor due to the use state, and there is a problem that the goal of uniformizing the deterioration of the photoreceptor surface as a whole cannot be achieved sufficiently.

  The present invention was devised to solve such problems, and an object of the present invention is to provide an image in which the life of the photoconductor is extended and the image quality is stabilized by using the exposure area of the photoconductor on average. It is to provide a forming apparatus.

  In order to solve the above-described problems, the image forming apparatus of the present invention is an optical scanning in which a laser beam from a laser emitting unit is deflected by a deflector to form a scanning beam, and an electrostatic latent image is written on the photosensitive member by the scanning beam. An image forming apparatus including an exposure history storage unit that stores a history of exposure position and exposure amount on the photoconductor, and an exposure position and exposure amount stored in the exposure history storage unit, And changing means for changing the direction of the image to be exposed so that the distribution of the exposure amount on the photosensitive member is made uniform.

  According to this configuration, the usage distribution on the surface of the photoconductor can be grasped by accumulating the history of the exposure position and the exposure amount (laser irradiation amount, that is, the printing amount) on the photoconductor. By changing the direction, the exposure area of the photoconductor can be used on average, and the photoconductor can be effectively used (long life) and the image quality can be stabilized (preventing local deterioration).

  The image forming apparatus according to the present invention further includes a print history storage unit that stores a history of print positions and print amounts of past print data for a preset period of time, and the change unit includes the exposure unit. Based on the exposure position and exposure amount stored in the history storage unit and the print position and print amount stored in the print history storage unit, exposure is performed so that the distribution of the exposure amount on the photoconductor is uniformized. It is good also as a structure which changes direction of an image.

  According to this configuration, by adding the print history data to the exposure history data, the exposure area of the photoconductor can be used more averagely.

  Further, according to the image forming apparatus of the present invention, the history data of the exposure position and the exposure amount stored in the exposure history storage unit is data corresponding to a two-dimensional direction of an axial direction and a rotational direction of the photosensitive member. There may be.

  According to this configuration, by using the data corresponding to the two-dimensional direction, the accuracy when changing the direction of the image to be exposed is increased, and the effect of equalization is further increased.

  According to the image forming apparatus of the present invention, the history data of the exposure position and the exposure amount stored in the exposure history storage unit may be data corresponding to a one-dimensional direction of the axial direction of the photoconductor. Good.

  According to this configuration, since the history data amount can be reduced, the configuration can be made at low cost.

  According to the image forming apparatus of the present invention, the changing unit further uniformizes the distribution of the exposure amount on the photoconductor based on the exposure position and the exposure amount stored in the exposure history storage unit. In this way, the exposure start position may be changed.

  According to this configuration, in addition to changing the orientation of the image to be exposed, the exposure start position is also changed, so that the exposure area of the photoconductor can be used on an average basis.

  According to the image forming apparatus of the present invention, the changing unit may first determine whether to change the orientation of the image, and then determine whether to change the exposure start position.

  According to the image forming apparatus of the present invention, the change by the changing unit may be performed for each job or for a predetermined period set in advance.

  According to this configuration, the processing can be simplified by periodically changing the image to be exposed.

  Further, according to the image forming apparatus of the present invention, the changing unit is configured to change the sensitivity based on the exposure position and exposure amount stored in the exposure history storage unit and the print position and print amount of the print data received this time. The orientation of the image to be exposed may be changed at the start of printing so that the distribution of the exposure amount on the body is made uniform.

  According to this configuration, it is possible to appropriately change the image to be exposed according to the print job.

  According to the image forming apparatus of the present invention, the angle for changing the orientation of the image can be any of 90 °, 180 °, and 270 °.

  According to this configuration, if the angle is changed, the image is not printed obliquely on the output paper.

  According to the image forming apparatus of the present invention, the changing unit may determine whether to change the orientation of the image in consideration of parameters other than the exposure that damages the photoconductor. Good.

According to this configuration, the orientation of the image to be exposed is changed in consideration of chemical damage to the photoconductor such as ozone and NO ₂ generated in the apparatus and mechanical damage to the photoconductor by a cleaning blade or the like. Can do.

  Further, according to the image forming apparatus of the present invention, when the stapling instruction is input from the user, the changing unit determines whether to change the image orientation based on the instructed stapling position. It is good also as composition which judges.

  According to this configuration, when changing the orientation of the image, it is possible to limit the image to one that is not affected by non-staples or the like.

  In addition, according to the image forming apparatus of the present invention, when the change is performed, the image forming apparatus may include an announcement unit that announces the change to the user. When changing the orientation of the image, the orientation of the paper also changes, so it is better to inform the user just in case.

  The image forming apparatus of the present invention is an image forming apparatus that deflects a light beam from a semiconductor laser or the like with a deflector to form a scanning beam and optically writes an electrostatic latent image on the photosensitive member with the scanning beam. In addition, a configuration may be provided that includes transmission means for transmitting the history data of the exposure position and exposure amount on the photosensitive member stored in the exposure history storage means to a server that manages the history.

  According to this configuration, the remote server manages the exposure history for each photoconductor, so that the photoconductor is detached from the image forming apparatus and attached to another image forming apparatus capable of uniform exposure, and the photoconductor Can be used effectively.

  According to the image forming apparatus of the present invention, by accumulating the exposure position and exposure history on the photoconductor, the use distribution on the surface of the photoconductor can be grasped, and the orientation of the image can be changed according to the use distribution. The exposure area of the photoreceptor can be used on average. As a result, it is possible to achieve effective use of the photoconductor (longer life) and stability of image quality (preventing local deterioration).

1 is a schematic side view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration of an LSU, and illustrates a state in which the inside of the LSU casing and the photoconductor are viewed from above (a direction orthogonal to the (main) scanning direction). FIG. 2 is a schematic diagram showing a configuration of an LSU, and shows a state in which the inside of the LSU casing and the photoconductor are viewed from the lateral direction ((main) scanning direction). 1 is a block diagram illustrating an electrical configuration of an image forming apparatus according to an embodiment. It is explanatory drawing which shows an example of the exposure history data corresponding to Example 1. FIG. It is explanatory drawing which showed the mode of angle change typically, and has shown the case where the image to expose is rotated 180 degree | times from the image before a change. It is explanatory drawing which showed the mode of angle change typically, and has shown the case where the image to expose is rotated 90 degree | times from the image before a change. It is explanatory drawing which showed the mode of angle change typically, and has shown the case where the image to expose is rotated -90 degrees (270 degrees) from the image before a change. It is explanatory drawing which shows an example of the printing history data which accumulate | stored and memorize | stored the printing position of the past printing data, and the printing amount log | history for the preset fixed period. It is explanatory drawing which shows an example of the printing history data which accumulate | stored and memorize | stored the printing position of the past printing data, and the printing amount log | history for the preset fixed period. It is explanatory drawing which shows an example of the exposure history data corresponding to Example 3. FIG. 6 is an explanatory diagram showing the amount of damage on the surface of the photoreceptor due to ozone generated inside the apparatus. It is explanatory drawing which added the damage amount of the photoreceptor surface by ozone to exposure history data.

  FIG. 1 is a schematic side view of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus 1 has a copying function for reading an original and forming an image on a sheet. The image reading apparatus 2, an original conveying apparatus (ADF) 3 provided on the upper side of the image reading apparatus 2, and the image reading apparatus 2. The image forming unit 4, the paper feed cassette 5, and the paper discharge tray 7 provided on the lower side are provided.

  The document conveying device 3 is supported by a hinge (a fulcrum, not shown) on the back side so as to be openable and closable with respect to the image reading device 2, and is opened and closed by raising and lowering the front end. When the document conveying device 3 is opened, the upper part of the image reading device 2 is opened so that the document can be placed manually. The document conveying device 3 automatically conveys the placed document onto the image reading device 2.

  The image reading apparatus 2 is supported by the hinge (fulcrum) 42 on the back side so as to be openable and closable, and is opened and closed by moving the front end portion up and down. The image reading device 2 reads the placed document or the document conveyed from the document conveying device 3 to generate image data.

  In the image forming apparatus 1, image data corresponding to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y) or a monochrome image using a single color (for example, black). Are treated. The image forming unit 4 is provided with four developing devices 12, photoconductors 13, drum cleaning devices 14, and chargers 15 for forming four types of toner images, each of which includes black, cyan, magenta, and Corresponding to yellow, four image stations Pa, Pb, Pc, and Pd are configured.

  The drum cleaning device 14 removes and collects residual toner on the surface of the photoreceptor 13. The charger 15 uniformly charges the surface of the photoconductor 13 to a predetermined potential. The optical scanning device 11 exposes the surface of the photoreceptor 13 to form an electrostatic latent image. The developing device 12 develops the electrostatic latent image on the surface of the photoconductor 13 to form a toner image on the surface of the photoconductor 13. By the series of operations described above, toner images of each color are formed on the surface of each photoconductor 13. The optical scanning device 11 will be described in detail with reference to FIGS. 2A and 2B described later.

  An intermediate transfer belt 21 is disposed on the upper side of the photoreceptor 13. The intermediate transfer belt 21 circulates in the direction of arrow C, the residual toner is removed and collected by the belt cleaning device 25, and the toner images of the respective colors formed on the surfaces of the photoreceptors 13 are sequentially transferred and superimposed. A color toner image is formed on the surface of the intermediate transfer belt 21.

  A nip area is formed between the transfer roller 26a of the secondary transfer device 26 and the intermediate transfer belt 21, and the sheet conveyed through the sheet conveyance path R1 is sandwiched and conveyed in the nip area. When the sheet passes through the nip area, the toner image on the surface of the intermediate transfer belt 21 is transferred and conveyed to the fixing device 17.

  The fixing device 17 includes a fixing roller 31 and a pressure roller 32 that rotate with a sheet interposed therebetween. The fixing device 17 sandwiches the recording paper on which the toner image is transferred between the fixing roller 31 and the pressure roller 32 and heats and presses the recording paper to fix the toner image on the recording paper.

  The paper feed cassette 5 is a tray for storing paper used for image formation, and is provided below the optical scanning device 11. The paper is pulled out from the paper feed cassette 5 by the pickup roller 33, transported through the paper transport path R 1, passes through the secondary transfer device 26 and the fixing device 17, and passes through the paper discharge roller 36 to the paper discharge tray 7. It is carried out. In the paper transport path R1, after the paper is temporarily stopped and the leading edges of the paper are aligned, the paper is fed in accordance with the transfer timing of the color toner image in the nip area between the intermediate transfer belt 21 and the transfer roller 26a. A registration roller 34 that starts conveyance, a conveyance roller 35 that facilitates conveyance of a sheet, and a paper discharge roller 36 are arranged.

  Further, when image formation is performed not only on the front side of the paper but also on the back side, the paper is conveyed in the reverse direction from the paper discharge roller 36 to the reverse path Rr, so that the front and back sides of the paper are reversed, and the paper is transferred to the registration roller 34. Then, the image is formed on the rear surface in the same manner as the front surface, and the paper is carried out to the paper discharge tray 7.

  Next, the optical scanning device (LSU) 11 will be described with reference to FIGS. 2A and 2B.

  FIG. 2 is a schematic diagram for explaining the configuration of the LSU 11, and FIG. 2A shows a state in which the inside of the housing of the LSU 11 and the photosensitive member 13 are viewed from above (a direction orthogonal to the (main) scanning direction). FIG. 2B shows a state seen from the horizontal direction ((main) scanning direction).

  In the LSU 11, as shown in FIG. 2A, components such as a semiconductor laser (LD) 111, a collimator lens 112, a cylinder lens 113, a polygon motor 114, and fθ lenses 115 and 116 are arranged in a housing 117. Has been configured.

  The LD 111 is a laser emitting unit that outputs (emits) laser light according to image data, and is held by an LD holder (LSU substrate) 117 a provided in a casing 117 that supports each component of the LSU 11. The collimator lens 112 is disposed on the laser emission side of the LD 111 and is for condensing the diffused light output from the LD 111 with respect to the photosensitive member 13 in the main scanning direction. The cylinder lens 113 is for condensing incident laser light with respect to the photosensitive member 13 in the sub-scanning direction.

  The polygon motor 114 includes a polygon mirror (deflector) 114a having a plurality of (for example, six) reflecting surfaces in the rotation direction and a motor 114b that rotationally drives the polygon mirror 114a. The polygon mirror 114a is rotated in the direction of arrow B in the figure by the motor 114b, and reflects the laser light in the main scanning direction. The laser light emitted from the cylinder lens 113 and condensed in both the main and sub scanning directions is deflected and reflected by the reflection surface (deflection surface) of the polygon mirror 114a. The laser beam deflected and reflected by the reflecting surface of the polygon mirror 114 a is incident on the fθ lenses 115 and 116. The fθ lenses 115 and 116 have polygon mirror surface tilt correction characteristics and fθ characteristics, and laser beams (scanning beams) that move at a constant angular velocity in the main scanning direction by a constant angular velocity motion of the polygon motor 114 are applied to the photosensitive member 13. It can be converted so that it can move at a constant linear velocity on the scan line.

  The laser light that has passed through the fθ lens 116 passes through the dust-proof member 118 and then forms an electrostatic latent image on the surface of the photoreceptor 13.

  The polygon motor 114 rotates in the direction of arrow B as described above, so that the laser beam scans on the surface of the photoconductor 13 in the main scanning direction indicated by the arrow X, and an image is formed on the surface of the photoconductor (drum) 13. Form. Note that scanning in the sub-scanning direction by laser light on the surface of the photoconductor 13 is performed by rotating the photoconductor 13 in the arrow Y direction, as shown in FIG.

  The housing 117 is made of, for example, a light-blocking resin material, and an opening 117b that is an optical path between the fθ lens 116 and the photosensitive member 13 is provided on a side surface thereof, and glass or the like is provided in the opening 117b. A dustproof member 118 made of a light transmissive material is attached with an adhesive or the like so as to be flush with the casing 117.

  FIG. 3 is a block diagram showing an electrical configuration of the image forming apparatus 1 according to the embodiment.

  The image forming apparatus 1 includes a control unit 50, a communication I / F unit 51, a storage unit 52, a display / operation unit 53, an image processing unit 54, and the like in addition to the above-described configuration. Has been.

  The control unit 50 is configured to be able to communicate with an external device (not shown) via the communication I / F unit 51. The communication I / F unit 51 includes, for example, a FAX communication unit, an Internet communication unit, an infrared communication unit, and the like.

  The control unit 50 includes, for example, one or a plurality of CPUs (Central Processing Units) 50a, a ROM 50b, a RAM 50c, an exposure control unit 50d, and the like, and loads various programs and data stored in the ROM 50b into the RAM 50c. The loaded program in the RAM 50c is executed. Thus, the overall operation of the image forming apparatus 1 is controlled based on the contents of instructions from the user while processing the data.

  The display / operation unit 53 includes, for example, an operation panel including a liquid crystal display and a transparent resistive film type touch panel, and operation keys including hard keys using contact contacts.

  The image processing unit 54 performs various processes on document data optically read by the image reading device 2 to generate image data for image formation. The generated image data is output to the optical scanning device 11 via the exposure control unit 50d of the control unit 50.

  The storage unit 52 stores the read document data and the generated image data, and stores exposure history data that is a history of the exposure position and exposure amount on the photosensitive member, which is a feature of the present invention. An exposure history storage unit 52a and a print history storage unit 52b that stores print history data that is a history of print positions and print amounts of past print data are provided.

  In the present embodiment, by using the exposure history data stored in the exposure history storage unit 52a and the print history data stored in the print history storage unit 52b, the usage distribution on the surface of the photoreceptor 13 can be grasped. By changing the direction of the image to be exposed according to the usage distribution, the exposure area of the photoconductor 13 is controlled so that it can be used on average. Hereinafter, the control for changing the direction of the image (electrostatic latent image) formed on the surface of the photoconductor 13 in accordance with the usage distribution on the surface of the photoconductor 13 will be described with specific examples.

(Example 1)
In the first embodiment, the exposure history data stored in the exposure history storage unit 52a is data corresponding to a one-dimensional direction. In the first embodiment, the print history storage unit 52b is not used.

  FIG. 4 shows an example of exposure history data corresponding to the first embodiment.

  This exposure history data is an example of history data in which the main scanning direction X of the photosensitive member 13 is the horizontal axis and the sub-scanning direction Y is the vertical axis, and each scanning line (exposure position) in the main scanning direction (axial direction) X. This is stored data corresponding to the one-dimensional direction in which the exposure amount along the sub-scanning direction Y is sequentially stored every time. FIG. 4 shows a line graph. As described above, since the accumulated data is data corresponding to the one-dimensional direction (that is, data corresponding to each exposure position in the main scanning direction X), the history data amount can be reduced, so that the apparatus is configured at low cost. Can do.

  The example shown in FIG. 4 shows that the left half in the main scanning direction X has a large exposure amount and the right half is hardly exposed. Therefore, in this case, the orientation of the image to be exposed may be changed so that the right side portion of the photoconductor 13 in the main scanning direction X is exposed more.

  Here, the angle for changing the direction of the image to be exposed can be any of 90 °, 180 °, and 270 °. With these three types of angle changes, the image is not printed obliquely on the output paper.

  5A to 5C are explanatory views schematically showing how the angle is changed. That is, FIG. 5A shows a case where the image 60a2 to be exposed is rotated 180 ° from the image 60a1 before the change, and FIG. 5B shows a case where the image 60b2 to be exposed is rotated 90 ° from the image 60b1 before the change. FIG. 5C shows a case where the image 60c2 to be exposed is rotated by −90 ° (270 °) from the image 60c1 before the change.

  Based on the exposure history data shown in FIG. 4 stored in the storage unit 52, the control unit 50 changes the orientation of the image to be exposed so that the distribution of the exposure amount on the photoconductor 13 is made uniform.

  Specifically, the control unit 50 sets the exposure position and exposure amount data stored in the exposure history storage unit 52a and the print data received this time in the sub scanning direction Y for each scanning line in the main scanning direction X. The print position (for each scan line) and the print amount data are compared with each other so that the exposure amount is made uniform for each scan line in the main scanning direction X (that is, the exposure amount). The optimum change angle is determined from the above three change angles so that the deviation value of the distribution for each scanning line is minimized. Then, the orientation of the image to be exposed is changed so as to be the determined change angle, and the image is output to the optical scanning device 11.

  By doing so, for example, in the case of FIGS. 5A to 5C, the exposure area of the left side portion in the main scanning direction X that is hardly exposed in any case is used more. Since the exposure amount of the exposure area is larger than the exposure amount of the right side exposure area, the exposure amount distribution is gradually uniformized in the main scanning direction X by repeating such printing. Become. As a result, it is possible to achieve effective use (long life) of the photoconductor 13 and stability of image quality (preventing local deterioration).

  In the first embodiment, the change of the image to be exposed is described as a configuration that is changed each time based on the received print data. However, if the change is made each time, the direction of the output paper is aligned. However, it may be inconvenient for the user. Therefore, in the second and subsequent embodiments, the past data is also accumulated for the print data, and it is determined whether to change the orientation of the image to be exposed in consideration of both the exposure history data and the print history data. Yes.

(Example 2)
The second embodiment is an embodiment in which both exposure history data and print history data are data corresponding to a one-dimensional direction.

  That is, also in the second embodiment, the exposure history data is the data shown in FIG.

  On the other hand, FIG. 6A accumulates and stores the print position and print volume history of past print data for a predetermined period (for example, the latest one week, one month, three months, six months, etc.). An example of the printed history data is shown.

  The print history data shown in FIG. 6A is an example of history data in which the main scanning direction X of the photosensitive member 13 is the horizontal axis and the sub-scanning direction Y is the vertical axis, and each scanning line in the main scanning direction (axial direction) X ( The accumulated data corresponding to the one-dimensional direction in which the amount printed in the sub-scanning direction Y (that is, the exposure amount) is sequentially accumulated for each exposure position). FIG. 6A shows a line graph. In this way, since the amount of history data can be reduced by making the data to be stored data corresponding to the one-dimensional direction, the apparatus can be configured at low cost.

  In the example shown in FIG. 6A, the printing tendency in the past certain period shows that the left half of the main scanning direction X is large and the right half is not printed much. Therefore, in this case, the orientation of the image to be exposed may be changed so that the right side portion of the photoconductor 13 in the main scanning direction X is exposed more.

  Here, the angle for changing the direction of the image to be exposed is one of the three types shown in FIGS. 5A to 5C. However, if there is no change, there are four types.

  That is, the controller 50 exposes exposure position and exposure amount data (FIG. 4) stored in the exposure history storage unit 52a, and print position and print amount data (FIG. 6A) stored in the print history storage unit 52b. ) And the exposure amount is made uniform for each scanning line in the main scanning direction X (that is, the deviation value of the distribution of the exposure amount for each scanning line is minimized). The optimum change angle is determined from the three change angles. Then, the orientation of the image to be exposed is changed so as to be the determined change angle, and the image is output to the optical scanning device 11.

  By the way, when the print history data is data as shown in FIG. 6B, for example, in the example shown in FIG. It shows that the amount of printing is large. Therefore, in this case, based on the exposure history data shown in FIG. 4 and the print history data shown in FIG. 6B, it is clear that the exposure amount distribution is made uniform if the orientation of the image to be exposed is not changed. It is. Accordingly, in this case, the exposure may be performed as it is (as it is) without changing the orientation of the image to be exposed.

  According to the second embodiment, by adding the print history data to the exposure history data, the exposure area of the photoconductor can be used more averagely.

  The change in the angle of the image to be exposed may be performed for each job or may be performed every predetermined period (for example, 1 month, 3 months, 6 months, etc.). The processing can be simplified by periodically changing the angle of the image to be exposed. This also applies to the following embodiments.

(Example 3)
In the first and second embodiments, the exposure history data and / or print history data is stored data corresponding to the one-dimensional direction. In the third embodiment, the case of stored data corresponding to the two-dimensional direction will be described. To do.

  FIG. 7 shows an example of exposure history data corresponding to the third embodiment.

  This exposure history data is history data indicating a state in which data is accumulated in the height direction (perpendicular to the paper surface) with the main scanning direction X of the photoconductor 13 as the horizontal axis and the sub-scanning direction Y as the vertical axis (that is, the vertical direction of the drawing). Is an example of history data in a state in which the photosensitive member 13 is developed), and exposure is performed for each intersection (or a constant width intersection region) in the main scanning direction (axial direction) X and the sub-scanning direction (rotation direction) Y. The accumulated data corresponding to the two-dimensional direction in which the obtained amount is sequentially accumulated. In FIG. 7, each intersection area is color-coded according to the exposure amount. Basically, the intersection area where the exposure amount is large is dark, and the intersection area where the exposure amount is small is shown lightly. Thus, by making the data to be stored data corresponding to the two-dimensional direction, the accuracy when changing the direction of the image to be exposed is improved, and the effect of equalization is further increased.

  In the third embodiment, the print history data is data corresponding to the one-dimensional direction shown in FIG. 6A.

  In the control unit 50, using the exposure history data shown in FIG. 7 and the print history data shown in FIG. 6A, control for changing the direction of the image (electrostatic latent image) formed on the surface of the photoreceptor 13 is performed as follows. To do.

  First, the control unit 50 temporarily converts the data corresponding to the two-dimensional direction shown in FIG. 7 into data corresponding to the one-dimensional direction. Here, the data obtained by converting the data corresponding to the two-dimensional direction shown in FIG. 7 into the data corresponding to the one-dimensional direction is assumed to correspond to the data shown in FIG.

  Next, the control unit 50 determines the orientation of the image to be exposed so that the distribution of the exposure amount on the photoconductor 13 is made uniform based on the data shown in FIG. 4 converted into data corresponding to the one-dimensional direction. To change.

  Specifically, the control unit 50 accumulates the exposure position and exposure amount data converted in the one-dimensional direction and the latest fixed period (for example, the latest one week, one month, three months, six months, etc.). 6A is compared with the data of the printing position and the printing amount corresponding to the one-dimensional direction shown in FIG. 6A, and the exposure amount is made uniform for each scanning line in the main scanning direction X (or for each intersection region of a certain width). As described above (that is, the deviation value of the distribution of the exposure amount for each scanning line (or for each intersection region having a constant width) becomes the smallest), the optimum change angle is determined from the above three change angles. To do.

  Next, the control unit 50 changes the exposure start position so that the distribution of the exposure amount on the photoconductor 13 is further uniformed based on the exposure history data corresponding to the two-dimensional direction shown in FIG.

  For example, in the example shown in FIG. 7, in the area on the right side in the main scanning direction X, a large area on the near side (lower side in the figure) in the sub-scanning direction Y is exposed, and the back side ( The upper area in the figure is hardly exposed. Further, the area on the near side in the sub-scanning direction Y (lower side in the figure) is exposed over almost the entire length in the main scanning direction X, but in the area on the far side (upper side in the figure) in the sub-scanning direction Y. In the main scanning direction X, almost no exposure is performed. Therefore, based on this result, the control unit 50 changes the exposure start position, that is, the exposure start position in the sub-scanning direction Y, which is the rotation direction of the photoconductor 13, from Y1 to, for example, Y2. As a result, the exposure area of the print data is shifted upward in FIG. 7 as a whole, so that there is a high possibility that an area with a small exposure amount is exposed.

  In the control unit 50, the orientation of the image to be exposed is changed so that the change angle determined above is obtained, the exposure start position is changed from Y1 to Y2, and the result is output to the optical scanning device 11.

  Thus, in addition to changing the orientation of the image to be exposed, the exposure start position is also changed, so that the exposure area of the photoconductor 13 can be used on an average basis.

  In the third embodiment, the print history data is described as data corresponding to the one-dimensional direction shown in FIG. 6A. However, the print history data also has the main scanning direction X of the photoconductor 13 as the horizontal axis and the sub-scanning direction. The history data corresponding to the two-dimensional direction of the developed state of the photosensitive member 13 with Y as the vertical axis may be used. Since this is a comparison between the data corresponding to the two-dimensional direction, more accurate control can be performed.

  In the third embodiment, it is first determined whether or not to change the orientation of the image to be exposed, and then whether or not to change the exposure start position. First, whether or not to change the exposure start position. It may be determined whether to change the orientation of the next image to be exposed.

Example 4
The fourth embodiment is an embodiment in which it is determined whether or not to change the orientation of the image and the exposure start position in consideration of parameters other than the exposure that damages the photosensitive member 13.

Here, as parameters other than exposure, chemical damage to the photosensitive member such as ozone and NO ₂ generated in the apparatus, mechanical damage to the photosensitive member by a cleaning blade, and the like can be considered. That is, chemical damage and mechanical damage differ in the amount of damage in the axial direction (main scanning direction X) of the photosensitive member 13 according to the respective characteristics, and also in the usage state of the apparatus and the installation environment. For this reason, it is not necessarily sufficient to make the distribution of only the exposure amount uniform in terms of effective use of the photoreceptor and stability of image quality. Therefore, considering both the amount of chemical damage and mechanical damage to the photoconductor and the amount of damage due to exposure, whether or not to change the orientation of the image to be exposed and the exposure start position, or the degree of change By determining, it becomes possible to achieve more effective use of the photoreceptor and stability of image quality.

  For example, in the exposure history data shown in FIG. 4, it seems that the exposure amount is averaged by using the left portion of the photoconductor 13, but other parameters shown in FIG. 8 (for example, ozone generated inside the apparatus) In consideration of the amount of damage on the surface of the photoconductor due to the above, as shown in FIG. Ozone generated inside is collected in an exhaust port provided on the back side of the apparatus, and is sucked and discharged to the outside. Therefore, the photoconductor 13 is also used more than the front side of the apparatus (right side in FIG. 8) when used for many years. The damage on the side (left side in FIG. 8) becomes larger.

  Therefore, in this case, the exposure may be performed as it is without changing the orientation of the image to be exposed.

(Example 5)
Example 5 is an example in consideration of the presence or absence of staples.

  In the stapling process, since the processing position is mechanically limited, it is not allowed to change the direction of the image to be exposed while ignoring this. Therefore, when a stapling instruction is input from the user, the control unit 50 determines whether or not to change the image orientation based on the instructed stapling position.

  Here, the determination as to whether or not to change may be made such that the orientation of the image to be exposed is not changed when a stapling instruction is input. Thereby, when changing the orientation of the image, it is possible to limit the image to one that is not affected by non-stapling or the like.

  On the other hand, even when there is an instruction for stapling, if the stapling positions are, for example, two positions on the rear and front of the paper, there is no problem even if the orientation of the image to be exposed is changed by 180 °. Therefore, when such a condition is met, the direction of the image to be exposed is changed by 180 °.

  Thereby, even when a stapling instruction is given, the distribution of the exposure amount on the photosensitive member 13 is made uniform by changing the direction of the image to be exposed.

(Example 6)
In the sixth embodiment, when the orientation of an image to be exposed is changed, the change itself and an angle to be changed are announced to the user.

  Here, as an announcement method, the direction of the image to be exposed may be changed and a change angle may be displayed as a message on the liquid crystal display of the display / operation unit 53. In addition, an audio output unit may be provided separately, and “the direction of the image to be exposed and the angle to be changed” may be output as audio from the audio output unit.

  According to this configuration, when the orientation of the image is changed, the orientation of the paper is also changed. Therefore, by notifying the user in advance, the user is not confused when taking out the printed matter from the image forming apparatus. .

(Example 7)
In each of the above embodiments, the exposure history data is described as being configured to be stored in the exposure history storage unit 52a. However, in Example 7, the history of exposure history data stored in the exposure history storage unit 52a is managed. It is configured to send to the server.

  That is, the image forming apparatus 1 according to the embodiment is configured to be able to communicate with a server (not shown) that manages the history via the communication I / F unit 51. Accordingly, every time the exposure history data in the exposure history storage unit 52a is updated, the control unit 50 transmits the updated data to the server.

  The timing at which the history data is transmitted to the server is not limited to the update time, but may be transmitted every predetermined period (for example, one week, one month, three months, etc.).

  According to this configuration, the remote server manages the exposure history for each photoconductor 13, so that the photoconductor 13 can be removed from the image forming apparatus 1 in the middle, and other image formation that can make the exposure dose distribution uniform. By attaching to the apparatus, the photoreceptor 13 can be effectively used.

  It should be noted that the embodiment disclosed herein is illustrative in all respects and does not serve as a basis for limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiment, but is defined based on the description of the scope of claims. Moreover, all the changes within the meaning and range equivalent to a claim are included.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image reader 3 Document feeder (ADF)
DESCRIPTION OF SYMBOLS 4 Image formation part 5 Paper feed cassette 7 Paper discharge tray 11 Optical scanning device 12 Developing device 13 Photoconductor 14 Drum cleaning device 15 Charger 17 Fixing device 21 Intermediate transfer belt 25 Belt cleaning device 26 Secondary transfer device 31 Fixing roller 32 Addition Pressure roller 33 Pickup roller 34 Registration roller 36 Paper discharge roller 50 Control unit 50a CPU
50b ROM
50c RAM
50d Exposure control unit 51 Communication I / F unit 52 Storage unit 52a Exposure history storage unit 52b Print history storage unit 53 Display / operation unit 54 Image processing unit 55 Bus

Claims (13)

An image forming apparatus including an optical scanning device that deflects a laser beam from a laser emitting unit with a deflector to form a scanning beam and writes an electrostatic latent image on the photosensitive member with the scanning beam,
Exposure history storage means for storing a history of exposure position and exposure amount on the photoreceptor;
Changing means for changing the orientation of the image to be exposed so that the distribution of the exposure amount on the photoconductor is made uniform based on the exposure position and the exposure amount stored in the exposure history storage means. An image forming apparatus. The image forming apparatus according to claim 1,
Printing history storage means for storing the history of the print position and print amount of past print data for a predetermined period of time set in advance;
The changing unit has a uniform distribution of the exposure amount on the photoconductor based on the exposure position and exposure amount stored in the exposure history storage unit and the print position and print amount stored in the print history storage unit. An image forming apparatus characterized in that the orientation of an image to be exposed is changed so as to be converted into an image. The image forming apparatus according to claim 1, wherein:
2. The image forming apparatus according to claim 1, wherein the exposure position and exposure history data stored in the exposure history storage means is data corresponding to a two-dimensional direction of an axial direction and a rotational direction of the photosensitive member. The image forming apparatus according to claim 1, wherein:
2. The image forming apparatus according to claim 1, wherein the exposure position and exposure history data stored in the exposure history storage means is data corresponding to a one-dimensional direction of the axial direction of the photoconductor. The image forming apparatus according to claim 3, wherein
The changing unit further changes the exposure start position so that the distribution of the exposure amount on the photoconductor is made uniform based on the exposure position and the exposure amount stored in the exposure history storage unit. Image forming apparatus. The image forming apparatus according to claim 5, wherein
The image forming apparatus according to claim 1, wherein the changing unit first determines whether or not to change the orientation of the image, and then determines whether or not to change the exposure start position. The image forming apparatus according to any one of claims 1 to 6, comprising:
2. The image forming apparatus according to claim 1, wherein the change by the changing unit is for each job or for a predetermined period set in advance. The image forming apparatus according to claim 1, wherein:
The changing unit equalizes the distribution of the exposure amount on the photoconductor based on the exposure position and exposure amount stored in the exposure history storage unit and the print position and print amount of the print data received this time. Thus, the image forming apparatus is characterized in that the orientation of an image to be exposed is changed at the start of printing. The image forming apparatus according to any one of claims 1 to 8, wherein
The image forming apparatus according to claim 1, wherein an angle for changing the orientation of the image is any one of 90 °, 180 °, and 270 °. The image forming apparatus according to any one of claims 1 to 9, wherein
The image forming apparatus according to claim 1, wherein the changing unit determines whether or not to change the orientation of the image in consideration of parameters other than the exposure that damage the photoconductor. An image forming apparatus according to any one of claims 1 to 10, wherein
The image forming apparatus according to claim 1, wherein when the user inputs a stapling instruction, the changing unit determines whether to change the image orientation based on the instructed stapling position. An image forming apparatus according to any one of claims 1 to 11, wherein
An image forming apparatus comprising an announcement means for announcing to the user that a change is to be made. An image forming apparatus that deflects a light beam from a semiconductor laser or the like with a deflector to form a scanning beam and optically writes an electrostatic latent image on the photosensitive member with the scanning beam,
An image forming apparatus comprising: transmission means for transmitting history data of exposure positions and exposure amounts on the photosensitive member stored in the exposure history storage means to a server that manages the history.