JP4839693B2 - Image forming apparatus and exposure unit position adjusting method in image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus provided with a detachable exposure apparatus and an exposure unit position adjusting method in the image forming apparatus.

  In recent years, a laser or LED (Light Emitting Diode) is known as an exposure light source of an exposure apparatus in an image forming apparatus that forms an image on a recording medium. As an exposure apparatus that employs an LED as an exposure light source, for example, a plurality of LEDs arranged according to a resolution set in advance along the main scanning direction of the exposure apparatus, and LEDs emitted according to image data are used. 2. Description of the Related Art An LED print head is known that includes optical means such as a GRIN (Graded-Index) lens that collects irradiated light to form an electrostatic latent image on a photoreceptor.

  The GRIN lens used in the LED print head is easily contaminated because it is easily affected by the surrounding environment. When the GRIN lens becomes dirty, the amount of light as an exposure apparatus is reduced, which may cause a reduction in image quality. Therefore, there is an operation for removing the LED print head every predetermined number of times of driving and cleaning the LED print head including the GRIN lens to recover the decrease in light amount.

  When the LED print head is not installed at an appropriate position with respect to the photoconductor (for example, when the relative distance between the photoconductor and the LED print head is not uniform in the main scanning direction), the LED The distance between the irradiation surface of the print head and the latent image surface of the photoconductor is not a predetermined distance, and the beam diameter of the light emitted from the LED varies, resulting in unevenness in the latent image, resulting in uneven density and blurring of line drawings. There is a problem that the image quality is deteriorated such that an image formed due to the occurrence of the image becomes unclear.

  Therefore, based on the measurement means (density sensor) obtained by measuring the respective density distributions from the image carrier on which the first and second toner images are formed, and the shift amount between the first and second density distributions. An exposure unit automatic focus adjustment and inclination correction apparatus having an MTF, and an inclination correction means for correcting the distance between the LED print head and the photosensitive drum and the inclination of the LED print head relative to the photosensitive drum so that the MTF is maximized. It is disclosed.

In addition, the measurement means (density sensor) that obtains the density distribution of the image carrier on which the toner image is formed, the MTF is obtained based on the density distribution, and the LED print head and the photosensitive drum so that the MTF is maximized. And an exposure unit automatic focus adjustment device having an inclination correction means for correcting the inclination of the LED print head relative to the photosensitive drum.
JP 2004-148748 A JP 2004-151543 A

  However, an image forming apparatus equipped with such a conventional exposure apparatus adjustment device needs to be provided with a measurement device dedicated to density distribution measurement, such as a potential measurement device that measures the potential on the photoreceptor in order to measure the density distribution. There is a problem that the cost of the entire apparatus increases. Further, the mechanism / device used by the service person who attaches / detaches the exposure apparatus to clean the exposure apparatus for the confirmation work after cleaning is large and the work efficiency is poor.

  An object of the present invention is to provide an image forming apparatus capable of improving the image quality formed on a recording medium at a low cost, and an exposure unit position adjusting method in the image forming apparatus.

According to a first aspect of the present invention, there is provided an image forming unit including a photoconductor and an exposure unit that is detachably attached in parallel to the photoconductor, and extends at the same density in the main scanning direction of the exposure unit. When a change in density appears in each divided area that is attached to each of the divided areas divided into a plurality of lines or strips and a predetermined interval along the main scanning direction of the exposure unit. Position adjustment amount for adjusting the position of the exposure unit by moving the end of the exposure unit in the main scanning direction in the direction in which the exposure unit irradiates light to the photosensitive member. A test image generating means for generating a test image comprising a sign image indicating a quantity, and a control means for causing the image forming means to perform an operation of forming the test image generated from the test image generating means on a recording medium And the image An input means for receiving a position adjustment amount of the exposure means in which the indicated marker image corresponding to the occurrence position of the density variation in the main scanning direction of the test image formed on the recording medium by forming means, the exposure means photoreceptor Adjusting means for adjusting the position of the exposure means by moving the end portion of the exposure means in the main scanning direction in the direction of irradiating the light, and adjusting the relative distance and / or parallelism between the photoconductor and the exposure means And a driving means for driving the adjusting means; a driving amount of the driving means is calculated based on the position adjustment amount received from the input means; and the driving means is driven based on the calculated driving amount. And an image forming apparatus including a drive control unit.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the test image is a linear or belt-like image extending at the same density in the main scanning direction, and the density is different from each other. It is characterized in that a plurality of exposure means are arranged at intervals in the sub-scanning direction.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the test images are spaced apart from each other in the main scanning direction of the exposure unit and in advance in the sub-scanning direction of the exposure unit. It includes a linear image group composed of a plurality of lines having a set length.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, a plurality of the linear image groups are arranged spaced apart from each other in the sub-scanning direction of the exposure unit. .

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the reading unit that reads the test image formed on the recording medium, and the reading unit reads the test image. It is determined whether or not a density change has occurred in the test image, and if it is determined that a density change has occurred, a density change position detecting means for specifying the position of the density change in the main scanning direction of the exposure means A position adjustment amount calculating means for calculating a position adjustment amount of the exposure means based on the position of the density change specified by the density change position detecting means, and a position adjustment amount calculated from the position adjustment amount calculating means. And a drive control means for driving the drive means based on the calculated drive amount.

According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the exposure unit includes a plurality of LEDs arranged in a main scanning direction of the exposure unit, and the LEDs And an optical means for condensing the light emitted from the light on the photoconductor to form an image.

According to a seventh aspect of the present invention, there is provided a linear or belt-like image extending at the same density in the main scanning direction of the exposure means detachably attached in parallel with the photosensitive member, and in the main scanning direction of the exposure means. A position adjustment amount of the exposure unit when a change in density appears in each divided region divided into a plurality of regions divided at predetermined intervals along the divided region. Test image generation for generating a test image comprising a marker image indicating a position adjustment amount when adjusting the position of the exposure means by moving the end of the exposure means in the main scanning direction in the direction of irradiating the body with light A step of performing a forming operation on the recording medium of the test image generated from the test image generating step, and an appearance position of the density change in the main scanning direction of the test image formed on the recording medium. Correspondingly An input step of accepting the position adjustment amount of the exposure means indicated by the label image, the location of the mobile to exposure means the ends of the main scanning direction of the direction in an exposure means for irradiating light the exposure means with respect to the photosensitive member adjusting the drive amount of the drive means for driving the adjusting means for adjusting the photoreceptor and the relative distance and / or parallelism between the exposing unit, is calculated based on the position adjustment amount that has been received from the input means, And a driving control step of driving the driving unit based on the calculated driving amount. The exposure unit position adjusting method in the image forming apparatus is characterized by the following.

According to an eighth aspect of the present invention, in the exposure unit position adjusting method in the image forming apparatus according to the seventh aspect , the test image includes linear or belt-like images extending at the same density in the main scanning direction. It is characterized in that a plurality of different densities are arranged at intervals in the sub-scanning direction of the exposure means.

A ninth aspect of the present invention is the exposure means position adjusting method in the image forming apparatus according to the seventh or eighth aspect , wherein the test images are spaced from each other in the main scanning direction of the exposure means, and the exposure means. And a linear image group including a plurality of lines having a length set in advance in the sub-scanning direction.

According to a tenth aspect of the present invention, in the exposure means position adjusting method in the image forming apparatus according to the ninth aspect , a plurality of the linear image groups are arranged at intervals in the sub-scanning direction of the exposure means. It is characterized by that.

The invention according to claim 11 is the exposure means position adjusting method in the image forming apparatus according to any one of claims 7 to 10 , wherein the reading step reads the test image formed on the recording medium; It is determined whether or not a density change has occurred in the test image read by the reading process, and if it is determined that a density change has occurred, the position of the density change in the main scanning direction of the exposure unit is specified. A density change position detecting step, a position adjustment amount calculating step for calculating a position adjustment amount of the exposure unit based on the position of the density change specified by the density change position detecting step, and the position adjustment amount calculating step. Drive that drives the adjustment unit based on the calculated position adjustment amount, and that drives the drive unit based on the calculated drive amount It is characterized in that it comprises a control step.

According to a twelfth aspect of the present invention, in the exposure unit position adjusting method in the image forming apparatus according to any one of the seventh to eleventh aspects, the exposure unit includes a plurality of exposure units arranged in the main scanning direction of the exposure unit. And an optical means for focusing the light emitted from the LED on the photoconductor to form an image.

According to the first or seventh aspect of the invention, an image in which the density change of the formed test image can be easily recognized, and the relative distance and / or parallelism between the exposure means and the photoconductor is the main scanning. Since it is possible to easily determine whether the image is uniform over the direction, an image forming apparatus that can improve the image quality formed on the recording medium at low cost can be provided. Further, the user can easily grasp the adjustment amount of the mounting position of the exposure means based on the sign image. In addition, since the position of the exposure unit is adjusted according to the input position adjustment amount, it is possible to save the user himself / herself from adjusting the position of the exposure unit using the adjustment unit, thereby improving convenience for the user. Can be made.

According to the invention described in claim 2 or 8 , since the same effect as in claim 1 or 7 can be obtained, a plurality of linear or belt-like images having different densities are formed. Since the visibility can be improved, the position adjustment accuracy of the exposure means can be improved.

According to the third or ninth aspect of the invention, the same effect as that of the first or second aspect, or the seventh or eighth aspect can be obtained. It can be easily recognized by the user, and it can be easily determined whether or not the relative distance and / or parallelism between the exposure means and the photoconductor is uniform over the main scanning direction.

According to the invention described in claim 4 or 10 , since the same effect as that of claim 3 or 9 can be obtained, a plurality of linear or belt-like images having different densities are formed. Since the visibility can be improved, the position adjustment accuracy of the exposure means can be improved.

According to the invention described in claim 5 or 11 , it is possible to obtain the same effect as that of any one of claims 1 to 4 or any one of claims 7 to 10. Since the position adjustment of the exposure unit is executed based on the test image, the user does not need to determine the change in the density of the test image, and the user himself / herself does not need to adjust the position of the exposure unit using the adjustment unit. Since it can be omitted, convenience for the user can be improved.

According to the invention described in claim 6 or 12 , the same effect as in any one of claims 1 to 5 or any one of claims 7 to 11 can be obtained. Since the position adjustment of the LED print head can be realized, the image quality formed on the recording medium can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the configuration will be described.
FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus 1 according to the present embodiment.
The image forming apparatus 1 reads an image from a document, forms an image of the read image on a recording medium P such as paper, and receives image data from a host device such as a PC, and records an image based on the image data. This is a digital multi-function peripheral having a printer function or the like that is formed on the medium P and output. As shown in FIG. 1, the image forming apparatus 1 includes an image reading unit 10 and a printing unit 20.

  The image reading unit 10 includes an automatic document feeder 11 called an ADF (Auto Document Feeder) and a reading unit 12.

  The automatic document feeder 11 includes a paper feed roller 11a that sequentially conveys documents stacked on the document tray 11g from the top, and a contact roller 11b that allows the document to pass through a contact glass that is a reading portion of the document while being in close contact therewith. And a guide roller 11c for guiding the document conveyed by the paper feed roller 11a along the contact roller 11b. A switching claw 11d that switches the transport direction of the document that has passed through the contact glass, a reversing roller 11e for reversing the front and back of the document, and a paper discharge tray 11f that discharges the document that has been read are provided.

  The reading unit 12 includes a scanner including a light source, a lens, a contact glass, a CCD (Charge Coupled Device) image sensor, and the like, and forms an image of reflected light of the light irradiated on the document and photoelectrically converts the light. An original image (analog image signal) is read, A / D converted, subjected to various image processing, and then output to the printing unit 20 as print data. Here, the image means not only image data such as graphics and photographs but also text data such as characters and symbols.

  The print unit 20 performs electrophotographic image formation based on input print data, and includes an image forming unit 30, a cleaning unit 40, a paper feeding unit 50, a transport unit 60, and a fixing unit. 70.

  The image forming unit 30 includes a photosensitive drum 31, a charging device 32, an LED printer head (hereinafter referred to as LPH) 33 as an exposure unit, a developing device 34, and a transfer device 35. Specifically, the photosensitive drum 31 charged by the charging device 32 is irradiated with light from the LPH 33 to form an electrostatic latent image. Then, the developing device 34 forms a toner image by attaching charged toner to the surface of the photosensitive drum 31 on which the electrostatic latent image is formed. The toner image formed on the photosensitive drum 31 by the developing device 34 is transferred to the recording medium P by the transfer device 35.

  Further, the image forming unit 30 realizes a function as an image forming unit that forms on the recording medium P a test image generated by the image developing unit 300 described later using the LPH 33.

  The LPH 33 includes a plurality of light emitting diodes (LEDs) arranged in the main scanning direction X as an exposure light source, and optical means in which a plurality of GRIN (Graded-Index) lenses are arranged in the main scanning direction X. The LED is selectively driven on the basis of image data generated by an image developing unit, which will be described later, and the light emitted from the driven LED is condensed on the photosensitive drum 31 to form an image. The LPH 33 is detachable from the image forming apparatus 1 for maintenance such as cleaning.

FIG. 2 shows a schematic diagram of the positional relationship between the LPH 33 and the photosensitive drum 31.
As shown in FIG. 2, the LPH 33 has a constant parallelism between the longitudinal direction W of the LPH 33 and the direction orthogonal to the moving direction of the photosensitive drum 31 (main scanning direction X), and the LPH 33 transmits light to the photosensitive drum 31. Of the adjusting mechanisms 310 and 320 provided at both ends of the LPH 33 so that the relative distance Z between the LPH 33 and the photosensitive drum 31 in the direction of irradiating the light is set at a predetermined distance in the main scanning direction X. The attachment portions 313 and 323 are detachably supported.

  The adjustment mechanisms 310 and 320 provided at both ends of the LPH 33 include screw members 311 and 321, support members 312 and 322, and attachment members 313 and 323. The screw members 311 and 321 are respectively coupled to attachment members 313 and 323 to which the end portions of the LPH 33 are attached, and are provided so as to be rotatable with respect to the support members 312 and 322. The adjusting mechanisms 310 and 320 adjust the position of the LPH 33 by moving the end of the LPH 33 in the directions Z1 and Z2 in which the LPH 33 irradiates the photosensitive drum 31 with light according to the rotation direction of the screw members 311 and 312. A function as an adjusting means is realized.

  After the toner image is transferred to the recording medium P, the cleaning unit 40 removes residual charges, residual toner, and the like on the surface of the photosensitive drum 31.

The paper feed unit 50 includes a plurality of paper feed trays 51 and a manual feed tray 52.
The paper feed tray 51 accommodates recording media P identified in advance for each size and type for each paper feed tray 51, and the recording media P accommodated by the paper feed rollers 51a are conveyed one by one from the top. Transport toward 60. The manual feed tray 52 can be loaded with various types of recording media P according to the needs of the user each time, and the recording media P loaded by the paper feed rollers 52a are fed one by one from the top to the transport unit 60. Transport toward.

  The transport unit 60 transports the recording medium P transported from the paper feed tray 51 or the manual feed tray 52 to the transfer device 35 via a plurality of intermediate rollers 61a, 61b, 61c and a registration roller 62.

  The fixing unit 70 thermally fixes the toner image transferred to the recording medium P transported by the transport unit 60. The recording medium P that has been subjected to the fixing process is output between the paper discharge rollers 63 and the paper output tray 64.

FIG. 3 shows a control block diagram of the image forming apparatus 1.
As shown in FIG. 3, the image forming apparatus 1 includes a main body control unit 100, a mechanism control unit 200, an image development unit 300, an image memory 400, an operation display unit 500, an external I / F 601, an image reading unit 10, a printing unit ( (Not shown) and the like, and each unit is connected by a bus 602 as communication means.

  The main body control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an HDD (Hard Disk Drive) 105 connected via an I / F 104, and the like. Yes.

  The CPU 101 reads the system program, each processing program, and data stored in the ROM 102 and develops them in the RAM 103 or the HDD 105, and centrally controls the operation of each part of the image forming apparatus 1 according to the developed programs. Timing control of the entire system, storage and storage control of image data using the RAM 103 or HDD 105, image processing (magnification, filter, γ conversion, etc.) of image data sent from the image reading unit 10 and the like for the printing unit 20 It performs input / output control of image data, interface (I / F) with other applications (FAX, printer, scanner, etc.) and operation control.

  Further, the CPU 101 temporarily stores image data transmitted from an external device such as a PC (Personal Computer) received via the external I / F 601 or image data transmitted from the image reading unit 10 in the RAM 103 or the HDD 105. And print data based on the image data is developed in the image development unit 300. The CPU 101 outputs a start instruction signal to the mechanism control unit 200 to cause each unit of the image forming apparatus to operate.

  The ROM 102 stores programs and data corresponding to the image forming apparatus 1 in advance, and stores a system program, various processing programs corresponding to the system, and data necessary for processing by the various processing programs. The ROM 102 also includes a test image generation program for forming a test image formed on the recording medium in the present embodiment, a plurality of patches such as the number of patches formed as test images to be described later and density information of each patch. Various data necessary for generating a test image, such as information on the number of divisions (number of regions) for dividing the latent image region in the main scanning direction X that can be latent images by the LPH 33 into a plurality of equal intervals. Pre-stored.

  The RAM 103 and the HDD 105 serve as temporary storage areas for programs, input or output data and parameters read from the ROM 102 in various processes executed by the CPU 101.

  The mechanism control unit 200 comprehensively controls various drive mechanisms and various sensors in the image forming apparatus 1 based on signals from the main body control unit 100. For example, the mechanism control unit 200 rotates the photosensitive drum 31 at a constant speed. The motor to be driven is controlled.

  The image development unit 300 generates data to be printed based on the print data received from the main body control unit 100 and stores the data in the page memory 401 in the image memory 400.

  The image development unit 300 also functions as a test image generation unit that generates a test image based on a test image generation program stored in the ROM 102, information such as the number of patches, density information of each patch, and the number of divisions. Realize.

  The image memory 400 includes a page memory 401 configured using a DRAM (Dynamic RAM) or the like. The page memory 401 is a memory for storing the print data generated by the image development unit 300, and outputs various signals based on the generated print data to the LPH 33 to drive the LPH 33.

  The operation display unit 500 includes an LCD (Liquid Crystal Display), an operation key group, an operation display control unit, and the like. On the LCD, a touch panel is provided so as to cover the LCD, and the operation display control unit performs various setting screens and image forming apparatuses for inputting various setting conditions in accordance with display signals input from the main body control unit 100. Are displayed on the LCD. In addition, the operation display control unit transmits an operation signal input from the operation key group or the touch panel to the main body control unit 100.

  The external I / F 601 is configured with various interfaces such as a network interface card (NIC), a modem (MODEM: DE-Modulator), and a USB (Universal Serial Bus), and is connected to be communicable. Send and receive information to and from each other.

  The LPH 33 includes an LED mounting substrate 33a on which a plurality of LEDs are mounted, optical means such as a GRIN lens array 33b in which a plurality of GRIN lenses are arranged to form an image of light emitted from the LEDs on the photosensitive drum 31, LED driving / A light amount correction circuit unit 33c is provided.

  The LED drive / light quantity correction circuit unit 33 c is a circuit that performs light quantity correction and drive operation of each LED based on a signal input from the image memory 400.

  LEDs are driven under the same conditions due to variations in mechanical and electrical characteristics during LED manufacturing, variations in the current resistance of the LED drive circuit, and electrical variations in the mounting member (LED mounting board 33a, etc.). However, it is known that a difference occurs in the light amount of each LED. Therefore, the LED drive / light quantity correction circuit unit 33c includes a correction unit that corrects the current amount and the rising drive characteristic for each LED and the light quantity of each LED so that the variation in the light quantity of the entire LPH 33 is within a certain range. Is provided.

FIG. 4 shows an example of a test image.
The test image T shown in FIG. 4 is formed of a plurality of patches P1, P2, and P3, a plurality of linear image groups L1, L2, and L3, and a marker image group MG.

  The plurality of patches P1, P2, and P3 are linear or strip-like images that extend at the same density in the main scanning direction X, and are spaced at different densities in the recording medium transport direction Y (sub-scanning direction of the LPH 33). It is arranged in multiple places. The density of each patch is preferably lower than the maximum output density that the image forming apparatus 1 can form. For example, when forming a black (Bk) patch, the maximum output density is 100% ( That is, a patch having a density of 10 to 30% with respect to black solid) is preferable. Further, in the case of an image forming apparatus that forms a color image, it is preferable that the density of the patch is set for each toner color. Furthermore, the patch is preferably formed by screen processing.

  The patch in the present embodiment is an example of a patch set to the same density over the entire width of the LPH 33 (the entire width region of the photosensitive drum 31). However, in order to reduce resources such as toner, the LPH 33 Alternatively, the patches may be formed in the region near the both ends of each of the two at the same density. Note that the shape of the patch is not limited to this, and any patch may be used as long as it can visually recognize a change in density caused by the relative distance Z between the LPH 33 and the photoconductor 31 becoming non-uniform in the main scanning direction X.

  The density change caused by the non-uniform relative distance Z between the LPH 33 and the photoconductor 31 in the main scanning direction X causes unevenness in the light intensity distribution on the photoconductor drum 31 due to the shift of the imaging position. This is a striped pattern generated by non-uniform density appearing in the recording medium conveyance direction Y (sub-scanning direction of LPH 33).

  By forming a plurality of patches having different densities, it is possible to improve the visibility of density changes, and therefore it is possible to improve the position adjustment accuracy of the LPH 33. Further, by forming patches set to the same density over the entire width of the LPH 33 (the entire width region of the photosensitive drum 31), the density change in the main scanning direction X that occurs in each patch can be easily recognized. It is possible to easily grasp whether or not the relative distance Z between the LPH 33 and the photosensitive drum 31 is uniform in the main scanning direction X.

  The plurality of linear image groups L1, L2, and L3 are spaced apart from each other in the main scanning direction X of the LPH 33, and have a predetermined length in the recording medium conveyance direction Y (sub-scanning direction of the LPH 33). The linear image L is formed. The linear image L has only to be thick enough to visually recognize blur or the like of the linear image due to density change caused by the relative distance Z between the LPH 33 and the photosensitive drum 31 becoming non-uniform in the main scanning direction X. For example, it is preferably formed by one dot line or two dot lines. The arrangement interval of the linear images L in the main scanning direction X is preferably an interval (for example, 10 [mm]) at which each linear image L can be visually recognized.

  The sign image group MG is formed from a plurality of sign images M made up of numbers or symbols assigned to the divided regions E1 to E7 divided into a plurality at equal intervals in the main scanning direction X. M indicates the position adjustment amount of the LPH 33 when a density change appears in the corresponding divided area.

  Further, the sign image group MG includes a sign image (center sign image) M0 indicating the center part of the irradiation surface of the LPH 33 in the main scanning direction X in order to make the center part of the LPH 33 visible. If there is no non-uniform image in the divided area corresponding to the center mark image M0, it can be determined that the relative distance Z between the LPH 33 and the photosensitive drum 31 is uniform, and in the main scanning direction X. By discriminating whether or not the distance from the center marker image M0 to both ends of the LPH 33 is equal, the positional deviation of the LPH 33 in the main scanning direction X can be grasped.

  Thus, by forming the test image, the appearance position of the density change appearing in the test image is visually recognized, and the relative distance Z or / and parallelism between the LPH 33 and the photosensitive drum 31 is uniform in the main scanning direction X. And the position of the LPH 33 is adjusted using the adjusting mechanisms 310 and 320 so that the relative distance Z between the LPH 33 and the photosensitive drum 31 is uniform in the main scanning direction X. Can be adjusted. Therefore, it is possible to improve the image quality formed on the recording medium at a low cost without the need for providing a special measuring instrument or the like.

[Modification 1]
The above description is based on the position adjustment amount indicated by the sign image corresponding to the density change appearance position by visually confirming the test image formed by the service person who performs maintenance such as cleaning of the LPH 33. Although the case where the adjustment mechanisms 310 and 320 are manually adjusted has been described, in the first modification, the image forming apparatus 1 installs the LPH 33 based on the position adjustment amount indicated by the marker image corresponding to the appearance position of the density change. This is an example of adjusting by moving the position.

  The illustration and description of the configuration similar to that of the above embodiment is omitted, and only different portions will be described. The first modification includes a drive mechanism unit as a drive unit such as a motor that individually rotates the screw members 311 and 322 of the adjustment mechanisms 310 and 320, respectively.

  In addition, the operation display unit 500 according to the first modification serves as an input unit that receives a position adjustment amount (for example, “+1” illustrated in FIG. 4) indicated by the marker image corresponding to the appearance position of the density change that appears in the test image. Realize the function.

  The mechanism control unit 200 calculates a drive amount (for example, the number of rotations of the motor) for moving the installation position of the LPH 33 based on the position adjustment amount received by the operation display unit 500, and based on the calculated drive amount. A function as drive control means for driving the drive mechanism unit and adjusting the installation position of the LPH 33 is realized.

  FIG. 5 shows a schematic diagram of the positional relationship between the LPH 33 and the photosensitive drum 31 in the first modification. As shown in FIG. 5, the mechanism drive unit 330 includes motors M <b> 1 and M <b> 2 that are driven according to the drive amount (rotation speed) input from the mechanism control unit 200.

  The motors M1 and M2 are connected to rotate the screw members 311 and 321 respectively. As the motors M1 and M2, it is preferable to use stepping motors or DC motors with high positioning accuracy.

  When the motors M1 and M2 are driven in accordance with the drive amount input from the mechanism control unit 200, the screw members 311 and 312 are directed to the ends of the LPH 33, and the LPH 33 irradiates the photosensitive drum 31 with light. The position of LPH 33 is adjusted by moving to Z1 and Z2.

  In this way, if the service person inputs the position adjustment amount indicated by the marker image corresponding to the appearance position of the density change using the operation display unit 500, the installation position of the LPH 33 is adjusted according to the input position adjustment amount. Therefore, the trouble of manually adjusting the position of the LPH 33 by manually rotating the screw members 311 and 312 can be saved, and the convenience for the service person can be improved.

[Modification 2]
The second modification is an example in which the position adjustment of the LPH 33 in the first modification is further automated, and the specification of the presence / absence of the density change and the appearance position of the density change that the serviceman has determined is automated. Similar to the first modification, the second modification includes a drive mechanism unit 330 as a drive unit such as motors M1 and M2 that individually rotate the screw members 311 and 322 of the adjustment mechanisms 310 and 320, respectively.

  The illustration and description of the configuration similar to that of Modification 1 is omitted, and only different portions will be described.

  The image reading unit 10 according to the second modification implements a function as a reading unit that reads a test image formed on a recording medium.

  Further, the main body control unit 100 determines whether or not a density change appears in the main scanning direction X of each patch of the test image read from the image reading unit 10, and / or depends on the density change in each linear image. When it is determined whether or not there is a blur or the like, and when it is determined that a density change has occurred, a density change position detection unit that specifies the appearance position of the density change in the main scanning direction X, and the specified density A function as position adjustment amount calculation means for calculating the position adjustment amount of the LPH 33 based on the change appearance position is realized.

  Then, the mechanism control unit 200 calculates a drive amount (for example, the number of rotations of the motor) for moving the installation position of the LPH 33 based on the position adjustment amount calculated by the main body control unit 100, and sets the calculated drive amount. Based on this, the drive mechanism 330 is driven, and a function as drive control means for moving the installation position of the LPH 33 is realized.

  In this way, the service person simply reads the formed test image by the image reading unit 10, and the installation position of the LPH 33 is adjusted according to the adjustment amount calculated based on the test image. This eliminates the trouble of discriminating the presence / absence of the image and the appearance position of the non-uniform image, and also eliminates the trouble of manually rotating the screw members 311 and 312, which makes it convenient to adjust the installation position of the LPH 33. Can be improved.

  In this embodiment, the image forming apparatus using the electrophotographic method has been described. However, the image forming apparatus includes an exposure device using a PLZT optical shutter array and exposes digital image data to a silver salt recording medium. The same effect can be obtained even if the present invention is applied to the apparatus. When the present invention is applied to an image forming apparatus that exposes such digital image data onto a silver salt recording medium, it depends on the type of writing light source (the type of wavelength of the light source) and the optical response of the recording medium. Thus, the density of the patch is set.

  Further, the present invention is not limited to the contents of the above embodiment, and can be appropriately changed without departing from the gist of the present invention.

1 is a cross-sectional configuration diagram of an image forming apparatus 1 in the present embodiment. 3 is a schematic diagram of a positional relationship between an LPH 33 and a photosensitive drum 31. FIG. 2 is a control block diagram of the image forming apparatus 1. FIG. It is an example of a test image. 10 is a schematic diagram of a positional relationship between an LPH 33 and a photosensitive drum 31 in Modification 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image reading part 11 Automatic document feeding part 11a Paper feed roller 11b Contact roller 11c Guide roller 11d Switching claw 11e Reversing roller 11f Paper discharge tray 11g Document tray 12 Reading part 20 Printing part 30 Image forming part 31 Photosensitive drum 32 Charging device 33 LPH
33a LED mounting substrate 33b GRIN lens array 33c LED drive / light quantity correction circuit unit 34 Development device 35 Transfer device 40 Cleaning unit 50 Paper feed unit 51 Paper feed tray 51a, 52a Paper feed roller 52 Manual feed tray 60 Transport units 61a, 61b, 61c Intermediate roller 62 Registration roller 63 Paper discharge roller 64 Paper discharge tray 100 Main body control unit 101 CPU
102 ROM
103 RAM
104 I / F
105 HDD
200 Mechanism control unit 300 Image development units 310 and 320 Adjustment mechanisms 311 and 321 Screw members 312 and 322 Support members 313 and 323 Mounting members 330 Drive mechanism unit 400 Image memory 401 Page memory 500 Operation display unit 601 External I / F
602 Buses E1 to E7 Divided area L Linear images L1 to L3 Linear image group M Marked image M0 Center marker image M1, M2 Motor MG Labeled image group P Recording medium P1 to P3 Patch T Test image X Main scanning direction Y Recording medium Transport direction Z The relative distance between the LPH and the photosensitive drum (focal length)

Claims (12)

An image forming unit including a photoconductor and an exposure unit detachably attached in parallel to the photoconductor;
A linear or belt-like image extending at the same density in the main scanning direction of the exposure unit and each divided region divided into a plurality at predetermined intervals along the main scanning direction of the exposure unit. The position adjustment amount of the exposure unit when a density change appears in each of the divided areas, and the end of the exposure unit in the main scanning direction is moved in the direction in which the exposure unit irradiates light to the photosensitive member. A test image generating means for generating a test image comprising a marker image indicating a position adjustment amount when adjusting the position of the exposure means, and
Control means for causing the image forming means to perform a forming operation on the recording medium of the test image generated from the test image generating means;
An input unit that receives a position adjustment amount of the exposure unit indicated by the marker image corresponding to an appearance position of a density change in a main scanning direction of a test image formed on the recording medium by the image forming unit;
The exposure unit moves the end of the exposure unit in the main scanning direction in the direction of irradiating light to the photoconductor to adjust the position of the exposure unit, and the relative distance and / or parallel between the photoconductor and the exposure unit. Adjusting means for adjusting the degree;
Driving means for driving the adjusting means;
Drive control means for calculating a drive amount of the drive means based on the position adjustment amount received from the input means, and driving the drive means based on the calculated drive amount;
Having
An image forming apparatus. The test image is
A plurality of linear or belt-like images extending at the same density in the main scanning direction are arranged at different densities and spaced from each other in the sub-scanning direction of the exposure unit;
The image forming apparatus according to claim 1. The test image is
Including a linear image group composed of a plurality of lines spaced apart from each other in the main scanning direction of the exposure unit and having a preset length in the sub-scanning direction of the exposure unit;
The image forming apparatus according to claim 1, wherein: The linear image group is:
A plurality of the exposure means are arranged at intervals in the sub-scanning direction;
The image forming apparatus according to claim 3. Reading means for reading a test image formed on the recording medium;
It is determined whether or not a density change has occurred in the test image read by the reading unit. If it is determined that a density change has occurred, the position of the density change in the main scanning direction of the exposure unit is determined. A density change position detecting means to be identified;
A position adjustment amount calculating means for calculating a position adjustment amount of the exposure means based on the position of the density change specified by the density change position detecting means;
A drive control unit that calculates a drive amount of the drive unit based on the position adjustment amount calculated from the position adjustment amount calculation unit, and drives the drive unit based on the calculated drive amount;
Providing
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The exposure means is an LED print head comprising a plurality of LEDs arranged in the main scanning direction of the exposure means, and an optical means for focusing the light emitted from the LEDs on the photoreceptor to form an image. There is,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. A linear or belt-like image extending at the same density in the main scanning direction of the exposure means detachably attached in parallel with the photosensitive member, and a plurality of images at predetermined intervals along the main scanning direction of the exposure means A position adjustment amount of the exposure unit when a change in density appears in each divided region, and the exposure unit irradiates the photoconductor with light. A test image generating step for generating a test image comprising a marker image indicating a position adjustment amount when the end of the exposure means in the main scanning direction is moved to adjust the position of the exposure means ;
A step of performing a forming operation on a recording medium of the test image generated from the test image generation step;
An input step of receiving a position adjustment amount of the exposure unit indicated by the marker image corresponding to an appearance position of the density change in the main scanning direction of the test image formed on the recording medium;
The exposure unit moves the end of the exposure unit in the main scanning direction in the direction of irradiating light to the photoconductor to adjust the position of the exposure unit, and the relative distance and / or parallel between the photoconductor and the exposure unit. A drive control step of calculating a drive amount of a drive unit that drives an adjustment unit that adjusts the degree based on a position adjustment amount received from the input unit, and driving the drive unit based on the calculated drive amount When,
Including,
An exposure unit position adjusting method in an image forming apparatus. The test image is
A plurality of linear or belt-like images extending at the same density in the main scanning direction are arranged at different densities and spaced from each other in the sub-scanning direction of the exposure unit;
The exposure means position adjusting method in the image forming apparatus according to claim 7. The test image is
Including a linear image group composed of a plurality of lines spaced apart from each other in the main scanning direction of the exposure unit and having a preset length in the sub-scanning direction of the exposure unit;
The exposure means position adjusting method in an image forming apparatus according to claim 7 or 8. The linear image group is:
A plurality of the exposure means are arranged at intervals in the sub-scanning direction;
The exposure means position adjusting method in the image forming apparatus according to claim 9. A reading step of reading a test image formed on the recording medium;
It is determined whether or not a density change has occurred in the test image read by the reading process. If it is determined that a density change has occurred, the position of the density change in the main scanning direction of the exposure unit is determined. A concentration change position detection step to be identified;
A position adjustment amount calculation step of calculating a position adjustment amount of the exposure unit based on the position of the density change specified by the density change position detection step;
A drive control step of calculating a drive amount of a drive unit that drives the adjustment unit based on the position adjustment amount calculated from the position adjustment amount calculation step, and driving the drive unit based on the calculated drive amount; ,
Including,
The exposure unit position adjusting method in the image forming apparatus according to claim 7, wherein: The exposure means is an LED print head comprising a plurality of LEDs arranged in the main scanning direction of the exposure means, and an optical means for focusing the light emitted from the LEDs on the photoreceptor to form an image. There is,
12. The exposure unit position adjusting method in the image forming apparatus according to claim 7, wherein the exposure unit position is adjusted.

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