JP4701839B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus capable of adjusting a shift of an image forming position.

  2. Description of the Related Art Conventionally, there has been known an image forming apparatus capable of forming a color image by providing a plurality of image forming units that form images of respective colors. For example, a color laser printer includes four photoconductors, and forms a toner image of each color of black (Bk), cyan (C), yellow (Y), and magenta (M) on each photoconductor. Then, these four color toner images are sequentially superimposed and transferred onto the recording medium conveyed by the conveying means, thereby forming a color image on the recording medium.

  In such an image forming apparatus, misregistration between the toner images of the respective colors may occur on the conveying unit due to an error of a laser optical system used for exposure of each photoconductor or an assembly error of the photoconductor. is there. Then, even in the image formed on the recording medium, a positional deviation occurs between the toner images of the respective colors.

  Therefore, in order to adjust this misregistration, a first color reference line is formed on the recording medium by the first image forming unit, and the other image forming unit intersects the reference line without being orthogonal to the reference line. In this way, the target lines of other colors are overlapped, the deviation of the intersection between the reference line and the target line is read by the scale, and the information on the deviation of the intersection read by the user is input, thereby scanning the laser used for exposure of the photosensitive member A technique has been proposed in which the start timing and the scanning range are adjusted to eliminate the positional deviation of each color (see Patent Document 1). According to Patent Document 1, it is not necessary to provide a sensor for reading the position shift of each color toner image, and the position shift can be adjusted with high accuracy at low cost.

Japanese Patent Laid-Open No. 11-218989

  However, in Patent Document 1, since the reference line is formed so as to extend in the main scanning direction or the sub-scanning direction, for example, as shown in FIG. 7A, when the reference line 1 is formed in the main scanning direction. The target line m that should originally be formed at the position of A is formed at the position of A1 with a positional shift only in the sub-scanning direction with respect to the reference line l. In the case of crossing, as shown in FIG. 7 (b), the target line m shifted to the position of A1 is slid in the sub-scanning direction and accurately adjusted to the position of A, but in FIG. 7 (c) As shown, the target line m that should originally be formed at the position A is formed at the position A2 with a positional shift with respect to the reference line l not only in the sub-scanning direction but also in the main scanning direction. If the reference line l intersects with “0”, the target line m is formed at the position A where it should be originally formed. And it is recognized, not at all made to adjust the positional deviation, there is a problem that as a result not accurately perform adjustment of the position deviation.

Accordingly, the present invention has been made in view of such a problem, and an object thereof is to provide an image forming apparatus capable of accurately adjusting a positional shift between toner images of respective colors at a low cost. And

  In order to achieve the above object, in the image forming apparatus according to claim 1, a first image forming unit that forms a developer image with a first color developer and a developer image with a second color developer. Second image forming means to be formed, transport means for transporting a recording medium carrying a developer image formed by the first image forming means and the second image forming means, and transport for transporting the recording medium by the transport means And a reference line formed by the first image forming means and carried on the recording medium so as to extend in a direction that intersects both directions perpendicular to the conveyance direction and a direction perpendicular to the conveyance direction or the conveyance direction The input means for inputting the information on the deviation of the intersection where the target line formed by the second image forming means and carried on the recording medium intersects, and the information on the deviation of the intersection inputted by the input means. And adjusting means for adjusting the relative positional deviation with respect to the reference line of the target line Zui, characterized by comprising a.

  The image forming apparatus according to claim 2 is characterized in that the information on the deviation of the intersection is based on a scale formed at a predetermined interval on the reference line by the first image forming means.

In the image forming apparatus according to claim 3, when the adjustment unit is formed on the recording medium so that the target line extends in the transport direction based on the information on the deviation of the intersection point input by the input unit , When the second image forming unit adjusts the scanning timing to start forming the target line in the direction orthogonal to the transport direction, and the target line is formed on the recording medium so as to extend in the direction orthogonal to the transport direction, The scanning timing for starting to form the target line in the transport direction by the two-image forming means is adjusted .

  According to the image forming apparatus of the first aspect, since the reference line is formed in a direction that intersects both the transport direction and the direction orthogonal to the transport direction, a position shift of the target line with respect to the reference line occurs in the transport direction, Even when the position deviation of the target line with respect to the reference line also occurs in the direction orthogonal to the conveyance direction, the position deviation can be accurately adjusted. Since the information on the intersection where the reference line and the target line intersect is input by the input unit, the relative positional deviation of the target line with respect to the reference line can be adjusted by the adjusting unit without using a reading sensor or the like. It is possible to reduce the cost of the apparatus.

  According to the image forming apparatus of the second aspect, the user can easily adjust the relative positional deviation of the target line with respect to the reference line by reading the scale and inputting the read scale information by the input unit. .

According to the image forming apparatus of the third aspect, when the target line is formed on the recording medium so as to extend in the transport direction, the second image forming unit starts to form the target line in a direction orthogonal to the transport direction. When the scanning timing is adjusted and the target line is formed on the recording medium so as to extend in a direction orthogonal to the transport direction, the scanning timing at which the target line starts to be formed in the transport direction is adjusted by the second image forming unit. Thus, it is possible to adjust the relative positional deviation of the target line with respect to the reference line.

[First Embodiment]
(overall structure)
An embodiment of the image forming apparatus of the present invention will be described below. Here, a tandem color laser printer 1 will be described as an image forming apparatus.

  First, the configuration of the color laser printer 1 of this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic sectional side view of the color laser printer 1. FIG. 2 is a block diagram showing the relationship between the control unit 67 of the color laser printer 1 and each component of the laser printer 1. The color laser printer 1 includes a visible image forming unit 3, a belt-like intermediate transfer body (ITB) 5, a fixing unit 7, a paper feeding unit 9, and a paper discharge tray 11.

<Configuration of visible image forming unit>
The visible image forming unit 3 serves as a first image forming unit for each visible image process using toner as a developer of black (Bk), cyan (C), yellow (Y), and magenta (M). The black visible image forming unit 3Bk, a cyan visible image forming unit 3C as a second image forming unit, a yellow visible image forming unit 3Y, and a magenta visible image forming unit 3M are divided into four. , Developing units 13Bk, 13C, 13Y, and 13M, photosensitive drums 15Bk, 15C, 15Y, and 15M, cleaning rollers 17Bk, 17C, 17Y, and 17M, charging units 19Bk, 19C, 19Y, and 19M, and exposure means, respectively. 21Bk, 21C, 21Y, and 21M.

  Hereinafter, each of these components will be described in detail.

<Developer configuration>
First, the developing device 13 (Bk, C, Y, M) is provided with developing rollers 23Bk, 23C, 23Y, 23M. The developing roller 23 (Bk, C, Y, M) is formed in a cylindrical shape using conductive silicone rubber as a base material, and further, a coating layer of a resin or rubber material containing fluorine is formed on the surface. The developing roller 23 (Bk, C, Y, M) does not necessarily have to be made of a conductive silicone rubber, and may be made of a conductive urethane rubber. The ten-point average roughness (Rz) of the surface is set to 3 to 5 μm, and is configured to be smaller than 9 μm which is the average particle diameter of the toner.

  Each developing device 13 (Bk, C, Y, M) is also provided with supply rollers 25Bk, 25C, 25Y, 25M. The supply roller (Bk, C, Y, M) is a conductive sponge roller, and is disposed so as to be in pressure contact with the developing roller 23 (Bk, C, Y, M) by the elastic force of the sponge. . As the supply roller 25 (Bk, C, Y, M), a foamed material such as conductive silicone rubber, EPDM, or urethane rubber can be used.

  Each developing device 13 (Bk, C, Y, M) is provided with a layer thickness regulating blade 27Bk, 27C, 27Y, 27M. The layer thickness regulating blade 27 (Bk, C, Y, M) is formed in a plate shape with a base end made of stainless steel or the like and fixed to the developer case 29Bk, 29C, 29Y, 29M, and the tip end is an insulating silicone rubber. Or an insulating fluorine-containing rubber or resin. The tip of the layer thickness regulating blade 27 (Bk, C, Y, M) is pressed against the developing roller 23 (Bk, C, Y, M) from below the developing roller 23 (Bk, C, Y, M). Is done.

  The toner stored in the developing device case 29 (Bk, C, Y, M) is a positively charged non-magnetic one-component developer, and a styrene-acrylic resin formed into a spherical shape by suspension polymerization. It has toner base particles having an average particle size of 9 μm formed by adding a well-known colorant such as carbon black and a charge control agent such as nigrosine, triphenylmethane, quaternary ammonium salt, or a charge control resin. The toner is constituted by adding silica as an external additive to the surface of the toner base particles. Further, the silica as the external additive is subjected to a known hydrophobizing treatment with a silane coupling agent, silicone oil or the like, the average particle diameter is 10 nm, and the addition amount is 0.6% by weight of the toner base particles. It is. Each developing device case 29 (Bk, C, Y, M) contains magenta, cyan, yellow, and black toners, respectively.

  Thus, the toner is an extremely spherical suspension polymerization toner, and further, 0.6% by weight of hydrophobically treated silica having an average particle diameter of 10 nm is added as an external additive, so that it is extremely fluid. Is excellent. Therefore, a sufficient charge amount can be obtained by frictional charging. Further, since there are no corners unlike the pulverized toner, it is difficult to receive mechanical force, has excellent followability to an electric field, and has good transfer efficiency.

<Configuration of photosensitive drum>
As an example, the photosensitive drum (OPC) 15 (Bk, C, Y, M) is formed by forming a positively chargeable photosensitive layer on an aluminum base material. The thickness of the photosensitive layer is 20 μm or more, and the aluminum substrate is used as an earth layer.

<Configuration of cleaning roller>
The cleaning roller 17 (Bk, C, Y, M) is a roller made of an elastic material such as a conductive sponge, and below the photosensitive drum 15 (Bk, C, Y, M), the photosensitive drum 15 ( Bk, C, Y, M). The cleaning roller 17 (Bk, C, Y, M) is configured so that a negative voltage having a polarity opposite to that of the toner is applied by a power source (not shown). The toner on the intermediate transfer member 5 is reversely transferred to the photosensitive drum 15 (Bk, C, Y, M) by the rubbing force with respect to Y, M) and the action of the electric field by the voltage, and the photosensitive drum 15 (Bk, C). , Y, M) is configured to remove the toner. In this embodiment, since a so-called cleanerless development method is employed, residual toner once removed by the cleaning roller 17 (Bk, C, Y, M) is removed in a predetermined cycle after the development process is completed. Return to the photosensitive drum 15 (Bk, C, Y, M) side again, collect with the developing roller 23 (Bk, C, Y, M), and return to the developing unit 13 (Bk, C, Y, M) for each color. It is configured as follows.

<Charger configuration>
The charger 19 (Bk, C, Y, M) is a scorotron type charger, and is more sensitive to the photosensitive drum 15 (Bk, C, Y, M) than the cleaning roller 17 (Bk, C, Y, M). On the downstream side in the rotation direction of M), the surface of the photosensitive drum 15 (Bk, C, Y, M) is opposed to the surface of the photosensitive drum 15 (Bk, C, Y, M) from the lower side of the photosensitive drum (Bk, C, Y, M). .

<Configuration of exposure means>
The exposure means 21 (Bk, C, Y, M) is composed of a known laser scanner unit. The exposure means 21 (Bk, C, Y, M) is arranged so as to overlap the developing unit 13 (Bk, C, Y, M) of the visible image forming unit 3 in the vertical direction, and the photosensitive drum. 15 (Bk, C, Y, M) and the charger 19 (Bk, C, Y, M) are arranged so as to overlap in the horizontal direction.

  The exposure means 21 (Bk, C, Y, M) is located downstream of the charger 19 (Bk, C, Y, M) in the rotational direction of the photosensitive drum 15 (Bk, C, Y, M). The surface of the photosensitive drum 15 (Bk, C, Y, M) is exposed with laser light.

  The surface of the photosensitive drum 15 (Bk, C, Y, M) is irradiated with laser light corresponding to the image data by the exposure means 21 (Bk, C, Y, M), so that the photosensitive drum 15 (Bk) is irradiated. , C, Y, M), an electrostatic latent image for each color is formed.

  The toner is positively charged, supplied from the supply roller 25 (Bk, C, Y, M) to the developing roller 23 (Bk, C, Y, M), and the layer thickness regulating blade 27 (Bk, C, Y, M). ) To form a uniform thin layer. Then, at the contact portion between the developing roller 23 (Bk, C, Y, M) and the photosensitive drum 15 (Bk, C, Y, M), it is formed on the photosensitive drum 15 (Bk, C, Y, M). The positively charged electrostatic latent image can be positively developed with positively charged toner by the reversal development method, and an extremely high quality image can be formed.

<Configuration of intermediate transfer member>
The belt-shaped intermediate transfer member 5 is formed by forming a conductive sheet such as polycarbonate or polyimide in a belt shape. As shown in FIG. 1, the belt-like intermediate transfer member 5 is stretched between two drive rollers 31 and 33, and is located in the vicinity of a position facing the photosensitive drum 15 (Bk, C, Y, M). Intermediate transfer rollers 35Bk, 35C, 35Y, and 35M are provided. The movement direction of the surface of the intermediate transfer member 5 on the side facing the photosensitive drum 15 (Bk, C, Y, M) is set to a direction of moving from the vertical direction upward to the downward direction.

  A predetermined voltage is applied to the intermediate transfer roller 35 (Bk, C, Y, M), and the toner image formed on the photosensitive drum 15 (Bk, C, Y, M) is transferred to the intermediate transfer member. 5 is configured so as to be transferred. In addition, a secondary transfer roller 37 is provided opposite to the roller 33 in the vertically downward direction with respect to the position where the toner image is transferred to the paper P as a recording medium, that is, the intermediate transfer member 5. A predetermined potential is also applied to the next transfer roller 37. As a result, the four color toner images carried on the belt-like intermediate transfer member 5 are transferred onto the paper P.

  As shown in FIG. 1, a cleaning device 39 is provided on the side of the intermediate transfer member 5 opposite to the side facing the photosensitive drum 15 (Bk, C, Y, M). The cleaning device 39 includes a scraping member 41 and a case 43. The toner remaining on the intermediate transfer member 5 is scraped off by the scraping member 41 and stored in the case 43.

<Configuration of fixing unit>
The fixing unit 7 includes a heating roller 45 and a pressure roller 47, and heats and presses the paper P carrying the four color toner images while nipping and conveying the paper P by the heating roller 45 and the pressure roller 47. As a result, the toner image is fixed on the paper P.

<Configuration of paper feed unit>
The paper feeding unit 9 is provided at the lowermost part of the apparatus, and includes a storage tray 49 that stores the paper P and a pickup roller 51 that feeds the paper P. The registration roller 53 as a conveying unit includes an exposing unit 21 (Bk, C, Y, M), a developing unit 13 (Bk, C, Y, M), a photosensitive drum 15 (Bk, C, Y, M), and The sheet P is supplied in a predetermined timing with the image forming process by the intermediate transfer member 5. The paper P fed from the pickup roller 51 is conveyed to the pressure contact portion between the intermediate transfer body 5 and the secondary transfer roller 37 by the registration roller 53.

<Configuration of device cover>
An upper surface cover 55 is provided at the uppermost portion of the apparatus so as to be rotatable about a shaft 55 a, and a part of the upper surface cover 55 constitutes the paper discharge tray 11. The paper discharge tray 11 is provided on the paper discharge side of the fixing unit 7, and is configured to store the paper P that is discharged from the fixing unit 7 and conveyed by the conveyance roller pairs 57, 59, and 61. Yes.

  Further, as shown in FIG. 1, the front cover 63 is configured to be rotatable about a shaft 63a in the arrow direction of FIG. By opening the front cover 63, the developing unit 13 (Bk, C, Y, M) can be replaced. Here, spring members 65Bk, 65C, 65Y, 65M are provided at positions where the front cover 63 faces the developing unit 13 (Bk, C, Y, M). When the front cover 63 is closed, the developing unit 13 ( Bk, C, Y, M) is configured to be pushed inward (to the left in FIG. 1).

<Configuration of control unit>
As shown in FIG. 2, the color laser printer 1 includes a control unit 67 as an adjustment unit including a CPU 69, a RAM 71, and a ROM 73. The control unit 67 controls the operation of the main motor 75, and the main motor 75 controls the photosensitive drum 15 (Bk, C, Y, M) and the driving rollers 31 and 33 through the driving gear 77. It is a motor to drive. Therefore, the control unit 67 controls the photosensitive drum 15 (Bk, C, Y, M) and the driving rollers 31 and 33 via the main motor 75 and the driving gear 77.

  Further, the control unit 67 includes the developing unit 13 (Bk, C, Y, M), the charging unit 19 (Bk, C, Y, M), the exposure unit 21 (Bk, C, Y, M), and the developing roller. 23 (Bk, C, Y, M) is controlled. And in order to take the timing which starts each each visible image formation part 3 (Bk, C, Y, M), it radiate | emits from each visible image formation part 3 (Bk, C, Y, M). The laser beam is detected by a BD sensor (synchronous detection sensor) 80.

  Further, when transferring the toner images of the respective colors onto the paper P, the control unit 67 is provided outside the main body of the color laser printer 1 when the toner images of the respective colors are not accurately superimposed and have shifted. The operation of each component of the laser printer 1 is controlled so as to adjust the positional deviation of the toner image of each color based on the information input by the operation key 90 as the input means.

(Example of image forming operation)
Next, the operation of the color laser printer 1 in the present embodiment as described above will be described.

  First, the photosensitive layer of the photosensitive drum 15 (Bk, C, Y, M) is uniformly charged by the charger 19 (Bk, C, Y, M).

  Next, the photosensitive layer of the photosensitive drum 15 (Bk, C, Y, M) is exposed according to the image data by the laser beam from the exposure unit 21 (Bk, C, Y, M). An electrostatic latent image for each color is formed on the exposed photosensitive layer of the photosensitive drum 15 (Bk, C, Y, M).

  In this exposure, laser beams from the exposure means 21 (Bk, C, Y, M) are respectively scanned at a predetermined scanning width on the photosensitive drum 15 (Bk, C, Y, M) by a polygon mirror (not shown). Thus, scanning is performed in the main scanning direction (direction orthogonal to the paper surface in FIG. 1). The scanning start position in this scanning is the laser light on the photosensitive drum 15 (Bk, C, Y, M) when a predetermined time has elapsed with reference to the time when the laser light is detected by the BD sensor 80 shown in FIG. It becomes the position.

  Then, the electrostatic latent image formed on the photosensitive layer of the photosensitive drum 15 (Bk, C, Y, M) by the black developing unit 13Bk, the cyan developing unit 13C, the yellow developing unit 13Y, and the magenta developing unit 13M A magenta toner, a cyan toner, a yellow toner, and a black toner are respectively attached to develop magenta, cyan, yellow, and black colors. The magenta, cyan, yellow, and black toner images formed in this way are once transferred onto the surface of the intermediate transfer member 5.

  Next, the toner remaining on the photosensitive drum 15 (Bk, C, Y, M) after the transfer is temporarily held by the cleaning roller 17 (Bk, C, Y, M). Each color toner image is formed to have a slight time difference in accordance with the moving speed of the intermediate transfer member 5 and the position of each photosensitive drum 15 (Bk, C, Y, M). The toner images of the respective colors are transferred so as to be superimposed on the intermediate transfer member 5.

  The four color toner images formed on the intermediate transfer member 5 as described above are transferred onto the paper P supplied from the paper supply unit 9 at the pressure contact position between the secondary transfer roller 37 and the intermediate transfer member 5. Is done. The toner image is fixed on the paper P in the fixing unit 7 and discharged onto the paper discharge tray 11. As described above, a four-color image is formed.

(Method of adjusting the positional deviation between the toner images of each color)
Next, in the color laser printer 1 of the first embodiment, a method for adjusting the positional deviation of the toner image of the other color that occurs with respect to the toner image of one color will be described. Since the adjustment method is the same as that for each color, in the first exemplary embodiment, the reference toner image is a black toner image, and the toner to be adjusted for relative positional deviation with respect to the reference black toner image. The image will be described as a yellow toner image.

  In the color laser printer 1 of the first embodiment, four color toner images are separately formed on the photosensitive drum 15 (Bk, C, Y, M), and these four color toner images are formed on the intermediate transfer member 5. Since the images are transferred in a superimposed manner, there are errors in the optical system in the exposure means 21 (Bk, C, Y, M) corresponding to each color, errors in assembly of the photosensitive drum 15 (Bk, C, Y, M), and the like. If there is, a positional deviation occurs between the toner images of the respective colors on the intermediate transfer member 5. If the toner image is transferred to the paper P in this state, the image of each color is displaced on the paper P.

  Therefore, the color laser printer 1 according to the first embodiment adjusts misalignment as follows. FIG. 3 is a diagram showing a reference pattern 101a and a target pattern 101b formed on the paper P, which are used when adjusting the positional deviation between the toner images of the respective colors in the conveyance direction of the paper P in the first embodiment. It is. FIG. 4 is an enlarged view showing the vicinity of the intersection Q where the reference pattern 101a and the target pattern 101b intersect. FIG. 5 shows the reference pattern 101a and the target pattern 101b formed on the paper P, which are used when adjusting the positional deviation between the toner images of the respective colors in the direction perpendicular to the conveyance direction of the paper P in the first embodiment. FIG. 3 and FIG. 5, an arrow written outside the paper P indicates the conveyance direction of the paper P.

<Adjustment of misalignment in the sub-scanning direction>
First, a method for adjusting the relative positional deviation of the yellow toner image that occurs in the paper P conveyance direction (hereinafter referred to as the sub-scanning direction) with respect to the black toner image will be described. As shown in FIG. 3, a misregistration adjustment pattern 101 including a reference pattern 101a as a reference line and a target pattern 101b as a target line is formed on a sheet P.

  The reference pattern 101a is formed using the black visible image forming unit 3Bk for forming a black image. The reference pattern 101a is composed of black line segments. The reference pattern 101a is formed on the paper P so as to extend so as to intersect both the sub-scanning direction and the direction orthogonal to the conveyance direction of the paper P (hereinafter referred to as the main scanning direction). Strictly speaking, as shown in FIG. 4, the reference pattern 101a is formed by a collection of rectangular black toner images whose longitudinal direction is parallel to the main scanning direction. As shown in FIG. 3, the reference pattern 101a has a scale 0 with the midpoint of the reference pattern 101a set to 0, and the scales 1, 2, 3, 4, 5 are formed at equal intervals on the right side of the scale 0. The scales -1, -2, -3, -4, and -5 are formed at equal intervals on the left side of the scale 0.

  The target pattern 101b is formed using a yellow visible image forming unit 3Y for forming a yellow image. The target pattern 101b is composed of yellow line segments. The target pattern 101b is formed on the paper P so as to extend in parallel with the main scanning direction.

  The image data corresponding to the reference pattern 101a and the target pattern 101b is stored in the ROM 73 (see FIG. 2) provided in the control unit 67. In addition, the ROM 73 also stores an angle θ formed by the reference pattern 101a and the target pattern 101b and a scale interval a (see FIG. 3). The control unit 67 controls the black visible image forming unit 3Bk and the yellow visible image forming unit 3Y based on the image data, and forms the reference pattern 101a and the target pattern 101b on the paper P.

  As shown in FIG. 3, even if the target pattern 101b is displaced by x in the main scanning direction with respect to the reference pattern 101a, the target pattern 101b is formed in parallel to the main scanning direction. Regardless of the size of the deviation x, the position of the intersection point Q with the reference pattern 101a is constant, so that it is possible to prevent the deviation in the sub-scanning direction from being erroneously adjusted.

  In FIG. 3, since the intersection point Q is on the scale “−2”, the user inputs “−2” using the operation key 90. When the information input with “−2” is transmitted to the control unit 67, the control unit 67 inputs “−2” into the following mathematical formula (1), and calculates the shift amount y in the sub-scanning direction.

数式（１）により副走査方向のずれ量ｙを算出した制御部６７は、対象パターン１０１bが副走査方向に対し、現在のタイミングよりｙだけ遅く、またはｙだけ早く形成されるように、ブラック可視像形成部３Ｂｋによる露光開始からイエロー可視像形成部３Ｙによる露光開始までの時間をずれ量ｙだけ増減して調整する。

The control unit 67 that has calculated the amount of deviation y in the sub-scanning direction using Equation (1) allows black so that the target pattern 101b is formed later by y or earlier than the current timing in the sub-scanning direction. The time from the start of exposure by the visual image forming unit 3Bk to the start of exposure by the yellow visible image forming unit 3Y is adjusted by increasing / decreasing by the shift amount y.

  As described above, the positional deviation of the yellow toner image with respect to the sub-scanning direction can be adjusted.

<Position adjustment in the main scanning direction>
Next, a method for adjusting the relative positional deviation of the yellow toner image generated in the main scanning direction of the paper P with respect to the black toner image will be described. As shown in FIG. 5, a misregistration adjustment pattern 101 ′ composed of a reference pattern 101a as a reference line and a target pattern 101b ′ as a target line is formed on the paper P.

  The reference pattern 101 ′ is composed of black line segments as in the reference pattern 101 formed at the time of adjusting the positional deviation in the sub-scanning direction, and scales from “−5” to “5” are formed. . Then, it is formed on the paper P so as to extend so as to cross both the sub-scanning direction and the main scanning direction.

  The target pattern 101b ′ is composed of yellow line segments, as is the case with the target pattern 101b formed when adjusting the positional deviation in the sub-scanning direction. The difference between the target pattern 101b ′ formed at the time of misalignment adjustment in the main scanning direction and the target pattern 102 formed at the time of misalignment adjustment in the sub scanning direction is that the paper extends so as to extend in parallel to the sub scanning direction. It is a point formed on P.

  As shown in FIG. 5, even if the target pattern 101b ′ is shifted by y in the sub-scanning direction with respect to the reference pattern 101a, the target pattern 101b ′ is formed in parallel in the sub-scanning direction. Regardless of the magnitude of the deviation y in the scanning direction, the position of the intersection point Q ′ with the reference pattern 101a is constant, so that it is possible to prevent the deviation in the main scanning direction from being erroneously adjusted.

  In FIG. 5, since the intersection point Q ′ is on the scale “−3”, the user inputs “−3” with the operation key 90. When the information input with “−3” is transmitted to the control unit 67, the control unit 67 inputs “−3” into the following formula (2), and calculates the shift amount x in the main scanning direction.

数式（２）により主走査方向のずれ量ｘを算出した制御部６７は、対象パターン１０１b'が主走査方向に対し、現在のタイミングよりｘだけ遅く、あるいは、ｘだけ早く形成されるように、イエロー可視像形成部３ＹによるレーザビームがＢＤセンサ８０によって検知されてから走査開始までの時間をずれ量ｘだけ増減して調整する。

The control unit 67 that has calculated the shift amount x in the main scanning direction according to Equation (2) causes the target pattern 101b ′ to be formed later than the current timing by x or earlier by x with respect to the main scanning direction. The time from the detection of the laser beam by the yellow visible image forming unit 3Y by the BD sensor 80 to the start of scanning is increased / decreased by the shift amount x.

  As described above, the positional deviation of the yellow toner image with respect to the main scanning direction can be adjusted.

  If both the adjustment of the relative displacement of the yellow toner image with respect to the black toner image in the sub-scanning direction and the adjustment of the relative displacement of the yellow toner image with respect to the black toner image in the main scanning direction are performed, even if both adjustments are performed Even when the toner image is misaligned in both the sub-scanning direction and the main scanning direction with respect to the black toner image, the misalignment in both directions can be accurately adjusted.

  Further, since the information of the intersection points Q and Q ′ at which the reference line 101a and the target line 101b and the reference line 101a and the target line 101b ′ intersect is input by the operation key 90, it is necessary to detect the positional deviation with a reading sensor or the like. In addition, the control unit 67 can adjust the relative positional deviation of the target line 101b with respect to the reference line 101a and the relative positional deviation of the target line 101b ′ with respect to the reference line 101a, thereby reducing the cost of the color laser printer 1. Become.

  Note that the relative displacement adjustment of the cyan toner image and the magenta toner image with respect to the black toner image may be performed in the same manner as the relative displacement adjustment of the yellow toner image with respect to the black toner image.

[Second Embodiment]
An image forming apparatus and a misregistration adjustment pattern 201 according to the second embodiment of the present invention will be specifically described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the component corresponding to 1st Embodiment, and the description which overlaps with 1st Embodiment is abbreviate | omitted. FIG. 6 shows a reference pattern 201a and target patterns 201b and 201b ′ formed on the paper P, which are used to adjust the positional deviation between the toner images of the respective colors in the two scanning directions in the second embodiment. FIG. An arrow written outside the paper P indicates the transport direction of the paper P.

  In this embodiment, as in the first embodiment, a target pattern parallel to one of the scanning directions is formed and the positional deviation in one scanning direction is adjusted, and then the reference pattern and the other scanning direction are adjusted. Rather than forming a parallel target pattern and adjusting the positional deviation in the other scanning direction, two reference patterns, a target pattern parallel to the sub-scanning direction and a target pattern parallel to the main-scanning direction, with respect to one reference pattern The target pattern is formed at a time, and the positional deviation in both scanning directions is adjusted.

  First, similar to the reference pattern 101a formed at the time of adjusting the positional deviation in the sub-scanning direction of the first embodiment, it is composed of black line segments, and scales from “−5” to “5” are formed. The reference pattern 201a is formed on the paper P so as to extend so as to intersect both the sub-scanning direction and the main scanning direction.

  Next, similar to the target pattern 101b formed at the time of adjusting the positional deviation in the sub-scanning direction and the target pattern 101b 'formed at the time of adjusting the positional deviation in the main scanning direction, target patterns 201b and 201b configured by yellow line segments are used. 'Is formed on the paper P so as to extend in parallel to the main scanning direction and the sub-scanning direction, and intersects the reference pattern 201a at the intersections Q and Q'.

  In FIG. 6, since the intersection point Q is on the scale “−2”, the user inputs “−2” using the operation key 90. When the information input with “−2” is transmitted to the control unit 67, the control unit 67 inputs “−2” into the above equation (1), and calculates the shift amount y in the sub-scanning direction.

  Since the intersection point Q ′ is on the scale “−3”, the user inputs “−3” with the operation key 90. When the information to which “−3” is input is transmitted to the control unit 67, the control unit 67 inputs “−3” to the above equation (2) and calculates the shift amount x in the main scanning direction.

  The control unit 67 that has calculated the amount of deviation y in the sub-scanning direction using Equation (1) enables black so that the target pattern 201b is formed later by y or earlier than the current timing in the sub-scanning direction. The time from the start of exposure by the visual image forming unit 3Bk to the start of exposure by the yellow visible image forming unit 3Y is adjusted by increasing / decreasing by the shift amount y.

  The control unit 67 that has calculated the shift amount x in the main scanning direction using Equation (2) causes the target pattern 201b ′ to be formed later than the current timing by x or earlier by x with respect to the main scanning direction. The time from the detection of the laser beam by the yellow visible image forming unit 3Y by the BD sensor 80 to the start of scanning is increased / decreased by the shift amount x.

  Thus, both the adjustment of the relative displacement of the yellow toner image with respect to the black toner image in the sub-scanning direction and the adjustment of the relative displacement of the yellow toner image with respect to the black toner image in the main scanning direction are both adjusted. Even when the toner image is misaligned in both the sub-scanning direction and the main scanning direction with respect to the black toner image, the misalignment in both directions can be accurately adjusted.

  Further, since the information of the intersections Q and Q ′ at which the reference line 201a and the target line 201b and the reference line 201a and the target line 201b ′ intersect is input by the operation key 90, it is necessary to detect the positional deviation with a reading sensor or the like. In addition, the control unit 67 can adjust the relative positional deviation of the target line 201b with respect to the reference line 201a and the relative positional deviation of the target line 201b ′ with respect to the reference line 201a, thereby reducing the cost of the color laser printer 1. Become.

  In addition, since the reference pattern 201a and the target patterns 201b and 201b ′ are formed by a single image forming process, it is possible to adjust the positional deviation in both scanning directions more efficiently.

  Note that the relative displacement adjustment of the cyan toner image and the magenta toner image with respect to the black toner image may be performed in the same manner as the relative displacement adjustment of the yellow toner image with respect to the black toner image.

[Modification]
The present invention has been described above based on the above embodiment, but the present invention is not limited to the above embodiment, and various improvements and modifications can be made without departing from the technical idea thereof.

  For example, the reference patterns 101a and 201a may not be formed of black line segments but may be formed of magenta, cyan, and yellow colors. Setting light-colored toner to the colors of the reference patterns 101a and 201a makes it difficult for the user to read the scale, so it is desirable to set dark-colored toner to the colors of the reference patterns 101a and 201a.

  The operation keys 90 as input means may be provided on the color laser printer 1 main body or on an information terminal device (not shown) connected to the color laser printer 1 via a network.

1 is a schematic sectional side view of a color laser printer 1. FIG. 2 is a block diagram illustrating a relationship between a control unit 67 of the color laser printer 1 and each component of the laser printer 1. FIG. FIG. 3 is a diagram illustrating a reference pattern 101a and a target pattern 101b formed on a sheet P, which are used when adjusting a positional deviation between toner images of respective colors in the conveyance direction of the sheet P in the first embodiment. It is an enlarged view showing the vicinity of the intersection Q where the reference pattern 101a and the target pattern 101b intersect. In the first embodiment, the reference pattern 101a and the target pattern 101b ′ formed on the paper P, which are used when adjusting the positional deviation between the toner images of the respective colors with respect to the direction orthogonal to the conveyance direction of the paper P, are shown. FIG. The figure which shows the reference | standard pattern 201a and target pattern 201b and 201b 'formed on the paper P used when adjusting the position shift with respect to the both scanning directions of the paper P between the toner images of each color in 2nd Embodiment. It is. (a) is a diagram showing a state in which the target line m, which should be originally formed at the position A, is formed at the position A1 with a positional shift in the sub-scanning direction with respect to the reference line l. . (b) is a figure which shows the state adjusted so that the target line m of Fig.7 (a) may be formed in the position of A. FIG. (c) shows that the target line m, which should be originally formed at the position A, is displaced in the scanning direction in the sub-scanning direction and the main scanning direction with respect to the reference line l to the position A2. It is a figure which shows the formed state.

DESCRIPTION OF SYMBOLS 1 Color laser printer (image forming apparatus) 3Bk Black visible image formation part (1st image formation means) 3M Magenta visible image formation part (2nd image formation means) 3C Cyan visible image formation part (2nd image formation means) ) 3Y yellow visible image forming unit (second image forming unit) 53 registration roller (conveying unit) 67 control unit (adjusting unit) 80 operation keys (input unit) 101, 102, 201 misregistration adjustment patterns 101a, 201a Pattern (reference line) 101b, 101b ', 201b, 201b' Target pattern (target line) P Paper (recording medium) Q, Q 'Intersection of reference pattern 101a, 201a and target pattern 101b, 201b and reference pattern 101a, 201a Of the target pattern 101b ', 201b'

Claims (3)

First image forming means for forming a developer image with a first color developer;
Second image forming means for forming a developer image with a second color developer;
Conveying means for conveying a recording medium carrying a developer image formed by the first image forming means and the second image forming means;
Formed by the first image forming unit and carried on the recording medium so as to extend in a direction intersecting both the transport direction in which the recording medium is transported by the transport unit and the direction orthogonal to the transport direction. Information on the deviation of the intersection at which the reference line that intersects the target line formed by the second image forming unit and carried on the recording medium so as to extend in the transport direction or in a direction orthogonal to the transport direction. Input means for inputting;
An image forming apparatus comprising: an adjusting unit configured to adjust a relative positional shift of the target line with respect to the reference line based on information on the shift of the intersection input by the input unit.   2. The image forming apparatus according to claim 1, wherein the information on the shift of the intersection is based on a scale formed on the reference line at a predetermined interval by the first image forming unit. In the case where the adjustment line is formed on the recording medium such that the target line extends in the transport direction based on the information on the shift of the intersection point input by the input unit , the second image forming unit Adjusting the scanning timing to start forming the target line in a direction orthogonal to the transport direction, and the target line is formed on the recording medium so as to extend in the direction orthogonal to the transport direction. The image forming apparatus according to claim 1 , wherein a scanning timing at which the target line is started to be formed in the transport direction is adjusted by a two-image forming unit.

Images