JP2010114498A - Image forming apparatus and image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and an image reading apparatus, capable of continuously reading reflection lights from at least two kinds of reference planes. <P>SOLUTION: An image reading section 30 is arranged on downstream side from an image forming section 10 on a sheet transfer path 60, and reads an image on a sheet P on which the image is formed by the image forming section 10. The image reading section has a reference member 33 arranged on a second surface side as a rear surface opposite to the first surface including the formed image of the sheet P when the sheet P is transferred and provided with at least two kinds of reference surfaces out of white reference surfaces 3311, 3312 as white reference, black reference surfaces 3321, 3322 as black reference and color reference surfaces 3331, 3332 which move to an image reading position on the sheet transfer path 60 and are read by the image reading means 32 in a state where a sheet is absent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image reading apparatus.

  2. Description of the Related Art Conventionally, there has been known an image forming apparatus such as an electrophotographic method or an ink jet method that includes an image reading unit that reads an image on a sheet on which an image has been formed. In such an image forming apparatus, for example, it is determined whether or not the color of the image read by the image reading unit is an intended color, and correction is performed as necessary.

  As a technique related to image reading, for example, a white reference surface serving as a reference for image correction is provided opposite to a reading optical system for reading an image, and the white reference surface can be moved in the document conveyance direction. A technique has been proposed in which correction data is read at a plurality of positions by moving to at least two different positions, the correction data are compared with each other, and if there is a difference, it is determined that the white reference surface is dirty (for example, a patent) Reference 1).

  Also, for example, a roller having a guide surface for guiding paper conveyance and a white reference surface as a reference for image correction is provided opposite to the reading optical system for reading an image, and this roller reads the guide surface when reading an image. A technique for switching to read the white reference plane during image correction has been proposed (see, for example, Patent Document 2).

  Also, for example, a roller having a black guide surface that guides paper conveyance and a white reference surface that serves as a reference for image correction is provided opposite to the reading optical system that reads an image. Has been proposed (see, for example, Patent Document 3).

In addition, for example, a technology is proposed in which a paper conveyance roller having a white reference surface serving as a reference for image correction is provided facing the reading optical system for reading an image, and the white reference surface is installed at a position recessed from the outer periphery of the roller. (For example, refer to Patent Document 4).
Japanese Patent Laid-Open No. 11-252331 JP 2001-313794 A JP 2003-348301 A Japanese Patent Laid-Open No. 05-319613

  An object of the present invention is to provide an image forming apparatus and an image reading apparatus capable of continuously reading reflected light from at least two types of reference surfaces.

The image forming apparatus according to claim 1, wherein the object is achieved.
Paper transport means for transporting paper,
An image forming unit that is provided on a paper transport path through which the paper is transported by the paper transport unit and forms an image on the transported paper;
An image reading unit that is disposed on the downstream side of the image forming unit on the paper conveyance path and reads an image on a sheet on which an image is formed in the image forming unit;
The image reading unit is
Illuminating an image reading position for reading an image from the paper on the paper transport path, an illumination light source disposed on the first surface side of the paper on which the image is formed when the paper is transported,
Image reading means for reading the reflected light from the first surface of the paper passing through the image reading position and generating image data;
When the paper is transported, the white paper is disposed on the second surface side which is the back surface of the first surface, moved to the image reading position, and read by the image reading means in the absence of the paper. And a reference member provided with at least two types of reference surfaces among a white reference surface serving as a reference for black, a black reference surface serving as a black reference, and a color reference surface serving as a color reference.

  Here, in the image forming apparatus according to claim 2, in addition to the at least two types of reference surfaces, the reference member further reads an image on a sheet passing through the image reading position by the image reading unit. It has a reading guarantee surface placed at a position facing the second surface of the sheet when the sheet is conveyed.

  The image forming apparatus according to claim 3, wherein the reference member has a rotatable polygonal prism shape, and one of the surfaces moves to the image reading position by rotation and the at least two types of reference surfaces The reading guarantee surface is a member formed on a surface having different polygonal column shapes.

  According to a fourth aspect of the present invention, in the reference member, the reference member has a polygonal column shape in which each of the at least two types of reference surfaces and the reading guarantee surface avoids a surface adjacent to the polygonal column shape. It is a member formed on a plurality of surfaces.

  The image forming apparatus according to claim 5, wherein the light reading member is disposed at a position where the image reading unit faces the first surface of the sheet when the sheet is conveyed at the image reading position. It is characterized by having a reading window.

Further, an image forming apparatus according to claim 6 is provided.
“The image reading unit includes a support member to which both the illumination light source and the image reading unit are fixed,
Of the paper transport path, a partial path through which the paper passes through the image reading unit is separated from both the upstream and downstream parts of the paper transport path and supported by the support member. Has been done "
It is characterized by that.

The image reading apparatus according to claim 7, which achieves the above object.
A sheet conveying means for conveying a sheet having an image formed on the first surface;
An image reading unit that is disposed on a paper transport path through which the paper is transported by the paper transport means and reads an image on the transported paper;
The image reading unit is
Illuminating an image reading position for reading an image from the paper on the paper transport path, an illumination light source disposed on the first surface side of the paper on which the image is formed when the paper is transported,
Image reading means for reading the reflected light from the first surface of the paper passing through the image reading position and generating image data;
When the paper is transported, the white paper is disposed on the second surface side which is the back surface of the first surface, moved to the image reading position, and read by the image reading means in the absence of the paper. And a reference member provided with at least two types of reference surfaces among a white reference surface serving as a reference for black, a black reference surface serving as a black reference, and a color reference surface serving as a color reference.

  Here, in the image reading apparatus according to claim 8, in addition to the at least two kinds of reference surfaces, the reference member further reads an image on a sheet passing through the image reading position by the image reading unit. It has a reading guarantee surface placed at a position facing the second surface of the sheet when the sheet is conveyed.

  The image reading apparatus according to claim 9, wherein the reference member has a rotatable polygonal column shape, and one of the surfaces moves to the image reading position by rotation, and the at least two types of reference surfaces The reading guarantee surface is a member formed on a surface having different polygonal column shapes.

  In the image reading apparatus according to claim 10, the reference member has a polygonal prism shape in which each of the at least two types of reference surfaces and the reading guarantee surface avoids a surface adjacent to the polygonal column shape. It is a member formed on a plurality of surfaces.

  Further, in the image reading apparatus according to claim 11, the light transmissive member is disposed at a position where the image reading unit faces the first surface of the sheet when the sheet is conveyed at the image reading position. It is characterized by having a reading window.

An image reading apparatus according to claim 12 is provided.
“The image reading unit includes a support member to which both the illumination light source and the image reading unit are fixed,
Of the paper transport path, a partial path through which the paper passes through the image reading unit is separated from both the upstream and downstream parts of the paper transport path and supported by the support member. Has been done "
It is characterized by that.

  According to the image forming apparatus of the first aspect and the image reading apparatus of the seventh aspect, the reflected light from the at least two kinds of reference surfaces can be continuously read at the image reading position.

  In the image forming apparatus according to claim 2 or the image reading apparatus according to claim 8, when the reading ensuring surface is moved to the image reading position, the at least two types of reference surfaces are retracted from the image reading position. The

  Further, according to the image forming apparatus according to claim 3 and the image reading apparatus according to claim 9, even if dust such as dust adheres to the at least two kinds of reference surfaces and the reading guarantee surface, the image forming apparatus can rotate a lot. The dust such as dust can be dropped by the rotation of the prismatic shape. According to the image forming apparatus of claim 3 or the image reading apparatus of claim 9, any one of the at least two types of reference planes and the reading guarantee plane by rotating a rotatable polygonal prism shape. When the surface is moved to the image reading position, the other surfaces except the one surface are retracted from the image reading position.

  Further, according to the image forming apparatus according to the fourth aspect and the image reading apparatus according to the tenth aspect, it is possible to switch to the reference surface or the reading ensuring surface free from dirt and dust. According to the image forming apparatus described in claim 4 and the image reading apparatus described in claim 10, a plurality of reference surfaces of the same type or a plurality of reading guarantee surfaces may be simultaneously soiled or dust attached. It is avoided that the patterns of dirt due to rubbing during rotation are the same.

  Further, according to the image forming apparatus of claim 5 or the image reading apparatus of claim 11, there is dirt or dust adhering to each reference surface or each reading security surface to be compared, or the reading window is dirty. It is possible to determine whether there is dust or dust.

  According to the image forming apparatus of claim 6 or the image reading apparatus of claim 12, the influence of vibrations from a portion upstream and a portion downstream from the partial path through which the paper passes the image reading portion is eliminated. Is done.

  Embodiments of the present invention will be described below with reference to the drawings.

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

  An image forming apparatus 1 illustrated in FIG. 1 is an image forming apparatus that employs a full-color tandem method, and includes an image forming unit 10, a sheet conveying unit 20, an image reading unit 30, a stain determination unit 40, and an image calibration. A necessity determination unit 50 is provided.

  As shown in FIG. 1, the image forming unit 10 includes an image forming unit 11 (11Y, 11M, 11C, 11K), an intermediate transfer body 12, a secondary transfer unit 13, a fixing device 14, and a cooler 15. It has.

  In the image forming unit 11, toners corresponding to the four color toners of Y (yellow), M (magenta), C (cyan), and K (black) are arranged in the circulation movement direction of the intermediate transfer body 12. A toner image is formed by electrophotography. That is, each image forming unit 11 includes a photoconductor 111, a charging unit 112, an exposure unit 113, a developing unit 114, a primary transfer unit 115, and the like, and toner images of each color of YMCK formed by each image forming unit 11 are stored. The images are sequentially superimposed on the intermediate transfer body 12 and transferred (primary transfer). The photosensitive member 111 is a drum-like member that forms an electrostatic latent image on the peripheral surface and holds the electrostatic latent image while rotating in the clockwise arrow A direction at a predetermined speed around an axis. . Further, the peripheral surface of the photosensitive member 111 is in contact with the intermediate transfer member 12. The charging unit 112 charges the peripheral surface of the photoconductor 111 to a predetermined potential. The exposure unit 113 forms an electrostatic latent image by irradiating the charged surface of the photoconductor 111 with a beam (reference numeral Bm in the figure) holding image information. The development unit 114 forms a toner image by attaching toner to the electrostatic latent image formed on the peripheral surface of the photoreceptor 111. The primary transfer unit 115 transfers (primary transfer) the toner image formed on the peripheral surface of the photoconductor 111 onto the intermediate transfer body 12. Here, a voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer unit 115, whereby the toner formed on the peripheral surface of the photoreceptor 111 corresponding to the toner of each color of YMCK. The images are sequentially electrostatically attracted onto the intermediate transfer member 12 so that a color toner image is formed on the intermediate transfer member 12 so as to overlap one another.

  The intermediate transfer body 12 is a belt-like member that forms a circumferential surface that circulates in the counterclockwise arrow B direction by various rolls. As these various rolls, a drive roll 121 that is driven by a motor (not shown) to circulate and move the intermediate transfer body 12, and has a function of giving a constant tension to the intermediate transfer body 12 and preventing meandering of the intermediate transfer body 12. A tension roll 122, an idle roll 123 that supports the intermediate transfer body 12, and a backup roll 132, which will be described later, are included.

  Here, the sheet conveying means 20 includes a pickup roll 22 that picks up and conveys the sheet P stored in the sheet tray 21 that is stored in a state where a plurality of sheets P are stacked, and a pickup roll 22. A transport roll 23 that transports the paper P picked up by the transport roller 60 along the paper transport path 60, and a transport chute 24 that feeds the paper P transported by the transport roll 23 to a secondary transfer position by the secondary transfer unit 13. , A transport belt 25 that transports the paper P after the secondary transfer to the fixing device 14, a transport chute 26 that feeds the paper P after the fixing to the cooler 15, and an image reading unit that transports the cooled paper P A transport roll 27 that feeds the paper P to 30 and a transport roll 28 that feeds the paper P that has passed through the image reading unit 30 to the outside of the image forming apparatus 1.

  The secondary transfer unit 13 includes a secondary transfer roll 131 disposed in contact with the toner image holding surface side of the intermediate transfer body 12 under pressure, and a back surface of the intermediate transfer body 12 with respect to the toner image holding surface side. And a backup roll 132 which is disposed at a location facing the secondary transfer roll 131 on the side and forms a counter electrode of the secondary transfer roll 131. A secondary transfer bias is stably applied to the backup roll 132. The metal power supply roll 133 is disposed in contact with the metal. A brush roll 134 for removing dirt attached to the secondary transfer roll 131 is disposed in contact with the secondary transfer roll 131. The secondary transfer unit 13 configured in this manner transfers (secondary transfer) the color toner images that overlap one on the intermediate transfer body 12 onto the conveyed paper P.

  Further, a belt cleaner 124 for cleaning the peripheral surface of the intermediate transfer body 12 after the secondary transfer is provided downstream of the secondary transfer unit 13 in the circulation movement of the intermediate transfer body 12. On the other hand, an image density sensor 125 for adjusting image quality is disposed upstream of the secondary transfer unit 13 in the circulating movement of the intermediate transfer body 12. Further, a reference sensor (home position sensor) that generates a reference signal that serves as a reference for taking the image forming timing in each image forming unit 11 is provided upstream of the Y-color image forming unit 11Y in the circulating movement of the intermediate transfer body 12. ) 126 is arranged. The reference sensor 126 recognizes a predetermined mark provided on the back surface of the intermediate transfer body 12 with respect to the toner image holding surface, generates a reference signal, and in response to an instruction based on the recognition of the reference signal, each image forming unit. Reference numeral 11 is configured to start image formation.

  The fixing device 14 is disposed downstream of the secondary transfer unit 13 in the paper transport direction. The fixing device 14 includes a fixing roll 141 having a heating mechanism 1411 and a pressure roll 142 provided so as to face the fixing roll 141. When the paper P that has passed through the secondary transfer unit 13 is conveyed between the fixing roll 141 and the pressure roll 142 facing each other, the unfixed toner that forms the color toner image on the paper P is fixed to the fixing roll 141. The heating mechanism 1411 is melted and fixed on the paper P, and an image composed of a fixed toner image is formed on the paper P.

  The cooler 15 is disposed downstream of the fixing device 14 in the sheet conveyance direction, and cools the fixed sheet P that has been conveyed. Thereby, the melted toner on the paper P is solidified.

  In the image forming apparatus 1 configured and operated in this manner, the image forming unit 10 forms an image based on the document image data on the paper P with a predetermined resolution.

  Next, the image reading unit 30 will be described.

  2 is an enlarged view of a portion C shown in FIG. 1, and FIG. 3 is a view of the image reading portion 30 shown in FIG. 2 as viewed from the left side in FIG.

  As shown in FIG. 1, the image reading unit 30 is provided downstream of the cooler 15 of the image forming unit 10 in the paper conveyance direction. The image reading unit 30 optically reads an image formed on the paper P by the image forming unit 10 and generates image data representing an image to be inspected. Hereinafter, the image data representing the image to be inspected is referred to as “inspection image data”. The image reading unit 30 optically reads any one of white reference surfaces 3311 and 3312, black reference surfaces 3321 and 3322, color reference surfaces 3331 and 3332, and read guarantee surfaces 3341 and 3342 described later. It also generates image data. Hereinafter, this image data is referred to as “dirt determination image data”.

  As shown in FIGS. 2 and 3, the image reading unit 30 includes an illumination light source 31, an image reading unit 32, a reference member 33, a reading window 34, and a support member 35.

  The illumination light source 31 is disposed on the first surface side on which an image is formed of the paper P when the paper P is transported, and the paper P in the paper transport path 60 passes through the image reading unit 30. An image reading position for reading an image from the paper P on the passing partial path 61 is illuminated.

  The image reading unit 32 includes three reflecting mirrors 321, an imaging lens 322, and an image sensor 323. The three reflecting mirrors 321 guide reflected light from the first surface of the paper P passing through the image reading position to the imaging lens 322 from the image reading position. The imaging lens 322 images the reflected light from the first surface of the paper P guided by the three reflecting mirrors 321 at the position of the image sensor 323. The image sensor 323 reads an image formed on the first surface of the paper P or in the absence of the paper P, white reference surfaces 3311 and 3312, black reference surfaces 3321 and 3322, color reference surfaces 3331, which will be described later. 3332 and an image sensor for reading any one of the read ensuring surfaces 3341 and 3342. The image sensor 323 receives the light imaged by the imaging lens 322 and generates inspection image data or dirt determination image data corresponding to the received light amount.

  The reference member 33 is disposed on the second surface side which is the back surface of the paper P when the paper P is conveyed. The reference member 33 has a rotatable octagonal prism shape, is rotated clockwise or counterclockwise by the drive source 330, and one of the surfaces moves to the image reading position by this rotation. On the two sides of the octagonal prism shape, avoiding the adjacent surfaces of the octagonal prism shape, the white reference white that is moved to the image reading position and read by the image reading means 32 in the absence of the paper P is provided. Each of the reference surfaces 3311 and 3312, the black reference surfaces 3321 and 3322 serving as the black reference, the color reference surfaces 3331 and 3332 serving as the color reference, and the reading guarantee surfaces 3341 and 3342 are formed to be replaceable. That is, here, the same kind of reference surface or the same reading guarantee surface is formed on the diagonal surface of the octagonal prism shape. The color reference surfaces 3331 and 3332 are formed by forming a plurality of different color patches. Further, the reading guarantee surfaces 3341 and 3342 face the second surface of the paper P when the paper P is conveyed when the image reading unit 32 reads the image on the paper P passing the image reading position. It is the surface placed at the position to be.

  The reading window 34 is a light transmitting member disposed at a position facing the first surface of the paper P when the paper P is conveyed at the image reading position.

  The support member 35 is a member to which both the illumination light source 31 and the image reading unit 32 are fixed. The partial path 61 of the paper transport path 60 through which the paper P passes the image reading unit 30 is separated and supported from both the upstream part and the downstream part of the partial transport path 61 of the paper transport path 60. It is supported by the member 35. The conveyance roll 27 and the conveyance roll 28 are arranged in the upstream portion and the downstream portion of the partial path 61, and these rolls vibrate when driven. With such a configuration, the reading in the image reading unit 30 is performed. In this case, the influence of the vibration is eliminated.

  Since the image forming apparatus 1 includes the image reading unit 30 as described above, the white reference surfaces 3311 and 3312, the black reference surfaces 3321 and 3322, and the color reference surfaces 3331 and 3332 formed on the reference member 33 are provided. By sequentially moving to the image reading position, reflected light from the white reference surfaces 3311 and 3312, the black reference surfaces 3321 and 3322, and the color reference surfaces 3331 and 3332 are continuously generated at the image reading position. Can be read. Further, since the reference member 33 has a rotatable octagonal prism shape, and one of the surfaces moves to the image reading position by rotation, white reference surfaces 3311 and 3312 formed on the reference member 33, black Even if dust such as dust adheres to the reference surfaces 3321 and 3322, the color reference surfaces 3331 and 3332, and the reading guarantee surfaces 3341 and 3342, the dust such as dust can be dropped by rotating the reference member 33. it can. Further, by rotating the reference member 33, any one of the white reference surfaces 3311 and 3312, the black reference surfaces 3321 and 3322, the color reference surfaces 3331 and 3332, and the reading guarantee surfaces 3341 and 3342 is set as the image reading position. By moving, the other surfaces except the one surface are retracted from the image reading position. Further, the same type of reference surface or the same reading guarantee surface is formed on the diagonal surface of the reference member 33 having an octagonal prism shape, that is, the same type of reference surface or the same reading guarantee surface is a distance from each other. Since the two reference surfaces of the same type or the two reading guarantee surfaces are soiled at the same time, or are simultaneously attached with dust, and the stain patterns due to rubbing during rotation are the same as each other Is avoided. Further, for example, since the white reference surface 3311, the black reference surface 3321, and the color reference surface 3331 can be read at the same position, the reading conditions of the illumination light source 31 and the image reading unit 32 can be different types. Can be the same with respect to the reference plane. Therefore, errors that occur during shading correction or color reading calibration of the image reading unit 30 can be greatly reduced.

  Here, an example will be described in which the density reference calibration of the image reading unit 30 is performed by reading each reference plane of white reference, black reference, and color reference.

  FIG. 4 is a diagram illustrating suppression of correction errors in the present embodiment when density reference calibration of the image reading unit is performed by reading each reference plane of white reference, black reference, and color reference. FIG. 5 is a diagram for explaining the generation of correction errors in the conventional example when the reference planes of white reference, black reference, and color reference are read to perform density reading calibration of the image reading unit.

  When the positions of the white reference, black reference, and color reference with respect to the reading optical system are different as in the conventional image reading unit, a difference occurs in illumination conditions and the like, as shown in FIG. A difference occurs in the reading value of the same density portion of the reference, and an error occurs in the amount to be corrected. In this embodiment, since each reference plane can be read under the same conditions, as shown in FIG. 4, there is no difference between the reading value of the white reference and the reading value of the same density portion of the color reference, and the amount to be corrected There is no error. That is, accurate correction is possible.

  Next, the dirt determination unit 40 will be described.

  The stain determination unit 40 is generated by reading one of the white reference surfaces 3311 and 3312, the black reference surfaces 3321 and 3322, the color reference surfaces 3331 and 3332, and the reading guarantee surfaces 3341 and 3342 by the image reading unit 30. Based on the dirt determination image data, it is determined whether there is dirt or dust attached to the read surface.

  Hereinafter, the stain determination unit 40 will be described in detail with reference to FIGS.

  FIG. 6 shows that one of the white reference surface 3311 of the two white reference surfaces 3311 and 3312 of the reference member 33 is read by the image reading unit 32 in the stain determination unit 40 and then the stain on one of the white reference surfaces 3311 is removed. It is a flowchart explaining the flow of operation | movement until it determines. Here, it is assumed that the other white reference surface 3312 of the two white reference surfaces 3311 and 3312 is not soiled.

  In the operation described in the flowchart shown in FIG. 6, the reference member 33 is rotated clockwise by the drive source 330, and one of the two white reference surfaces 3311 and 3312 is rotated by the rotation of the reference member 33 to the image reading position. Is started after being moved to (step S11).

  In the state where the sheet P is not present at the image reading position, the image reading unit 32 of the image reading unit 30 reads one white reference surface 3311 moved to the image reading position in step S11, and the image data for stain determination Is generated (step S12).

  The reference value when there is no dirt or dust adhering to one of the white reference surface 3311 and the reading window 34 is compared with the image data for dirt determination generated by reading the one white reference surface 3311 in step S12 ( Step S13).

  If the comparison result in step S13 is smaller than a predetermined value (for example, the density distribution fluctuation is within 3%), the stain determination image data generated by reading one white reference surface 3311 in step S12 is stored. The routine proceeds to the normal correction routine, and the operation shown in this flowchart ends. (Step S14).

  When the comparison result in step S13 is larger than a predetermined value (for example, the density distribution fluctuation is 3% or more), the reference member 33 is rotated counterclockwise by the drive source 330, and two white references are generated by this rotation. Of the surfaces 3311 and 3312, the other white reference surface 3312 is moved to the image reading position, and the other white reference surface is read by the image reading means 32 of the image reading unit 30 in a state where the sheet P is not present at the image reading position. 3312 is read, and dirt determination image data is generated (step S15).

  The stain determination image data generated by reading one white reference surface 3311 in step S12 is compared with the stain determination image data generated by reading the other white reference surface 3312 in step S15 (step S15). S16).

  If the comparison result in step S16 is smaller than a predetermined value (for example, the density distribution fluctuation is within 3%), it is determined that dirt other than the two white reference surfaces 3311 and 3312 (for example, dirt attached to the reading window 34). In step S12, the process proceeds to the normal correction routine using the dirt determination image data generated by reading one of the white reference planes 3311, and the operation shown in this flowchart ends. (Step S17).

  If the comparison result in step S16 is larger than a predetermined value (for example, the density distribution fluctuation is 3% or more), it is determined that one white reference surface 3311 is dirty (step S18).

  In response to the determination in step S18, the dirt reference image data generated by cleaning one white reference surface 3311, replacing one white reference surface 3311, or reading the other white reference surface 3312 in step S15. Is used to proceed to the normal correction routine, and a warning that one of the white reference planes 3311 is dirty is issued, and the operation shown in this flowchart ends. (Step S19).

  FIG. 7 shows an operation in the stain determination unit 40 after the two white reference surfaces 3311 and 3312 of the reference member 33 are read by the image reading unit 32 until the stain of the two white reference surfaces 3311 and 3312 is determined. It is a flowchart explaining the flow of.

  In the operation illustrated in the flowchart of FIG. 7, the reference member 33 is rotated clockwise by the drive source 330, and one of the two white reference surfaces 3311 and 3312 is rotated by the rotation of the reference member 33. Is started after being moved to (step S21).

  In a state where the sheet P is not present at the image reading position, the image reading unit 32 of the image reading unit 30 reads one white reference surface 3311 moved to the image reading position in step S21, and the image data for stain determination Is generated. Thereafter, the reference member 33 is rotated counterclockwise by the drive source 330, and by this rotation, the other white reference surface 3312 of the two white reference surfaces 3311 and 3312 is moved to the image reading position. In the absence of the paper P, the other white reference surface 3312 is read by the image reading unit 32 of the image reading unit 30 to generate image data for stain determination (step S22).

  The stain determination image data generated by reading one white reference surface 3311 in step S22 is compared with the stain determination image data generated by reading the other white reference surface 3312 in step S22 (step S22). S23).

  If the comparison result in step S23 is smaller than a predetermined value (for example, the density distribution variation is within 3%), the stain determination image data generated by reading one white reference surface 3311 in step S22 is stored. The routine proceeds to the normal correction routine, and the operation shown in this flowchart ends. (Step S24).

  If the comparison result in step S23 is larger than a predetermined value (for example, the density distribution fluctuation is 3% or more), the contamination determination image data generated by reading one white reference surface 3311 in step S22 Of the dirt determination image data generated by reading the other white reference surface 3312 in step S22, the white reference surface corresponding to the dirt determination image data whose value is closer to black is dirty. Is determined (step S25).

  Upon receiving the determination in step S25, cleaning the white reference surface determined to be dirty in step S25, replacing the white reference surface determined to be dirty in step S25, or dirty in step S25. The process proceeds to the normal correction routine using the image data for dirt determination generated by reading the white reference surface that has not been determined, and a warning that the white reference surface determined to be dirty is dirty, The operation shown in this flowchart ends. (Step S26).

  Here, the two white reference surfaces 3311 and 3312 of the reference member 33 are taken as an example and described with reference to FIGS. 6 and 7, but the two black reference surfaces 3321 and 3322 of the reference member 33 are also described. The contamination can be determined by the same operation flow as the flowcharts shown in FIGS.

  FIG. 8 shows a stain determination unit 40 that cleans one color reference surface 3331 after one of the two color reference surfaces 3331 and 3332 of the reference member 33 is read by the image reading unit 32. It is a flowchart explaining the flow of operation | movement until it determines. Here, it is assumed that the other color reference surface 3332 of the two color reference surfaces 3331 and 3332 is not soiled.

  In the operation described in the flowchart shown in FIG. 8, the reference member 33 is rotated clockwise by the driving source 330, and one of the two color reference surfaces 3331 and 3332 is rotated by the rotation of the reference member 33. (Step S31).

  In a state where the sheet P is not present at the image reading position, the image reading unit 32 of the image reading unit 30 reads one color reference surface 3331 moved to the image reading position in step S31, and the image data for stain determination Is generated (step S32).

  A reference value when no dirt or dust adheres to one color reference surface 3331 and the reading window 34 is compared with image data for stain determination generated by reading one color reference surface 3331 in step S32 ( Step S33).

  If the comparison result in step S33 is smaller than a predetermined value (for example, the density distribution variation is within 3%), the stain determination image data generated by reading one color reference surface 3331 in step S32 is stored. The routine proceeds to the normal correction routine, and the operation shown in this flowchart ends. (Step S34).

  When the comparison result in step S33 is larger than a predetermined value (for example, the density distribution fluctuation is 3% or more), the reference member 33 is rotated counterclockwise by the drive source 330, and two color references are generated by this rotation. The other color reference surface 3332 of the surfaces 3331 and 3332 is moved to the image reading position, and the other color reference surface is read by the image reading means 32 of the image reading unit 30 in the state where the sheet P is not present at the image reading position. 3332 is read, and dirt determination image data is generated (step S35).

  The stain determination image data generated by reading one color reference surface 3331 in step S32 is compared with the stain determination image data generated by reading the other color reference surface 3332 in step S35 (step S35). S36).

  If the comparison result in step S36 is smaller than a predetermined value (for example, the density distribution fluctuation is within 3%), it is determined that the stains other than the two color reference surfaces 3331 and 3332 (eg, stains attached to the reading window 34). The process proceeds to the normal correction routine using the stain determination image data generated by reading one color reference surface 3331 in step S32, and the operation shown in this flowchart is completed. (Step S37).

  If the comparison result in step S36 is larger than a predetermined value (for example, the density distribution variation is 3% or more), it is determined that one color reference surface 3331 is dirty (step S38).

  In response to the determination in step S38, the stain reference image data generated by cleaning one color reference surface 3331, replacing one color reference surface 3331, or reading the other color reference surface 3332 in step S35. Is used to proceed to the normal correction routine, and a warning is given that one of the color reference planes 3331 is dirty, and the operation shown in this flowchart ends. (Step S39).

  FIG. 9 shows that one of the two reading guarantee surfaces 3341 of the reference member 33 is read by the image reading means 32 in the stain determination unit 40 and then the one reading guarantee surface 3341 is stained. It is a flowchart explaining the flow of operation | movement until it determines. Here, it is assumed that the other reading guarantee surface 3342 of the two reading guarantee surfaces 3341 and 3342 is not soiled.

  9, the reference member 33 is rotated clockwise by the driving source 330, and one of the two reading guarantee surfaces 3341 and 3342 is rotated by the rotation of the reference member 33. Is started after being moved to (step S41).

  In the state where the sheet P is not present at the image reading position, the image reading means 32 of the image reading unit 30 reads one reading guarantee surface 3341 moved to the image reading position in step S41, and the image data for stain determination Is generated (step S42).

  The reference value when there is no dirt or dust adhering to one reading guarantee surface 3341 and the reading window 34 is compared with the image data for dirt determination generated by reading one reading guarantee surface 3341 in step S42 ( Step S43).

  If the comparison result in step S43 is smaller than a predetermined value (for example, the density distribution fluctuation is within 3%), it is determined that one reading guarantee surface 3341 is not dirty, and the operation shown in this flowchart ends. . (Step S44).

  When the comparison result in step S43 is larger than a predetermined value (for example, the density distribution fluctuation is 3% or more), the reference member 33 is rotated counterclockwise by the drive source 330, and two reading guarantees are performed by this rotation. The other reading guarantee surface 3342 of the surfaces 3341 and 3342 is moved to the image reading position, and the other reading guarantee surface is provided by the image reading means 32 of the image reading unit 30 in the state where the sheet P is not present at the image reading position. 3342 is read, and dirt determination image data is generated (step S45).

  In step S42, the dirt determination image data generated by reading one reading guarantee surface 3341 is compared with the dirt determination image data generated by reading the other reading guarantee surface 3342 in step S45 (step S45). S46).

  If the comparison result in step S46 is smaller than a predetermined value (for example, the density distribution fluctuation is within 3%), it is determined that dirt other than the two reading security surfaces 3341 and 3342 (for example, dirt attached to the reading window 34). It is determined that one of the reading guarantee surfaces 3341 is not dirty, and the operation shown in this flowchart ends. (Step S47).

  If the comparison result in step S46 is larger than a predetermined value (for example, the density distribution fluctuation is 3% or more), it is determined that one reading guarantee surface 3341 is dirty (step S48).

  In response to the determination in step S48, the cleaning of one scanning security surface 3341, the replacement of one scanning security surface 3341, or the other scanning security surface 3342 is used, and the scanning security surface 3341 is dirty. And the operation shown in this flowchart ends. (Step S49).

  As described with reference to FIGS. 6 to 9, each of a plurality of reference surfaces of the same type formed on the reference member 33 or each of a plurality of reading guarantee surfaces is performed by the image reading unit 32 of the image reading unit 30. By reading and comparing at the image reading position, it is determined whether or not each reference surface or each reading security surface to be compared is attached with dirt or dust, and switched to a reference surface or reading security surface without dirt or dust attached. be able to.

  Further, each reference surface or each reading guarantee surface to be compared is obtained by reading each of a plurality of reference surfaces of the same type or each of a plurality of reading guarantee surfaces by the image reading means 32 of the image reading unit 30 at the image reading position. Compared to the reference value when there is no dirt or dust on the reading window, there is dirt or dust on each reference surface or each reading security surface to be compared, or dirt or dust on the reading window. It can be determined whether there is adhesion.

  In addition, when one of the two reference surfaces of the same type or one of the two reading security surfaces is moved to the image reading position, the reference member 33 is rotated clockwise to be the same. Since the reference member 33 is rotated counterclockwise when the other reference surface of the two types of reference surfaces or the other reading security surface of the two reading security surfaces is moved to the image reading position, the rotation It is avoided that the patterns of dirt due to rubbing at the same time are the same.

  Next, the image calibration necessity determination unit 50 will be described.

  The image calibration necessity determination unit 50 needs image calibration for stabilizing the color of the image formed on the paper P by the image forming unit 10 based on the inspection image data generated by the image reading unit 30. Determine whether or not. The color stability here means a state in which, when a plurality of (for example, 100) printed materials are output from the same document image data, the color difference between the plurality of printed materials is minimized. In addition, when the image calibration necessity determination unit 50 determines that image calibration is necessary, for example, the image calibration is warned and an image calibration instruction is received from the user, and an image according to the instruction is received. Adjust processing conditions and image forming conditions. In this embodiment, an image calibration necessity determination unit 50 is provided as an example of a determination unit that determines whether or not adjustment of at least one of an image processing condition and an image formation condition is necessary. Further, as an example of a warning unit, an image calibration necessity determination unit 50 is provided as an example of a reception unit that receives information.

  In the above-described embodiment, the example in which the image forming apparatus of the present invention is an electrophotographic image forming apparatus has been described. However, the image forming apparatus of the present invention is not limited to this, for example, an inkjet system Any type of image forming apparatus may be used.

  Further, in the above-described embodiment, the reference member has a rotatable octagonal prism shape, and the white reference surfaces 3311 and 3312 are provided on the two surfaces of the octagonal prism shape that avoid the adjacent surfaces of the octagonal prism shape. In the above description, the black reference surfaces 3321 and 3322, the color reference surfaces 3331 and 3332, and the reading guarantee surfaces 3341 and 3342 are formed. However, the reference member according to the present invention is not limited to this. When the sheet is conveyed, the sheet is disposed on the second surface side which is the back surface of the first surface on which the image is formed, moved to the image reading position, and read by the image reading unit in the absence of the sheet. It is sufficient that at least two kinds of reference planes among a white reference plane, a black reference plane, and a color reference plane are provided.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is an enlarged view of the C section shown in FIG. FIG. 3 is a view of the image reading unit 30 shown in FIG. 2 as viewed from the left side in FIG. 2. It is a figure explaining suppression of the correction error in this embodiment when reading each reference plane of white reference, black reference, and color reference and performing density reading calibration of the image reading unit. It is a figure explaining generation | occurrence | production of the correction error in a prior art example, when each reference surface of a white reference | standard, a black reference | standard, and a color reference | standard is read and the density | concentration reading calibration of an image reading part is performed. An operation flow in the stain determination unit from when one of the two white reference surfaces of the reference member is read by the image reading unit to when the stain on one of the white reference surfaces is determined will be described. It is a flowchart. 6 is a flowchart for explaining an operation flow in a stain determination unit from when two white reference surfaces of a reference member are read by an image reading unit to when a stain on two white reference surfaces is determined. An operation flow in the stain determination unit from when one color reference surface of the two color reference surfaces of the reference member is read by the image reading unit to when the stain on one color reference surface is determined will be described. It is a flowchart. An operation flow in the stain determination unit from when one of the two read-guaranteed surfaces of the reference member is read by the image reading unit to when the stain on one of the read-guaranteed surfaces is determined will be described. It is a flowchart.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image forming part 11 (11Y, 11M, 11C, 11K) Image forming unit 111 Photoconductor 112 Charging part 113 Exposure part 114 Developing part 115 Primary transfer part 12 Intermediate transfer body 121 Drive roll 122 Tension roll 123 Idle roll 124 Belt Cleaner 125 Image Density Sensor 126 Reference Sensor 13 Secondary Transfer Unit 131 Secondary Transfer Roll 132 Backup Roll 133 Power Supply Roll 134 Brush Roll 14 Fixing Device 141 Fixing Roll 1411 Heating Mechanism 142 Pressure Roll 15 Cooler 20 Paper Conveying Means 21 Paper Tray 22 Pickup rolls 23, 27, 28 Transport rolls 24, 26 Transport chute 25 Transport belt 30 Image reading unit 31 Illumination light source 32 Image reading means 321 Three reflecting mirrors 322 Imaging 323 Image sensor 33 Reference member 330 Drive source 3311, 3312 White reference surface 3321, 3322 Black reference surface 3331, 3332 Color reference surface 3341, 3342 Reading security surface 34 Reading window 35 Support member 40 Dirt determination unit 50 Necessity of image calibration Judgment unit 60 Paper transport path 61 Partial path

Claims (12)

Paper transport means for transporting paper,
An image forming unit that is provided on a paper transport path through which the paper is transported by the paper transport unit and forms an image on the transported paper;
An image reading unit that is disposed on the downstream side of the image forming unit on the sheet conveyance path and reads an image on a sheet on which an image is formed in the image forming unit;
The image reading unit is
Illuminating an image reading position for reading an image from a sheet on the sheet conveyance path, an illumination light source disposed on the first surface side of the sheet on which the image is formed when the sheet is conveyed;
Image reading means for reading reflected light from the first surface of the paper passing through the image reading position and generating image data;
The white paper is disposed on the second surface side, which is the back surface of the first surface when the paper is conveyed, moved to the image reading position and read by the image reading means in the absence of the paper. And a reference member provided with at least two kinds of reference surfaces among a white reference surface serving as a reference for black, a black reference surface serving as a black reference, and a color reference surface serving as a color reference. Forming equipment.   In addition to the at least two types of reference planes, the reference member further reads the image on the sheet passing through the image reading position by the image reading unit, and the first of the sheet when the sheet is conveyed. 2. The image forming apparatus according to claim 1, further comprising a reading guarantee surface placed at a position facing the two surfaces.   The reference member has a rotatable polygonal prism shape, and one of the surfaces moves to the image reading position by rotation, and the at least two types of reference surfaces and the reading guarantee surface are different surfaces of the polygonal prism shape, respectively. The image forming apparatus according to claim 2, wherein the image forming apparatus is a member formed on the surface.   The reference member is a member in which each of the at least two types of reference surfaces and the reading guarantee surface is formed on a plurality of polygonal prism-shaped surfaces avoiding adjacent surfaces of the polygonal prism shape. The image forming apparatus according to claim 3.   The image reading unit includes a reading window in which a light transmission member is disposed at a position of the image reading position facing the first surface of the sheet when the sheet is conveyed. Item 5. The image forming apparatus according to Item 4. The image reading unit includes a support member to which both the illumination light source and the image reading unit are fixed,
Of the paper transport path, a partial path through which the paper passes through the image reading unit is separated from both the upstream and downstream parts of the paper transport path and supported by the support member. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. A sheet conveying means for conveying a sheet having an image formed on the first surface;
An image reading unit that is disposed on a sheet conveyance path along which the sheet is conveyed by the sheet conveying unit and reads an image on the conveyed sheet;
The image reading unit is
Illuminating an image reading position for reading an image from a sheet on the sheet conveyance path, an illumination light source disposed on the first surface side of the sheet on which the image is formed when the sheet is conveyed;
Image reading means for reading reflected light from the first surface of the paper passing through the image reading position and generating image data;
The white paper is disposed on the second surface side, which is the back surface of the first surface when the paper is conveyed, moved to the image reading position and read by the image reading means in the absence of the paper. And a reference member provided with at least two kinds of reference surfaces among a white reference surface serving as a reference for black, a black reference surface serving as a black reference, and a color reference surface serving as a color reference. Reader.   In addition to the at least two types of reference planes, the reference member further reads the image on the sheet passing through the image reading position by the image reading unit, and the first of the sheet when the sheet is conveyed. 8. The image reading apparatus according to claim 7, further comprising a reading security surface placed at a position facing the two surfaces.   The reference member has a rotatable polygonal prism shape, and one of the surfaces moves to the image reading position by rotation, and the at least two types of reference surfaces and the reading guarantee surface are different surfaces of the polygonal prism shape, respectively. The image reading apparatus according to claim 8, wherein the image reading apparatus is a member formed on the surface.   The reference member is a member in which each of the at least two types of reference surfaces and the reading guarantee surface is formed on a plurality of polygonal prism-shaped surfaces avoiding adjacent surfaces of the polygonal prism shape. The image reading apparatus according to claim 9.   The image reading unit includes a reading window in which a light transmission member is disposed at a position of the image reading position facing the first surface of the sheet when the sheet is conveyed. Item 15. The image reading device according to Item 10. The image reading unit includes a support member to which both the illumination light source and the image reading unit are fixed,
Of the paper transport path, a partial path through which the paper passes through the image reading unit is separated from both the upstream and downstream parts of the paper transport path and supported by the support member. The image reading apparatus according to claim 7, wherein the image reading apparatus is configured as described above.

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