JP2009271273A - Recording material surface image pickup device and image forming apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording material surface image pickup device with improved judging accuracy in the recording material surface image pickup device judging the type of recording material by picking up an image of a surface of the recording material by an image sensor and detecting the surface smoothness and to provide an image forming apparatus provided with the same. <P>SOLUTION: The recording material surface image pickup device is provided with: a radiating LED 42 for radiating light on the surface of the recording material P; an imaging lens 44S for imaging reflected light from the recording material P; a CMOS area sensor 43A for outputting a picture voltage signal according to the amount of light obtained by picking up the reflected light which is imaged by the imaging lens 44S; and a drive and operation section 40c for converting the outputted picture voltage signal from the CMOS area sensor 43A to digital signals. In this case, the image of the recording material is picked up while being held in a stance curved to separate from the radiating LED 42 in the vicinity of the picked-up section on the recording material P. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a recording material surface imaging device that images the surface of a recording material, and an image forming apparatus including the same.

  Conventionally, an image forming apparatus such as a copying machine or a laser printer includes a latent image carrier that carries a latent image, a developing device that visualizes the latent image as a developer image by applying a developer to the latent image carrier, Transfer means for transferring the developer image from the latent image carrier onto the recording material. Further, a fixing device is provided for fixing the developer image on the recording material by heating and pressurizing the recording material on which the developer image has been transferred under predetermined fixing conditions.

  In such an image forming apparatus, for example, the size and type of recording paper as a recording material are set by a user on an operation panel or the like provided in the image forming apparatus body, and a control unit provided in the apparatus body responds to the setting. Control transfer conditions and fixing conditions.

  In general, the surface properties (surface smoothness) are often different for each type of recording material. By controlling the transfer conditions and fixing conditions for each type of recording material in this way, the type of recording material differs. However, good image quality can be realized. The transfer conditions controlled by the control unit include, for example, a transfer bias and a recording material conveyance speed during transfer, and the fixing conditions include, for example, a fixing temperature and a recording material conveyance speed during fixing. .

  In recent years, a method has been proposed in which a sensor for discriminating the type of recording material is arranged in the image forming apparatus, and control is performed so that a transfer condition, a fixing condition, or the like is set according to the discrimination result of the sensor. According to this configuration, it is possible to save the user from setting the type of recording material, which leads to improvement in usability.

As a conventional example in which a means for discriminating the type of recording material is provided in the image forming apparatus as described above, Patent Document 1 discloses that the surface of the recording material is imaged by a CMOS sensor, and the surface of the recording material is smoothed from the imaging result. A technique for discriminating the type of recording material by detecting the property is disclosed. Patent Reference 2 discloses a technique for detecting the surface property and thickness of a recording material by irradiating the recording material with ultrasonic waves and detecting the reflectance and transmittance from the recording material.
JP 2002-182518 A Japanese Patent Laid-Open No. 2004-219856

  Thus, conventionally, when detecting the surface smoothness of a recording material, the surface of the recording material is directly imaged by a CMOS sensor (Patent Document 1), or an ultrasonic wave is applied to the recording material (Patent Document 2). Etc. were adopted.

  On the other hand, according to the study by the inventors of the present application, the method described in Patent Document 1 directly captures the shadow caused by the unevenness of the surface, so that it is more than the method using ultrasonic waves. It has been found that the detection accuracy of surface smoothness is excellent. However, the technique for imaging the surface of the recording material as disclosed in Patent Document 1 causes the following problems.

For example, recording materials such as coated paper and non-coated paper can visually distinguish the presence or absence of surface irregularities or the size and depth thereof. Therefore, by imaging the surfaces of these recording materials, it becomes possible to reliably detect the surface smoothness of each recording material, and as a result, it is possible to accurately distinguish between coated paper and non-coated paper. .

  However, for example, recording materials such as general office paper and bond paper may not be able to clearly distinguish the difference in size and depth of the surface irregularities. Therefore, even when two non-coated papers having different surface roughness are discriminated as in these recording materials, it is difficult to reliably detect the surface smoothness of each recording material. As a result, it becomes difficult to accurately discriminate these recording materials.

  For example, the bond paper may be misclassified as general office paper, or the general office paper may be misclassified as bond paper, resulting in deterioration of image quality or image failure without printing under proper printing conditions. become.

  Therefore, the present invention relates to a recording material surface imaging apparatus that discriminates the type of recording material by sensing the surface smoothness by imaging the surface of the recording material and detecting the surface smoothness. And an image forming apparatus including the same.

In order to solve the above problems, in the present invention,
A light irradiation means for irradiating the surface of the recording material with light;
Imaging means for imaging reflected light from the recording material;
Imaging means for imaging the reflected light imaged by the imaging means, and outputting an electrical signal corresponding to the amount of the captured light;
Arithmetic means for converting an electrical signal output from the imaging means into a digital signal;
With
The recording material is picked up in the vicinity of the imaged portion on the recording material while being held in a curved posture so as to move away from the light irradiation means.

In the image forming apparatus of the present invention,
The recording material surface imaging device described above;
A control unit that detects the smoothness of the surface of the recording material based on the digital signal output from the arithmetic unit, and determines the type of the recording material based on the detection result;
Image forming means controlled by the control unit;
It is characterized by providing.

  According to the present invention, in a recording material surface imaging apparatus that determines the type of recording material by imaging the surface of the recording material and detecting the surface smoothness, the light irradiation means for irradiating the recording material interferes with the recording material. Therefore, light irradiation can be performed on the surface of the recording material at a shallow angle. As a result, it is possible to provide a recording material surface imaging device with improved discrimination accuracy and an image forming apparatus including the same.

  The best mode for carrying out the present invention will be exemplarily described in detail below based on the embodiments with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

[First Embodiment]
Hereinafter, with reference to FIG. 1 to FIG. 4, a recording material surface imaging device according to the first embodiment of the present invention,
An image forming apparatus including the same will be described.

(Overall configuration of image forming apparatus)
First, the overall configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG. In the present embodiment, a case where an electrophotographic color image forming apparatus is used as the image forming apparatus will be described. The image forming apparatus main body according to the present embodiment employs a tandem system in which an intermediate transfer belt is provided and a plurality of image carriers are arranged along the intermediate transfer belt.

  The image forming apparatus is provided for each of toners of each color of cyan (C), magenta (M), yellow (Y), and black (Bk), and a paper feeding unit 15 on which a plurality of recording papers P as recording materials are placed. Station.

  Each color station is provided with photosensitive drums 1Y, 1M, 1C, and 1Bk as image carriers configured to be rotatable by a drive source (not shown). Further, around the photosensitive drums 1Y, 1M, 1C, and 1Bk, charging rollers 2Y, 2M, 2C, and 2Bk as primary charging units, exposure light scanner units 11Y, 11M, 11C, and 11Bk, and a developing unit 8Y as developing units are provided. , 8M, 8C, and 8Bk.

  Further, primary transfer rollers 4Y, 4M, 4C, and 4Bk are disposed at positions facing the photosensitive drums 1Y, 1M, 1C, and 1Bk, and the intermediate transfer belt 24 is disposed at the nip portion between the photosensitive drum 1 and the primary transfer roller 4. Is pinched.

  The intermediate transfer belt 24 is configured to be movable in a state where a predetermined tension is applied by a driving roller 23 that drives the intermediate transfer belt 24, a stretching roller 13, and a secondary transfer counter roller 26. Further, the recording paper P fed from the paper feeding unit 15 is transported to the nip portion between the secondary transfer roller 25 and the secondary transfer counter roller 26 via the transport path, and further, to the secondary transfer roller 25. A fixing unit 21 is provided on the downstream side of the nip portion of the secondary transfer counter roller 26.

  The image forming apparatus according to the present embodiment includes exposure light scanner units 11Y, 11M, 11C, and 11Bk, primary transfer rollers 4Y, 4M, 4C, and 4Bk, a secondary transfer roller 25, a secondary transfer counter roller 26, and a fixing unit. A control unit 10 that controls the driving of the unit 21 and the like is provided. The control target of the control unit 10 is not limited to these, and any drive member that constitutes the image forming apparatus such as the rotational speed of the photosensitive drum 1 and the moving speed of the intermediate belt 24 can be the control target.

  Next, an image forming process for forming an image on the recording paper P by the image forming apparatus configured as described above will be described.

  The photosensitive drums 1Y, 1M, 1C, and 1Bk in the present embodiment are provided with an organic optical transmission layer on the outer periphery of an aluminum cylinder, and a driving force of a driving motor (not shown) is transmitted to respond to an image forming operation. It rotates clockwise.

  In starting the image forming process, when the control unit 10 receives a print image signal from an input unit (not shown), the paper feed rollers 17 and 18 are driven by a command from the control unit 10, and the recording paper P is fed from the paper feed cassette 15. Are sent one by one in the downstream direction of the transport path.

The recording material P is once sandwiched between the conveyance (registration) roller 19a and the conveyance (registration) counter roller 19b, stopped, put into a standby state, and sent to each station in synchronization with the image forming operation. A recording material surface imaging device 40 that detects the surface smoothness of the recording paper P and outputs the information to the control unit 10 is provided in front of the transport rollers 19a and 19b. The recording material surface imaging device 40 will be described in detail later.

  On the other hand, the control unit 10 applies an exposure light scanner to the photosensitive drums 1Y, 1M, 1C, and 1Bk whose surfaces are charged to a constant potential by the charging rollers 2Y, 2M, 2C, and 2Bk, based on the input print image signal. Exposure light is emitted from the sections 11Y, 11M, 11C, and 11Bk. Thereby, electrostatic latent images based on the print image signals are formed on the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1Bk.

  The electrostatic latent images formed on the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1Bk are visualized as toner images by electrostatically supplying toner from the developing devices 8Y, 8M, 8C, and 8Bk. In other words, yellow (Y), magenta (M), cyan (C), and black (Bk) toner images are formed on the photosensitive drum 1 of each station. Each developing device 8 is provided with sleeves 5Y, 5M, 5C, and 5Bk, and a developing bias for visualizing the electrostatic latent image is applied to the sleeves 5Y, 5M, 5C, and 5Bk. ing.

  The photosensitive drum 1, the charging roller 2, and the developing device 8 are integrally configured, and are configured to be removable from the image forming apparatus main body as toner cartridges 31Y, 31M, 31C, and 31Bk in which these are integrated. ing.

  The intermediate transfer belt 24 is in contact with each photosensitive drum 1 at the nip portion between the photosensitive drums 1Y, 1M, 1C, and 1Bk and the primary transfer rollers 4Y, 4M, 4C, and 4Bk, and is counterclockwise when forming a color image. It rotates in synchronization with the rotation of 1Y, 1M, 1C, 1K. The monochromatic toner images developed on the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1Bk are sequentially transferred to the surface of the intermediate transfer belt 24 by the action of the primary transfer bias applied to the primary transfer roller 4, and are transferred onto the intermediate transfer belt 24. A multi-color toner image is formed on the surface.

  The multicolor toner image formed on the intermediate transfer belt 24 is conveyed to a secondary transfer nip portion formed by a secondary transfer roller 25 and a secondary transfer counter roller 26. Then, the recording paper P waiting in a state of being sandwiched between the transport rollers 19 a and 19 b is transported to the secondary transfer nip portion in synchronization with the multicolor toner image on the intermediate transfer belt 24. Thereafter, in the secondary transfer nip portion, the multicolor toner image on the intermediate transfer belt 24 is collectively transferred onto the recording paper P by the action of the secondary transfer bias applied to the secondary transfer roller 25.

  The recording paper P on which the multicolor toner image is transferred is conveyed to the fixing unit 21. The fixing unit 21 melts and fixes the multicolor toner image on the recording paper P while conveying the recording paper P. As shown in FIG. 1, the fixing unit 21 heats the recording paper P, and the recording paper. A pressure roller 21b for pressing P against the fixing roller 21a is provided. The fixing roller 21a and the pressure roller 21b are formed in a hollow shape, and heaters 21ah and 21bh are incorporated therein, respectively.

  The recording paper P on which the multicolor toner image is fixed in the fixing unit 21 is discharged to the paper discharge tray 16 by the discharge roller 20, and the image forming operation is completed.

  Further, the image forming apparatus is provided with a cleaning member 28, and the cleaning member 28 cleans and collects the toner remaining on the intermediate transfer belt 24. The residual toner collected here is stored in the cleaner container 29 as waste toner.

  The series of image forming processes described above is controlled by the control unit 10 provided in the image forming apparatus.

(Configuration of recording material surface imaging device)
A recording material surface imaging device 40 according to the present embodiment will be described with reference to FIGS. 2 shows a schematic configuration of the recording material surface imaging device 40 according to the present embodiment, FIG. 3 shows an image of the surface of the recording material, and FIG. 4 shows the recording material. The histogram of the digital signal obtained by the surface imaging device 40 is shown.

  The recording material surface imaging device 40 according to the present embodiment includes an irradiation LED 42 that is a light irradiation unit, a CMOS area sensor 43A that is an imaging unit, and an imaging lens 44S that is an imaging unit. Further, the recording material surface imaging device 40 is installed so as to straddle the curved portion and the flat portion in the transport path before the pair of transport rollers 19a and 19b.

  Further, on the opposite side of the recording material surface imaging device 40 with respect to the recording material P, a backup member 41 is provided as a holding member that holds the posture of the recording paper P during imaging. The backup member 41 in the present embodiment is provided with a curved portion and a flat portion. The imaging lens 44S and the CMOS area sensor 43A are installed so as to face a flat portion of the backup member 41, and one curved portion has a curvature radius of 30 mm so as to avoid interference with the irradiation LED 42. It is curved.

  With this configuration, in the present embodiment, the recording material P is held in a curved posture so as to move away from the irradiation LED 42 in the vicinity of the imaging target portion on the recording material P.

  The recording paper P is always pressed against the backup member 41 with a constant tension by the action of the paper feed roller 18 and the transport rollers 19a and 19b. The backup member 41 is from the back side of the imaged portion of the recording paper P. It contacts the recording material P. As a result, the recording material P can be imaged while maintaining a posture with a certain curvature and avoiding the interference with the irradiation LED 42 while suppressing a deviation from the focal position of the imaging system in a flat portion. Become.

  With such a configuration, it is possible to detect information that reflects the surface smoothness of the recording paper P that is conveyed from the paper feed cassette 15 or the like and is partially curved. The information reflecting the surface smoothness refers to, for example, shading information resulting from the unevenness when the unevenness of the recording paper is irradiated with light.

  The recording material surface imaging device 40 detects the information reflecting the surface smoothness when the recording material P is sent out from the paper feed cassette 15 or the like into the image forming apparatus and is held between the conveyance (registration) rollers 19a and 19b. Being done while being stopped. Then, based on the detection information sent from the recording material surface imaging device 40, the control unit 10 sets the optimum transfer bias / fixing temperature and controls the image forming apparatus (image forming means).

  Light using the irradiation LED 42 as a light source is emitted toward the surface of the recording paper P. The irradiation LED 42 is arranged so as to irradiate light obliquely at a predetermined angle. In the present embodiment, the surface including the imaging target portion on the surface of the recording paper P, and the irradiation direction of the light from the irradiation LED 42 The LED 42 for irradiation was arrange | positioned so that the angle which becomes may be 5 degree | times.

  By irradiating light obliquely from such a low angle, it becomes possible to make the shadow caused by the irregularities on the surface of the recording material P more prominent and smaller than when irradiating light from a high angle. It is possible to extract a shadow caused by shallow unevenness.

  Thus, the reflected light including the shadow information reflecting the surface smoothness of the recording material P is condensed via the imaging lens 44S and imaged on the CMOS area sensor 43A. Then, the CMOS area sensor 43A outputs a video voltage signal (electrical signal) that changes in accordance with the amount of reflected light for each imaged area to the drive / calculation unit (calculation means) 40a.

  When the video / voltage signal output from the CMOS area sensor 43A is received, the driving / calculating unit 40a performs A / D conversion on the video voltage signal and outputs the converted 256-gradation digital signal to the control unit 10.

  In the present embodiment, the effective pixel size of the CMOS area sensor 43A is 1.5 mm long × 1.5 mm wide and has a resolution of 600 dpi. Therefore, in combination with the imaging lens 44S, an area of 3.0 mm length × 3.0 mm width on the surface of the recording material can be imaged with a resolution of 300 dpi.

  When the digital signal obtained by the above configuration is imaged as lightness information, it is as shown in FIG. 3A is an image of the surface of the coated paper having a smooth surface, and FIG. 3B is an image of the surface of the bond paper having a rough surface. Further, when the lightness information (digital signal) is converted into a histogram, distributions as shown in FIGS. 4A and 4B are obtained.

  The control unit 10 determines the average value Imax of signals from the five areas with the highest lightness (high voltage) in the lightness information (digital signal) and the signals from the five areas with the lowest lightness (low voltage). An average value Imin is calculated, and ΔI which is a difference between them is obtained. For example, since the shadow of the reflected light is clear in the bond paper having a rough surface, ΔI is large, and in the coated paper having a smooth surface, there is not much difference in the shadow of the reflected light, and ΔI is small.

  Thus, the control unit 10 detects the surface smoothness of the recording paper P from the magnitude of ΔI. Then, an optimal secondary transfer bias and fixing temperature are calculated from the detection result, and the image forming apparatus is controlled to operate under the calculated settings.

In the present embodiment, coated paper (manufactured by HP: Photo & Image: 120 g / m ² paper), plain paper (manufactured by Canon Inc .: Office Planner: 68 g / m ² paper), bond using the image forming apparatus described above. Three types of recording paper (paper made by Fox River Paper: Fox River Bond: 90 g / m ² paper) are passed through 100 sheets each, and recording paper P by the recording material surface imaging device 40 each time one paper is passed. The discrimination operation was performed.

  Further, in order to show the effect of the recording material surface imaging device 40 according to the present embodiment more easily, a comparative experiment with a comparative example was performed. That is, as a comparative example, an apparatus in which the irradiation LED is arranged so that the angle between the recording paper surface and the LED light irradiation direction is 30 ° so as to avoid interference with the recording paper without curving the recording paper. The same discrimination operation as that of the present embodiment was performed using

  As a result, the discriminating error rates of the recording material types by the recording material surface imaging devices of the present embodiment and the comparative example were as shown in Table 1. According to the results shown in Table 1, it was confirmed that the determination error rate was lower when the LED light irradiation angle was 5 ° than when the LED light irradiation angle was 30 °.

[Second Embodiment]
With reference to FIGS. 5 and 6, a recording material surface imaging device according to a second embodiment of the present invention and an image forming apparatus including the same will be described. The same parts as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted. Here, only the parts different from the first embodiment are described. Do.

(Configuration of image forming apparatus)
FIG. 5 shows a schematic configuration of the image forming apparatus according to the present embodiment. In the image forming apparatus according to the present embodiment, the arrangement of the recording material surface imaging device 40 and the CMOS line sensor 43L are used as imaging means (the first embodiment is the CMOS area sensor 43A). The form is different. Other configurations are substantially the same as those of the first embodiment.

  As shown in FIG. 5, the recording material surface imaging device 40 according to the present embodiment is installed with respect to the curved conveyance path before the conveyance roller pair 19a, 19b. According to this configuration, it is possible to detect information reflecting the surface smoothness of the recording paper P in a curved state that is conveyed from the paper feed cassette 15 or the like and is in a curved conveyance path. In addition, this curved conveyance path | route is curving so that it may distance from LED42 for irradiation.

  The timing at which the recording material surface imaging device 40 detects information reflecting the surface smoothness is such that the recording material P is fed into the apparatus main body from the paper feed cassette 15 or the like and is sandwiched between the transport rollers 19a and 19b. This is performed while waiting until the next transfer nip is conveyed. Then, based on the information detected by the recording material surface imaging device 40, the control unit 10 sets the optimum transfer bias / fixing temperature and controls the image forming apparatus.

(Configuration of recording material surface imaging device)
Next, the recording material surface imaging device 40 according to the present embodiment will be described. FIG. 6A is a schematic configuration diagram of the recording material surface imaging apparatus 40 according to the present embodiment. The recording material surface imaging device 40 includes an irradiation LED 42 that constitutes a light irradiation unit, a light guide plate 45, a CMOS line sensor 43L that is an imaging unit, and an imaging lens array 44A that is an imaging unit.

  Further, on the opposite side of the recording material surface imaging device 40 with respect to the recording material P, a backup member 41 is provided as a holding member that holds the posture in which the recording paper P is curved during imaging. The backup member 41 in the present embodiment is provided with a curved portion, and holds the recording paper P in a curved posture with a curvature radius of 30 mm so that the recording paper P moves away from the irradiation LED 42.

  Specifically, the recording paper P is always pressed against the backup member 41 with a constant tension by the action of the paper feed roller 18 and the transport rollers 19a and 19b, and the backup member 41 is an imaged portion of the recording paper P. The recording material P comes into contact with the recording material P from the back side. As a result, the recording material P can be transported while maintaining a posture with a certain curvature while suppressing a deviation from the focal position of the imaging system.

  Further, the longitudinal direction of the CMOS line sensor 43L and the imaging lens array 44A is set so as to be orthogonal to the conveyance direction of the recording material P and the imaging direction thereof is directed toward the center of curvature of the recording material P.

FIG. 6B is a schematic view of the schematic configuration of the illumination system of the recording material surface imaging device 40 shown in FIG. The irradiation LED 42 is attached to the side surface portion of the light guide plate 45, and the irradiation light emitted from the irradiation LED 42 is irradiated in the direction of the arrow in the figure by the action of the light guide plate 45, so It is the structure which irradiates uniformly over the whole length direction.

  Note that the irradiation direction of the irradiation light viewed from the cross-sectional direction is such that the irradiation LED 42 and the light guide plate 45 are set so that the angle (LED light irradiation angle) formed with the surface including the tangent line in the imaged portion of the recording paper P is 5 °. installed. Note that the imaged portion of the present embodiment may include a curved portion of the recording material P.

  In this manner, the vicinity of the imaging target portion of the recording material P is held in a posture that is curved so as to be away from the irradiation LED 42, and by imaging the curved portion, the irradiation LED 42, the light guide plate 45, and the recording paper P interfere with each other. And can irradiate light at a lower angle. Therefore, it is possible to make the shading caused by the unevenness on the surface of the recording paper P more prominent and to easily detect a subtle unevenness difference.

  The reflected light including the shadow information reflecting the surface smoothness of the recording paper P is collected through the lens array 44L and focused on the CMOS line sensor 43L. The CMOS line sensor 43L reflects the reflected light for each imaged area. A video voltage signal (electrical signal) that changes according to the amount of light is output. The drive / arithmetic unit 40a receives the video voltage signal output from the CMOS line sensor 43L, performs A / D conversion on the video voltage signal, and outputs the converted digital signal to the control unit 10.

  While performing such a series of imaging operations, the recording paper P is moved in the transport direction, and the digital information received by the control unit 10 is sequentially connected to create area information. The CMOS line sensor 43L used in the present embodiment has an effective pixel length (longitudinal direction) of 10 mm and a resolution of 300 dpi.

  Further, the control unit 10 moves the recording paper P by 10 mm in the transport direction until the recording paper P is transported to the secondary transfer nip portion while being sandwiched between the transport rollers 19a and 19b. Perform the action. As a result, area information of 10 mm length × 10 mm width on the surface of the recording material can be obtained with a resolution of 300 dpi × 300 dpi.

  The control unit 10 analyzes the obtained area information by the same method as in the first embodiment, thereby detecting the surface smoothness of the recording paper P and discriminating the type of the recording paper P from the detection result. To do. Then, the optimal secondary transfer bias and fixing temperature are calculated, and the image forming apparatus is controlled to operate with the calculated settings.

Here, using the image forming apparatus according to the present embodiment, coated paper (manufactured by HP: Photo & Image: 120 g / m ² paper), plain paper (manufactured by Canon Inc .: Office Pla)
nner: 68 g / m ² paper), bond paper (manufactured by Fox River Paper): Fox
Three types of recording paper (River Bond: 90 g / m ² sheets) were passed through each 100 sheets, and the recording material P was discriminated by the recording material surface imaging device 40 each time one sheet was passed.

  As a result, the recording material discrimination error rate by the recording material surface imaging apparatus 40 according to the present embodiment is as shown in Table 2.

  In this embodiment, the backup member 41 that backs up the recording paper P from the back side is used as the holding member. However, the configuration of the holding member is not limited to this. For example, as shown in FIG. 7, a rib member 46 that contacts the recording material P is provided from the surface side of the imaging target portion of the recording paper P, and the recording paper P is pressed against the curved portion of the rib member 46. Even if it is the structure hold | maintained in the curved state, the effect similar to the above is acquired.

  In the present embodiment, the recording paper P is held in a posture with a curvature so that the imaging surface side is convex, and the curvature portion is imaged by the line sensor 43L. The purpose is to prevent the light irradiation means from interfering with each other.

  Therefore, as long as the object can be achieved, the line sensor 43L is not necessarily configured to image the curvature portion of the recording material. For example, the part imaged by the line sensor 43L may be a flat surface, and the recording material P may be curved at a position where it can interfere with the light irradiation means provided in the vicinity of the imaging unit.

  In the first embodiment and the second embodiment described above, the LED is used as the light source. However, for example, a xenon tube, a halogen lamp, or the like may be used. In addition, a CCD type sensor may be used as the image pickup means instead of the CMOS type sensor.

  Further, it has been described that the result determined by the control unit 10 based on the detection result of the recording material surface imaging device 40 is fed back to the control of the transfer bias, the fixing temperature, etc. The feedback destination is not limited to this. For example, various control parameters in each process of electrostatic latent image formation and development and a series of image formation speeds (process speeds) can be fed back to perform these control operations.

  In the first embodiment and the second embodiment, the recording paper P is used as the recording material. However, the recording material surface imaging device according to the present invention and the image forming apparatus including the recording material P include paper. In addition to the material, a sheet material such as OHP may be used as the recording material.

  As described above, according to the present invention, in the recording material surface imaging apparatus for discriminating the type of the recording material by imaging the surface of the recording material and detecting the surface smoothness, the recording material surface imaging apparatus with improved discrimination accuracy. And an image forming apparatus including the same can be provided.

1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment. 1 is a schematic configuration diagram of a recording material surface imaging apparatus according to a first embodiment. FIG. The figure which shows what imaged the surface of two types of recording materials as brightness information. The figure which shows what formed the histogram of the digital signal. FIG. 3 is a schematic configuration diagram of an image forming apparatus according to a second embodiment. The schematic block diagram of the recording material surface imaging device which concerns on 2nd Embodiment. The schematic block diagram of the rib member in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control part 40 Recording material surface imaging device 40C Drive / calculation part 43A CMOS area sensor 44S Imaging lens P Recording paper

Claims (7)

A light irradiation means for irradiating the surface of the recording material with light;
Imaging means for imaging reflected light from the recording material;
Imaging means for imaging the reflected light imaged by the imaging means, and outputting an electrical signal corresponding to the amount of the captured light;
Arithmetic means for converting an electrical signal output from the imaging means into a digital signal;
With
A recording material surface imaging apparatus, wherein the recording material is imaged in a vicinity of an imaged portion on the recording material while maintaining a curved posture so as to move away from the light irradiation means. The imaged part is
The recording material surface imaging apparatus according to claim 1, further comprising a curved portion of the recording material. The imaging means is a line sensor,
The recording material surface imaging apparatus according to claim 1, wherein the reflected light is imaged while the recording material is conveyed in a direction orthogonal to a longitudinal direction of the line sensor. The recording material,
The recording material surface imaging apparatus according to claim 1, further comprising a holding member that holds the recording material in a curved posture so as to move away from the light irradiation unit. The holding member is a holding member having a curved portion,
The recording material surface imaging apparatus according to claim 4, wherein the recording material surface imaging device is a backup member that holds the recording material in a curved posture by contacting the recording material from a back surface side of the imaging target portion. The holding member is a holding member having a curved portion,
The recording material surface imaging apparatus according to claim 4, wherein the recording material surface imaging device is a rib member that holds the recording material in a curved posture by contacting the recording material from a surface side of the imaging target portion. The recording material surface imaging device according to any one of claims 1 to 6,
A control unit that detects the smoothness of the surface of the recording material based on the digital signal output from the arithmetic unit, and determines the type of the recording material based on the detection result;
Image forming means controlled by the control unit;
An image forming apparatus comprising:

Images