JP2012123273A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve discrimination accuracy, while securing excellent conveyability for a recording material.SOLUTION: An image forming apparatus includes recording material detection means including a light source emitting light for irradiating the first irradiation area and second irradiation area of the surface of the recording material and imaging means imaging the surface of the recording material and having such a relation that the center light beam of a luminous flux with which the first irradiation area is irradiated and the center light beam of a luminous flux with which the second irradiation area is irradiated cross each other, when the center light beams are projected onto the surface of the recording material and detects information on the surface state of the recording material based on an image obtained by imaging the first irradiation area and the second irradiation area by the imaging means. The image forming apparatus further includes a first opening which is provided between the surface of the recording material and the light source and through which the luminous flux with which the first irradiation area is irradiated passes and a second opening which is provided between the surface of the recording material and the light source and through which the luminous flux with which the second irradiation area is irradiated passes, and a contact surface coming into contact with the surface of the recording material, to support the conveyed recording material is formed between the first opening and the second opening.

Description

  The present invention relates to an image forming apparatus that detects a surface state of a recording sheet based on a surface image picked up by an image pickup unit.

  An image forming apparatus such as a copying machine or a laser beam printer transfers a developer image visualized by a developing device to a recording paper under a predetermined transfer condition, and heats and heats the transferred recording paper under a predetermined fixing condition. The developer image is fixed on the recording paper by pressing.

  Conventionally, in such an image forming apparatus, for example, a user sets the size and type (hereinafter also referred to as a paper type) of a recording sheet as a recording sheet on an operation panel or the like provided in the main body of the image forming apparatus. In accordance with the setting, transfer conditions (for example, transfer bias and recording paper conveyance speed during transfer) and fixing conditions (for example, fixing temperature and recording paper conveyance speed during fixing) are controlled.

  In recent years, the surface state of recording paper is imaged by an area sensor, surface smoothness is detected from the captured surface image, the type of recording paper is determined, and transfer conditions or fixing conditions are controlled according to the determination results. A technique has been proposed (see Patent Document 1). As described above, the method of imaging the surface of the recording paper with the area sensor directly captures the shadow caused by the unevenness of the surface, so that the discrimination accuracy is excellent. In particular, when distinguishing between coated paper (glossy paper) and non-coated paper (plain paper), excellent accuracy can be obtained in discriminating recording paper that can visually distinguish the presence / absence of unevenness and its size and depth. ing.

JP 2004-38879 A

  However, for example, in the case of discriminating general office paper as recording paper, the appearance of shading caused by surface irregularities varies greatly depending on the fiber orientation direction (border direction) of the paper. That is, when light is irradiated from a direction orthogonal to the fiber orientation direction of the paper, a high-contrast photographed image is obtained in which the surface irregularities are emphasized. However, when light is irradiated from the same direction as the fiber orientation direction, As a result, it is difficult to produce a shadow due to the image, and the captured image has a low contrast. For this reason, even when the same paper is used, the contrast difference between the captured images is severe between when the paper is passed vertically and when the paper is passed horizontally.

  In order to deal with such a problem, in Patent Document 1, it is assumed that the fiber orientation direction of most recording papers coincides with the longitudinal direction or the lateral direction (0 °) or is within ± 15 °. Light is irradiated obliquely in the range of 15 ° to 75 ° with respect to the transport direction. And the improvement of discrimination | determination precision is aimed at by imaging the irradiation area | region with an area sensor. However, the fiber orientation direction of the recording paper differs depending on the mixing ratio of the recording paper raw material in the manufacturing process. For this reason, as in recent years, the fiber orientation directions of recording papers that have undergone manufacturing processes at various manufacturing bases are various, and are not necessarily coincident (0 °) or ± with respect to the longitudinal direction or the lateral direction of the recording paper. It is not always within 15 °. Therefore, as in Patent Document 1, only by imaging one area irradiated with light from one direction, depending on the relationship between the fiber orientation direction of the recording paper and the light irradiation direction, even if the same recording paper, There is a risk of different discrimination results.

  Therefore, in order to reduce the variation in the detection result due to the relationship between the fiber orientation direction of the recording paper and the light irradiation direction and improve the discrimination accuracy for the recording paper of any fiber orientation direction, the following FIG. A configuration as shown is conceivable.

  8A and 8B are diagrams showing a recording material detection device 40 as a reference example, in which FIG. 8A is a top view of the recording material detection device, and FIG. 8B is a cross-sectional view taken along line AA in FIG. In addition, in (a), in order to make intelligible the position of a light source etc., it shows as a partially transparent figure of the upper part. The recording material detection device 40 uses the bullet-shaped LED 41 installed on the substrate 45 in the housing 44 as a light source, and transmits the cover member C through the optical path 46 toward the recording material P that moves in the direction of the arrow in the figure. The surface property of the recording material P is illuminated by an image sensor (line sensor) 43 that is illuminated at a shallow angle of about 10 ° to 15 ° and the reflected light is collected by a light condensing element (rod lens) 42 and placed on a substrate 45. Is imaged. The central light beam (light path) 46 of the light beam emitted from the light sources 41R and 41L and applied to the recording material P is arranged so as to intersect when projected onto the recording material P. Then, the surface state of the recording material is detected based on an image obtained by imaging the recording material P irradiated to the light source 41R and an image obtained by imaging the recording material irradiated to the light source 41L.

  With this configuration, it is difficult to be influenced by the fiber orientation direction forming the recording material, and the discrimination accuracy can be improved.

  Here, in order to improve the discrimination accuracy, it is necessary to capture a higher contrast image. For this purpose, it is conceivable that the light emission amount of the light source 41 increases. However, a light source with a large light emission amount increases the volume of the light source element and enlarges the apparatus. In addition, since the amount of heat generated is large, the housing 44, the substrate 45, and the like are thermally expanded, and the detection accuracy may be deteriorated. Therefore, it is conceivable to increase the amount of light that irradiates the recording material by eliminating the cover member C and eliminating the light reflected from the surface of the cover member C when passing through the cover member C. FIG. 9 shows a cross-sectional view of such a recording material detection apparatus as a reference example.

  Thus, when the cover member C is eliminated, a concave portion is formed on the surface of the recording material detection device 40 that contacts the recording material P, and when the recording material P is conveyed in the X direction, the leading end of the recording material is caught by the concave portion. This increases the possibility of jamming.

  In view of the above problems, an object of the present invention is to provide an image forming apparatus provided with a recording material discrimination unit that improves the discrimination accuracy while ensuring good transportability of the recording material.

A light source that emits light for irradiating the first irradiation region and the second irradiation region on the surface of the recording material, and an imaging unit that images the surface of the recording material, and a central ray of a light beam that irradiates the first irradiation region; A recording material detection unit that intersects when the central ray of the light beam that irradiates the second irradiation region is projected onto the surface of the recording material, and the imaging unit images the first irradiation region and the second irradiation region; An image forming apparatus that detects information on a surface state of a recording material based on an image,
Provided between the recording material surface and the light source, provided between the recording material surface and the light source, a first opening through which a light beam that irradiates the first irradiation region passes, and the second irradiation region A second opening through which the irradiated light flux passes, and a contact surface that contacts the surface of the recording material and supports the recording material to be conveyed is between the first opening and the second opening. It is characterized by being formed.

  According to the present invention, it is possible to provide an image forming apparatus including a recording material determination unit that improves the determination accuracy while ensuring good conveyance of the recording material.

1 is a schematic cross-sectional view of an image forming apparatus equipped with a recording material detection device. The top view of the optical path structure of a recording material detection apparatus. (A) Top view of recording material detection apparatus. (B) BB sectional drawing. (A) The BB cross section of the recording material detection apparatus in (b). (B) Top view of the recording material detection apparatus. (C) The side view of the recording material detection apparatus of (b). (A) Top view of the recording material detection apparatus without a taper surface. (B) Top view of the recording material detection apparatus. (C) The side view of the recording material detection apparatus of (a). (D) The side view of the recording material detection apparatus of (b). The figure which shows the housing | casing upper surface of a recording material detection apparatus. The figure which shows the housing | casing upper surface of a recording material detection apparatus. (A) Top view of recording material detection apparatus of reference example. (B) AA sectional view of the recording material detection apparatus of (a). Sectional drawing of the recording material detection apparatus of a reference example.

<First Embodiment>
The recording material detection apparatus of this embodiment is mounted on an electrophotographic color image forming apparatus.

(Image forming device)
FIG. 1 is a schematic cross-sectional view of an image forming apparatus 100 on which the recording material detection device of the present embodiment is mounted. First, the configuration and operation of the image forming unit of the image forming apparatus 100 will be described. The image forming unit includes a sheet feeding unit 15, a photosensitive member (hereinafter referred to as a photosensitive drum) 1 (1Y, 1M, 1C, 1Bk) for each color CMYBk station, and a charging roller 2 (2Y, 2M, 2C, 2Bk), exposure scanner unit 11 (11Y, 11M, 11C, 11Bk), developing device 8 (8Y, 8M, 8C, 8Bk) as developing means, intermediate transfer belt 24, drive roller 23 for driving the intermediate transfer belt, and The tension roller 13, the secondary transfer counter roller 26, the primary transfer roller 4 (4Y, 4M, 4C, 4Bk), the secondary transfer roller 25, the secondary transfer counter roller 26, and the fixing unit 21, and the control operation thereof. It is comprised by the control part 10.

  When the control unit 10 receives the image forming signal, the recording material P is fed into the image forming apparatus from the paper feeding cassette 15 by the paper feeding rollers 17 and 18, and is once sandwiched between the registration roller pairs 19a and 19b and stopped. stand by.

  On the other hand, the control unit 10 rotates the photosensitive drum 1 in a clockwise direction in the drawing by a driving source (not shown). The rotating photosensitive drum 1 is charged by the charging roller 2 and exposed in accordance with an image signal received by the exposure scanner unit 11, thereby forming an electrostatic latent image on the surface.

  Here, the developing devices 8 (8Y, 8M, 8C, 8Bk) are means for visualizing the electrostatic latent image on the photosensitive drum 1, and yellow (Y), magenta (M), cyan (C), black ( Bk) is developed. Each developing device 8 is provided with a sleeve 5 (5Y, 5M, 5C, 5Bk), and a developing bias for visualizing the electrostatic latent image is applied thereto.

  The electrostatic latent image formed on the surface of the photosensitive drum 1 is developed as a single color toner image by the action of the developing device 8.

  The intermediate transfer belt 24 is in contact with each of the photosensitive drums 1Y, 1M, 1C, and 1Bk, and rotates in the counterclockwise direction in synchronization with the rotation of the photosensitive drum 1 when forming a color image. The single-color toner image developed on the surface of the photosensitive drum 1 (1Y, 1M, 1C, 1Bk) is sequentially transferred onto the intermediate transfer belt 24 by the action of the primary transfer bias applied to the primary transfer roller 4, and is multicolored. It becomes a toner image. The multicolor toner image on the intermediate transfer belt 24 is conveyed to a secondary transfer nip portion formed by the intermediate transfer belt and the secondary transfer roller 25. At the same time, the recording material P that has been waiting while being held between the conveying roller pair 19ab is conveyed to the secondary transfer nip portion while being synchronized with the multicolor toner image on the intermediate transfer belt by the registration roller pairs 19a and 19b. Is done. Then, the multicolor toner image on the intermediate transfer belt 24 is collectively transferred onto the recording material P by the action of the secondary transfer bias applied to the secondary transfer roller 25.

  The fixing unit 21 melts and fixes the transferred multi-color toner image while conveying the recording material P, and as shown in FIG. 1, the fixing roller 21a for heating the recording material P and the recording material P are fixed to the fixing roller. A pressure roller 21b is provided for pressure contact with 21a. 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 material P to which the multicolor toner image has been transferred is conveyed by the fixing roller 21a and the pressure roller 21b, and heat and pressure are applied to fix the multicolor toner image on the recording material P. Thereafter, the recording material P is discharged to the paper discharge tray 16 by the discharge roller 20, and the image forming operation is completed. The cleaning means 28 cleans the toner remaining as a transfer residue on the intermediate transfer belt 24, and the transfer residual toner collected here is stored in a cleaner container 29 as waste toner.

  Such a series of image forming operations is controlled by the control unit 10 provided in the image forming apparatus.

  In the image forming apparatus of FIG. 1, the recording material detection device 50 of the present invention is installed in the recording material discrimination section in front of the registration roller pair 19a, 19b, and the surface of the recording material P conveyed from the paper feed cassette 15 or the like. Information reflecting smoothness is detected. In the present embodiment, the recording material detection device 50 determines the recording material while the recording material P is fed from the paper feed cassette 15 or the like into the image forming apparatus and is held between the pair of registration rollers 19a and 19b and stopped. Done. Then, based on the discrimination information output by the recording material detection device 50, the control unit 10 sets an image forming condition such as an optimal transfer bias and a fixing temperature to control the image forming apparatus.

(Recording material detector)
Next, the recording material detection apparatus will be described. FIG. 3A is a top view of the recording material detection device 50. In order to make the arrangement of the light source and the like easier to understand, a part of the housing 54 is shown in a transparent state. (B) is BB sectional drawing of (a). In the recording material detection device 50, two light sources 51 </ b> R and a bullet-type LED as L, an imaging lens array as a condensing member 52, and a CMOS line sensor as an imaging unit 53 are provided in a housing 54. The two light sources 51R, L and the image pickup means 53 are installed on a substrate 55 in the housing 54. The optical axes 56R, L are the central rays of the light beams emitted from the light sources 51R, L. The light beams from the light sources 51R and L are incident at a shallow angle whose optical axis is inclined by 10 ° to 15 ° with respect to the recording material P. The light reflected by the surface of the recording material P is collected by the light collecting member 52 and enters the image pickup means 53. In this way, it is possible to take an image of the shadow of the surface of the recording material P that is irradiated with light. At this time, a region irradiated with the light beam emitted from the light source 51L on the surface of the recording material P is defined as a first light irradiation region, and a region irradiated with the light beam emitted from the light source 51R is defined as a second light irradiation region. The arrow in FIG. 3B indicates the conveyance direction T of the recording material P. The image pickup means 53 is a line sensor in which a plurality of pixels are arranged in a direction orthogonal to the conveyance direction T, and the recording material P surface is sequentially conveyed one line (a plurality of pixels arranged in one direction of the recording material P surface once). The image is taken for each area). By imaging a plurality of lines on the surface of the recording material P in this manner, an image of the surface of the recording material P having a horizontal width corresponding to the length of one line and a vertical width corresponding to the length of conveying the recording material can be obtained. it can.

  This will be described more specifically. FIG. 2 is a top view of the optical path configuration of the recording material detection apparatus. The imaging positions of the recording material P irradiated from the light sources 51R and 51L through the optical paths 56R and 56L are shown in FIG. The light beams emitted from the light sources 51R and 51L irradiate the first light irradiation region Prj-R and the second light irradiation region Prj-L on the recording material P with a predetermined spread angle. The image pickup means 53 picks up an area corresponding to the image pickup means 53 in the first and second light irradiation areas on the recording material P irradiated with this light. That is, the area corresponding to the imaging unit 53 in the area on the recording material P is the width WPrj-R of the imaging unit 53 in which the reflected light in the first and second light irradiation areas Prj-R and Prj-L. And a region incident on a portion having a width WPrj-L. By this imaging means 53, an image having a width WPrj-R and an image having a width WPrj-L can be obtained. The image picked up by the width WPrj-R of the image pickup means 53 and the two images picked up by the width WPrj-L are images showing shading due to irregularities on the surface of the recording material P, and the surface properties (surface state) of the recording material P It is an image which shows. The type of recording paper is determined based on this image.

  In the present embodiment, the optical axis 56R and the optical axis 56L intersect when projected onto the surface of the recording material P, and the image captured with the width WPrj-R and the width WPrj-L of the imaging unit 53 is captured. The obtained image becomes an image of the surface of the recording material P irradiated with light at different angles. Thus, by determining the surface property of the recording material using the images of the surfaces of the two recording materials P irradiated with light at different angles, the relationship between the direction of the fibers of the recording paper P and the direction of light irradiation is obtained. It is possible to reduce the variation in the detection result.

  Here, in the present embodiment, the recording material detection device 50 is not provided with a transmissive member such as the cover member C shown in the reference example of FIG. 8, and light is emitted from the light sources 51R and L to the recording material P. Irradiate directly. For this reason, compared with the case where a cover member is provided, there is no light reflected on the surface of the cover member when passing through the cover member. Therefore, the amount of light irradiating the recording material is increased, and a high-contrast image is captured and recorded. The material discrimination accuracy can be improved.

  However, since the cover member is eliminated, a concave portion is formed on the surface of the recording material detection device 50 that contacts the recording material P, as described above. There is a risk of jamming.

  Therefore, in the present embodiment, the contact surface S that contacts the recording material P at a position that does not affect the determination of the recording material P and supports the recording material that is conveyed so as not to be caught by the concave portion is formed. The distance between the recording material P and the imaging means 53 is determined by the recording material P contacting the contact surface S.

  As shown in FIG. 2, the central part of the width WPrj-D of the image pickup means 53 has an image pickup function. However, since the area corresponding to this central portion of the recording material P is irradiated with light from both the light sources 51R and L, the surface properties of the recording material P do not appear well even when imaged. For this reason, the recording material P is not imaged in the central portion of the image pickup means 53, and the image pickup means 53 is provided with only parts (WPrj-R, WPrj-L) necessary for image pickup, and one line is composed of two line sensors. It may be configured. However, in terms of handling including the positioning accuracy of the image sensor itself, the position accuracy between the image sensors, and the like, it is easier to assure workability and positioning accuracy with a single component. One line sensor having

  In the present embodiment, a rib R is provided at a portion corresponding to the width WPrj-D, which is the central portion of the image pickup means 53, which is a portion that does not affect the determination of the recording material P, and the above-described recording material is provided on the rib R. An abutting surface S that abuts on P and supports the recording material is provided. That is, in the casing 54, the light beam from the light source 51 </ b> L passes through the portion corresponding to the width WPrj-R of the image pickup unit 53 to irradiate the recording material P, and the reflected light beam passes through the width of the image pickup unit 53. There is a first opening Ar that enters the WPrj-R. Similarly, in the casing 54, the part corresponding to the width WPrj-L of the image pickup means 53 is irradiated with the recording material P through the light beam from the light source 51R, and the reflected light beam is passed through the image pickup means. There is a second opening Al incident on 53 width WPrj-L. The contact surface S is formed between the first opening Ar and the second opening Al along the transport direction T of the recording material P, and the transported recording material P is supported by the contact surface S. Be guided. For this reason, it is difficult to generate a jam and the recording material P is stably conveyed.

  As described above, in the present embodiment, the amount of light that irradiates the surface of the recording material P by directly irradiating the surface of the recording material P from two directions without passing through the cover glass or the like. The recording material P can be discriminated with high accuracy. Further, the recording material P can be stably conveyed by providing the contact surface S between the two openings.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 4B is a top view of the recording material detection device 60. In order to make the arrangement of the light source and the like easier to understand, a part of the housing 64 is shown in a transparent state. (A) is the BB cross section of the recording material detection apparatus 60 in (b). (C) is a side view of the recording material detection device 60, and is a cross-sectional view seen from the downstream side in the transport direction T. The recording material detection device 60 is illuminated toward the recording material P via the optical paths 66R and L using the chip-mounted LEDs 61R and L installed on the substrate 65 in the housing 64 as a light source. At this time, the recording material irradiation direction is deflected in the apparatus by deflectors (reflecting mirrors) 67R and 67R and guided to the recording material P. The light irradiated on the surface of the recording material P is reflected and collected by the light collecting member 62, and the surface properties of the recording material are imaged by the imaging means 63 installed on the substrate 65. As described above, the optical path from the light source to the imaging means is different from that of the first embodiment in that the optical path is via the light sources 61R and L and the deflectors 67R and L, and the imaging means 63 is the first one. This is the same as in the first embodiment. Then, the recording material detection device 60 determines the recording material P in the same manner as the recording material detection device 50 of the first embodiment. In other words, the light source 61R, 61L irradiates the recording paper P from two directions through the deflectors 67R, 67L and the optical paths 66R, 66L so that the surface property of the recording paper can be discriminated irrespective of the orientation direction of the recording paper fiber. Has been. The deflector 67 is made of a sheet material having a high reflectivity such as a metal film (trademark) obtained by forming a reflective film or the like on the surface of a plate material such as glass or acrylic or by depositing aluminum on a PET base material of Toray Industries, Inc. It may be formed by bonding with a double-sided tape or the like. Further, a reflective surface may be directly formed on a part of the housing 64 by vapor deposition or the like. Also in the recording material detection device 60, as in the first embodiment, a rib R is provided between the first opening Ar and the second opening Al to form the contact surface S.

  In the present embodiment, in order to reduce optical detection noise, the inner peripheral surfaces of the first opening Ar and the second opening Al (side surfaces of the rib R and the surface facing the rib R of the housing 64) are tapered. A surface is formed. This tapered surface will be described in detail. FIG. 5A is a top view of the recording material detection apparatus having no taper surface (shown in a state where a part of the casing 64 is seen through in order to make the arrangement of the light source and the like easier to understand). (C) is a side view of the recording material detection apparatus of (a). (B) is a top view of the recording material detection device 60 of the present embodiment (shown in a state where a part of the housing 64 is seen through in order to make the arrangement of the light source and the like easier to understand). (D) is a side view of the recording material detection device 60 of the present embodiment.

  The optical axes (light ray centers) of the light beams from the light sources 61R and L after the deflector are indicated by 66R and 66L, respectively. Of the luminous fluxes from the light sources 61R and L, the light rays that are spread and emitted with respect to the optical axis are denoted by 66R-a, 66R-b, 66L-a, and 66L-b. For example, the light beam 66L-a emitted from the light source 61L so as to spread rightward with respect to the optical axis 66L is an outer surface (outer surface) Sr surface along the transport direction of the inner peripheral surface of the first opening. The light is reflected, enters the condenser lens 62 and the image pickup means 63, and becomes an optical noise component. In addition, the light beam 66L-b that is emitted to the left with respect to the optical axis 66L is reflected on the inner surface (the left side surface of the rib R) R-l along the conveying direction of the inner peripheral surface of the second opening. Similarly, the light enters the condenser lens 62 and the image pickup means 63 and becomes an optical noise component. Similarly, the light emitted from the light source 61R may become an optical noise component.

  Therefore, in the present embodiment, as shown in FIGS. 5B and 5D, the surfaces Sr and l, and the surfaces Rr and l, which are inner peripheral surfaces of the first opening Ar and the second opening Al, are provided. A tapered surface is attached to. This taper surface is inclined with respect to the direction orthogonal to the surface of the recording material P, and the widths of the first opening Ar and the second opening Al increase in the direction orthogonal to the surface of the recording material P toward the imaging means 63. Inclined to spread. For this reason, the light beams 66L-a, b, 66R-a, b emitted from the light source are reflected downward. Thus, the light rays 66L-a, b, 66R-a, b reflected downward on the inner peripheral surfaces of the first opening Ar and the second opening Al are the width WPrj-R which is the imaging region of the imaging means 63. , WPrj-L does not enter. For this reason, it can be reduced that light other than the reflected light from the surface of the original recording material P is incident on the image pickup means and becomes optical noise.

  As described above, in this embodiment, as in the first embodiment, the recording material P is directly irradiated from the two directions onto the surface of the recording material P without passing through the cover glass or the like. A sufficient amount of light for irradiating the surface can be secured and the recording material P can be discriminated with high accuracy. Further, by providing the contact surface S between the two openings, the recording material P can be stably conveyed.

  Further, in the present embodiment, a tapered surface is provided on the inner peripheral surfaces of the two openings so that light reflected by the tapered surface does not enter the imaging region of the imaging unit 63, and an optical noise component is reduced. The discrimination accuracy of the recording material P can be improved.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. FIG. 6 is a view showing the upper surface of the housing of the recording material detection device 70. Components similar to those of the second embodiment are denoted by the same reference numerals and description thereof is omitted. The widths of the first opening Ar and the second opening Al in the direction orthogonal to the conveyance direction T of the recording material P are increased from the upstream to the downstream in the conveyance direction T. That is, the side surface portion of the rib R is inclined with respect to the transport direction T so that the width of the rib R in the direction orthogonal to the transport direction T is changed from Lb to Lu (Lu <Lb) from upstream to downstream in the transport direction T. It is configured. Such non-uniformity can prevent light from the light sources 61R and L described above from entering the imaging region of the imaging means 63. In this embodiment, although Lu <Lb, the width of the first opening Ar and the second opening Al in the direction perpendicular to the conveyance direction T of the recording material P is equal to the conveyance direction T, as Lu ≠ Lb. As long as it is non-uniform toward.

  Similarly, the surfaces of the first and second openings Ar, Al facing the ribs R on the inner peripheral surface are inclined with respect to the transport direction T so as to provide the gap LS as shown in the figure, thereby similarly providing the light sources 61R, L. Can be prevented from entering the imaging area of the imaging means 63.

  Next, another embodiment of the present embodiment will be described. FIG. 7 is a view showing the upper surface of the housing of the recording material detection device 70. Note that the condensing lens 62 and the imaging means 63 are omitted because they are arranged in the same manner as in FIG. Of the inner peripheral surfaces of the first opening Ar and the second opening Al, the shape of the surface along the transport direction T is a sawtooth shape having a length Lt and an inclination θ. Thereby, similarly, the light from the light sources 61R and L can be prevented from entering the imaging region of the imaging means 63.

  As described above, in this embodiment, as in the first embodiment, the recording material P is directly irradiated from the two directions onto the surface of the recording material P without passing through the cover glass or the like. A sufficient amount of light for irradiating the surface can be secured and the recording material P can be discriminated with high accuracy. Further, by providing the contact surface S between the two openings, the recording material P can be stably conveyed.

  Further, in the present embodiment, the width of the two openings in the direction perpendicular to the conveyance direction T of the recording material P is inclined with respect to the conveyance direction T so as to be non-uniform toward the conveyance direction T. is doing. For this reason, it is possible to prevent the light reflected by the inner peripheral surfaces of the two openings from entering the imaging region of the imaging means 63, reduce the optical noise component, and improve the discrimination accuracy of the recording material P. it can.

  In addition, you may comprise the shape of the internal peripheral surface of the opening part of this embodiment combining with 2nd Embodiment.

DESCRIPTION OF SYMBOLS 50 Recording material detection apparatus 51R, L Light source 52 Condensing member 53 Imaging means 54 Case 55 Substrate 56R, L Optical path 60 Recording material detection apparatus 61R, L Light source 62 Condensing member (Condensing lens)
63 Imaging means 64 Housing 65 Substrate 66R, L Optical path 67R, L Reflector Ar Ar first opening Al Second opening R Rib S Contact surface Rr, Rl, Sr, Sl Inner circumference Surface T Recording material conveyance direction

Claims (5)

A light source that emits light for irradiating the first irradiation region and the second irradiation region on the surface of the recording material, and an imaging unit that images the surface of the recording material, and a central ray of a light beam that irradiates the first irradiation region; A recording material detecting means that intersects the central beam of the light beam that irradiates the second irradiation region when projected onto the surface of the recording material;
An image forming apparatus for detecting information on a surface state of a recording material based on an image obtained by imaging the first irradiation area and the second irradiation area by the imaging unit,
Provided between the recording material surface and the light source, provided between the recording material surface and the light source, a first opening through which a light beam that irradiates the first irradiation region passes, and the second irradiation region A second opening through which the irradiated light flux passes,
An image forming apparatus, wherein an abutting surface that abuts the recording material surface and supports the conveyed recording material is formed between the first opening and the second opening.   The inner peripheral surface of the first opening is configured such that light emitted from the light source and reflected by the inner peripheral surface does not enter the portion of the imaging unit that images the first irradiation region and the second irradiation region. The image forming apparatus according to claim 1, wherein the image forming apparatus has an arbitrary shape.   The inner peripheral surface of the first opening portion is inclined with respect to the direction orthogonal to the surface of the recording material so that the width of the first opening portion increases in the direction orthogonal to the recording material surface toward the imaging unit. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus.   The width of the inner peripheral surface of the first opening portion in a direction perpendicular to the recording material conveyance direction of the first opening portion is inclined with respect to the conveyance direction. The image forming apparatus described.   5. The image forming apparatus according to claim 1, wherein a condition for forming an image on the recording material is controlled based on the detected information on a surface state of the recording material. 6.

Images