JP2005114866A - Recording material discrimination device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve useability by discriminating the kind of a recording material while conducting fixing or the like under an optimum fixing condition for various kinds of recording materials. <P>SOLUTION: In a recording material discrimination device, a video reading sensor 123 is provided with a reflection LED301, a transmissive light quantity detection LED302 which is arranged on the opposite side of a recording material 304, a CMOS area sensor 211 and an image formation lens 303. The surface of the recording material 304 is illuminated by the light beams being emitted from a light source, i.e., the reflection LED301. Reflected light beams from the recording material 304 are converged by the lens 303 and image formed on the CMOS area sensor 211. Note that the transmissive LED302 uses a light source having a longer wavelength than the wavelength of the reflection LED301. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a recording material determination device and an image forming apparatus, and more specifically, a recording material determination device and an image forming apparatus for detecting the reflected light from the surface of the recording material and the transmitted light amount of the recording material to determine the type. About.

  Image forming apparatuses such as copying machines and laser printers fix the developer image by transferring an image visualized and developed by a developing unit to a recording material and heating and pressing under predetermined fixing processing conditions. The predetermined fixing conditions vary greatly depending on the material, thickness, surface treatment, and the like of the recording material. Therefore, in order to use a plurality of types of recording materials, fine setting according to the type of the recording material is required.

  Conventionally, in such an image forming apparatus, for example, the user can set the size and type of the recording material on the operation panel or the like provided in the main body of the image forming apparatus (the paper type when the recording material is paper), and the user can The fixing processing conditions (for example, the fixing temperature and the conveyance speed of the recording material passing through the fixing device) are changed.

  For this reason, in recent years, the type of recording material is automatically determined using a sensor for determining the recording material inside the image forming apparatus, and development conditions, transfer conditions, or fixing conditions are variably controlled corresponding to the determined types. Technology has been proposed.

  In such a technique for automatically detecting the type of recording material, for example, a surface image of the recording material is captured by a CCD sensor, and this information is converted into fractal dimension information to detect the surface smoothness of the recording material. Method, a method of capturing the surface image of the recording material with a CCD sensor or CMOS sensor, detecting the roughness of the recording material from the magnitude relationship of the light, and discriminating the paper type from the surface smoothness, A method of detecting the thickness of the recording material from the length has been proposed (see, for example, Patent Document 1).

JP 2002-182518 A

  However, the method for detecting the surface smoothness of the recording material described above is to detect the recording material having the same surface smoothness and different compression state of the paper fiber, for example, plain paper and cardboard, and the cardboard is determined to be plain paper. Since the development conditions, fixing conditions, and transfer conditions cannot be set to be suitable for the recording paper, there is a problem that the fixing property is deteriorated.

  On the other hand, in the above method for determining the thickness of the recording material, since the smoothness of the surface of the recording material is not known, gloss paper or the like is less likely to transmit light than plain paper, so the material thickness is determined to be thick and appropriate. I cannot set the correct conditions.

  Further, in recent years, despite the variety of types of recording materials, the demand for print quality is higher, and it is required to accurately discriminate a wide variety of recording materials.

  The present invention has been made in view of the above problems, and provides a recording material determination device and an image forming apparatus that automatically determine various types of recording materials and perform image formation under appropriate conditions. With the goal.

  In order to achieve such an object, the invention described in claim 1 of the present invention is an image reading method for obtaining an image on the surface of a recording material by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material. And a reflection type determination means for determining a predetermined attribute of the recording material using an image on the surface of the recording material obtained by the image reading means, and the recording material based on the attribute obtained by the reflection type determination means In the recording material discriminating apparatus for discriminating the type of the recording material, the transmitted light obtained by passing through the recording material is irradiated by irradiating the recording material with predetermined irradiation light having a wavelength longer than the irradiation light used in the reflection type determination means. And a transmission type determination unit that determines an attribute different from the reflection type determination unit of the recording material, and records based on the attribute obtained by the transmission type determination unit in addition to the attribute obtained by the reflection type determination unit. Material And discriminates the kind.

  The invention described in claim 2 includes image reading means for obtaining an image on the surface of the recording material by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material. In a recording material discriminating apparatus, comprising a reflection type judging means for judging a predetermined attribute of a recording material using an image of the material surface, and discriminating the type of the recording material based on the attribute obtained by the reflection type judging means, the reflection type By irradiating the recording material with a predetermined amount of irradiation light that is stronger than the irradiation light used in the determining means, the transmitted light is transmitted through the recording paper, and by adjusting the amount of the predetermined irradiation light A transmission type determination unit for determining an attribute different from the reflection type determination unit of the recording material using transmitted light in which a difference between the amount of reflected light and the amount of transmitted light is within a predetermined range; Attribute obtained by In addition, and discriminates the type of the recording material based on the attribute obtained by the transmission type determination means.

  According to a fourth aspect of the present invention, there is provided a reflection type irradiating means for irradiating a recording material with a predetermined light to obtain reflected light reflected from the surface of the recording material, and an image obtained by receiving reflected light or transmitted light from the recording material. Reading means for detecting the amount of light and a reflection type irradiation means for irradiating the recording material with light, causing the reading means to read the reflected light obtained by the reflection type irradiation means as an image, and recording material based on the image In a recording material discriminating apparatus comprising a control means for discriminating the type of light, a predetermined light having a wavelength longer than the predetermined light irradiated to the recording material by the reflective irradiation means in order to obtain transmitted light that passes through the recording material The control means irradiates the recording material with light by the reflection type irradiation means and the transmission type irradiation means, and the reading means reads the reflected light obtained by the reflection type irradiation means as an image. Set And the quantity of the resulting transmitted light by transmission illumination means is detected, and wherein the determining the type of the recording medium based on the light intensity of the image with the transmitted light.

  According to a fifth aspect of the present invention, there is provided a reflection type irradiating means for irradiating a recording material with a predetermined light to obtain reflected light reflected from the surface of the recording material, and an image obtained by receiving reflected light or transmitted light from the recording material. Reading means for detecting the amount of light and a reflection type irradiation means for irradiating the recording material with light, causing the reading means to read the reflected light obtained by the reflection type irradiation means as an image, and recording material based on the image And a recording material discriminating apparatus having a control means for discriminating the type of the recording material in order to obtain transmitted light that passes through the recording material with a predetermined amount of light that is stronger than the predetermined light that is irradiated to the recording material by the reflection type irradiation means. And a transmission type irradiating means for irradiating the predetermined light so that the difference between the light quantity of the reflected light and the light quantity of the transmitted light is within a predetermined range by adjusting the light quantity of the predetermined light. Type irradiation means and transmission type irradiation hand And irradiates the recording material with light, causes the reading means to read the reflected light obtained by the reflection-type irradiation means as an image, and detects the amount of transmitted light obtained by the transmission-type irradiation means, thereby transmitting the image and transmission. The type of the recording material is determined based on the amount of light.

  According to a seventh aspect of the present invention, there is provided a latent image carrier that carries a latent image, a developing unit that visualizes the latent image as a developer image by applying a developer to the latent image carrier, and is conveyed in a predetermined direction. The developer image is fixed to the recording material by transferring and transferring the developer image by the developing device to the recording material to be recorded, and the recording material to which the developer image has been transferred by the transferring device being heated and pressed under predetermined fixing processing conditions. An image of the surface of the recording material obtained by the image reading means, including a fixing means for causing the image to be obtained by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material. And a reflection type determination unit that determines a predetermined attribute of the recording material using the recording medium. The type of the recording material is determined based on the attribute obtained by the reflection type determination unit, and the fixing processing condition corresponding to the determined type is used. Developer In the image forming apparatus for fixing the recording material to the recording material, the transmitted light obtained by transmitting the recording material by irradiating the recording material with a predetermined irradiation light having a wavelength longer than the irradiation light used in the reflection type determination means And a transmission type determination unit that determines an attribute different from the reflection type determination unit of the recording material, and the fixing unit is obtained by the transmission type determination unit in addition to the attribute obtained by the reflection type determination unit. The type of the recording material is determined based on the attribute, and the developer image is fixed on the recording material according to the fixing processing condition corresponding to the determined type.

  According to an eighth aspect of the present invention, there is provided a latent image carrier that carries a latent image, a developing unit that visualizes the latent image as a developer image by applying a developer to the latent image carrier, and is conveyed in a predetermined direction. The developer image is fixed to the recording material by transferring and transferring the developer image by the developing device to the recording material to be recorded, and the recording material to which the developer image has been transferred by the transferring device being heated and pressed under predetermined fixing processing conditions. An image of the surface of the recording material obtained by the image reading means, including a fixing means for causing the image to be obtained by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material. And a reflection type determination unit that determines a predetermined attribute of the recording material using the recording medium. The type of the recording material is determined based on the attribute obtained by the reflection type determination unit, and the fixing processing condition corresponding to the determined type is used. Developer In the image forming apparatus for fixing the recording material to the recording material, it is transmitted light obtained by transmitting the recording material by irradiating the recording material with predetermined irradiation light having a light intensity stronger than the irradiation light used in the reflection type determination unit. Thus, by adjusting the light quantity of the predetermined irradiation light and using the transmitted light in which the difference between the light quantity of the reflected light and the light quantity of the transmitted light is within a predetermined range, an attribute different from that of the reflection type determination unit of the recording material is set. A transmissive type determining unit for determining, and the fixing unit determines the type of the recording material based on the attribute obtained by the transmissive type determining unit in addition to the attribute obtained by the reflective type determining unit. The developer image is fixed on the recording material according to fixing processing conditions corresponding to the above.

  According to a tenth aspect of the present invention, there is provided a latent image carrier that carries a latent image, a developing unit that applies a developer to the latent image carrier, a transfer unit that transfers a developer image to a recording material, and heating and heating. The latent image is developed by a fixing unit that fixes the developer image onto the recording material by pressing, a reflective irradiation unit that irradiates the recording material with predetermined light to obtain reflected light reflected from the surface of the recording material, and a developing unit. Reading means for visualizing as an agent image, transferring the visualized image to a recording material conveyed in a predetermined direction by a transfer means, receiving reflected light or transmitted light from the recording material as an image, and detecting the amount of light And the reflection type irradiation means irradiates the recording material with light, the reading means reads the reflected light obtained by the reflection type irradiation means as an image, the type of the recording material is determined based on the image, and the determined type Predetermined fixing corresponding to In an image forming apparatus having a control means for fixing a recording material transferred by a fixing means under a physical condition and discharging the fixed recording material, a reflection type irradiating means for obtaining transmitted light that passes through the recording material A transmission type irradiation means for irradiating predetermined light having a wavelength longer than the predetermined light irradiated by the control means, and the control means records the reflection type irradiation means and the transmission type irradiation means before transfer by the transfer means. The material is irradiated with light, the reading means is caused to read the reflected light obtained by the reflection type irradiation means as an image, and the amount of transmitted light obtained by the transmission type irradiation means is detected. The type of the recording material is determined based on the amount of light, and the developer image is fixed on the recording material according to fixing processing conditions corresponding to the determined type.

  The invention according to claim 11 is a latent image carrier for carrying a latent image, a developing means for applying a developer to the latent image carrier, a transfer means for transferring the developer image to a recording material, and heating and heating. The latent image is developed by a fixing unit that fixes the developer image onto the recording material by pressing, a reflective irradiation unit that irradiates the recording material with predetermined light to obtain reflected light reflected from the surface of the recording material, and a developing unit. Reading means for visualizing as an agent image, transferring the visualized image to a recording material conveyed in a predetermined direction by a transfer means, receiving reflected light or transmitted light from the recording material as an image, and detecting the amount of light And the reflection type irradiation means irradiates the recording material with light, the reading means reads the reflected light obtained by the reflection type irradiation means as an image, the type of the recording material is determined based on the image, and the determined type Predetermined fixing corresponding to In an image forming apparatus having a control means for fixing a recording material transferred by a fixing means under a physical condition and discharging the fixed recording material, a reflection type irradiating means for obtaining transmitted light that passes through the recording material A predetermined amount of light that is stronger than the predetermined amount of light that is irradiated with the predetermined amount, and the difference between the amount of reflected light and the amount of transmitted light falls within a predetermined range by adjusting the amount of the predetermined light. The transmissive irradiating means for irradiating light is provided, and the control means causes the reflective irradiating means and the transmissive irradiating means to irradiate the recording material with light before transferring by the transfer means, and the reading means is responsive to the reflective irradiating means. The obtained reflected light is read as an image, and the amount of transmitted light obtained by the transmission type irradiation means is detected, and the type of the recording material is determined based on the image and the amount of transmitted light. Fixing processing conditions corresponding to the type Characterized in that for fixing to the recording material more developer image.

  According to the present invention, the image reading means includes an image reading means for obtaining an image of the surface of the recording material by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material. In a recording material discriminating apparatus, comprising a reflection type judging means for judging a predetermined attribute of a recording material using an image, and discriminating the type of the recording material based on the attribute obtained by the reflective type judging means, the reflective type judging means By irradiating the recording material with a predetermined irradiation light having a longer wavelength than the irradiation light used, the transmitted light obtained by transmitting the recording material is used to determine an attribute different from the reflection type determination means of the recording material. In addition to the attribute obtained by the reflection type judging means, the type of the recording material is discriminated based on the attribute obtained by the transmission type judging means, so that the type of the recording material is accurately discriminated. Do DOO so can while improving usability, it is possible to obtain a good fixed image by performing the fixing or the like in an optimum fixing condition even in various kinds of recording materials.

Hereinafter, a recording material discriminating apparatus, an image forming apparatus, and a method thereof according to the present invention will be described with reference to the drawings.
(Image forming device)
The recording material discriminating apparatus and method of the present invention are used in a general image forming apparatus as shown in FIG. In FIG. 1, an image forming apparatus 101 includes a paper cassette 102, a paper feed roller 103, a transfer belt drive roller 104, a transfer belt 105, yellow, magenta, cyan, and black photosensitive drums 106 to 109, and a transfer roller 110 for each color. To 113, yellow, magenta, cyan, and black cartridges 114 to 117, yellow, magenta, cyan, and black optical units 118 to 121, and a fixing unit 122, respectively.

  The image forming apparatus 101 generally transfers an image of yellow, magenta, cyan, and black on a recording material by using an electrophotographic process, and controls the temperature of the toner image transferred by a fixing unit 122 including a fixing roller. Heat fix. The optical units 118 to 121 for each color are configured so as to form a latent image by exposing and scanning the surfaces of the photosensitive drums 106 to 109 with a laser beam, and these series of image forming operations are performed on the recording material to be conveyed. Synchronization is performed so that the image is transferred from a predetermined position.

  Further, the image forming apparatus 101 is provided with a paper feed motor for feeding and transporting recording paper as a recording material, and the fed recording paper is desired on the surface thereof while being transported to a transfer belt and a fixing roller. Form an image of

  The image reading sensor 123 is disposed before the recording paper is transported to the transfer belt, irradiates the surface of the recording material that has been transported, collects the reflected light and forms an image, and forms the surface of the recording material. The image of the specific area is read out.

  A control CPU 210, which is a control unit of the image forming apparatus 101 described below with reference to FIG. 2, applies a desired amount of heat to the recording material by the fixing unit 122, thereby fusing and fixing the toner image on the recording material. Let

  Next, with reference to FIG. 2, the operation of the control CPU of one embodiment of the recording material discrimination apparatus and image forming apparatus using the method of the present invention will be described. FIG. 2 is a diagram showing the configuration of each unit controlled by the control CPU 210. As shown in FIG. In FIG. 2, a CPU 210 is connected to a CMOS sensor 211 and polygon mirrors, motors, and lasers 212 to 215 included in an optical unit for each color, and scans the laser on the photosensitive drum surface to draw a desired latent image. The optical unit is controlled. Similarly, a paper feed motor 216 for transporting the recording material, a paper feed solenoid 217 used to start driving the paper feed roller for feeding the recording material, and whether or not the recording material is set at a predetermined position. Paper presence / absence sensor 218 to be detected, primary charging necessary for electrophotographic process, development, primary transfer, high voltage power source 219 for controlling secondary transfer bias, drum driving motor 220 for driving the photosensitive drum and transfer roller, transfer belt And a belt driving motor 221, a fixing unit, and a low-voltage power supply unit 122 for driving the rollers of the fixing unit. Further, the control CPU 210 monitors the temperature with a thermistor (not shown) and performs control to keep the fixing temperature constant.

  The control CPU 210 is connected to the memory 224 by a bus or the like (not shown), and the memory 224 stores all of the above control and the processing performed by the control CPU 210 in each embodiment described in the present specification. A program and data for executing a part are stored. That is, the control CPU 210 uses the program and data stored in the memory 224 to execute the operation of each embodiment of the present invention.

  The control CPU 210 is connected to the memory 223 by a bus or the like (not shown), and the memory 223 stores all of the above control and the processing performed by the control CPU 210 in each embodiment described in the present specification. A program and data for executing a part are stored. That is, the control CPU 210 executes the operations of the embodiments of the present invention using the program and data stored in the memory 223.

  The ASIC 223 performs motor speed control inside the CMOS sensor 211 and the optical units 212 to 215 and speed control of the paper feed motor based on an instruction from the control CPU 210. The speed control of the motor is performed by detecting a tack signal from a motor (not shown) and outputting an acceleration or deceleration signal to the motor so that the interval between the tack signals becomes a predetermined time. For this reason, it is more advantageous to reduce the control load of the CPU 210 if the control circuit is configured by a circuit based on the hardware of the ASIC 223.

  When the control CPU 210 receives an instruction print command from a host computer (not shown), the paper presence / absence sensor 218 determines the presence / absence of a recording material, and if there is paper, the paper feed motor 216, the drum drive motor 220, The belt drive motor 221 is driven, and the paper feed solenoid 217 is driven to convey the recording material to a predetermined position.

  When the recording material is conveyed to the position of the CMOS sensor 211, the control CPU 210 instructs the ASIC 223 to image the CMOS sensor 211, and the CMOS sensor 211 captures a surface image of the recording material. At this time, after activating the Sl_select, the ASIC 223 outputs SYSCLK of a predetermined pulse at a predetermined timing, and captures imaging data output from the CMOS sensor 211 via Sl_out.

  On the other hand, the gain setting of the CMOS sensor 211 is performed by setting the value determined in advance by the control CPU 210 to a register in the ASIC 223 so that the ASIC 223 activates Sl_select and then outputs SYSCLK of a predetermined pulse at a predetermined timing. Thus, the gain is set for the CMOS sensor 211 via Sl_in.

  The ASIC 223 includes a recording material discriminating apparatus and method 702 for implementing the recording material discriminating apparatus of the present invention, which will be described below. Are stored in registers A and B. The CPU 210 reads the calculation result for determining the attribute of the recording material stored in the register A and the register B in the control circuit 702, determines the type of the fed recording material, and according to the result To change the image forming conditions.

  Examples of the control of various image forming conditions executed by the CPU 210 include the following.

  For example, if the type of recording material is glossy paper with a gloss level higher than that of plain paper, the CPU 210 increases the developing bias (increases the potential difference with respect to the surface potential of the photosensitive drum) than that of plain paper and applies it to the surface of the recording material. Control is performed to increase the glossiness of the image on the recording material by increasing the amount of toner adhering. This is because it is desired to increase the glossiness of the image on the recording material when printing using gloss paper. As shown in FIG. 1, the developing bias (voltage) refers to a voltage applied from the high voltage power supply 219 to the developing roller based on an instruction from the CPU 210.

  Further, the CPU 210 controls to change the fixing temperature of the fixing unit 222 (a target temperature to be maintained by a heater (not shown) in the fixing unit 222) according to the type of recording material fed. In the case of thick paper that is thicker than plain paper, the thick paper has a heat capacity larger than that of plain paper, so that there is a problem that fixing properties are deteriorated even if a toner image is fixed on the thick paper at the same fixing temperature as that of plain paper. Therefore, when the CPU 210 determines that the recording material is thick paper, the CPU 210 controls the toner to fix the toner on the thick paper at a fixing temperature higher than that of the plain paper.

  Further, the CPU 210 determines the type of the fed recording material, and controls to change the recording material conveyance speed in accordance with the result. Control of the conveyance speed is realized by resetting the speed control register value of the ASIC 223 that actually controls the speed by the CPU 210. Specifically, when the type of recording material is thick paper that is thicker than plain paper, the thick paper has a larger heat capacity than plain paper, so the toner image can be fixed on the thick paper at the same transport speed as plain paper. Has the problem of getting worse. Therefore, if the CPU 210 determines that the type of recording material is cardboard, the recording material conveyance speed is the conveyance speed when passing plain paper so that the amount of heat supplied to the cardboard increases per unit time. Set slower.

  In addition, the fixing temperature condition is changed for recording materials having different basis weights.For example, in a recording material having a relatively large thickness, the heat capacity is large, so the fixing temperature is controlled to be high. A method for fixing a small recording material at a low fixing temperature is also conceivable. Alternatively, the recording material conveyance speed can be changed and controlled according to the basis weight of the recording material.

  Further, in the case of OHT or glossy paper, it is possible to improve the image quality by discriminating these and improving the fixability of the toner adhering to the surface of the recording material and increasing the gloss.

  As described above, in the present embodiment, the first calculation and the second calculation are performed by the ASIC hardware circuit from the surface image of the recording material imaged by the CMOS area sensor, and the result is that the CPU is the high voltage transmission power supply. It is possible to control to change the developing bias condition, the fixing temperature of the fixing unit, or the recording material conveyance speed.

[First Embodiment]
Next, a recording material discrimination device according to an embodiment of the present invention will be described. FIG. 3 is a schematic diagram illustrating a schematic configuration for detecting the surface smoothness, the reflected light amount, and the transmitted light amount of the recording material, and can be said to be the diagram that best represents the present invention.

  As shown in FIG. 3, the image reading sensor 123 is a reflective LED 301 that is a first irradiating means, and a second irradiating means that is a second irradiating means for detecting the amount of transmitted light that is installed on the opposite side of the recording material 304. It includes an LED 302, a CMOS area sensor 211 as reading means, and an imaging lens 303. Here, the sensor 211 can be a CCD sensor.

  Light using the reflective LED 301 as a light source is emitted toward the surface of the recording material 304. In this embodiment, the light source is an LED, but a xenon tube, a halogen lamp, or the like can also be used. The reflected light from the recording material 304 is condensed through the lens 303 and forms an image on the CMOS area sensor 211. Thereby, an image on the surface of the recording material 304 can be read.

  In the present embodiment, the LED 301 is disposed so that the LED light irradiates the recording material 304 with light at an angle as shown in FIG.

(Determination of recording material type)
FIG. 4 is a diagram showing a comparison between an analog image on the surface of the recording material 304 read by the CMOS area sensor 211 of the video reading sensor 123 and a digital image obtained by digitally processing the output from the CMOS area sensor 211 into 8 × 8 pixels. is there. Here, the digital processing is performed by converting the analog output from the CMOS area sensor 211 into 8-bit pixel data by A / D conversion.

  In FIG. 4, the recording material A401 is a so-called rough paper in which the paper fibers on the surface are relatively sandwiched, the recording material B402 is a so-called plain paper that is generally used, and the recording material C403 is sufficiently compressed in the paper fibers. It is a gloss paper, and each is an enlarged image of the surface. These images 401 to 403 read into the CMOS sensor 211 are digitally processed to become images 404 to 406 shown in FIG. Thus, the image on the surface varies depending on the type of recording material. This is a phenomenon that occurs mainly because the fiber state on the paper surface is different.

  Apart from this, the amount of reflected light of the recording material is generally calculated from the total or average value of the light input to each pixel. However, depending on the embodiment, only the result of one light receiving pixel can be used.

  As described above, the surface state of the paper fiber of the recording material can be identified by an image obtained by digitally processing the image obtained by reading the surface of the recording material by the CMOS area sensor 211. Discrimination becomes possible.

  The recording material surface is identified by reading a part of the surface of the recording material as an image composed of 8 × 8 pixels, and the pixel density Dmax that is the maximum density for one line in the direction orthogonal to the recording material conveyance direction in the image. The density Dmin of the pixel having the lowest density is detected, and Dmax−Dmin is averaged for each line. The material (smoothness) that is an attribute of the recording material can be determined based on the value of Dmax−Dmin obtained by the averaging process.

  That is, when the paper fiber on the surface is rough like the recording material A, many shadows of the fiber are generated. As a result, the difference between the bright part and the dark part is large, and Dmax−Dmin becomes large. On the other hand, the image of the surface of a recording material having a sufficiently smooth fiber and a high smoothness like the recording material C has less fiber shadow and Dmax−Dmin becomes small. By this comparison, the material of the recording material is determined and used as a part of information for determining the type.

  Similarly, in FIG. 4, an image 407 is a surface enlarged image in a light irradiation region of light transmitted through the recording material by the transmission LED 302 of the recording paper D which is a thin paper, and the image 408 is generally used. A surface enlarged image of the light irradiation region by the transmission LED 302 of the recording paper E which is so-called plain paper, and an image 409 is a surface expansion image of the light irradiation region by the transmission LED 302 of the recording paper F which is a thick paper. These images 407 to 409 read by the CCD sensor 211 are digitally processed to become images 410 to 412 in FIG.

  In this way, the amount of transmitted light and its image vary depending on the type of recording paper. This is a phenomenon that occurs mainly because the fiber state on the paper surface and the compressed state of the paper fiber are different.

  Since the above-described control processor needs to process video sampling processing, gain and filter calculation processing from the CMOS area sensor 211 in real time, it is desirable to use a digital signal processor.

  Next, a method for measuring the transmittance of the recording material 304 will be described. The light that uses the transmitting LED 302 as the second irradiation means as a light source is irradiated toward the recording material 304 from the opposite side of the image reading sensor 123 so as to enter the reading area of the image reading sensor 123 on the recording material. The

  FIG. 5 is a diagram showing the surface of the recording material 304 read by the CMOS area sensor 211 of the image reading sensor 123 using the transmissive LED 302 and digitally processing the output from the CMOS area sensor 211 into 8 × 8 pixels. It is. The light transmitted through the recording material 304 is condensed through the lens 303 and enters the CMOS area sensor 211. At this time, normally, the total amount or the average value of the light amounts input to each pixel in the entire sensor area or in a predetermined range is used as the transmitted light amount, but only the result of one light receiving pixel can be used.

  FIG. 6 is a diagram showing the relationship between the basis weight of the recording material and the transmitted light. For example, a recording material with a large basis weight such as thick paper has a small amount of transmitted light, whereas a recording material with a low basis weight such as thin paper has a large amount of transmitted light. Based on this characteristic, the material thickness, which is one of the attributes of the recording material, is determined based on the amount of transmitted light, which is one piece of information for determining the type of the recording material.

There are the following types of recording materials assumed in the present embodiment, and the type is determined according to the surface state and the material thickness as will be described below. The basis weight described below refers to the weight per unit volume of the recording material.
(1) Thin paper (basis weight: weight per unit area to 64 g / m ² )
(2) Plain paper (basis weight: 65 to 105 g / m ² )
(3) Cardboard 1 (basis weight: 106 to 135 g / m ² )
(4) Cardboard 2 (basis weight: 136 g / m ² ~)
(5) Gloss paper (6) Gloss film (7) OHT

  Since (7) is transparent and has high light transmittance, two sets (1) to (6) and (7) are determined based on the amount of light reflected from the recording material.

  Three sets (1) to (4), (5), and (6) are determined from the contrast ratio of the image obtained from the reflected light of the recording material. Here, in this embodiment, when detecting the light / dark ratio for this determination, normalization is performed based on the amount of reflected light. That is, if there is a difference in the total light amount of the two-dimensional image, the value of Dmax−Dmin also changes, so normalization is performed so that the average value of the light amount of the entire two-dimensional image matches.

  The basis weights of (1) to (4) are different depending on the amount of transmitted light, and the received light amount of transmitted light when a constant amount of light is irradiated from the back of the paper is (1)> (2 )> (3)> (4), so that there are four types (1), (2), (3), and (4). Here, in the present embodiment, the determination is performed using the average value of the transmitted light amount of all the pixels including 8 × 8 pixels.

  By combining the above determinations, various recording materials (1) to (7) can be accurately determined.

(Implementation of recording material discrimination function)
A control circuit of the CMOS area sensor 211 for performing the above operation will be described with reference to FIG. FIG. 7 is a block diagram showing a control circuit of the CMOS area sensor 211. In FIG. 7, the CPU 210 as a determination unit includes a control circuit 702, a CMOS area sensor 211, an interface control circuit 704, an arithmetic circuit 705, a register A 706, a register B 707, and a control register 708.

  Next, the operation will be described. When the CPU 210 gives an operation instruction for the CMOS area sensor 211 to the control register 708, the CMOS area sensor 211 starts capturing the recording material surface image. That is, charge accumulation in the CMOS area sensor 211 is started. When the CMOS area sensor 211 is selected by Sl_select from the interface circuit 704 and SYSCLK is generated at a predetermined timing, the captured digital image data is transmitted from the CMOS area sensor 211 via the Sl_out signal.

  The imaging data received via the interface circuit 704 is calculated by the control circuit 702, and the calculation result is stored in the register A 706 and the register B 707. The CPU 210 determines the attribute of the recording material from the values of the two registers.

  The value stored in the register A706 is a value obtained by averaging Dmax−Dmin for 8 lines for a part of the surface of the recording material acquired as an image by the CMOS area sensor 211. When acquiring this image, LED 301 irradiates the surface of the recording material. The value stored in the register B707 is a value obtained by averaging the amount of light of each pixel of 8 × 8 pixels with respect to a part of the surface of the recording material acquired as an image by the CMOS area sensor 211. This image is acquired. In this case, the transmitting LED 302 irradiates the back surface of the recording material.

  Next, a sensor circuit block diagram will be described with reference to FIG. FIG. 8 is a circuit block diagram of the CMOS area sensor. In FIG. 8, a CMOS area sensor 211 includes a CMOS sensor portion 801, and, for example, sensors for 8 × 8 pixels are arranged in an area. CMOS area sensor 211 further includes vertical shift registers 802 and 803, output buffer 804, horizontal shift register 805, system clock 806, and timing generator 807.

  Next, the operation will be described. When the Sl_select signal 813 is activated, the CMOS sensor unit 801 starts accumulating charges based on the received light. Next, when the system clock 806 is supplied, the vertical shift registers 802 and 803 sequentially select the pixel columns to be read out by the timing generator 807, and the data is sequentially stored in the output buffer 804.

  Data stored in the output buffer 804 is transferred to the A / D converter 808 by the horizontal shift register 805. The pixel data digitally converted by the A / D converter 808 is controlled at a predetermined timing by the output interface circuit 809, and is output to the Sl_out signal 810 while the Sl_select signal 813 is active.

  On the other hand, the control circuit 811 can be controlled to change the A / D conversion gain from the Sl_in signal 812. For example, if the contrast of the captured image cannot be obtained, the CPU can always capture with the best contrast by changing the gain.

  As described above, by using the two irradiation means, that is, the reflection LED 301 as the first irradiation means and the transmission LED 302 as the second irradiation means, the surface state, reflectance, and transmittance of various recording materials. Can be detected, and the type of recording material can be determined.

  In the present embodiment, a light source having a wavelength longer than that of the reflective LED 301 is used for the transmissive LED 302. For example, if the reflective LED 301 is visible light, the transmissive LED 302 can use infrared rays.

  FIG. 9 shows recording material transmission characteristics using visible light or infrared light LEDs having different wavelengths as the transmission LED 302. As shown in FIG. 9, the transmittance for transmitting the recording material is higher when an LED having a longer wavelength is used as the light source. Accordingly, when the thickness of the recording material is determined by the transmitted light, a light source having a long wavelength that can take a wide dynamic range for detection, for example, an infrared light LED, can be detected accurately and stably. Is very effective for. In the present invention, the reflective LED used for detecting the reflected light from the surface of the recording material is a visible light LED having the highest photosensitivity in the CMOS area sensor, and the transmissive LED used for detecting the transmitted light quantity is more reflective than the reflective LED. Also, an example using an infrared LED having a long wavelength, for example, is used. As a result, the recording material has high transparency, and the S / N ratio is improved, so that the dynamic range is increased and the detection reliability is improved.

  As described above, using the two irradiation means of the reflection LED for recording surface photographing as the reflection light irradiation means and the transmission LED as the transmission light irradiation means for detecting the thickness of the recording material by the transmitted light, and By using an LED having a wavelength longer than that of the LED for reflection, the surface property state, reflectance and transmittance of various recording materials can be accurately detected, and the type of the recording material can be determined. It becomes possible.

[Second Embodiment]
In the second embodiment, the basic configuration other than the configuration of the transmitted light detection unit is the same as that of the first embodiment, and a detailed description thereof will be omitted. In the present embodiment, the transmissive LED 302 emits light with a light intensity stronger than that of the reflective LED 301.

  Although the sensitivity gain of the CMOS area sensor 211 can be changed, the light sensitivity of the device is fixed. Therefore, even in the case of a plurality of light sources, it is easy to specify the gain within a certain range as a common dynamic range of detection and that the light amount of the plurality of light sources is as close as possible. It becomes possible. In general, the amount of light that is transmitted through the recording material and detected through the recording material is less than the amount of light that is reflected and received by the surface of the recording material. It is desirable to increase the amount of light in order to widen the dynamic range. As a result, the S / N ratio is improved, the dynamic range is increased, and the detection reliability can be improved.

  As described above, the LED for recording the surface of the recording material and the LED for transmission for detecting the thickness of the recording material by the transmitted light are used, and the light amount of the LED for transmission is larger than the light amount of the LED for reflection. By controlling in such a manner, it is possible to accurately detect the surface state, reflectance, and transmittance of various recording materials, and to determine the type of recording material.

[Third Embodiment]
In the third embodiment, since the basic configuration other than the configuration of the transmitted light detection unit is the same as that of the first embodiment, detailed description thereof is omitted. In this embodiment, the transmissive LED 302 is configured by using an LED having a narrower directivity than the reflective LED 301.

  Although the sensitivity gain of the CMOS area sensor 211 can be changed, the light sensitivity of the device is fixed. Therefore, even in the case of a plurality of light sources, it is easy to specify the gain within a certain range as a common dynamic range of detection and that the light amount of the plurality of light sources is as close as possible. It becomes possible. In general, the amount of light that is transmitted through the recording material and detected through the recording material is less than the amount of light that is reflected and received by the surface of the recording material. In particular, in order to detect thick recording paper with high accuracy, it is desirable to increase the amount of light in order to widen the dynamic range for detection. As shown in the second embodiment, in the method of increasing the amount of light of the transmissive LED 302, the LED device must be driven with a large current, and the cost of the LED may increase.

  In the third embodiment, this problem is solved by using a narrow directivity LED. As shown in FIG. 10, there are LED devices having wide directivity (weak) and narrow directivity (strong). If a narrow directivity LED is used, the light can be concentrated without greatly changing the LED drive current, and the amount of light per unit area can be increased. Therefore, it is suitable as a light source for transmission used for transmitted light detection. is there. In the present embodiment, an example of LED devices with different directivities is given and a configuration using narrow directivity is proposed. However, the LED may have the same directivity, and a system that realizes the same function by disposing a lens as a separate component on the front surface of the LED may be used. As a result, the S / N ratio is improved, the dynamic range is increased, and the detection reliability can be improved.

  As described above, the LED for recording the surface of the recording material and the LED for detecting the thickness of the recording material by transmitted light are used, and the LED having the directivity narrower than the light amount of the reflecting LED is used. By using and controlling to perform LED driving, it is possible to accurately detect the surface state, reflectance, and transmittance of various recording materials, and to determine the type of recording material.

1 is a schematic view showing an image forming apparatus used in an embodiment of the present invention. It is a figure which shows the structure of each unit which the control CPU by one Embodiment of this invention controls. FIG. 3 is a schematic diagram illustrating a schematic configuration for performing surface smoothness of a recording material and detection of a reflected light amount and a transmitted light amount. It is a figure which shows contrast with the analog image of the recording material surface read by an image | video reading sensor, and the digital image which digitally processed the analog output to 8x8 pixel. It is the figure which digitally processed and displayed the image of the recording material read by the image | video reading sensor to 8x8 pixel using LED for permeation | transmission. It is a figure which shows the relationship between the basic weight of a recording material, and transmitted light. It is a block diagram which shows the control circuit of the CMOS area sensor by one Embodiment of this invention. It is a figure which shows the circuit block diagram of the CMOS area sensor by one Embodiment of this invention. It is a figure which shows the recording material permeation | transmission characteristic using visible light or infrared light LED from which a wavelength differs as LED for permeation | transmission. It is a figure which shows the radiation intensity distribution of LED with a narrow directivity, and wide LED.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Image forming apparatus 102 Paper cassette 103 Paper feed roller 104 Transfer belt drive roller 105 Transfer belts 106-109 Photosensitive drums 110-113 for yellow, magenta, cyan, black Transfer rollers 114-117 for each color Yellow, magenta, cyan, Black cartridges 118 to 121 Optical units 122 for yellow, magenta, cyan, and black Fixing unit 123 Image reading sensor 210 Control CPU
211 CMOS sensors 212 to 215 Polygon mirror, motor and laser 216 Paper feed motor 217 Paper feed solenoid 218 Paper presence sensor 219 High voltage power supply 220 Drum drive motor 221 Belt drive motor 222 Low voltage power supply 223 ASIC
224 Memory 301 LED for reflection
302 LED for transmission
303 Lens 304 Recording Material 702 Control Circuit 704 Interface Control Circuit 705 Arithmetic Circuit 706 Register A
707 Register B
708 Control register 801 CMOS sensor part 802, 803 Vertical shift register 804 Output buffer 805 Horizontal shift register 806 System clock 807 Timing generator 808 A / D converter 809 Output interface circuit 810 Sl_out signal 811 Control circuit 812 Sl_in signal 813 Sl_select signal

Claims (12)

Including image reading means for obtaining an image of the surface of the recording material by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material, and using the image of the surface of the recording material obtained by the image reading means In the recording material discriminating apparatus for determining the type of the recording material based on the attribute obtained by the reflection type judging means, comprising a reflection type judging means for judging a predetermined attribute of the recording material,
By irradiating the recording material with predetermined irradiation light having a wavelength longer than the irradiation light used in the reflection type determination means, the transmitted light obtained through the recording material is used, and the recording material A transmission type determination means for determining an attribute different from the reflection type determination means;
A recording material discriminating apparatus for discriminating the type of the recording material based on the attribute obtained by the transmission type judging means in addition to the attribute obtained by the reflection type judging means. Including image reading means for obtaining an image of the surface of the recording material by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material, and using the image of the surface of the recording material obtained by the image reading means In the recording material discriminating apparatus for determining the type of the recording material based on the attribute obtained by the reflection type judging means, comprising a reflection type judging means for judging a predetermined attribute of the recording material,
By irradiating the recording material with predetermined irradiation light having a light intensity stronger than the irradiation light used in the reflection type determination means, the transmitted light is transmitted through the recording paper, Transmission that determines an attribute different from that of the reflection type determination unit of the recording material by using transmitted light in which the difference between the amount of reflected light and the amount of transmitted light is within a predetermined range by adjusting the amount of light With a type determining means,
A recording material discriminating apparatus for discriminating the type of the recording material based on the attribute obtained by the transmission type judging means in addition to the attribute obtained by the reflection type judging means.   3. The recording material discriminating apparatus according to claim 2, wherein the predetermined irradiation light uses a light source having higher directivity than irradiation light used in the reflection type determination means. In order to obtain reflected light reflected from the surface of the recording material, a reflection type irradiating means for irradiating the recording material with predetermined light, reflected light or transmitted light from the recording material is received and read as an image, and the amount of light is detected. Reading means, and causing the reflection type irradiation means to irradiate the recording material with light, causing the reading means to read the reflected light obtained by the reflection type irradiation means as an image, and based on the image, In the recording material discriminating apparatus provided with the control means for discriminating the type,
In order to obtain transmitted light that passes through the recording material, the recording material includes transmission type irradiation means for irradiating predetermined light having a wavelength longer than the predetermined light irradiated by the reflection type irradiation means,
The control unit causes the reflection type irradiation unit and the transmission type irradiation unit to irradiate the recording material with light, causes the reading unit to read reflected light obtained by the reflection type irradiation unit as an image, and A recording material discriminating apparatus characterized in that the amount of transmitted light obtained by the transmission type irradiation means is detected and the type of the recording material is discriminated based on the image and the amount of transmitted light. In order to obtain reflected light reflected from the surface of the recording material, a reflection type irradiating means for irradiating the recording material with predetermined light, reflected light or transmitted light from the recording material is received and read as an image, and the amount of light is detected. Reading means, and causing the reflection type irradiation means to irradiate the recording material with light, causing the reading means to read the reflected light obtained by the reflection type irradiation means as an image, and based on the image, In the recording material discriminating apparatus provided with the control means for discriminating the type,
In order to obtain transmitted light that passes through the recording material, the recording material is a predetermined amount of light that is stronger than the predetermined light irradiated by the reflection type irradiation means, and the light amount of the predetermined light is adjusted. A transmission type irradiation means for irradiating predetermined light in which a difference between the light amount of the reflected light and the light amount of the transmitted light is within a predetermined range;
The control unit causes the reflection type irradiation unit and the transmission type irradiation unit to irradiate the recording material with light, causes the reading unit to read reflected light obtained by the reflection type irradiation unit as an image, and A recording material discriminating apparatus characterized in that the amount of transmitted light obtained by the transmission type irradiation means is detected and the type of the recording material is discriminated based on the image and the amount of transmitted light.   6. The recording material discriminating apparatus according to claim 5, wherein the predetermined light of the transmission type irradiation unit uses a light source having a higher directivity than the predetermined light used in the reflection type irradiation unit. A latent image carrier for carrying a latent image, a developing means for visualizing the latent image as a developer image by applying a developer to the latent image carrier, and a developing means for recording material conveyed in a predetermined direction A transfer means for transferring the developer image according to the method, and fixing the developer image on the recording material by heating and pressurizing the recording material on which the developer image has been transferred by the transfer means under predetermined fixing processing conditions. A fixing unit; and a video reading unit that obtains an image of the surface of the recording material by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material, and the recording material surface obtained by the video reading unit Reflection type determination means for determining a predetermined attribute of the recording material using the image of the recording material, and determining the type of the recording material based on the attribute obtained by the reflection type determination means, and to the determined type Corresponding said In the image forming apparatus to be fixed on the recording material the toner image by coating treatment conditions,
By irradiating the recording material with predetermined irradiation light having a wavelength longer than the irradiation light used in the reflection type determination means, the transmitted light obtained through the recording material is used, and the recording material A transmission type determination means for determining an attribute different from the reflection type determination means;
The fixing unit determines the type of the recording material based on the attribute obtained by the transmission type determination unit in addition to the attribute obtained by the reflection type determination unit, and corresponds to the determined type. An image forming apparatus, wherein the developer image is fixed on a recording material according to fixing processing conditions. A latent image carrier for carrying a latent image, a developing means for visualizing the latent image as a developer image by applying a developer to the latent image carrier, and a developing means for recording material conveyed in a predetermined direction A transfer means for transferring the developer image according to the method, and fixing the developer image on the recording material by heating and pressurizing the recording material on which the developer image has been transferred by the transfer means under predetermined fixing processing conditions. A fixing unit; and a video reading unit that obtains an image of the surface of the recording material by irradiating the recording material with light and reading reflected light reflected from the surface of the recording material, and the recording material surface obtained by the video reading unit Reflection type determination means for determining a predetermined attribute of the recording material using the image of the recording material, and determining the type of the recording material based on the attribute obtained by the reflection type determination means, and to the determined type Corresponding said In the image forming apparatus to be fixed on the recording material the toner image by coating treatment conditions,
By irradiating the recording material with predetermined irradiation light having a light intensity stronger than the irradiation light used in the reflection type determination means, the transmitted light is transmitted through the recording paper, Transmission that determines an attribute different from that of the reflection type determination unit of the recording material by using transmitted light in which the difference between the amount of reflected light and the amount of transmitted light is within a predetermined range by adjusting the amount of light With a type determining means,
The fixing unit determines the type of the recording material based on the attribute obtained by the transmission type determination unit in addition to the attribute obtained by the reflection type determination unit, and corresponds to the determined type. An image forming apparatus, wherein the developer image is fixed on a recording material according to fixing processing conditions.   The image forming apparatus according to claim 8, wherein the predetermined irradiation light uses a light source having higher directivity than irradiation light used in the reflection type determination unit. A latent image carrier for carrying a latent image, a developing means for applying a developer to the latent image carrier, a transfer means for transferring the developer image to a recording material, and the developer image by heating and pressing. A fixing means for fixing the recording material to the recording material, a reflective irradiation means for irradiating the recording material with predetermined light to obtain reflected light reflected from the surface of the recording material, and the latent image as a developer image by the developing means. Reading that visualizes and transfers the visualized image to the recording material conveyed in a predetermined direction by the transfer means, receives reflected light or transmitted light from the recording material, reads it as an image, and detects the amount of light And the reflection type irradiation means irradiates the recording material with light, the reading means reads the reflected light obtained by the reflection type irradiation means as an image, and the type of the recording material is determined based on the image. Discriminate In predetermined fixing treatment condition corresponding to another is the type to fix the recording material which has been transferred by said fixing means, an image forming apparatus having a control means for discharging the fixed recording material,
In order to obtain transmitted light that passes through the recording material, the recording material includes transmission type irradiation means for irradiating predetermined light having a wavelength longer than the predetermined light irradiated by the reflection type irradiation means,
The control unit irradiates the recording material with light to the reflection type irradiation unit and the transmission type irradiation unit before transferring by the transfer unit, and causes the reading unit to reflect the reflection type obtained by the reflection type irradiation unit. The light is read as an image, and the amount of transmitted light obtained by the transmission type irradiation means is detected, and the type of the recording material is determined based on the image and the amount of transmitted light. An image forming apparatus, wherein the developer image is fixed on a recording material according to the fixing processing condition corresponding to the type. A latent image carrier for carrying a latent image, a developing means for applying a developer to the latent image carrier, a transfer means for transferring the developer image to a recording material, and the developer image by heating and pressing. Fixing means for fixing the recording material to the recording material, reflection type irradiation means for irradiating the recording material with predetermined light to obtain reflected light reflected from the surface of the recording material, and developing the latent image as a developer image Reading that visualizes and transfers the visualized image to the recording material transported in a predetermined direction by the transfer means, receives reflected light or transmitted light from the recording material as an image, and detects the amount of light And the reflection type irradiation means irradiates the recording material with light, the reading means reads the reflected light obtained by the reflection type irradiation means as an image, and the type of the recording material is determined based on the image Discriminate In predetermined fixing treatment condition corresponding to another is the type to fix the recording material which has been transferred by said fixing means, an image forming apparatus having a control means for discharging the fixed recording material,
In order to obtain transmitted light that passes through the recording material, the recording material is a predetermined amount of light that is stronger than the predetermined light irradiated by the reflection type irradiation means, and the light amount of the predetermined light is adjusted. A transmission type irradiation means for irradiating predetermined light in which a difference between the light amount of the reflected light and the light amount of the transmitted light is within a predetermined range;
The control unit irradiates the recording material with light to the reflection type irradiating unit and the transmission type irradiating unit before transferring by the transfer unit, and causes the reading unit to obtain the reflection obtained by the reflective type irradiating unit. The light is read as an image, and the amount of transmitted light obtained by the transmission type irradiation means is detected, and the type of the recording material is determined based on the image and the amount of transmitted light. An image forming apparatus, wherein the developer image is fixed on a recording material according to the fixing processing condition corresponding to the type. The image forming apparatus according to claim 11, wherein the predetermined light of the transmission type irradiation unit uses a light source having higher directivity than the predetermined light used in the reflection type irradiation unit.

Images