JP2007169037A - Printer having recorded medium kind discriminating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer having a recorded medium kind detecting device, advantageous to a size and cost, by accurately and stably discriminating a kind of recorded medium, even when discriminating between plain paper and coat paper and discriminating details in a glossy paper group. <P>SOLUTION: This printer uses the visible light including the ultraviolet area light for an illuminating means of the recorded medium kind detecting device, and is provided with two places of diffused light receiving parts receiving the diffused light and a regular reflection light receiving part receiving the regular reflection light, and is constituted so that the diffused light receiving part of one place has an optical filter cutting off a beam of light of a specific wave length area existing outside a wave length area for receiving the light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printing apparatus including a recording medium type discrimination device.

  2. Description of the Related Art Conventionally, devices such as printers and printing machines that perform recording on a recording medium such as recording paper with ink have been widely used.

  In recent years, the types of recording media have diversified with market demands and the development of recording equipment. Recording paper, postcards and other thick paper with improved ink quality by providing an ink receiving layer on the surface of the paper, cloth that can be recorded with a printer, etc. A wide variety of recording media have been put into practical use.

  An ink jet printer is a representative device that supports these various recording media.

  In an ink jet printer, the degree of bleed and color development on the ink medium varies depending on the type of recording medium. Therefore, in order to obtain the best image quality, the ink discharge amount and the number of ink discharges are set according to the medium, and this setting is performed by the user instructing the medium type from the instruction means of the host computer or printer.

  As the types of recording media increase, the number of options for this instruction increases, giving the user troublesome operations. In addition, even if an incorrect instruction is given, the user cannot be warned from the printer, so that it is possible that a printed matter with inferior image quality may be output despite the use of special paper that can be output with high image quality. .

  Also, if there is no printer near the user in a network printer, etc., after confirming what kind of recording medium is stored in the recording medium storage unit, it is necessary to specify the medium type after going to the printer location. There is a need to. In such a case, it is very inefficient.

  In order to solve such drawbacks, a device for detecting the type of recording medium has been devised, and a typical one is to measure the difference in reflectance on the surface of the recording medium as disclosed in Patent Document 1, and In this method, the type is determined by the threshold method.

  However, this discrimination method can discriminate between plain paper and OHP sheets or glossy paper, but when there is little difference in reflectance, such as discrimination between plain paper and coated paper, or detailed discrimination within glossy paper groups. It was difficult to distinguish accurately. Specifically, when the difference in reflectance is very small, the measurement values may overlap, so that accurate determination is difficult.

In view of this, a device for discriminating the type of recording medium in more detail has been made. A typical one is to determine the fluorescence intensity characteristic of the surface of the recording medium using a light beam including a wavelength band that excites the fluorescence phenomenon as described in Patent Document 2, and add the determination result to the recording medium. There is a method of increasing the type discrimination accuracy. As described in Patent Document 3, a recording medium is irradiated with short-wavelength light included in the ultraviolet region and long-wavelength light included in the visible light region or infrared region, and recording is performed based on the difference in absorbance obtained for each irradiation light. This is a method for discriminating a medium. Here, the difference in absorbance means the ratio between the intensity of irradiated light and the intensity of light transmitted or reflected through a paper sheet.
Japanese Patent Laid-Open No. 2-138805 JP 2002-167082 A JP 2003-315260 A

  However, in the method described in Patent Document 2, a plurality of light emitting units or optical filters are switched for detailed determination, and a plurality of complicated light emitting unit driving circuits are required. I felt inconvenience. Furthermore, it may be inconvenient in terms of cost because it may be necessary to maintain a balance between temperature characteristics and deterioration of a plurality of light emitting sections.

  Even in the method described in Patent Document 3, switching between a plurality of light emitting units or optical filters occurs as in the method described in Patent Document 2, and there may be inconveniences in terms of size and cost. . In addition, since there is only one light receiving unit, the output data cannot cope with dirt and temperature changes such as mist and paper dust, changes in light quantity and sensitivity due to element life, etc., and the discrimination performance becomes unstable, which is inconvenient. I could feel that.

  The present invention is a recording medium type detection device that can accurately and stably determine the type of recording medium such as discrimination between plain paper and coated paper and detailed discrimination within a glossy paper group, and is advantageous in terms of size and cost. An object of the present invention is to provide a printing apparatus provided with

  In the recording medium type discriminating apparatus for discriminating the type of recording medium, the present invention provides an irradiation means for irradiating the recording medium with visible light including ultraviolet light, and the light irradiated by the irradiation means Regular reflection light receiving means for receiving reflected light regularly reflected on the surface of the recording medium, and a plurality of diffusely reflected light for receiving reflected light diffused and reflected by the irradiation means on the surface of the recording medium A plurality of diffusely reflected lights, comprising: a light receiving means; and a determining means for determining the type of the recording medium based on the amount of reflected light obtained from the regular reflected light receiving means and the plurality of diffusely reflected light receiving means. At least one diffusely reflected light receiving unit among the light receiving units is characterized in that the wavelength range for receiving light is limited by a filter that blocks light in a predetermined wavelength range.

  According to the present invention, a recording medium storage unit that can store a plurality of recording media to be printed, a feeding unit that feeds the recording medium one by one from the recording medium storage unit, and an ultraviolet light for the illumination unit. Two diffused light receiving parts that receive diffused light and visible light receiving parts that receive specular reflected light are provided using visible light including area light, and one diffused light receiving part is outside the wavelength range to be received. By having an optical filter that blocks light in a specific wavelength range, even when discriminating between plain paper and coated paper or detailed discrimination within glossy paper groups, the recording medium can be accurately and stably recorded. Therefore, it is possible to provide a printing apparatus including a recording medium type detecting device that is advantageous in terms of size and cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, what attached | subjected the same code | symbol has the same structure or effect | action, The duplication description about these shall be abbreviate | omitted suitably.

<Embodiment 1>
FIG. 1A is a perspective view of a printing apparatus 1 provided with a recording medium type detection apparatus according to the present invention. Here, 2 is a recording medium storage unit, and 3 is a recording medium stored in the recording medium storage unit 2.

  FIG. 1 is a longitudinal sectional view of a printing apparatus 1 provided with a recording medium type detection device.

  A case where printing is performed will be described with reference to FIG. First, the type of the recording medium 3 at the top of the recording medium storage unit 2 is discriminated by the recording medium type detection unit 4, and conditions for optimal printing are prepared. Next, when a printing instruction is issued, the recording medium 3 stored in the recording medium storage unit 2 is fed one by one from the recording medium storage unit 2 by rotation of a paper supply roller (not shown). 21 is inserted into the nip portion between the conveying rollers 22 and 23. After the recording medium 3 is conveyed to a position where printing is performed, printing by the print head 24 on a carriage (not shown) is continued along with the line feed of the recording medium 3, and the paper discharge roller 25 and a spur as a pressing unit. 26 and discharged in the Z direction.

  Here, the recording medium type detection unit 4 is attached to the support member 5. This support member is rotatably attached to a chassis (not shown) of the printing apparatus 1 at a point P and is urged in the A direction by a spring (not shown). Further, between the support member 5 and the recording medium type detection unit 4, there is a spring 6 that adjusts the position of the recording medium type detection unit 4 corresponding to the difference in the remaining amount of the recording medium 3. The spring 6 is in close contact with the top surface of the recording medium 3 on the recording medium storage unit 2. When the recording medium 3 is fed, the support member 5 is rotated in the C direction by the shaft 7 that moves in the B direction in conjunction with the rotation of a feeding roller (not shown). The urging of the three surfaces is released, and smooth paper feeding becomes possible.

  Further, when the recording medium 3 is set in the recording medium storage unit 2, the spring 6 is moved by a force for setting the recording medium 3 that has entered below using the inclined surface portion 4 c of the recording medium type detection unit 4. It can be shrunk. The recording medium type detection unit 4 is provided with rollers 47 and 48 that are pivotally supported by the recording medium type detection unit 4 and rotate in accordance with the movement of the recording medium 3. Can be done.

  FIG. 2 shows the recording medium type detection unit 4 that is detecting the type of the recording medium 3.

  Here, as visible light including ultraviolet light in its light component, light emitted from the light emitting unit 41 made of, for example, a purple LED illuminates the surface of the recording medium 3 as shown in the figure.

  Sensors 42 and 43 are photodiodes or phototransistors that receive light diffusely reflected from the recording medium 3, perform photoelectric conversion according to the amount of incident light, and output electrical signals. Here, in the middle of the optical path to the sensor 42, an optical filter 8 for blocking light in a specific wavelength region outside the wavelength region to be received is provided. The optical filter 8 is, for example, SC41 (manufactured by Fuji Photo Film Co., Ltd.), and in this case, a wavelength region shorter than 410 nm is blocked.

  Reference numeral 44 denotes a sensor comprising a photodiode or a phototransistor that receives light regularly reflected from the recording medium 3, and performs photoelectric conversion according to the amount of incident light and outputs an electrical signal.

  The recording medium 3 is obtained by combining the electrical signal output by the diffuse reflection light based on the violet light and the electrical signal output by the regular reflection light and comparing the value with each recording medium stored in advance as data. The type of can be determined in detail. It should be noted that the electrical signal output by the diffuse reflected light is different depending on whether the optical filter 8 is provided on the way or not.

  In this case, only the light passing through the optical filter 8, that is, the light excited by the ultraviolet region light contained in the purple LED 41 (around the central wavelength of 420 to 450 nm) reaches the sensor 42 and is detected. Both the reflected light of the purple LED 41 (center wavelength around 400 nm) and the light excited by the ultraviolet region light contained in the purple LED 41 (center wavelength around 420 to 450 nm) reach the sensor 43 and are detected.

  Here, the light receiving holes 45 and 46 of the sensors 42 and 43 may be provided in a shape parallel to the optical axis.

  FIG. 4 shows the result of detecting the surface of a plurality of types of recording media using the recording medium detection unit. The horizontal axis represents the diffused light sensor output signal value (S2 (no filter)) when the optical filter 8 is not provided when various recording media 3 are irradiated by the purple LED 41, and the specular reflected light sensor output signal value (S1). Shows the value divided by. The vertical axis represents the value obtained by dividing the diffused light sensor output signal value (S2 (SC41)) when the optical filter 8 is provided by the diffused light sensor output signal value (S2 (no filter)) when the optical filter 8 is not provided. It is.

  In this case, it is possible to discriminate for each recording medium 3 as well as group discrimination such as OHP, glossy paper, plain paper, and coated paper.

  FIG. 5 shows an example in which the diffused light sensor output signal value (S2 (no filter)) is determined only by a value obtained by dividing the diffused light sensor output signal value (S2 (no filter)) by the regular reflection light sensor output signal value (S1) as in the conventional example. As can be seen from FIG. 5, some of the values on plain paper and coated paper overlap, and even group discrimination may not be satisfactory. Further, although it is possible to perform group discrimination for glossy paper, it may not be possible to make discrimination for each glossy paper.

  Since the present invention uses a value obtained by dividing a diffused light sensor output with a filter by a diffused light sensor output without a filter and a value obtained by dividing a diffused light sensor output without a filter by a specularly reflected light sensor output, The paper type can be discriminated stably for a long time. Specifically, even when dirt such as mist or paper dust, temperature changes, changes in light intensity or sensitivity due to the life of the element, etc. occur, these can be canceled, so stable discrimination performance over a long period of time The paper type can be determined.

  Here, since visible light (violet LED) including ultraviolet region light is used as the light emitting unit 41, it is very advantageous in terms of cost compared to the case of using ultraviolet LED (center wavelength around 365 to 385 nm). Become. Furthermore, since it is arranged in a line on the optical axis, it is advantageous in terms of size.

  In addition, since there is only one light emitting part, it is not necessary to consider a complicated LED drive circuit or a balance between the deterioration rate and temperature characteristics of each LED as compared with the case of having a plurality of light emitting parts. It is very easy to use and advantageous in terms of cost.

<Embodiment 2>
As shown in FIG. 3, even if the sensors 42 and 43 are arranged on the left and right sides of the vicinity of the optical axis instead of on the optical axis, the same effect as in FIG. 2 can be obtained.

  In this case, the lateral width can be reduced (L ′ <L) as compared with the configuration of FIG. 2, but the depth direction is increased (D ′> D).

1 is a longitudinal sectional view of a printing apparatus provided with a recording medium type detection device according to the present invention. It is a figure which shows the structure of the recording medium type detection unit in 1st Embodiment based on this invention. It is a figure which shows the structure of the recording medium kind detection unit in 2nd Embodiment which concerns on this invention. It is a figure which shows the result of having detected the surface of several types of recording media using the recording medium type detection unit in the 1st Embodiment of this invention. FIG. 6 is a diagram illustrating a result of detecting the surface of a plurality of types of recording media using a recording medium type detection unit in the first embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printing apparatus main body provided with recording medium type detection apparatus 2 Recording medium storage part 21 Paper feed port 22, 23 Conveyance roller 24 Print head 25 Paper discharge roller 26 Spur 3 Recording medium 4 Recording medium type detection unit 4c Slope Part 41 Purple light emitting part 42 Light receiving part for diffused light 43 Light receiving part for diffused light 44 Light receiving part for specularly reflected light 45 Light receiving hole 46 Light receiving hole 47, 48 Roller 5 Support member 6 Spring 7 Shaft 8 Optical filter (SC41)

Claims (3)

In the recording medium type discriminating apparatus for discriminating the type of recording medium,
Irradiation means for irradiating visible light including ultraviolet light to the recording medium;
Specularly reflected light receiving means for receiving reflected light that is regularly reflected on the surface of the recording medium by the light irradiated by the irradiating means;
A plurality of diffusely reflected light receiving means for receiving reflected light diffused and reflected on the surface of the recording medium by the light irradiated by the irradiation means;
Discriminating means for discriminating the type of the recording medium based on the amount of reflected light obtained from the regular reflection light receiving means and the plurality of diffuse reflection light receiving means;
Recording medium type discrimination characterized in that at least one diffuse reflection light receiving means among the plurality of diffuse reflection light receiving means restricts the wavelength range to be received by a filter that blocks light in the usual wavelength range apparatus. In a printing apparatus comprising a recording medium storage unit capable of storing a plurality of recording media to be printed, and a recording medium type determination unit capable of determining the type of the recording medium stored in the recording medium storage unit ,
Illumination means for irradiating the recording medium;
It consists of photoelectric conversion means that receives reflected light from the recording medium and photoelectrically converts it,
Using visible light including ultraviolet light in the illumination means,
The photoelectric conversion means is provided with two diffused light receiving parts for receiving diffused light on the surface of the recording medium by visible light including ultraviolet light and a regular reflected light receiving part for receiving specularly reflected light. The printing apparatus, wherein the light receiving unit includes an optical filter that blocks light in a specific wavelength region outside the wavelength region to be received.   The printing apparatus according to claim 2, wherein the optical filter is configured to block light having a wavelength shorter than a wavelength of the excited light.

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