JP2009058614A - Image forming apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly measure the surface condition of printing paper even in various use environments and to exert appropriate transfer control or fixing control in printing. <P>SOLUTION: A light emitting section 35 emits light to conveyed printing paper 41 at a predetermined angle. A first light emitting section 37 receives regular reflection light from the printing paper 41 and outputs a first measurement signal. A second light receiving section 39 receives diffusion reflected light and outputs a second measurement signal. A correcting section 51 calculates correction values corresponding to the respective deviations of the first and second measurement signals from reference values when a reference member 47 is displaced to the area of illumination by the light emitting section 35. Using the correction values, the correcting section 51 corrects the first and second measurement signals obtained when a reflection preventing member 49 is displaced to the area of the illumination. Based on the first and second measurement signals, a transfer fixing control section 13 outputs control signals which controls transfer or fixing of an image on the printing paper 41. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming method, and an image suitable for, for example, a copying machine or a multi-function peripheral (MFP) that enables good image formation on printing paper having various surface states. The present invention relates to a forming apparatus and an image forming method.

  Image forming apparatuses such as copiers and multifunction machines can print on various types of printing papers with different thicknesses and surface conditions. Therefore, it is necessary to appropriately control the transfer and fixing of the toner image, and various proposals have been made.

  For example, there is a paper type discrimination method disclosed in JP-A-7-196207 (Patent Document 1).

  This patent document 1 receives a print command from a host computer by a printer, and before starting printing, feeds printing paper from a paper feed tray and stops at a predetermined position, and a projector that forms an optical axis across the printing paper A configuration in which the amount of light transmitted through the printing paper is detected by a light receiver, converted into a voltage corresponding to the light quantity, compared with a predetermined threshold voltage, and the type of printing paper is determined based on the comparison result This eliminates the need for the operator to determine the type of printing paper, and prevents erroneous printing on different printing paper.

  Furthermore, an image forming apparatus disclosed in Japanese Patent Laid-Open No. 2006-30978 (Patent Document 2) has also been proposed.

The configuration of this patent document 2 has glossiness detecting means including a light emitting portion and a light receiving portion in an image forming apparatus capable of performing double-sided recording by transferring an image onto both sides of the paper with a single sheet passing, and reflected on the paper. The gloss on the one side and the other side of the paper is detected by the reflected light that has been detected by the gloss level detecting means, and the toner on the image carrier in the image forming unit is detected based on the detection result of the gloss level detecting means. Even when sheets having different glossiness on the front and back surfaces are used by controlling the amount of adhesion, a difference in image quality between both sides of the sheet is reduced to obtain a high-quality double-sided image.
JP 7-196207 A JP 2006-30978 A

  However, the above-described paper type determination method disclosed in Patent Document 1 corresponds to the amount of light transmitted through the printing paper and attempts to ensure a good printing state by determining the type of printing paper in units. Since the surface state of the printing paper is not taken into consideration, there is room for improvement in obtaining a high-quality printing state for various printing papers having different surface states.

  On the other hand, in the image forming apparatus disclosed in Patent Document 2, the glossiness of the paper is calculated based on the reflected light from the paper, and the toner adhesion amount on the image carrier is controlled on the basis of the calculation result, thereby improving the image quality on both sides of the paper. The difference is reduced and the glossiness of the paper is also taken into consideration, but in order to achieve high image quality, it is necessary to consider the thickness of the paper and the roughness of the surface of the paper in addition to the glossiness. Similarly, there is room for improvement in order to obtain a high-quality print state on a printing paper having various surface states.

  Further, in the image forming apparatus, dust such as paper dust is likely to adhere to the projector and the light receiver (light emitting unit and light receiving unit) that detect the state of the paper, and it is difficult to prevent accurate measurement due to these stains. Has also been pointed out.

  Although it is conceivable to attach a cleaning mechanism to the measurement surfaces of the projector and the light receiver, it is not practical because the dirt cannot be completely removed and the configuration becomes complicated.

  SUMMARY OF THE INVENTION The present invention has been made to solve such problems. An image forming apparatus and an image forming method capable of accurately measuring the surface state of printing paper and easily performing appropriate transfer control or fixing control based on the measurement. The purpose is to provide.

  In order to solve such a problem, an image forming apparatus according to the present invention includes a light emitting unit that irradiates light at a predetermined angle with respect to a print sheet before image formation conveyed for image formation, and the print sheet. A first light-receiving unit that receives specularly reflected light from the side and outputs a first measurement signal corresponding thereto, and a second measurement that receives diffusely reflected light from the printing paper side and responds accordingly A second light-receiving unit that outputs a signal, a reference member that is opposite to the first light-receiving unit of the printing paper and that is displaceable in an irradiation region by the light-emitting unit, and the same as the reference member An antireflection member that is displaceably disposed at a position and suppresses reflection of irradiation light, and when the reference member is displaced to the irradiation region, according to a deviation between the first and second measurement signals and a predetermined reference value Each correction value is calculated, and the antireflection member is applied to the irradiation area. A correction unit that corrects the first and second measurement signals obtained when the image is moved with the correction value, and controls transfer or fixing of the image to the printing paper based on the corrected first and second measurement signals. And a transfer / fixing control unit that outputs a control signal to output the control signal.

  In the image forming apparatus of the present invention, the reference member and the antireflection member may be arranged on the same plane and slidably driven in parallel with the printing paper by the slide member.

  In the image forming apparatus of the present invention, a configuration in which the correction unit variably corrects the measurement signal from the first and / or second light receiving unit with the correction value is also possible.

  In the image forming apparatus of the present invention, a configuration in which the correction unit corrects the driving power to the light emitting unit by changing the correction value is also possible.

  In the image forming apparatus of the present invention, a configuration in which the light emitting unit intermittently emits light in pulses is also possible.

  In the image forming apparatus of the present invention, the transfer / fixing control unit differs from the predetermined reference values for the glossiness, paper thickness, and surface roughness of the printing paper obtained based on the first and second measurement signals. It is also possible to output a toner transfer amount control signal, a fixing temperature control signal or a fixing speed control signal corresponding to the above as the control signal.

  In the image forming method according to the present invention, the light emitting unit for irradiating light is arranged at a predetermined angle with respect to the printing paper before image formation conveyed for image formation, and the positive side from the printing paper side is arranged. A first light receiving unit that receives reflected light and outputs a first measurement signal is disposed on the printing paper, receives diffuse reflected light from the printing paper side, and outputs a second measurement signal. A second light receiving unit is disposed on the printing paper, a reference member is disposed on the irradiation region on the opposite side of the printing paper from the first light receiving unit, and the first and second light receiving units A correction value corresponding to the deviation between the output first and second measurement signals and a predetermined reference value is calculated, and an antireflection member is disposed in the irradiation region instead of the reference member. The first and second measurement signals output from the second light receiving unit are supplemented with the first and second measurement signals. It is corrected by a value, which is corrected method of outputting a control signal for controlling the transfer or fixing of the image on the printing paper on the basis of their first and second measurement signals.

  In the image forming method of the present invention, the reference member and the antireflection member may be arranged on the same plane and slid in parallel with the printing paper.

  In the image forming method of the present invention, a configuration in which the measurement signal output of the first and / or second light receiving unit is corrected by changing the correction value is also possible.

  In the image forming method of the present invention, a configuration in which the measurement signal is corrected by changing the driving power to the light emitting unit by the correction value is also possible.

  In such an image forming apparatus and image forming method according to the present invention, when light is emitted from the light emitting unit to the printing paper before image formation, the first light receiving unit receives the regular reflection light from the printing paper side. Then, the first measurement signal is output, and the second light receiving unit receives the diffuse reflected light from the printing paper side and outputs the second measurement signal. Obtained when the correction values corresponding to the deviations between the first and second measurement signals and the predetermined reference value when displaced into the region are respectively calculated and the antireflection member is disposed instead of the reference member A control signal that corrects the first and second measurement signals with the correction values, and controls transfer or fixing of the image onto the printing paper by the transfer and fixing control unit based on the corrected first and second measurement signals. Output, accurate measurement of the surface condition of printing paper Possible, this through an appropriate transcriptional control or the fixing control based, it is easy to obtain a printing state of the image quality with respect to the printing paper.

  In the present invention, when the reference member and the antireflection member are arranged on the same plane and are slid in parallel with the printing paper by the slide member, the surface state of the printing paper can be measured more accurately.

  In the present invention, in the configuration in which the measurement signal from the first and / or second light receiving unit is corrected, the output of the measurement signal is corrected by the correction value, and the surface state of the printing paper can be accurately measured.

  In the present invention, in the configuration in which the driving power to the first and / or second light receiving unit is corrected, the driving power is corrected by the correction value, and the surface state of the printing paper can be accurately measured.

  In the present invention, the configuration in which the light emitting unit intermittently emits light in pulses can increase the amount of light from the light emitting unit without increasing the driving power to the light emitting unit, and maintain a high S / N ratio. It is possible to obtain an image quality printing state.

  In the present invention, the transfer-fixing control unit determines a toner corresponding to a difference from a predetermined reference value with respect to the glossiness, thickness, and surface roughness of the printing paper obtained based on the first and second measurement signals. In the configuration in which the transfer amount control signal, the fixing temperature control signal or the fixing speed control signal is output as the control signal, it is possible to reliably obtain a high-quality print state through the toner transfer amount control, the fixing temperature control or the fixing speed. It is.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The image forming method according to the present invention will be described in the course of describing the image forming apparatus.

  FIG. 1 is a schematic block diagram for explaining the outline of an image forming apparatus A according to the present invention.

  1, the image forming apparatus A includes an image reading unit 3, a storage unit 5, a printing unit 7, an operation display unit 9, a detection unit 11, and a transfer fixing control unit 13 with the control unit 1 as a center. (MFP). Note that the image forming apparatus A has a configuration other than this, but since it is not the gist of the present invention, description and illustration are omitted.

  As shown in FIG. 2, the image reading unit 3 is disposed at the upper part of the main body case 15 of the apparatus, and optically reads an image from, for example, a printed document having a plurality of pages under the control of the control unit 1. A known scanner or the like that generates electronic image data as a print job by performing filter processing or the like, and stores and controls image data for each page in the storage unit 5.

  The storage unit 5 is a readable / writable hard disk, for example, that stores read image data from the image reading unit 3, reference values to be described later, and control management data, and stores an operation program of the control unit 1.

  The printing unit 7 conveys a plurality of paper feeding units 17 and 19 in which different printing papers are set, which are arranged at the lower part of the main body case 15, and the printing paper that is primarily fed from the paper feeding units 17 and 19. A transfer path 21, a registration roller 23 arranged in the middle of the transfer path 21 for controlling the secondary feeding timing of printing paper, a toner cassette 25 containing toner, and the above-described image data to print image image data. A transfer unit 27 that develops and develops toner with toner from the toner cassette 25 and transfers the toner onto the printing paper, a fixing unit 29 that fixes the toner image transferred onto the printing paper, and reversely conveys the printing paper for duplex printing. This is a monochrome or color print engine having a reversing conveyance unit 31 and the like.

  In the case of a color configuration, the toner cassette 25 and the transfer unit 27 are arranged for three colors or four colors.

  The operation display unit 9 is a publicly known unit that also serves as a touch input unit that instructs operation of the image forming apparatus A under the control of the control unit 1 and a liquid crystal display unit that displays the operation state.

  Details of the detection unit 11 and the transfer fixing control unit 13 will be described later.

  The control unit 1 controls the image reading unit 3, the storage unit 5, the printing unit 7, the operation display unit 9, the detection unit 11, and the transfer and fixing control unit 13. And a ROM having a startup program.

  The present invention is mainly configured by the detection unit 11 and the transfer / fixing control unit 13 in FIG.

  As shown in FIG. 2, the detection unit 11 is arranged in front of the registration roller 23 in the conveyance path 21, and as shown in FIG. 3, the detection unit 11 is a sensor housing whose lower side is opened toward the conveyance path 21. A support portion 33, a light emitting element 35 disposed toward the conveyance path 21 in the support portion 33, a regular reflection light reception element 37, a diffuse reflection light reception element 39, and a printing paper 41 on the conveyance path 21 are placed. The spacing member 43, the reference plate 47 stacked on the common support plate 45, the antireflection plate 49 stacked on the common support plate 45 together with the reference plate 47, and a correction unit 51 described later are formed. This is a so-called media sensor. The code | symbol D in FIG. 2 is dust.

  The light emitting element 35 is disposed obliquely so that the optical axis is positioned at an angle of about 60 ° to 85 ° with respect to a virtual perpendicular S from a virtual point P where the printing paper 41 conveyed on the conveyance path 21 exists. As shown in FIG. 4, the light emitting unit such as an LED that irradiates the virtual point P with light such as visible light or infrared light emitted by a drive signal from the drive unit 53.

  FIG. 4 is an electrical block diagram of the light emitting element 35, the specular reflection light receiving element 37, the diffuse reflection light receiving element 39, the correction unit 51, the drive unit 53, and the like of the detection unit 11.

  As shown in FIG. 3, the regular reflection light-receiving element 37 is disposed obliquely so that the optical axis is positioned at the same angle of about 60 ° to 85 ° in the opposite direction to the light-emitting element 35 around the virtual perpendicular S. The first light receiving unit outputs a first measurement signal having an electric level corresponding to the intensity of light regularly reflected from the light emitting element 35 on the printing paper 41. Mainly, the glossiness on the surface of the printing paper 41 is measured.

  The light receiving element 39 for diffuse reflection is arranged so as to face the virtual point P (printing paper 41) with the optical axis on the virtual perpendicular S, and the light diffused and reflected by the printing paper 41 from the light emitting element 35. The second light receiving unit outputs a second measurement signal having an electric level corresponding to strength. The thickness of the printing paper 41 is mainly measured, and the surface roughness of the printing paper 41 is also measured by the first and second measurement signals.

  The spacing member 43 is a member that keeps the spacing between the printing paper 41 and the reference plate 47 or the antireflection plate 49 constant by sandwiching the printing paper 41 on the transport path 21 by the reference plate 47 or the antireflection plate 49. It is.

  When the printing paper 41 is transported to a position where it is placed on the spacing member 43, it is temporarily stopped for measurement, but the presence or absence of the stop is not an essential requirement of the present invention.

  The reference plate 47 and the antireflection plate 49 are overlapped and fixed so as to be in contact with each other by being divided into half regions on the common support plate 45.

  3 and 5, the common support plate 45 can be moved back and forth in the direction between the reference plate 47 and the antireflection plate 49 by a slide member (not shown), and includes a virtual point P in the spacing member 43. The stop control is performed so that the reference plate 47 or the antireflection plate 49 covers the through hole 55 formed in the predetermined region.

  The reference plate 47 is a plate-like reference member having a white surface, for example, and reflects the irradiation light from the light emitting element 35 before the printing paper 41 is conveyed. The first and second measurement signals at the test level are obtained from the regular reflection light receiving element 37 and the diffuse reflection light receiving element 39.

  The antireflection plate 49 is a black sheet-shaped antireflection member portion that is difficult to reflect the light emitted from the light emitting element 35, and is printed paper up to a position that covers the through-hole 55 of the spacing member 43 during the actual printing operation. 41 is conveyed, and is used when the reflected light from the printing paper 41 is received by the regular reflection light receiving element 37 and the diffuse reflection light receiving element 39 by the irradiation light from the light emitting element 35.

  The correction unit 51 is similar to the image forming apparatus A, and in a very clean environment, the first light when the regular reflection light receiving element 37 and the diffuse reflection light receiving element 39 receive light from the reference plate 47 or the similar reflection member described above. The first and second measurement signals obtained by displacing the reference plate 47 in the actual image forming apparatus A to the irradiation area by the light emitting element 35 and the reference values of the second measurement signals in advance. According to the deviation from the reference value, it has a function of calculating each correction value for reducing the deviation.

  For example, the reference value levels a of the first and / or second measurement signals obtained in a clean environment are each “10”, and the first obtained by using the reference plate 47 in the actual image forming apparatus A. If the level b of each of the first and / or second measurement signals is “8”, a correction value “a / b” for reducing the deviation is calculated, and reflection is performed using the correction value “a / b”. If the first and / or second measurement signals due to the reflected light from the printing paper 41 are increased and corrected using the prevention plate 49, the deviation can be reduced.

  The correction unit 51 corrects the first and second measurement signals obtained when the antireflection plate 49 is displaced to the irradiation region by the light emitting element 35 with the correction value, and the corrected first and second measurement signals are corrected. It has a function of outputting a signal to the transfer fixing controller 13.

  As shown in FIG. 4, the transfer and fixing control unit 13 receives the first and second measurement signals corrected by the correction unit 51 under the control of the control unit 1, and these first and second measurement signals. And a control signal for controlling the transfer or fixing of the image on the printing paper 41 to the transfer unit 27 and the fixing unit 29 of the printing unit 7.

  That is, the transfer fixing control unit 13 calculates and measures the regular reflection light amount and the diffuse reflection light amount based on the corrected first and second measurement signals, and determines the glossiness, thickness, and surface roughness of the printing paper 41 as follows. And a function of outputting a transfer control signal and / or a fixing control signal corresponding to the measured glossiness, paper thickness, and surface roughness as a control signal. In the following equation, symbols A, B, and C are constants.

Glossiness = A x (regular reflection light quantity)
Paper thickness = B x (diffuse reflected light amount)
Surface state = C x ((regular reflected light amount) / (diffuse reflected light amount))

  Since the component of specular reflection light becomes smaller as the glossiness representing the surface state of the printing paper 41 becomes lower, the glossiness of the printing paper 41 is determined from the intensity level of the specular reflection light received by the regular reflection light receiving element 37. Since the diffuse reflection light component becomes larger as the printing paper 41 becomes thicker, the thickness of the printing paper 41 is determined from the intensity level of the diffuse reflection light received by the diffuse reflection light receiving element 39. Is possible.

  The roughness of the surface of the printing paper 41 can also be determined using the ratio of the regular reflection light and the diffuse reflection light received by the regular reflection light receiving element 37 and the diffuse reflection light receiving element 39.

  The control signals output by the transfer fixing control unit 13 are “transfer voltage / current control signal” and “toner density control signal” as toner transfer amount control signals, and “fixing temperature control signal” and “fixing speed control signals” as fixing control signals. Etc.

  For example, when the glossiness of the printing paper 41 is higher (brighter) than a predetermined gloss reference value, as shown in the control management data of FIG. 6, a fixing temperature control signal for raising the fixing temperature accordingly is used for fixing to lower the fixing speed. Each of the toner density control signals for increasing the toner density is output as a speed control signal, and when the glossiness is lower (darker) than a predetermined gloss reference value, a fixing temperature control signal for lowering the fixing temperature accordingly is used to increase the fixing speed. A fixing speed control signal and a toner density control signal for lowering the toner density are output.

  In FIG. 6, (upper) and (lower) indicate that these changes slightly affect the fixing temperature, the fixing speed, the transfer voltage, and the toner density, and (-) hardly affects.

  When the thickness of the printing paper 41 is thicker than a predetermined thickness reference value, a fixing temperature control signal for increasing the fixing temperature, a fixing speed control signal for decreasing the fixing speed, and a transfer voltage / current control signal for increasing the transfer voltage accordingly. When the thickness is less than the thickness reference value, a fixing temperature control signal for decreasing the fixing temperature, a fixing speed control signal for increasing the fixing speed, and a transfer voltage / current control signal for decreasing the transfer voltage are output accordingly. To do.

  Further, when the surface roughness of the printing paper 41 is finer than the roughness reference value, a fixing temperature control signal for increasing the fixing temperature, a fixing speed control signal for increasing the fixing speed, and a transfer voltage / current for increasing the transfer voltage accordingly. When each control signal is output and the surface is rougher than the roughness reference value, a fixing temperature control signal for lowering the fixing temperature, a fixing speed control signal for lowering the fixing speed, and a transfer voltage / current control signal for lowering the transfer voltage accordingly. Are output respectively.

  The transfer voltage / current control signal, toner density control signal, fixing temperature control signal and fixing speed control signal are output in a preset ratio relationship, and the transfer voltage / current control signal and toner density control signal are output to the printing unit. 7, the fixing temperature control signal and the fixing speed control signal are output to the fixing unit 29 of the printing unit 7.

  The transfer unit 27 controls the toner transfer amount corresponding to the surface of the printing paper 41 having a high glossiness to be larger than that when the glossiness is low. For example, according to the transfer voltage / current control signal. When the toner image is transferred to the printing paper 41, the amount of charge on the printing paper 41 is increased, and a latent image amount is formed on a transfer drum (not shown) that forms the transfer unit 27 in accordance with the toner density control signal. Increase the amount of light.

  Similarly, the fixing unit 29 controls the toner fixing corresponding to the surface of the printing paper 41 having high glossiness to be stronger than that in the case of low glossiness, but the fixing roller 29 controls the heating roller according to the fixing temperature control signal. The heating temperature is raised and variable so as to lower the conveyance speed of the printing paper 41 by the heating roller and pressure roller in accordance with a fixing speed control signal.

  Next, the operation of the image forming apparatus of the present invention will be briefly described with reference to the flowchart of FIG.

  First, when the printing operation program is started, the slide member displaces the common support plate 45 through the control of the control unit 1 in step S1 (see FIG. 3), the reference plate 47 is displaced to the measurement position, and the spacing member 43. The through hole 55 is covered and stopped.

  In the next step S2, in the absence of the printing paper 41, the irradiation light from the light emitting element 35 is received by the regular reflection light receiving element 37 and the diffuse reflection light receiving element 39, and a first measurement signal at a reference level is obtained. At the same time, the correction unit 51 calculates a correction value for reducing the deviation according to the deviation between the first and second measurement signals and the reference value, and then supplies the printing paper 41 to the primary feed in step S3. Paper is conveyed to the spacing member 43.

  In step S4, the antireflection plate 49 is displaced to the measurement position to cover the through hole 55 (see FIG. 5), and the reflected light from the printing paper 41 is diffused by the regular light receiving element 37 and the diffused light from the light emitting element 35. The light receiving element 39 for reflection receives the first and second measurement signals, and the correction unit 51 corrects the first and second measurement signals with the correction values, thereby correcting the first and second corrected signals. 2 measurement signals are output as measurement values to the transfer and fixing control unit 13.

  In step S6, the transfer / fixing control unit 13 calculates the glossiness, thickness, and surface roughness of the printing paper 41 from the first and second measurement signals, and increases and decreases the transfer voltage and toner density based on these. Control signals (transfer voltage / current control signal, toner density control signal) are transferred to the transfer unit 27 of the printing unit 7, and control signals (fixing temperature control signal, fixing speed control signal) for increasing and decreasing the fixing temperature and fixing speed are printed on the printing unit 7. To the fixing unit 29.

  These procedures correspond to the image forming method of the present invention.

  Thereafter, as described above, when the transfer unit 27 transfers the toner image to the printing paper 41 according to the transfer voltage, the charge amount to the printing paper 41 is changed, and the transfer is performed according to the toner density control signal. Since the amount of latent image forming light on the transfer drum forming the portion 27 is varied, the surface is measured, and the toner transfer amount is controlled in response to the printing paper 41 secondarily fed from the registration roller 23. It is transcribed with.

  Further, the fixing unit 29 controls the heating roller according to the control signal of the fixing temperature to change the fixing temperature to the printing paper 41 or the fixing conveyance speed by the heating roller and the pressure roller to change the printing paper. The degree of toner fixing to 41 is controlled and discharged.

  As described above, the image forming apparatus A according to the present invention includes a light emitting element (light emitting unit) 35 that emits light at a predetermined angle to the conveyed printing paper 41 before image formation, and the printing paper 41 side. A regular reflection light receiving element (first light receiving portion) 37 that receives regular reflection light and outputs a first measurement signal corresponding thereto, and receives diffuse reflection light from the print paper 41 side and responds accordingly. The diffuse reflection light receiving element (second light receiving portion) 39 for outputting the second measurement signal and the print paper 41 opposite to the regular reflection light receiving element 37 and displaced to the irradiation region by the light emitting element 35. A reference member (reference plate) 47 that can be arranged, an antireflection plate (antireflection member) 49 that can be displaced at the same position as the reference plate 47 and suppresses reflection of irradiation light, and the reference plate 47 emits light. When displaced to the irradiation area by the element 35, the first of them Correction values corresponding to the deviation between the second measurement signal and the predetermined reference value are calculated, and the first and second obtained when the antireflection plate 49 is displaced to the irradiation region by the light emitting element 35. A correction unit 51 that corrects the measurement signal with the correction value, and a transfer / fixing control unit 13 that outputs a control signal for controlling transfer or fixing of the image onto the printing paper 41 based on the corrected first and second measurement signals. It is equipped with.

  Therefore, even if the light emitting and receiving surfaces of the light emitting element 35, the specular reflection light receiving element 37, and the diffuse reflection light receiving element 39 are dirty or their usage atmosphere is dirty, the measurement signal can be increased and corrected according to the environmental conditions. Therefore, it is possible to accurately measure the surface state such as the glossiness, thickness or surface roughness of the surface of each printing paper 41, and appropriate transfer control and fixing control can be performed accordingly. It is easy to obtain a high-quality print state.

  In addition, since the reference plate 41 and the antireflection plate 49 are arranged on the same plane and are driven to slide in parallel with the printing paper 41 by the slide member, the surface state is further maintained by keeping the distance from the printing paper 41 constant. It becomes possible to measure more accurately.

  Further, the transfer / fixing control unit 13 determines the toner transfer amount according to the difference from the predetermined reference value with respect to the glossiness, paper thickness or surface roughness of the printing paper 41 obtained based on the first and second measurement signals. Since the control signal, the fixing temperature control signal or the fixing speed control signal is output as the control signal, it is possible to reliably obtain a high-quality print state through the toner transfer amount control, the fixing temperature control or the fixing speed.

  The image forming apparatus of the present invention described above has a configuration in which the obtained first and second measurement signals are varied and corrected by the correction value, but the present invention is not limited to this.

  For example, as indicated by a broken line in FIG. 4, a configuration in which the correction unit 51 outputs a correction value to the drive unit 53 to variably correct the drive power to the light emitting element 35 is possible. Even if the light emitting element 35 is driven by a signal, the surface state of the printing paper 41 can be accurately measured.

  Note that the reference plate 47 and the antireflection plate 49 are not limited to the sheet-like member as described above, and the back surface of the printing paper 41 abuts in a region including the virtual point P irradiated with light from the light emitting element 35. If it is a member, the object of the present invention can be achieved.

  By the way, in the image forming apparatus of the present invention, the above-described driving unit 43 in FIG. 4 causes the light emitting element 35 to emit light intermittently in a pulse shape, that is, for example, several milliseconds to several tens of milliseconds at a predetermined duty ratio. When the pulse lighting is used, for example, the driving current can be increased as compared with the case of continuous light emission.

  With such a configuration, it is possible to increase the light emission amount without increasing the driving power within a predetermined period, and it is possible to obtain a high-quality print state while maintaining a good S / N ratio.

  In the image forming apparatus A according to the present invention described above, the single-sided printing of only the front surface has been described. However, in the present invention, the double-sided printing can also be performed. The same detection unit (not shown) may be arranged so that a control signal can be output from the transfer and fixing control unit 13 for the back surface.

  Note that the image forming method according to the present invention also has the same effect as the image forming apparatus.

1 is a schematic block diagram showing an embodiment of an image forming apparatus according to the present invention. 1 is a diagram illustrating a configuration example of an image forming apparatus according to the present invention. FIG. 2 is a main part configuration diagram illustrating a main part of the image forming apparatus according to the present invention. FIG. 2 is a main part block diagram illustrating a main part of the image forming apparatus according to the present invention. It is a figure explaining operation | movement of the image forming apparatus in this invention. It is a figure which shows the control management data in the image forming apparatus of this invention. 3 is a flowchart illustrating an operation of the image forming apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control part 3 Image reading part 5 Memory | storage part 7 Printing part 9 Operation display part 11 Detection part 13 Transfer fixing control part 15 Main body case 17, 19 Paper feeding part 21 Conveyance path 23 Registration roller 25 Toner cassette 27 Transfer part 29 Fixing part 31 Reverse conveyance part 33 Support part (sensor housing)
35 Light emitting element (light emitting part)
37 Light receiving element for regular reflection (first light receiving part)
39 Light receiving element for diffuse reflection (second light receiving part)
41 Printing paper 43 Spacing member 45 Common support plate 47 Reference plate (reference member)
49 Antireflection plate (Antireflection member)
51 Correction Unit 53 Drive Unit A Image Forming Apparatus

Claims (10)

A light emitting unit that irradiates light at a predetermined angle with respect to the printing paper before image formation conveyed for image formation;
A first light receiving unit that receives specularly reflected light from the printing paper side and outputs a first measurement signal according to the received light;
A second light receiving unit that receives diffusely reflected light from the printing paper side and outputs a second measurement signal according to the received light;
A reference member disposed on the side opposite to the first light receiving portion of the printing paper and displaceable in an irradiation region by the light emitting portion;
An antireflective member disposed so as to be displaceable at the same position as this reference member and suppressing reflection of the irradiation light;
When the reference member is displaced to the irradiation area, a correction value corresponding to a deviation between the first and second measurement signals and a predetermined reference value is calculated, and the antireflection member is displaced to the irradiation area. A correction unit that corrects the first and second measurement signals obtained when the correction value is corrected with the correction value;
An image forming apparatus comprising: a transfer and fixing control unit that outputs a control signal for controlling transfer or fixing of an image on the printing paper based on the corrected first and second measurement signals. The image forming apparatus according to claim 1, wherein the reference member and the antireflection member are arranged on the same plane and are driven to slide in parallel with the printing paper by a slide member. The image forming apparatus according to claim 1, wherein the correction unit corrects the measurement signal from the first and / or second light receiving unit with the correction value. The image forming apparatus according to claim 1, wherein the correction unit corrects the driving power to the light emitting unit by changing the correction value. The image forming apparatus according to claim 1, wherein the light emitting unit emits light intermittently in a pulse shape. The transfer / fixing control unit is configured to output a toner transfer amount control signal corresponding to a difference from a predetermined reference value for the glossiness, paper thickness, and surface roughness of the printing paper obtained based on the first and second measurement signals. The image forming apparatus according to claim 1, wherein a fixing temperature control signal or a fixing speed control signal is output as the control signal. A light emitting unit that emits light is arranged at a predetermined angle with respect to the printing paper before image formation conveyed for image formation,
A first light receiving unit that receives specularly reflected light from the printing paper side and outputs a first measurement signal is disposed on the printing paper;
A second light receiving unit that receives diffusely reflected light from the printing paper side and outputs a second measurement signal is disposed on the printing paper;
A reference member is disposed on the irradiation region on the opposite side of the printing paper from the first light receiving unit,
Calculating correction values corresponding to deviations between the first and second measurement signals output from the first and second light receiving units and a predetermined reference value,
An antireflection member that suppresses reflection of the irradiation light instead of the reference member is disposed in the irradiation region,
Correcting the first and second measurement signals output from the first and second light receiving units with the correction value;
Outputting a control signal for controlling transfer or fixing of an image on the printing paper based on the corrected first and second measurement signals;
An image forming method. The image forming method according to claim 9, wherein the reference member and the antireflection member are arranged on the same plane and are slid parallel to the printing paper. 9. The image forming method according to claim 7, wherein the measurement signal from the first and / or second light receiving unit is corrected by changing the correction value. The image forming method according to claim 7 or 8, wherein the first and second measurement signals are corrected by varying driving power to the light emitting unit according to the correction value.

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