JP2006259589A - Basis weight detector and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a basis weight detector and an image forming apparatus for which problems in terms of mounting are solved. <P>SOLUTION: The image forming apparatus comprises: a clock generation part for generating clock signals of a prescribed first frequency; a drive signal generation part for processing the clock signals and generating drive signals of a prescribed second frequency; a sound wave generation part for originating the sound waves of the second frequency toward a recording medium according to the drive signals generated by the drive signal generation part; a sound wave reception part for receiving the sound waves originated by the sound wave generation part and made to pass through the recording medium; a basis weight calculation part for calculating the basis weight of the recording medium on the basis of the strength of the sound waves received by the sound wave reception part; and a control part operated on the basis of the clock signals for controlling a forming condition in image formation based on the basis weight calculated by the basis weight calculation part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a basis weight detection device that detects basis weight, and an image forming apparatus that forms an image by fixing a toner image on a sheet-like recording medium.

In recent years, with the spread of computers, image forming apparatuses centering on printers have become widespread as means for printing information created on computers on paper, and constitute such image forming apparatuses. Technologies related to various elements are also widely used. Many of these image forming apparatuses output a toner image by transferring the toner image onto a conveyed recording medium and fixing the toner image on the recording medium. In such an output process, image formation for forming an image, such as the conveyance speed of the recording medium, the transfer voltage used when transferring the toner image, and the optimum temperature for fixing the toner image. Optimum conditions vary depending on the mass per unit area of the recording medium used for output, that is, the basis weight, so in some image forming apparatuses, the image forming conditions were determined according to the basis weight of the recording medium. Some image forming apparatuses perform the above output. In such an image forming apparatus, conventionally, the user himself / herself manually inputs the basis weight to determine the image forming conditions. However, it is troublesome to manually input the basis weight. Recently, there is provided an image forming apparatus that includes a basis weight detection device that detects the basis weight of a recording medium from the transmission intensity of ultrasonic waves that pass through the recording medium, thereby eliminating the need for a user to manually input the basis weight. It has been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2004-219856

  However, although the principle of measuring the basis weight is shown in Patent Document 1, various problems arise when the basis weight detection device is mounted on the image forming apparatus.

  For example, when calculating the basis weight from the transmission intensity of the ultrasonic wave, it is necessary to grasp the ultrasonic frequency. In the basic weight detection device described in Patent Document 1, the ultrasonic frequency is stable. It is assumed that However, in order to generate ultrasonic waves having such a stable frequency, expensive parts such as a crystal oscillator are required, which increases the manufacturing cost. In addition, in such a basis weight detection device that does not use an expensive oscillator, the ultrasonic frequency may fluctuate, and the basis weight was calculated from the ultrasonic transmission intensity on the assumption that the frequency is stable. In this case, it is difficult to calculate a correct basis weight.

  Further, in the basis weight detection device described in Patent Document 1, since it is necessary to wire between an oscillation side that emits ultrasonic waves and a reception side that receives ultrasonic waves that have passed through the recording medium, the conveyance of the movement of the recording medium is performed. The presence of such wiring becomes an obstacle to the operation when the path is opened during a paper jam removal operation or the like. Further, in such a basis weight detection device, the ultrasonic wave oscillating side and the ultrasonic wave receiving side are arranged obliquely with respect to the surface of the recording medium, so that the recording medium and the ultrasonic wave transmitting side are correct. Although the influence of the standing wave generated when arranged on the other hand is suppressed, such an arrangement has a drawback that the installation space of the basis weight detection device becomes large.

  In view of the above circumstances, an object of the present invention is to provide a basis weight detection device and an image forming apparatus that solve a mounting problem.

In order to achieve the above object, the first basis weight detection device of the present invention is:
A sound wave generating unit that obtains drive energy wirelessly and emits a sound wave toward the sheet-like recording medium by the drive energy;
An energy transmitter for wirelessly transmitting the drive energy to the sound wave generator;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
And a basis weight calculating unit that calculates the basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiving unit.

  The sound wave here may be an ultrasonic wave or an audible sound wave.

  The first basis weight detection device of the present invention can wirelessly send the driving energy of the sound wave generation unit necessary for generating the sound wave. do not need. For this reason, the freedom degree of arrangement | positioning by the side of a sound wave generation part is high, design and mounting are easy, and the cost of an assembly is also reduced.

  Further, in the first basis weight detection device of the present invention, “the energy transmission unit transmits the driving energy by a fluctuating electromagnetic field that varies with time, and the sound wave generation unit receives the fluctuating electromagnetic field, thereby A form of “obtaining driving energy” is a preferable form.

  By using means using an electromagnetic field as means for sending drive energy wirelessly, drive energy can be sent simply and efficiently.

In order to achieve the above object, the second basis weight detection device of the present invention comprises:
A sound wave generator that emits sound waves toward a sheet-like recording medium in an oblique direction with respect to the surface of the recording medium;
A sound wave receiving unit that receives the sound wave emitted by the sound wave generating unit and passed through the recording medium at a position shifted from the center of propagation of the sound wave;
And a basis weight calculating unit that calculates the basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiving unit.

  In general, a part of the sound wave generated by the sound wave generating unit forms a standing wave between the sound wave generating unit and the recording medium, and this standing wave interferes with the sound wave generated by the sound wave generating unit to record. In some cases, the calculation of the basis weight of the medium is hindered. Conventionally, a set of a sound wave generator and a sound wave receiver that face each other is arranged obliquely with respect to the surface of the recording medium to suppress the influence of such a standing wave. In the arrangement, there is a drawback that the installation space of the basis weight detection device becomes large.

  In the second basis weight detection device of the present invention, the sound wave receiving unit receives the sound wave at a position shifted from the center of the propagation of the sound wave emitted by the sound wave generating unit, thereby preventing the influence of the standing wave, and the basis weight. The installation space for the detection device can be reduced.

  In the second basis weight detection device of the present invention, “the sound wave receiving unit receives the sound wave that has passed through the recording medium, facing the recording medium at a position shifted from the center of propagation of the sound wave”. The form “is” is a preferred form.

  With such a basis weight detection device, the sound wave receiving unit can be provided at a position where the sound wave that has passed through the recording medium can be easily received while preventing the influence of the standing wave.

In order to achieve the above object, the third basis weight detection device of the present invention is:
A sound wave generator that emits sound waves toward a sheet-like recording medium;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A frequency detection unit that directly or indirectly detects the frequency of the sound wave emitted by the sound wave generation unit;
A basis weight calculating unit that calculates the basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiving unit and the frequency detected by the frequency detecting unit is provided.

  It is known that an apparatus that emits a sound wave having a predetermined frequency does not normally use expensive parts such as a crystal oscillator, and thus causes fluctuations in the frequency of the emitted sound wave. It is also known that when the basis weight is calculated from the sound wave that has passed through the recording medium, the calculated value changes according to the frequency of the sound wave.

  The third basis weight detection device of the present invention detects the frequency of the sound wave emitted by the sound wave generator directly or indirectly and calculates the basis weight according to the frequency, so that even if there is a fluctuation in frequency, the basis weight is detected. The amount can be calculated accurately.

  Moreover, in the 3rd basic weight detection apparatus of this invention, "The said frequency detection part obtains the frequency of the sound wave directly by analyzing the waveform of the sound wave received by the said sound wave reception part." Is a preferred form.

  By using the sound wave received by the sound wave receiving unit that is used when calculating the basis weight, it is possible to accurately detect the frequency.

  In the third basis weight detection device of the present invention, “the sound wave generator operates according to a periodic drive signal and emits a sound wave having the same frequency as that of the drive signal, and the frequency detector However, a mode in which the frequency of the sound wave emitted from the sound wave generation unit is indirectly obtained by detecting the frequency of the drive signal is also a preferable mode.

  By detecting the frequency of the sound wave from the frequency of the drive signal that is the origin of the frequency of the sound wave generated by the sound wave generator, the frequency can be detected more easily than by directly analyzing the received sound wave.

  In the third basis weight detection apparatus of the present invention, the basis weight of the recording medium is calculated when the frequency detected by the frequency detection unit is a frequency within a predetermined frequency region. Is also a preferred form. "If the detected frequency is outside the frequency range, a warning is issued".

  It is known that it is difficult to calculate the basis weight from the sound wave that has passed through the recording medium when the frequency of the sound wave emitted by the sound wave generation unit belongs outside a predetermined frequency region.

  When the frequency of the sound wave emitted by the sound wave generator is such a frequency that it is difficult to calculate the basis weight, a warning is given to the user and the basis weight value with low reliability is used by mistake. Can be prevented.

In order to achieve the above object, a first image forming apparatus of the present invention includes:
In an image forming apparatus for forming an image by fixing a toner image on a sheet-like recording medium,
A clock generator for generating a clock signal of a predetermined first frequency;
A drive signal generator that processes the clock signal to generate a drive signal of a predetermined second frequency;
A sound wave generator that emits a sound wave of the second frequency toward the recording medium in accordance with the drive signal generated by the drive signal generator;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A basis weight calculating unit that calculates a basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiving unit;
And a control unit that operates based on the clock signal and controls the forming conditions in the image formation based on the basis weight calculated by the basis weight calculation unit.

  The first image forming apparatus of the present invention can stabilize the frequency of the sound wave because the drive signal for generating the sound wave in the sound wave generating unit is obtained from the clock signal. Further, the cost can be reduced by sharing the clock generation source between the sound wave generation unit and the control unit.

  Further, in the first image forming apparatus of the present invention, a form in which “the driving signal generation unit processes the clock signal by a frequency dividing circuit and a low-pass filter” is a preferable form.

  By using the frequency divider and the low-pass filter, a desired signal can be obtained with a simple circuit.

In order to achieve the above object, the second image forming apparatus of the present invention provides:
In an image forming apparatus for forming an image by fixing a toner image on a sheet-like recording medium,
A sound wave generating unit that obtains drive energy wirelessly and emits a sound wave toward the sheet-like recording medium by the drive energy;
An energy transmitter for wirelessly transmitting the drive energy to the sound wave generator;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A basis weight calculating unit that calculates a basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiving unit;
And a control unit that controls the forming conditions in the image formation based on the basis weight calculated by the basis weight calculation unit.

  Since the second image forming apparatus of the present invention can wirelessly send the driving energy of the sound wave generating unit necessary for generating the sound wave, the sound wave generating unit side needs wiring to obtain the driving energy. And not. For this reason, the freedom degree of arrangement | positioning at the sound wave generation part side is high, design and mounting are easy, and installation cost is also reduced.

  Further, in the second image forming apparatus of the present invention, “the sound wave generator emits a sound wave at a predetermined position in the image forming apparatus, and the sound wave generator is detachably held at the predetermined position. The form “with a holding mechanism” is a preferred form.

  By providing the above-described holding mechanism, it is easy to remove the recording medium when the recording medium is jammed between the sound wave generator and the sound wave receiver.

In order to achieve the above object, a third image forming apparatus of the present invention provides:
In an image forming apparatus for forming an image by fixing a toner image on a sheet-like recording medium,
A sound wave generator that emits sound waves toward a sheet-like recording medium in an oblique direction with respect to the surface of the recording medium;
A sound wave receiving unit that receives the sound wave emitted by the sound wave generating unit and passed through the recording medium at a position shifted from the center of propagation of the sound wave;
A basis weight calculation unit that calculates the basis weight of the recording medium based on the intensity of the sound wave received by the sound wave reception unit, and a formation condition in the image formation is controlled based on the basis weight calculated by the basis weight calculation unit. And a control unit.

  In the third image forming apparatus of the present invention, the sound wave receiving unit receives the sound wave at a position shifted from the center of the propagation of the sound wave, so that the standing wave formed between the sound wave generating unit and the recording medium is the sound wave generating unit. The installation space can be reduced while preventing the calculation of the basis weight of the recording medium from interfering with the sound wave emitted by the.

In order to achieve the above object, a fourth image forming apparatus of the present invention provides:
In an image forming apparatus for forming an image by fixing a toner image on a sheet-like recording medium,
A sound wave generator that emits sound waves toward a sheet-like recording medium;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A frequency detection unit that directly or indirectly detects the frequency of the sound wave emitted by the sound wave generation unit;
Basis weight calculator for calculating the basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiver and the frequency detected by the frequency detector, and the basis weight calculated by the basis weight calculator And a control unit that controls the forming conditions in the image formation based on the amount.

  The fourth image forming apparatus of the present invention calculates the basis weight corresponding to the frequency even if there is fluctuation of the frequency of the generated sound wave by directly or indirectly detecting the frequency of the sound wave emitted by the sound wave generating unit. It can be performed.

  In the fourth image forming apparatus of the present invention, a "basis weight setting unit that receives an operation to set a basis weight is provided, and the basis weight calculation unit has a frequency detected by the frequency detection unit being a predetermined frequency. When the frequency is within the frequency domain, the basis weight of the recording medium is calculated, and when the detected frequency is outside the frequency domain, a warning is issued. When the basis weight calculation unit issues a warning, it controls the formation conditions in the image formation based on the basis weight set by the basis weight setting unit instead of the basis weight calculated by the basis weight calculation unit. The form "is to do" is a preferred form.

  When the frequency of the sound wave generated by the sound wave generation unit is a frequency at which it is difficult to calculate the basis weight, the image forming apparatus in such a form is configured to perform image formation based on the basis weight set by the user. By controlling the forming conditions, it is possible to prevent an inappropriate control of the image forming conditions from being used due to the use of a calculated basis weight value with poor reliability.

  In the fourth image forming apparatus of the present invention, a “basis weight storage unit that receives an operation and stores a set value of a basis weight is provided, and the basis weight calculation unit has a frequency detected by the frequency detection unit. When the frequency is within a predetermined frequency range, the basis weight of the recording medium is calculated, and when the detected frequency is outside the frequency range, a warning is issued. When the basis weight calculation unit issues a warning, the formation condition in the image formation is based on the basis weight stored by the basis weight storage unit instead of the basis weight calculated by the basis weight calculation unit. The form of “controlling” is also a preferable form.

  When the frequency of the sound wave emitted by the sound wave generator is a frequency at which it is difficult to calculate the basis weight, the image forming apparatus in such a form can perform image formation based on the preset basis weight. By controlling the forming conditions, it saves the user the trouble of inputting the basis weight and minimizes the possibility of improper control of the image forming conditions by using the calculated basis weight with poor reliability. To the limit.

  According to the basis weight detection device and the image forming apparatus of the present invention, the mounting problem can be solved.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is an overall configuration diagram of a color tandem type image forming apparatus corresponding to an embodiment of the image forming apparatus of the present invention, including an embodiment of the basis weight detecting apparatus of the present invention.

  The image forming apparatus 1000 includes four toner image forming units 6K, 6C, 6M, and 6Y that respectively correspond to toners of black (K), cyan (C), magenta (M), and yellow (Y). In each toner image forming unit, the toner image formed by receiving the laser light emitted from each exposure unit 7 is superimposed by the intermediate transfer belt 5 and further transferred onto the conveyed paper in the transfer unit 9. Transcribed. The toner image thus transferred is further subjected to heat and pressure by the fixing device 10 to fix the toner.

  The upper part of the image forming apparatus 1000 is provided with four toner cartridges 4K, 4C, 4M, and 4Y corresponding to toners of black, cyan, magenta, and yellow, respectively, and these four toner cartridges form each toner image. Each color component toner is replenished to the portion (toner replenishment path is not shown). Also, the paper used for transferring the toner image is classified and stored in the three trays 1a, 1b, and 1c according to the size. Selected from. The selected paper is transported using the three transport rolls 3a, 3b, 3c, adjusted in position by the registration roll pair 8, and then transported to the transfer unit 9, where the toner image is transferred. In FIG. 1, the paper conveyance path at this time is shown as a path indicated by an upward arrow.

  In the case of single-sided printing, the paper passes through this paper conveyance path only once, and after the toner image is transferred and fixed, it passes through the paper discharge roll pair 13 and is discharged to the paper discharge tray 2. In the case of duplex printing, after the paper passes through this paper conveyance path, the toner image is transferred and fixed on one side of the paper, and then returned to the paper output tray 2 and returned to the path indicated by the downward arrow. Then, the registration roller pair 8 is turned upward again, and this time, the toner image is transferred and fixed on the opposite surface and discharged to the paper discharge tray 2.

  In this image forming apparatus 1000, the sheet conveyance path is arranged substantially vertically on the left side as described above, and this sheet conveyance path is opened to the outside by opening the side cover 14, so that a paper jam removing operation and fixing are performed. The part replacement work is performed with the side cover 14 open.

  The image forming apparatus 1000 includes a CPU (not shown in FIG. 1) that controls various conditions related to image formation as described above. Specifically, the CPU controls the temperature in the fixing device 10, sets a transfer voltage value used for transfer in the transfer unit 9, and controls a drive motor (not shown in FIG. 1) used for transporting the paper. Various setting values related to image formation are displayed on the display screen 90, and various setting values designated by the user via the operation panel 91 are set as control values.

  Furthermore, in this image forming apparatus 1000, a sound wave generating unit 70A that emits ultrasonic waves and a sound wave receiving unit 70B that receives ultrasonic waves are provided below the registration roll pair 8 so as to sandwich the paper conveyance path. The sound wave generation unit 70A and the sound wave reception unit 70B constitute a basis weight detection device 70 that detects the basis weight of the conveyed paper.

  Next, the basis weight detection device 70 will be described.

  FIG. 2 is a diagram illustrating a configuration of the basis weight detection device illustrated in FIG. 1.

  The basis weight detection device 70 is roughly divided into a sound wave generation unit 70A that emits ultrasonic waves and a sound wave reception unit 70B that receives ultrasonic waves. The sound wave generating unit 70A is composed of a sheet metal 74A, a sound wave generating part 72A provided on the sheet metal 74A, and a coil 73A for supplying electric power for operating the sound wave generating part 72A. The unit 70B includes a sheet metal 74B, a sound wave receiving unit 72B provided on the sheet metal 74B, a coil 73B for inducing power to the coil 73A, and a basis weight calculation unit 75B that calculates the basis weight of the paper. Has been.

  Here, the sound wave generation unit 70A corresponds to an example of the sound wave generation unit referred to in the present invention, and the sound wave reception unit 72B, the basis weight calculation unit 75B, and the coil 73B respectively correspond to the sound wave reception unit and the basis weight calculation according to the present invention. This corresponds to an example of the unit and the energy transmission unit.

  The sound wave generating unit 72A is provided with an ultrasonic wave generating element 71A, and the ultrasonic wave generating element 71A emits an ultrasonic wave. The emitted ultrasonic wave spreads and propagates to a fan-shaped region within a range indicated by a dotted line in the figure, which is opened by a predetermined angle with the direction indicated by the arrow Y in the figure as a center. A part of the ultrasonic wave propagated in this way passes through the paper 85, directly faces the paper 85, and is provided at a position shifted from the direction indicated by the arrow Y on the sound wave receiving unit 72B. Received by element 71B.

  When the ultrasonic wave generating element 71A and the ultrasonic wave receiving element 71B are arranged to face each other at a position facing the paper 85, a part of the sound wave generated by the ultrasonic wave generating element 71A is the sound wave generating unit. A standing wave may be formed between the paper 85 and the standing wave may interfere with the sound wave generated by the sound wave generating unit 70B. Therefore, in the present embodiment, as shown in FIG. 2, an arrangement is used in which the direction indicated by the arrow Y, which is the direction in which the intensity of the ultrasonic wave is the highest, is inclined with respect to the surface of the paper 85. The generation of standing waves is suppressed. Further, since the ultrasonic wave receiving element 71B receives the sound wave at a position facing the sheet, shifted from the direction indicated by the arrow Y in the right direction in the figure, the ultrasonic wave receiving element 71B is opposed to the ultrasonic wave generating element 71A. The installation space for the entire basis weight detection device is smaller.

  From the intensity of the ultrasonic wave received by the sound wave receiving unit 70B, the transmission intensity associated with passing through the paper is calculated, and the data is sent to the basis weight calculation unit 75B. The basis weight calculation unit 75B calculates the basis weight of the sheet from the ultrasonic transmission intensity, and the calculation result is transmitted to the CPU 61 that controls the image forming apparatus 1000. The CPU 61 relates to image formation based on the calculation result. Control various conditions. Specifically, control of the temperature in the fixing device 10 shown in FIG. 1, setting of a transfer voltage value used for transfer in the transfer unit 9, control of the drive motor 110 used for paper conveyance, and the like are performed.

  The image forming apparatus 1000 includes a clock generation unit 62 that generates a clock signal for transmitting operation timing to the CPU 61. The frequency of the clock signal generated by the clock generation unit 62 is reduced by the frequency dividing circuit 63. Further, the high frequency component of the pulse wave is removed by the low pass filter 64. The converted signal is sent to the coil 73B on the sound wave receiving unit 72B and used as a drive signal for driving the sound wave generating unit 72A. When this drive signal is applied to the coil 73B, power is induced in the coil 73A of the sound wave generating unit 70B provided at a position facing the coil 73B on the sound wave receiving unit 72B, and sound waves are generated by the induced power. The unit 72A is driven.

  As described above, in this image forming apparatus 1000, since the driving signal for generating the sound wave in the sound wave generating unit 72A is obtained from the clock generating unit 62 that supplies the CPU 61 with the clock signal, the frequency of the sound wave can be stabilized. it can. In addition, since the clock generation source is shared by the sound wave generation unit 72A and the CPU 61, the cost is reduced. Further, since this drive signal is transmitted wirelessly by electromagnetic induction, no wiring is required on the sound wave generation unit 70A side in order to obtain energy necessary for driving. For this reason, the freedom degree of arrangement | positioning at the sound wave generation part side is high, design and mounting are easy, and installation cost is also reduced.

  As described above, since the sound wave generation unit 70A side does not require wiring, it is easy to open the paper conveyance path by separating the sound wave generation unit 70A side from the sound wave reception unit 70B side. Easier to perform removal and maintenance work. Hereinafter, a mechanism for opening the paper conveyance path in the image forming apparatus 1000 will be described.

  FIG. 3 is a view showing the vicinity of the sheet conveyance path in a state where the side cover is opened in the image forming apparatus shown in FIG.

  In the image forming apparatus shown in FIG. 1, an image is formed with the side cover 14 closed, and as shown in FIG. 3, when removing a paper jam or replacing a part of the fixing device. Then, the side cover 14 is opened, and the sheet conveyance path is opened to the outside. The side cover 14 is configured to be rotatable about a side cover rotation shaft 15, and the side cover 14 is opened and closed by this rotation. When the side cover 14 is opened, each roll pair of the first transport roll pair 3a, the registration roll pair 8 and the paper discharge roll pair 13 is moved to the original position without moving. The transfer part 9 is also separated into a part that moves together with the side cover 14 and a part that stays in its original position without moving. Further, when the side cover 14 is opened, the basis weight detection device 70 includes the sound wave receiving unit 70B remaining on the image forming apparatus main body side, while the sound wave generating unit 70A forms an image together with the side cover 14. It is configured to be separated from the apparatus main body side.

  4 is an enlarged view of the vicinity of the basis weight detection device shown in FIG. 2 when the side cover 14 side shown in FIG. 3 is separated from the main body side of the image forming apparatus.

  As shown in FIG. 4, when the paper 86 is clogged between the sound wave generating unit 70A and the sound wave receiving unit 70B and it is necessary to open the paper transport path, the sound wave generating unit is moved in the direction indicated by the arrow in the drawing. 70A moves, and the paper conveyance path between the sound wave generating unit 70A and the sound wave receiving unit 70B is opened.

  Next, the contents of control performed by the CPU 61 according to the basis weight of the paper will be described.

  FIG. 5 is a diagram showing control switching performed in accordance with the basis weight of the paper calculated by the basis weight detection device shown in FIG. 2, and FIG. 6 is a diagram showing each control content to be switched.

  As shown in FIG. 5, in the image forming apparatus 1000, the setting No. is set according to the basis weight of the paper calculated by the basis weight detection device 70. 1 to setting No. 1 The control contents can be switched to 6 levels which are distinguished by 6 setting numbers. The object to be controlled here is an image forming condition. Specifically, as shown in FIG. 6, the transfer voltage used for transfer in the transfer unit 9 shown in FIG. A high fixing temperature, and a sheet conveyance speed when conveying the sheet. In addition, as the setting number is larger, six-step control is performed in which the transfer voltage and the fixing temperature are lowered and the sheet conveyance speed is increased.

  The above is the description of the color tandem type image forming apparatus 1000 which includes the embodiment of the basis weight detecting apparatus of the present invention and corresponds to the embodiment of the image forming apparatus of the present invention.

  Subsequently, another embodiment different from the above-described embodiment will be described.

  The basis weight detection device and the image forming apparatus described here are different from the basis weight detection device 70 shown in FIG. 2 and the image forming apparatus 1000 shown in FIG. 1 in that the frequency of the ultrasonic wave used for calculating the basis weight. Therefore, a frequency detector for detecting the frequency of the ultrasonic wave is provided, and the basis weight of the paper and the control of the image forming conditions are performed according to the detected frequency. Configurations, functions, and control contents other than these points are the same as those of the basis weight detection device 70 and the image forming apparatus 1000 shown in FIG. For example, the overall configuration of the image forming apparatus is different from the basis weight detection device 70 shown in FIG. 1 in that a basis weight detection device having a different configuration is used and the difference in basis weight detection device. Is the same as the overall configuration of FIG. In the following, the description will be focused on the points different from the embodiment shown in FIG.

  FIG. 7 is a diagram illustrating a configuration of a basis weight detection apparatus including a frequency detection unit that detects the frequency of ultrasonic waves.

  In FIG. 7, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and redundant description of the same components is omitted. The basis weight detection device 701 shown in FIG. 7 is different from the basis weight detection device 70 shown in FIG. 2 in that the basis weight detection device 701 applies an AC voltage to the coil 73B on the sound wave receiving unit 72B. 76B and a frequency detector 771 that detects the frequency of the ultrasonic wave received by the sound wave receiver 72B. Further, unlike the image forming apparatus 1000 shown in FIG. 2, the image forming apparatus according to the present embodiment has a basis weight storage unit 92 that stores the basis weight given by the user, as shown in FIG. The basis weight setting part 93 which sets the calculated basis weight as a basis weight setting value is provided.

  The frequency of the AC voltage supplied from the coil power source 76B shown in FIG. 7 often fluctuates from the set frequency as a result of the circuit element being affected by environmental changes. On the other hand, the basis weight of the paper is calculated from the transmission intensity (or transmittance) of the ultrasonic wave. However, it is known that the calculated value varies depending on the frequency, and therefore, an accurate basis weight is calculated. Therefore, it is necessary to grasp the frequency of the ultrasonic wave used for calculating the basis weight.

  FIG. 8 is a diagram showing the relationship between the basis weight of the paper and the transmittance of the ultrasonic waves with respect to the ultrasonic waves having four types of frequencies.

  FIG. 8 is a graph showing the correspondence between the transmittance of ultrasonic waves and the basis weight of paper for ultrasonic waves having frequencies of 4.0 kHz, 4.1 kHz, 4.2 kHz, and 4.5 kHz, respectively. . As shown in the figure, it is understood that the correspondence relationship represented by the graph curve is different when the frequency is different. In the image forming apparatus of this embodiment, a graph curve of each frequency is stored, and the basis weight is calculated using a graph curve corresponding to the detected frequency. For this reason, the image forming apparatus of the present embodiment can calculate an accurate basis weight even when the frequency fluctuates.

  Further, calculation of the basis weight may be difficult depending on the frequency range of the ultrasonic wave. As shown in the figure, the graph with the higher frequency is a linear graph with a constant ultrasonic transmittance, and the tendency that the ultrasonic transmittance does not change even if the basis weight of the paper changes is stronger. I understand that. For this reason, when using ultrasonic waves that hardly change in transmittance with respect to changes in basis weight, such as ultrasonic waves with a frequency of 4.5 kHz shown in the figure, the basis weight of the paper is accurately determined from the transmittance. It is difficult to calculate the frequency, and the frequency belonging to such a frequency range is not suitable for calculating the basis weight. Since the frequency of the ultrasonic wave fluctuates from the set value, it may occur that the frequency is not suitable for calculating the basis weight. For this reason, it is necessary to grasp the frequency of the ultrasonic wave used for calculating the basis weight.

  Hereinafter, calculation of the basis weight of the paper and control of the image forming conditions performed according to the detected frequency even when the frequency fluctuates in this way will be described.

  In this image forming apparatus, when the ultrasonic frequency is a frequency at which it is difficult to accurately calculate the basis weight, an automatic input mode that uses the basis weight stored in advance as a set value and a basis weight to the user. Two modes, a manual input mode that prompts input and uses the input basis weight as a set value, can be selected. Which mode is used is determined on the display screen 90 by the user via the operation panel 91 shown in FIGS.

  Hereinafter, the basis weight calculation of the paper and the control of the image forming conditions performed under each mode will be described with reference to flowcharts.

  FIG. 9 is a flowchart showing control of image forming conditions when the manual input mode is selected.

  First, the frequency detection unit 771 shown in FIG. 7 analyzes the waveform of the ultrasonic wave received by the sound wave reception unit 72B to detect the frequency (step S1), and the result is input to the basis weight calculation unit 751B. The The basis weight calculation unit 751B determines whether the input frequency belongs to a frequency range suitable for measuring the basis weight of the paper (step S2).

  If it is determined in step S2 that the frequency is suitable for measuring the basis weight of the sheet (step S2; Yes), the basis weight of the sheet is calculated from the ultrasonic frequency and transmission intensity (step S2). S3) Using the obtained basis weight, the CPU 69 shown in FIG. 7 determines the six-stage image forming conditions relating to the transfer voltage, the fixing temperature, and the sheet conveyance speed described in FIGS. 5 and 6 (step S4). ). Then, image formation is performed under the determined image formation conditions (step S5).

On the other hand, if it is determined in step S2 that the frequency is not suitable for measuring the basis weight of the paper (step S2; No), the basis weight calculation unit 751B gives a warning to the CPU 69 and receives this warning. The CPU 69 displays a warning message informing the user that the ultrasonic frequency is not suitable for basis weight detection on the display screen 90 shown in FIGS. 1 and 7 (step S6). Further, the CPU 69 stops the image formation performed at that time (step S7), and displays a message “Please set the paper basis weight” on the display screen 90. When the user receives this message and inputs the basis weight via the operation panel 91, the basis weight setting unit 93 shown in FIG. 8 sets the input basis weight as the basis weight for control (step S9), and the CPU 69. Determines image forming conditions based on the set basis weight (step S4). Then, image formation is performed under the image forming conditions.

  As described above, in this manual input mode, when it is difficult to accurately calculate the basis weight from the ultrasonic frequency, the user can input an appropriate basis weight, so that the basis weight is not reliable. It is possible to prevent inappropriate control of the image forming condition by the calculated value.

  This completes the description of the control of the image forming conditions when the manual input mode is selected. Next, control of image forming conditions when the automatic input mode is selected will be described.

  FIG. 10 is a flowchart showing control of image forming conditions when the automatic input mode is selected.

  First, a basis weight value used when it is difficult to accurately calculate the basis weight from the ultrasonic frequency is input by the user via the operation panel 91, and the basis weight value is shown in FIG. (Step S10). Subsequently, the frequency detection unit 771 shown in FIG. 7 analyzes the waveform of the ultrasonic wave received by the sound wave receiving unit 72B to detect the frequency (step S12), and the result is input to the basis weight calculation unit 751B. The The basis weight calculation unit 751B determines whether or not the input frequency belongs to a frequency range suitable for measuring the basis weight of the paper (step S12).

  If it is determined in step S12 that the frequency is suitable for measuring the basis weight of the sheet (step S12; Yes), the basis weight of the sheet is calculated from the ultrasonic frequency and transmission intensity (step S12). S13) Using the obtained basis weight, the CPU 69 shown in FIG. 7 determines the six-stage image forming conditions related to the transfer voltage, the fixing temperature, and the sheet conveyance speed described in FIGS. 5 and 6 (step S14). ). Then, image formation is performed under the determined image formation conditions (step S15).

  On the other hand, if it is determined in step S12 that the frequency is not suitable for measuring the basis weight of the paper (step S12; No), the basis weight calculation unit 751B gives a warning to the CPU 69 and receives this warning. The CPU 69 displays a warning message informing the user that the ultrasonic frequency is not suitable for basis weight detection on the display screen 90 shown in FIGS. 1 and 7 (step S16). In step S10, image forming conditions (default image forming conditions) based on the basis weight stored in the basis weight storage unit 92 are set (step S17), and image formation is performed under the image forming conditions (step S17). ).

  As described above, in this automatic input mode, by controlling the formation conditions in image formation based on a preset basis weight, the user himself / herself can save time and effort to input the basis weight. It is possible to minimize control of inappropriate image forming conditions due to a poor calculated basis weight.

  The above is the description of the basis weight detection device that detects the frequency and the image forming device that performs control according to the frequency.

  In these basis weight detection devices and image forming apparatuses, the frequency detection unit 771 shown in FIG. 7 detects the frequency from the ultrasonic wave received by the sound wave reception unit 72B. As a method of detecting the frequency from the ultrasonic wave, It is also conceivable to detect the frequency of the ultrasonic wave indirectly by detecting the frequency of the voltage of the coil power supply 76B for operating the ultrasonic wave generator 72A. Below, such a basic weight detection apparatus is demonstrated.

  This basis weight detection device is different from the basis weight detection device 701 described with reference to FIG. 7 in that the frequency is detected by detecting the frequency of the voltage of the coil power supply 76B. The configuration and control of the basis weight detection device are the same as those of the basis weight detection device 701 described with reference to FIG. 7 and will be described below focusing on frequency detection.

  FIG. 11 is a diagram illustrating the configuration of a basis weight detection device that detects the frequency of ultrasonic waves from the frequency of the voltage of the coil power supply 76B.

  In FIG. 11, the same components as those shown in FIG. 7 are denoted by the same reference numerals, and redundant description of the same components is omitted. The basis weight detection device 702 shown in this figure is different from the basis weight detection device 701 shown in FIG. 7 in that the frequency detection unit 772B of the basis weight detection device 702 detects the frequency of the voltage of the coil power supply 76B. is there. The control described with reference to FIGS. 9 and 10 is performed according to the detected frequency. According to such a frequency detection method, it is possible to easily detect the frequency rather than directly examining the received sound wave.

1 is an overall configuration diagram of a color tandem type image forming apparatus that includes the basis weight detecting apparatus of the present invention and operates as an embodiment of the image forming apparatus of the present invention. FIG. It is a figure showing the structure of the basic weight detection apparatus shown in FIG. FIG. 2 is an enlarged view of the vicinity of a sheet conveyance path in a state where a side cover is opened in the image forming apparatus illustrated in FIG. 1. FIG. 4 is an enlarged view of the vicinity of the basis weight detection device shown in FIG. 2 when the side cover side shown in FIG. 3 is separated from the main body side of the image forming apparatus. It is a figure showing the control switching performed according to the basic weight of the paper calculated by the basic weight detection apparatus shown in FIG. It is a figure showing each control content changed. It is a figure showing the structure of the basic weight detection apparatus provided with the frequency detection part which detects the frequency of an ultrasonic wave. It is a figure showing the relationship between the basic weight of a paper, and the transmittance | permeability of an ultrasonic wave with respect to the ultrasonic wave which has four types of frequencies. 6 is a flowchart illustrating control of forming conditions for image formation when a manual input mode is selected. 6 is a flowchart showing control of image forming conditions when an automatic input mode is selected. It is a figure showing the structure of the basic weight detection apparatus which detects the frequency of an ultrasonic wave from the frequency of the voltage of the power supply 76B for coils.

Explanation of symbols

1000 Image forming apparatus 1a, 1b, 1c Tray 2 Paper discharge tray 3a, 3b, 3c Conveying roll pair 4K, 4C, 4M, 4Y Toner cartridge 5 Intermediate transfer belt 6K, 6C, 6M, 6Y Toner image forming unit 7 Exposure unit 8 Registration roll pair 9 Transfer unit 10 Fixing device 110 Drive motor 90 Display screen 91 Operation panel 13 Paper discharge roll pair 14 Side cover 15 Side cover rotating shaft 70A Sound wave generating units 70B, 701B, 702B Sound wave receiving units 70, 701, 702 Basis weight Detection device 71A Ultrasonic wave generating element 71B Ultrasonic wave receiving element 72A Sound wave generating part 72B Sound wave receiving part 73A, 73B Coil 74A, 74B Sheet metal 75B, 751B, 752B Basis weight calculating part 85, 86 Paper 61, 69 CPU
62 Clock generator 63 Frequency divider 64 Low pass filter 771B, 772B Frequency detector 76B Power supply for coil 92 Basis weight storage unit 93 Basis weight setting unit

Claims (16)

A sound wave generating unit that obtains drive energy wirelessly and emits a sound wave toward the sheet-like recording medium by the drive energy;
An energy transmitter for wirelessly transmitting the drive energy to the sound wave generator;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A basis weight detection device comprising: a basis weight calculation unit that calculates a basis weight of the recording medium based on the intensity of sound waves received by the sound wave reception unit. The energy transmission unit sends the driving energy by a fluctuating electromagnetic field that fluctuates over time.
The basis weight detection device according to claim 1, wherein the sound wave generating unit obtains the driving energy by receiving the fluctuating electromagnetic field. A sound wave generator that emits sound waves toward the sheet-shaped recording medium in an oblique direction with respect to the surface of the recording medium;
A sound wave receiving unit that receives the sound wave emitted by the sound wave generating unit and passed through the recording medium at a position shifted from the center of propagation of the sound wave;
A basis weight detection device comprising: a basis weight calculation unit that calculates a basis weight of the recording medium based on the intensity of sound waves received by the sound wave reception unit.   The basis weight according to claim 3, wherein the sound wave receiving unit receives the sound wave that has passed through the recording medium, facing the recording medium at a position shifted from the center of propagation of the sound wave. Detection device. A sound wave generator that emits sound waves toward a sheet-like recording medium;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A frequency detector that directly or indirectly detects the frequency of the sound wave emitted by the sound wave generator;
A basis weight comprising a basis weight calculation unit that calculates a basis weight of the recording medium based on the intensity of the sound wave received by the sound wave reception unit and the frequency detected by the frequency detection unit. Detection device.   The basis weight detection device according to claim 5, wherein the frequency detection unit directly obtains the frequency of the sound wave by analyzing the waveform of the sound wave received by the sound wave reception unit. The sound wave generating unit operates according to a periodic drive signal and emits a sound wave having the same frequency as the frequency of the drive signal;
The basis weight detection device according to claim 5, wherein the frequency detection unit indirectly obtains the frequency of the sound wave emitted from the sound wave generation unit by detecting the frequency of the drive signal.   The basis weight calculation unit calculates the basis weight of the recording medium when the frequency detected by the frequency detection unit is a frequency within a predetermined frequency region, and the detected frequency is outside the frequency region. 6. The basis weight detection device according to claim 5, wherein a warning is issued when the frequency is reached. In an image forming apparatus for forming an image by fixing a toner image on a sheet-like recording medium,
A clock generator for generating a clock signal of a predetermined first frequency;
A drive signal generator that processes the clock signal to generate a drive signal of a predetermined second frequency;
A sound wave generator that emits a sound wave of the second frequency toward the recording medium in accordance with the drive signal generated by the drive signal generator;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A basis weight calculating unit that calculates a basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiving unit;
An image forming apparatus comprising: a control unit that operates based on the clock signal and controls a forming condition in the image formation based on the basis weight calculated by the basis weight calculation unit.   The image forming apparatus according to claim 9, wherein the drive signal generation unit processes the clock signal by a frequency divider and a low-pass filter. In an image forming apparatus for forming an image by fixing a toner image on a sheet-like recording medium,
A sound wave generating unit that obtains drive energy wirelessly and emits a sound wave toward the sheet-like recording medium by the drive energy;
An energy transmitter for wirelessly transmitting the drive energy to the sound wave generator;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A basis weight calculating unit that calculates a basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiving unit;
An image forming apparatus comprising: a control unit that controls a forming condition in the image formation based on the basis weight calculated by the basis weight calculating unit. The sound wave generator emits a sound wave at a predetermined position in the image forming apparatus;
The image forming apparatus according to claim 11, further comprising a holding mechanism that detachably holds the sound wave generation unit at the predetermined position. In an image forming apparatus for forming an image by fixing a toner image on a sheet-like recording medium,
A sound wave generator that emits sound waves toward the sheet-shaped recording medium in an oblique direction with respect to the surface of the recording medium;
A sound wave receiving unit that receives the sound wave emitted by the sound wave generating unit and passed through the recording medium at a position shifted from the center of propagation of the sound wave;
A basis weight calculation unit that calculates the basis weight of the recording medium based on the intensity of the sound wave received by the sound wave reception unit, and controls the formation conditions in the image formation based on the basis weight calculated by the basis weight calculation unit. And an image forming apparatus. In an image forming apparatus for forming an image by fixing a toner image on a sheet-like recording medium,
A sound wave generator that emits sound waves toward a sheet-like recording medium;
A sound wave receiver that receives sound waves emitted by the sound wave generator and passed through the recording medium;
A frequency detector that directly or indirectly detects the frequency of the sound wave emitted by the sound wave generator;
Basis weight calculator for calculating the basis weight of the recording medium based on the intensity of the sound wave received by the sound wave receiver and the frequency detected by the frequency detector, and the basis weight calculated by the basis weight calculator An image forming apparatus comprising: a control unit that controls a forming condition in the image forming based on the amount. It is equipped with a basis weight setting section that receives the operation and sets the basis weight.
The basis weight calculation unit calculates the basis weight of the recording medium when the frequency detected by the frequency detection unit is a frequency within a predetermined frequency region, and the detected frequency is outside the frequency region. If it is a frequency, it will issue a warning,
When the basis weight calculation unit issues a warning, the control unit replaces the basis weight calculated by the basis weight calculation unit with the basis weight set by the basis weight setting unit. The image forming apparatus according to claim 14, wherein the image forming apparatus controls forming conditions in forming. A basis weight storage unit that receives the operation and stores the set value of the basis weight.
The basis weight calculation unit calculates the basis weight of the recording medium when the frequency detected by the frequency detection unit is a frequency within a predetermined frequency region, and the detected frequency is outside the frequency region. If it is a frequency, it will issue a warning,
When the basis weight calculation unit issues a warning, the control unit replaces the basis weight calculated by the basis weight calculation unit with the basis weight stored in the basis weight storage unit. The image forming apparatus according to claim 14, wherein the image forming apparatus controls forming conditions in forming.

Images