JP4681779B2 - SURFACE IDENTIFICATION DEVICE AND IMAGE FORMING DEVICE - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention includes a surface property identification device that identifies a difference in surface friction resistance of a measured object, a difference in surface roughness that causes the difference, and a difference in surface material.PowerThe present invention relates to an image forming apparatus such as a sub-photo printer, a copying machine, an ink jet printer, a thermal head printer, a dot impact printer, a facsimile, and a composite device thereof.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, various image forming apparatuses are apparatuses for forming an image on a sheet-like recording material such as plain paper, postcard, cardboard, sealed letter, OHP plastic thin plate, etc. In an apparatus such as a printer, a copying machine, or a facsimile using the method, a toner image is formed on a recording material by an electrostatic image forming unit using toner as a developer, and then the recording material is heated and heated by a fixing unit. The toner image is melted and fixed under pressure to form an image.
[0003]
In addition, apparatuses such as printers, copiers, and facsimiles using an ink jet system, which is another system, use ink as a recording agent, and use a large number of nozzles having minute orifices utilizing a mechanical or thermal reaction. An image is formed on the recording material by image forming means for ejecting ink from the configured recording head at a high speed.
[0004]
In addition, printers, copiers, facsimiles, and other devices using other types of thermal transfer systems use an ink ribbon as a recording agent, and an image forming unit that thermally transfers ink from the ink ribbon using a thermal head. An image is formed.
[0005]
By the way, these devices have been improved in recent years, and devices for higher image quality and higher processing speed have been realized by various means. At the same time, cost reduction measures have been devised to reduce costs. Advancing and becoming widespread.
[0006]
However, the types of recording materials used in these image forming apparatuses vary widely, from plain paper to high-grade paper with special surface treatment for sealed letters and resin sheets for OHP. Accordingly, since it has been used all over the world, it is necessary to cope with it so that a good image can be formed on any recording material used in various places. The roughness of the recording material surface, which greatly affects the recording material, is a very important factor.
[0007]
For example, in an apparatus employing an electrophotographic system, when the surface of the recording material used is smooth (hereinafter referred to as smooth paper) or rough (hereinafter referred to as rough paper), the paper surface from the heating source in the fixing unit The heating efficiency for transferring heat to the surface differs according to the difference in thermal resistance due to the difference in surface properties, and even if the rough paper is fixed at an appropriate fixing temperature with smooth paper, it causes insufficient fixing. It is necessary to fix at a high temperature. For this reason, the current apparatus uses the temperature at which rough paper can be fixed as the standard fixing temperature, and is always fixed at an excessive temperature for smooth paper, and even for rougher paper. Since a higher fixing temperature is required, a selection mode is provided for allowing the user to change the setting of the fixing temperature when using such paper.
[0008]
FIG. 2A shows a basic configuration of a printer that employs an electrophotographic system as a specific example of these.
[0009]
That is, FIG. 2A is a cross-sectional view of a main part of a conventional printer. In the printer, the surface of the photosensitive drum 2 is uniformly charged to a predetermined polarity by the charging roller 1 and then exposed to a laser or the like. Only the area where the photosensitive drum 2 is exposed by the means 3 is neutralized to form a latent image on the photosensitive drum 2. The latent image is developed by the toner 5 of the developing device 4 to be visualized as a toner image. That is, the toner 5 of the developing device 4 is frictionally charged with the same polarity as the charging surface of the photosensitive drum 2 between the developing blade 4a and the developing sleeve 4b, and DC and AC are developed in the developing gap portion where the photosensitive drum 2 and the developing sleeve 4b face each other. A bias is applied in a superimposed manner, and the toner 5 is selectively attached to the latent image forming portion of the photosensitive drum 2 while floating and vibrating by the action of an electric field, and then the toner 5 is transferred by the transfer roller 10 and the photosensitive drum 2. The photosensitive drum 2 is conveyed to the nip portion by rotation.
[0010]
On the other hand, the recording material 7 such as paper on which an image is recorded is fed at the leading end from the recording material storage box 7 'to the vertical conveying roller pair 6' by the paper feeding roller pair 7 ", and then the vertical conveying roller pair. 6 'is conveyed to the pre-transfer conveyance roller 6, and further conveyed by the pre-transfer conveyance roller 6 to the transfer nip portion along the transfer guide plate 9 at a predetermined entry angle from the pre-transfer conveyance roller 6. Before the recording material 7 is transported to the nip portion, the surface of the recording material 7 is charged by rubbing with various members that are in contact before the recording material 7 is transported to this region. Since there is a possibility, a static eliminating brush 8 for removing such unnecessary charging that causes disturbance of an image when performing electrostatic recording is provided so as to be in contact with the back side of the recording material 7 being conveyed and grounded. Has been.
[0011]
In the transfer portion, in order to electrostatically attract the toner 5 on the photosensitive drum 2 and move it to the recording material 7 side, a high voltage having a polarity opposite to that of the toner 5 is applied to the transfer roller 10 on the back surface of the recording material 7, and recording is performed. The toner 5 is electrostatically attracted to the back surface of the material 7 and the toner image is transferred to the recording material 7, and the back surface of the recording material 7 is charged with a polarity opposite to that of the toner 5 to hold the transferred toner 5. A transfer charge for continuing is applied to the back surface of the recording material 7.
[0012]
Finally, the recording material 7 onto which the toner image has been transferred is conveyed to a fixing device 12 composed of a heating rotator 13 and a pressure roller 14 that forms a nip portion, and a fixing temperature preset in the nip portion is set. The toner image is fixed by being heated and pressurized while being controlled at a constant temperature by a constant temperature control means 16 provided on the heating rotator 13 side so as to be held.
[0013]
In addition, since the deposits such as toners having different polarities remain slightly on the surface of the photosensitive drum 2 after the toner image transfer, the surface of the photosensitive drum 2 after passing through the transfer nip portion is the surface of the photosensitive drum 2 by the cleaning container 11. After the adhering matter is scraped off and cleaned by the cleaning blade 11a that is in contact with the counter, the apparatus waits for the next image formation.
[0014]
Among the above processes, a contact heating type fixing device with good thermal efficiency and safety is widely known as an image fixing method. Conventionally, a release layer is mainly formed on the surface of a metal cylindrical metal core. Then, a heat fixing roller containing a halogen heater inside the cylinder and an elastic layer made of heat-resistant rubber formed on the metal core, and a pressure roller formed by forming a pressure-side release layer on the surface are pressed. In recent years, a heat roller fixing device constituted by contact has been used. However, as a method with higher heating efficiency, a heat resistance resin film 13'c having a low heat capacity as shown in FIG. A fixing film 13 ′ having a conductive primer layer 13′b and a release layer 13′a formed on the surface thereof, and a heater holder 13′d that also serves as a ceramic heater 15 and a film guide member inside the fixing film 13 ′. And gold for uniform pressure A film heating type in which a pressure roller 14 formed by forming a silicon rubber layer 14b and a PFA tube layer 14a on a pressure cored bar 14c is pressed against a fixing film unit 13 'composed of a stay 13'e. A fixing device is used.
[0015]
In the ceramic heater 15 of the film heating type fixing device, as shown in the sectional view of FIG. 2 (C), silver palladium (Ag / Pd), RuO2, Ta2N is formed on one surface of a ceramic substrate 15a made of alumina or the like. Are formed in two rows, the surface of which is covered with a protective glass 15c, and a thermistor 15d is provided as a temperature detecting means on the surface opposite to the surface on which the heating element is formed. Is formed.
[0016]
This type of film heating type fixing device has higher heat transfer efficiency than the conventional heat roller method using a cylindrical metal containing a halogen heater as a fixing roller from the viewpoint of promoting energy saving in recent years, and the apparatus is also started up. Although it has been attracting attention as a fast method and has been applied to higher-speed models, it is necessary to reduce the heat capacity of the heating surface of the fixing unit in order to emphasize the rate of temperature increase. It is difficult to form an elastic layer on the heating surface, and a hard heating surface is used. For this reason, this type of fixing method has a configuration in which a difference in heating efficiency is likely to occur due to unevenness on the surface of the recording material.
[0017]
In various image forming apparatuses such as a printer using such a fixing device, as the processing speed is increased as described above, there is a problem that a difference in fixing property becomes remarkable due to a difference in paper type. The user himself / herself needs to input an appropriate fixing mode to the printer in advance according to the type of paper that the user intends to use. FIG. 3 is a flowchart showing the fixing process in the image forming process of such a conventional apparatus. Here, two kinds of selections can be made, that is, normal smooth paper and rough paper having a rough surface as a paper type setting. An example is shown.
[0018]
In the flowchart shown in FIG. 3, when rough paper is selected, fixing is performed by raising the temperature by α by the fixing temperature T of normal paper. Full power heating is performed at the upper limit of the rated power of the heater until it reaches the fixing temperature, and after reaching the target value, fixing is performed by keeping the heater temperature constant, which decreases according to the amount of heat taken away as the paper passes. In order to keep the temperature, constant temperature control is performed until the last paper is fixed.
[0019]
The flow of the fixing process shown in this flowchart is basically the same for both the heat roller fixing device and the film heating type fixing device. However, in the latter, the temperature is controlled by detecting the temperature behind the heater substrate. The heat storage effect of the entire fixing device accompanying the paper causes the heating action by members other than the heater such as the pressure roller to work, and the actual fixing nip temperature may be higher than the control temperature of the heater. In this type of fixing device, it is not appropriate to refer to the control temperature as the fixing temperature, and this control temperature will be referred to as the temperature control temperature in the future). For this reason, hot offset caused by excessive heating (a phenomenon in which the toner is excessively melted and partially remains on the fixing film side, and then reattaches to an inappropriate position on the paper) and the toner splatters due to the generation of a large amount of water vapor. As a measure to prevent bad effects such as paper conveyance failure, it is necessary to lower the heating temperature of the heater step by step at a predetermined rate according to the number of sheets. The amount of sheets to be passed that is made higher than the temperature and lowers the temperature is set by individually obtaining an appropriate value according to the characteristics of each paper.
[0020]
FIG. 4 is a graph showing changes in temperature control temperature for each sheet and each number of sheets of the conventional image forming apparatus designed to lower the temperature control temperature step by step, and according to such setting, FIG. A film heating type fixing device having a fixing speed of 16 sheets per minute has been realized.
[0021]
However, forcing the user to select a mode in order to switch the fixing condition each time depending on the type of paper used in this way increases the work burden on the user, and if the selection mode is wrong, fixing the print amount. However, there is a possibility that power is wasted due to excessive heating, power is wasted, image defects occur due to high temperature offset, and toner contamination of the fixing device is caused.
[0022]
Further, in a usage environment in which a single network printer is shared by a plurality of users as in recent years, a special user uses a special paper to switch the mode setting accordingly, and then the special paper is used. May be left on the device, and when used by other users who do not know that, the modes may not match and may not be properly fixed, causing the problem described above. It is high.
[0023]
Also, regarding the number of fixing modes that can be set, there are strictly different levels of actual paper smoothness, and it is impossible to set optimum conditions for each of them. The number of setting modes is limited by batch-fixing papers with smoothness in a range in the same mode. For certain papers, fixing may be performed using more power than necessary. Depending on the combination, inefficient fixing may be performed.
[0024]
On the other hand, in the apparatus employing the ink jet method, the amount of ink required differs between the case where the recording material used is smooth paper and the case of rough paper, and an image on the rough paper with an appropriate amount of ink on smooth paper. Even if it is formed, the ink permeates in the thickness direction of the paper and causes a lack of density, so it is necessary to eject more ink to the rough paper. For this reason, in the current apparatus, the ink discharge amount for rough paper is used as the standard discharge amount, and images are always formed with excess ink on smooth paper.
[0025]
In addition, the amount of electric power required for the recording material used for smooth paper and rough paper is different in devices that employ the thermal transfer method. However, since the thermal resistance is large, the transferability of the ink is lowered and the density is insufficient.
[0026]
As described above, all current apparatuses consume extra temperature, ink, and power to prevent image quality deterioration due to the surface roughness of the recording material. To prevent this, the surface roughness of the recording material It is necessary to switch these conditions depending on the situation, but at present, only a method that forces the user to change the setting has been considered.
[0027]
For this reason, several proposals have been made so far for detecting the roughness of the recording material surface and changing the image forming conditions in accordance with the detection result, and among them, the recording material surface roughness Examples of the proposed detection principle of the detection means for the above are those disclosed in Japanese Patent Application Laid-Open Nos. 2000-314618 and 2000-356507. In these proposals, the contact means that contacts the surface of the recording material detects physical phenomena such as vibration and rubbing sound caused by rubbing against the surface of the recording material, and detects the difference in the detected amount as the difference in surface roughness. As a specific configuration thereof, a configuration is proposed in which a piezoelectric element is provided in the contact means and vibration is converted into an electrical signal and detected.
[0028]
[Problems to be solved by the invention]
However, the above-described proposal does not disclose in detail the specific configuration conditions necessary for a member (hereinafter referred to as a probe) that is actually brought into contact with the surface of the recording material, and a simple linear probe is located upstream in the scanning direction. However, only one configuration is shown in which one end is fixed and the downstream end is brought into contact with the diagonal scanning direction so as not to be opposed to the oblique scanning direction. It is difficult.
[0029]
That is, the difference in surface roughness between smooth paper and rough paper actually used as a recording material is measured by a surface roughness meter used as a normal measuring instrument. The unevenness difference is 15 to 20 μm at the maximum, and the unevenness on the surface of the paper that has been recognized as rough paper is within the range of 22 to 40 μm at the maximum. Further, the difference between the smooth paper near the rough paper and the rough paper near the smooth paper is only about several μm apart. In order to read such a small unevenness by obliquely contacting the surface of the recording material being conveyed with a linear probe,
-The probe tip must have a very sharp needle shape so that it can follow irregularities of several μm.
-On the other hand, wear resistance that can withstand rubbing with tens of thousands of recording materials by the end of the life of the device and rigidity that does not easily deform even when paper deformed when a jam occurs is required
-A contact pressure that is strong enough to prevent the tip of the probe from jumping up even when rubbed at the recording material conveyance speed is required.
-On the other hand, a light contact pressure that can be followed without crushing the uneven surface of the soft recording material is required.
It is very difficult to make these contradictory conditions compatible, and at least from the viewpoint of durability and reliability, a needle-like probe cannot be used practically, and a probe that is somewhat rigid It must be realized. For this reason, as a practical probe, a thin plate-like probe having higher rigidity and less scratching the recording material surface is conceivable, and the recording material surface is scanned by a side having a finite length instead of a point. A method of discriminating by the difference in strength of vibration caused by the averaged surface roughness is conceivable, and this type of configuration is shown in Japanese Patent Laid-Open No. 2000-356507.
[0030]
FIG. 5 shows the configuration of a surface roughness sensor using a thin plate probe, and FIG. 6 shows the result of scanning a plurality of recording material surfaces actually having different surface roughnesses using the surface roughness sensor using a thin plate probe. Indicates.
[0031]
FIG. 5A is a top view of the surface roughness sensor, and FIG. 5B is a cross-sectional view of the surface roughness sensor viewed from the side in the scanning direction. The shape of the probe viewed from the top is T-shaped. The linear cross-sectional probe 17 having a linear cross-sectional shape is used.
[0032]
This linear cross-section probe 17 has a piezoelectric element 19 adhered on a SUS T-shaped sheet metal 18 having a thickness of 0.15 mm, and the piezoelectric element side electrode 19 ′ and the sheet metal side electrode 18 ′ are respectively soldered to support rotation. A long side portion of a T-shape is fixed on the shaft 20, and a tip 17 ′ having a short side width of 5 mm is brought into contact with the upstream surface of the recording material on the downstream side in the scanning direction at an oblique angle of 30 °, and a twist (not shown) A coil spring is provided on the rotation support shaft 20 so that a pressure of 3 to 10 g is applied to the tip of the sensor with the frame of the apparatus as a fixed end.
[0033]
The linear cross-section probe 17 is a vertical vibration (strictly speaking, a vibration reciprocating on an arc-shaped locus drawn by the sensor front end portion) generated at the sheet metal front end portion 17 ′ by rubbing with the paper, ignoring paper transportability. Although the horizontal component during vibration can be increased by bringing the sensor into contact with the scanning surface close to the vertical, in this conventional configuration, the position where the sensor tip can completely contact the paper is only one point of the initial contact position. After the sensor tip is rubbed up at that position, the external force of the horizontal component accompanying the paper conveyance becomes difficult to act, so the vibration component in the scanning direction is excessive even at the expense of the paper conveyance property. It can be considered that the vibration component in the vertical direction due to the irregularities on the paper surface does not increase, but the signal of the piezoelectric element generated by generating distortion in the sheet metal is amplified (not shown) Amplified by a factor of 40 in the circuit and 2 msec in the measuring instrument (The sampling speed that can be processed by a normal printer) is captured (however, the configuration in which the sensor is pressure-fixed using a rotation support shaft in the above configuration is not described in the conventional example) Although only the configuration for fixing the end portion on the counter-contact side is shown, if the end portion on the counter-contact side is completely fixed when actually transporting the paper, unless it is set to a light pressure so much There is a possibility that it may interfere with paper conveyance or damage the paper surface. On the other hand, if the contact pressure is too low, there will be a problem that the paper will not be rubbed sufficiently. Therefore, the rotation support shaft fixing method devised by the present inventor is used for the convenience of experimental accuracy).
[0034]
The recording materials evaluated at this time are rough paper and smooth paper having a difference in smoothness as shown in FIG. 6A (A is a bond-type rough paper, B is a standard smooth paper, and C is High-quality rough paper with corrugated protrusions on the surface, and each number indicates the basis weight of each type of paper), and these recording materials are sequentially and continuously provided at a speed of 141 mm / sec. When the sensor was transported and scanned, the signal level was too low at 3 g weight, and the result when pressure was applied at 10 g weight is the graph of FIG. The graph of FIG. 6B is because the paper with higher smoothness in FIG. 6A is less likely to generate vibration in the sensor, and the rough paper with lower smoothness is more likely to generate vibration according to the unevenness. The level of the signal strength should be opposite to the level of the smoothness shown in FIG.
[0035]
However, as can be seen from the graph of FIG. 6B, although the sensor signal tends to be slightly lower in B75 and B105, which are papers with particularly high smoothness, the signals of smooth paper and rough paper as a whole. There is no difference in strength or it is reversed. Even if the contact between the sensor and the paper is improved by using the rotation support shaft fixing method as described above, the difference in smoothness of the paper is sufficient with this sensor. It was difficult to distinguish between smooth paper and rough paper by detecting.
[0036]
For this reason, the present inventor has improved the sensor probe configuration as shown in the example of FIG. 7 in order to dramatically improve the surface property discrimination performance and make it practical by a detection method using a piezoelectric element. Thus, the discrimination performance can be greatly improved by setting the probe tip portion to be able to vibrate back and forth on the scanning plane in the scanning direction and setting the tip contact portion to the measurement surface against the scanning direction.
[0037]
FIGS. 7A and 7B and FIGS. 8A and 8B are respectively a top view of a paper surface roughness detection sensor proposed by the present inventor, a cross-sectional view of the paper surface roughness detection sensor, and a paper surface. It is sectional drawing of the probe of a roughness detection sensor, the smoothness comparison graph for explaining operation | movement at the time of the probe scanning of a paper surface roughness detection apparatus, and a surface roughness detection comparison graph.
[0038]
In FIG. 7A, the same elements as those shown in FIG. 5 are denoted by the same reference numerals, and the feature of this configuration is composed of two bending curved portions, as is apparent from FIG. An S-shaped cross-sectional sensor 22 having a fixed end on the upstream side with respect to the scanning direction and a tip contact portion on the downstream side is used. With this setting, the entire sensor 22 is set in the forward direction with respect to the scanning direction. In addition, the sensor front end also comes into contact with the paper surface at an angle in the forward direction that does not interfere with the entrance of the conveyed paper, while the upstream corner of the front end touches the paper surface while biting in the opposite direction to the scanning direction. As shown in FIG. 8 (B), as a result of identifying the paper having different smoothness as shown in FIG. 8 (B), the overall smoothness of each paper is obtained. Correspondingly, it was possible to obtain a signal waveform that clearly corresponds to the difference in strength.
[0039]
When a piezoelectric element is used for the application of the present invention including the configuration of the conventional example, the signal generated by the piezoelectric element is likely to be a pulse waveform as described above.
Since the sheet metal on which the piezoelectric element is formed basically fixes only one end, the tip of the abutting sheet metal can be freely displaced above the scanning plane with a relatively light mass. The front end of the sheet metal that is in contact with the scanning surface with a light contact pressure can be displaced at high speed and can be stopped quickly.
[0040]
Since the moving speed of the surface of the paper to be scanned is sufficiently high with respect to the above characteristics of the front end of the sheet metal, the front end of the sheet metal is flipped up by the surface of the paper, and after a momentary non-contact state is formed, it landes again. During the continuous scanning, the jumping and landing occur almost simultaneously, the impact strength is doubled and the generation time of each signal is detected in a short time.
[0041]
This is due to the features of the configuration and the usage pattern. By setting in this way, a large detection signal level can be generated with respect to the unevenness difference of several μm.
[0042]
In particular, the method of fixing the end portion on the abutting side using the rotation support shaft devised by the inventor further improves the degree of freedom of displacement of the tip end portion of the sheet metal. Contributing to amplification, and further improving the structure of the sensor tip and the contact condition described above, the followability of the sheet metal tip to the paper surface is increased (finally the tip is flipped up similarly) However, the signal generation intensity at the time of landing and landing becomes stronger because the frictional force is received more strongly and the signal generation strength at the time of landing is also stronger). It can be generated by attaching and dramatically improving the distinctiveness.
[0043]
However, when the identification signal is generated in the form of a pulse in this way, even in the improved method, the details of each waveform are clearly settled at a low level on average, as in B163 paper. Regardless, there is a case where a high pulse noise signal is generated locally. In addition to this example, sudden vibration or strong electrical noise is applied from the outside, or partial wrinkles and The possibility that an abnormally high level is generated in the signal waveform when there is a flaw or deformation cannot be denied, and it is an inconvenient signal waveform for simply identifying with one threshold level.
[0044]
Therefore, a plurality of heating conditions, fixing conditions, or image forming conditions are set according to the type of paper, and the user selects a mode suitable for the paper each time according to the paper used for switching these conditions. In such an image forming apparatus, if the user makes a mistake or the user does not know that the paper type has been changed by a network printer, the heat treatment is insufficient, the fixing property, the density, etc. This may cause image defects, conversely waste heat due to excessive heating, image defects due to high temperature offset, toner contamination of the fixing device, and excessive developer consumption. It was.
[0045]
Further, the roughness of the recording material already proposed as one solution to the above problem is measured as a difference in vibration intensity by rubbing a sheet metal having a piezoelectric element, and based on the result. In the method of switching the control of heating temperature, fixing temperature, image forming conditions, etc., it is not possible to detect a sufficient vibration intensity difference by simply rubbing the linear sheet metal tip against the surface of the recording material. It is impossible to identify rough paper.
[0046]
In addition, when a sensor with an improved probe tip configuration that has already been proposed as an improvement measure of the above solution is used, a signal corresponding to the smoothness can be obtained as a whole. There is a risk that an abnormally high signal is generated locally, and there are cases where the form of the identification signal is inconvenient.
[0047]
  The present invention has been made under such circumstances, and uses a surface property identification device that can reliably identify the surface roughness and the like of a recording material in a stable state with very little identification error.PaintingAn object of the present invention is to provide an image forming apparatus.
[0048]
  In order to achieve the above object, in the present invention, a surface identification device is provided as follows.NotoConfigure the cage.
(1) By scanning the tip of the probe having a piezoelectric element while contacting the surface to be measured, a pulsed electric signal is generated from the piezoelectric element, and the surface of the surface to be measured is generated based on the intensity difference of the electric signal. A surface property identification device for identifying surface properties, comprising integration processing means for integrating the pulse-shaped electric signal generated within a predetermined time, wherein the integration result of the integration processing is used as an identification signal. The probe having the piezoelectric element has a scanning direction vibration part that can vibrate by repeatedly deforming and restoring in the scanning direction at the tip of the contact side of the probe, and the object to be measured is against the scanning direction. The surface is brought into contact with an angle and a pressure that enable scanning while biting within a strength range that does not hinder scanning, and the scanning direction vibrating portion comes into contact with a side closer to the end of the probe opposite to the contact side On the side edge A scanning surface in the case where the first bent portion and the second bent portion bent in the direction opposite to the first bent portion are arranged in this order, and the upstream side in the scanning direction is set to the right side of the paper surface; A surface property identification apparatus, wherein the probe is processed so that a cross-sectional shape of the probe viewed from a cross section perpendicular to the scanning direction is an S-shape.
[0074]
[Action]
When scanning the probe tip with a piezoelectric element in contact with the surface of the object to be measured, a difference in surface properties of the surface of the object to be measured is detected as a pulse signal waveform at the piezoelectric element through vibration generated at the tip. In response to sudden mechanical / electrical noise and abnormally high pulse signal generation due to partial scratches / deformation on the surface of the object being measured These unwanted local noise components in the waveform are mitigated so that they can be detected as a simple comparable identification signal with little effect on the overall trend, so identification based on conventional pulsed waveforms Compared with the method, the S / N is greatly improved, and the surface property of the surface of the object to be measured can be identified with high reliability by a stable identification signal with very little identification error.
[0075]
In addition, as a specific configuration of the integration processing unit, after amplifying the signal generated in the piezoelectric element unit to a desired level by the amplification circuit and strengthening the current drive capability, an integration circuit configured by an integration resistor and a capacitor, More preferably, a good signal with a high S / N in which the noise component is suppressed can be obtained by hardware integration of the pulse signal through a two-stage integration circuit using two stages of the integration circuit.
[0076]
In addition, a discharging resistor having a resistance value sufficiently larger than the integrating resistor is provided in parallel with the capacitor portion of the integrating circuit, and the signal level after the object to be measured is automatically detected by self-discharging at a desired ratio. It can be restored to the initial level.
[0077]
Further, by providing a switching circuit in parallel with the capacitor part of the integration circuit, the integration period and the discharge period in the integration circuit part can be switched at a desired timing under the control of the CPU.
[0078]
Further, by providing an amplifier circuit in the subsequent stage of the integration circuit, it is possible to freely adjust the signal level to a desired level without causing a decrease in S / N.
[0079]
Further, the integration process can be realized in software by using a method in which a signal generated by the piezoelectric element is guided to the CPU via an A / D conversion circuit and the result of the integration calculation process by the CPU is used as an identification signal. The circuit configuration can be simplified.
[0080]
Further, without directly integrating the generated signal of the piezoelectric element, the result obtained by integrating the number of times that a signal level higher than the first threshold is generated in the generated signal during a predetermined period is used as an identification signal, The circuit configuration can also be simplified by identifying by comparison.
[0082]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to examples of laser beam printers, ink jet printers, and thermal head printers. The present invention is not limited to the form of the apparatus, and can be implemented in the form of a method supported by the description of the embodiments.
[0083]
【Example】
Example 1
1A to 1C are a block diagram showing a configuration of a surface roughness detection signal processing system used in the “laser beam printer” of Embodiment 1, a signal processing circuit diagram, and surface roughness detection by integral signal processing. It is a comparison graph.
[0084]
In this embodiment, a laser beam printer adopting an electrophotographic film heating type fixing device having the same configuration as that shown in FIG. 2A is used as the apparatus main body, and the surface roughness detection sensor is shown in the above-described figure. The S-shaped cross-sectional shape sensor 22 having the improved cross-sectional shape shown in FIG. 7 is used.
[0085]
In the present embodiment, as shown in FIG. 1A, as the signal processing method of this sensor, the signal detected by the surface roughness sensor unit 22 using this sensor is an amplification circuit unit surrounded by a broken line part in the figure. 23 and the signal processing circuit unit including the integration circuit unit 24, and the signal processing circuit unit integrates in hardware, thereby improving the signal discrimination, and the result of the threshold signal source 25 generating a predetermined threshold level and the comparator As a result, if an identification signal higher than the threshold value is output, the paper is determined as a rough paper, and conversely, if an identification signal lower than the threshold value is output, the paper is determined as a smooth paper in a binary manner. In each case, a flag of 1 and 0 is generated and taken into the CPU 28, and a paper leading edge sensor unit 27 for detecting a paper leading edge provided separately on the CPU side (not shown in the configuration of FIG. 2). Usually, this kind of equipment Based on the information, the sensor needs to detect the moment when the leading edge of the paper passes as a reference necessary for alignment to start image formation on the paper, and is mainly composed of a photo interrupter) Read the flag of the comparison result between the integrated signal value of the paper surface roughness sensor and the threshold level after a predetermined time from the moment the paper passes (therefore, the set position of the surface roughness sensor is always the paper transport direction relative to the paper leading edge sensor) In accordance with the result, the CPU sends a signal for controlling the fixing device to the fixing temperature and the fixing temperature control circuit unit 29 at a predetermined fixing temperature and sequence.
[0086]
In this embodiment, the specific circuit configuration of the broken line portion in FIG. 1A is as shown in FIG. 1B, and the inverting amplification portion composed of an Op amplifier and resistors R0, R1, and R2 is used. The signal of the sensor is inverted and amplified (the sensor signal is generated with ± bipolarity), the signal is accumulated in the integrating circuit composed of the resistor R3 and the capacitor C1, and simultaneously connected to C1 in parallel, sufficiently larger than R3 It is designed to attenuate the potential of C1 at an appropriate rate via the discharge resistor Rd.
[0087]
FIG. 1C shows an example of a sensor detection result for the paper type shown in FIG. 8A when such a signal processing circuit is used. In this example, elements having values of R0 = 10 kΩ, R2 / R1 = 1000, R3 = 100 kΩ, C1 = 1 μF, and Rd = 10 MΩ are used as the values of the constituent elements of each circuit, as shown in FIG. Compared with the response signal of the sensor of FIG. 8B in which the signal processing circuit of this embodiment is not added, the response signal of the sensor is sharper than the unstable pulse waveform of FIG. 8B. The integrated waveform with little fluctuation is easy to sample data, and a signal having a locally abnormally high level included in B105 or B163 in FIG. For example, in the graph of FIG. 1C, if the threshold value is 0.35 V, each paper type can be easily classified into rough paper and smooth paper, and a specific signal at that time As a processing procedure,
(1) Based on the signal from the paper leading edge sensor, data integrated in a period from when the paper leading edge passes through the surface roughness sensor to when the central portion of the paper passes is taken into the comparator.
(2) The threshold signal is set to 0.35v in advance, and the signal of the threshold signal source is compared with the integrated value.
(2-A) If the paper is rough paper, the integrated value is 0.35v or more, so the flag at that time is set to 1.
(2-B) If the paper is smooth paper, the integrated value is lower than 0.35v, so the flag at that time is set to 0.
(3) The CPU
(3-A) When flag 1 is received, control is performed so that the fixing temperature is raised to the temperature for rough paper.
(3-B) When the flag 0 is received, the fixing temperature is controlled to be lowered to the smooth paper temperature.
In this way, it can be controlled.
[0088]
However, when there are actually only two types of fixing modes, the fixing mode corresponding to one of the paper types is normally used as the standard mode, and the detection result only when the opposite paper type is detected. The mode is switched to the fixing mode according to the condition.
[0089]
In this case, set the temperature for rough paper fixing in the initial state where the paper type is unknown, and after detecting the sensor,
(1) When it is determined that the paper is rough paper, fixing is performed with the fixing temperature as it is and a temperature control sequence for continuous paper passing.
[0090]
(2) When the paper is determined to be smooth paper, the fixing temperature is lowered to the smooth paper fixing temperature, and the temperature adjustment sequence for continuous paper feeding is also switched to the smooth paper fixing sequence.
Thus, preferential treatment of rough paper can avoid the risk of fixing the rough paper at low temperatures and forming an image with poor fixing due to an erroneous detection. Since it takes too much time to raise the temperature to the required temperature after the sensor detects rough paper after setting, it is more advantageous to set in this way.
[0091]
On the other hand, even if the smooth paper is erroneously detected as rough paper, it is possible to stop the damage by consuming excess energy only for a short time from the initial printing operation to the detection time of the sensor.
[0092]
Further, when the reproducibility of the signal waveform was evaluated by passing 10 sheets of the same paper continuously in order to confirm the reliability of the signal processing of this embodiment, the fluctuation range of the signal level of each paper is the same for all paper types. In both cases, the signal level of smooth paper such as B90 and B163 of smooth paper in the graph of FIG. Since the signal level is less than 60% of the low A60 signal level, the signal level of rough paper and smooth paper with a level difference of about twice is stable and the fluctuation range within 10% is maintained. Therefore, it is considered that there is no risk of false detection at least within the range of the durable life of the sensor, and it can be seen that improvement of discrimination and reliability can be achieved at the same time by performing the signal processing of this example. It was.
[0093]
By providing the sensor having the above signal processing function on the paper feeding path of the paper feeding section and the transfer section inside the electrophotographic laser beam printer of this embodiment, the paper on which the laser beam printer is automatically used is provided. Therefore, it is possible to perform fixing with a fixing temperature corresponding to each surface property and a temperature control switching sequence during continuous paper feeding. This eliminates the trouble of selecting an appropriate fixing temperature and temperature control switching sequence during continuous paper feeding, and also causes improper fixing conditions to be selected due to a user's judgment error, resulting in insufficient fixing of the image after fixing. Occurrence can be prevented.
[0094]
In addition, since the current apparatus does not require the user to frequently change the fixing conditions, a certain amount of rough paper can be fixed on the same smoothing condition as smooth paper that is used more frequently under the same conditions. Set the temperature slightly higher than the necessary and sufficient fixing temperature for the paper (that is, use a slightly rough paper that the user cannot clearly recognize as rough paper when using smooth paper normally) However, this generally means that excessive heat energy is always consumed when fixing smooth paper that is frequently used, which saves energy. It was an unfavorable situation from the viewpoint.
[0095]
However, when this sensor is attached to this device for automatic identification, it is fixed at the optimum fixing temperature that is necessary and sufficient for smooth paper, and at an optimum fixing temperature that is necessary and sufficient for slightly rough paper. Since it becomes possible to fix, it becomes possible to save the heat energy that has been consumed excessively by the smooth paper that has been used most often so far, considering the effect of this difference on a global scale It is also possible to obtain an energy saving effect.
[0096]
On the other hand, even if the smooth paper is erroneously detected as rough paper, it is possible to stop the damage by consuming excess energy only for a short time from the initial printing operation to the detection time of the sensor.
[0097]
It should be noted that, depending on the detection result of the surface roughness sensor, it is also possible to implement a sequence in which the recording material heating time or heating processing interval is changed instead of the sequence for controlling the fixing temperature.
[0098]
(Example 2)
9A to 9C are a block diagram, a signal processing circuit diagram, and a surface roughness detection comparison graph by integrated signal processing, showing the configuration of the surface roughness detection signal processing system in the “laser beam printer” of the second embodiment. It is.
[0099]
In this embodiment, the same preconditions as in Embodiment 1 are used. In this embodiment, as a signal processing method of the surface roughness sensor, as shown in FIG. The level of the integration signal can be adjusted to a desired level by using a new post-stage amplifier circuit provided at the rear stage.
[0100]
The threshold signal source is a multiple threshold signal source 25 ′ capable of generating a plurality of levels, and a multi-value comparator 26 ′ capable of comparing multiple values is also used in the comparator.
In this embodiment, the output of the integrating circuit can be adjusted to a desired level by the amplifier circuit at the subsequent stage, and the discriminability can be improved by selecting a signal level range that is easy to discriminate, and more detailed by expanding the signal level. It is also possible to perform various level divisions.
[0101]
In this embodiment, the specific circuit configuration of the broken line portion in FIG. 9A is as shown in FIG. 9B, and is configured by an Op amplifier and resistors R01 and R02 at the subsequent stage of the integration circuit. A non-inverting amplifier circuit is formed, and R02 / R01 = 11, and the amplification factor at the subsequent stage is set to about 11 times.
[0102]
FIG. 1C shows an example of a sensor detection result for the paper type shown in FIG. 8A when such a signal processing circuit is used. In this example, the response signal of the sensor shown in FIG. 9C is substantially the same as the response signal of the sensor shown in FIG. 1C to which the subsequent amplification of the first embodiment is not added. FIG. 1 shows that only the signal level is enlarged about 11 times as it is, and there is no particular tendency for the S / N to decrease, and conversely, discrimination was performed with a weak signal level of 0.1 V or less. Compared to the case of (C), the threshold value setting in 1v unit is improved to a level that can be set, and the reliability of identification is remarkably improved.
[0103]
On the contrary, it becomes possible to subdivide the type of identification into a plurality of stages by using the above-mentioned characteristic by the latter stage amplification. For example, as shown by two broken lines in FIG. Since a threshold value can be set, and the signal level for extremely smooth paper (sheet) like OHT in the graph is sufficiently lower than 2v, it can be classified as very smooth paper.
[0104]
Conventionally, OHT has been fixed at a fixing temperature for plain paper including relatively light rough paper, and its fixing property was originally very good, but conversely with the recent increase in the speed of image forming apparatus devices. As the fixing temperature rises, the OHT temperature rises excessively, and at the same time, the time until it reaches the discharge tray from the fixing unit is shortened due to the higher speed of the apparatus. When the OHT on the paper tray is discharged at a high temperature, and a plurality of OHTs are continuously printed, the OHT is fused with the toner remelted at the high surface temperature of the OHT itself. Has occurred.
[0105]
On the other hand, the signal levels for other smooth papers fall within the range of 2v or more and less than 5v, and all the rough papers are 5v or more, and therefore can be classified into at least three types of smoothness.
[0106]
As a specific signal processing procedure at that time,
(1) Based on the signal from the paper tip sensor, a comparator that can output 2-digit binary data that is integrated from the surface roughness sensor to the passage of the center of the paper after the paper tip passes. take in.
[0107]
(2) Two types of threshold signals 2v and 5v are prepared in advance, and first, the signal of the 5v threshold signal source is compared with the integrated value.
(2-A) If the paper is rough paper, the integrated value is 5v or more, so the flag at that time is set to 11.
(2-B) If the paper is smooth paper, the integrated value is lower than 5v, so the threshold at that time is switched to 2v.
(2-C) If the paper is normal smooth paper, the integrated value is higher than 2v, so the flag at that time is set to 10.
(2-D) If the paper is very smooth, the integrated value is lower than 2v, so the flag at that time is generated as 00.
[0108]
(3) The CPU
(3-A) When the flag 11 is received, control is performed so that the fixing temperature is raised to the temperature for rough paper.
(3-B) When the flag 10 is received, the fixing temperature is controlled to be lowered to the smooth paper temperature.
(3-C) When the flag 00 is received, the fixing temperature is controlled to be further lowered to a very smooth paper temperature.
In this way, it can be controlled.
[0109]
In this case, in the initial state where the paper type is unknown, the temperature is set for fixing the rough paper, and after detection of the sensor,
(1) When it is determined that the paper is rough paper, fixing is performed with the fixing temperature as it is and a temperature control sequence for continuous paper passing.
[0110]
(2) When the paper is determined to be smooth paper, the fixing temperature is lowered to the smooth paper fixing temperature, and the temperature adjustment sequence for continuous paper feeding is also switched to the smooth paper fixing sequence.
[0111]
(3) When it is determined that the paper is very smooth paper, the fixing temperature is further lowered to a very smooth paper fixing temperature, and the temperature adjustment sequence for continuous paper feeding is also switched to the paper fixing sequence.
In other words, it is advantageous to handle rough paper with priority, and conversely, even if smooth paper is mistakenly detected as rough paper, only excess energy is consumed for a short period from the initial printing operation to the detection time of this sensor. Can be stopped by damage.
[0112]
In addition, the signal processing reliability of the present embodiment is more stable than that of the first embodiment, in particular, more stable characteristics against electrical noise. It is further improved in combination with being classifiable.
[0113]
By providing the sensor having the above signal processing function on the paper conveyance path of the paper feeding unit and the transfer unit in the electrophotographic laser beam printer according to the present example, an effect equal to or greater than that of the first example can be obtained. In addition, since it becomes possible to recognize very smooth paper such as OHT that can be fixed at a low temperature, it is possible to save the thermal energy that was wasted on these papers, and in the paper discharge unit, OHT It is also possible to prevent the occurrence of a problem that the toners are fused with each other.
[0114]
In each of the above-described embodiments, the threshold level of each component is determined according to the level of the identification signal integrated to the center of the paper for the sake of simplification. There is a possibility that the identification result of the first sheet may not be reflected in the fixing unit, and the second sheet is mainly for continuous printing (assuming that all the paper types are basically the same). There is a possibility that the function is limited to a function that optimizes the fixing control by feeding back the identification result to subsequent sheets. In practice, however, the integral signal processing method of the present invention does not necessarily integrate up to half of the paper, and the signal level difference necessary for distinguishing between rough paper and smooth paper is even in the integrated signal for scanning of about 20 mm at the leading edge of the paper. It is sufficiently formed (substantially similar to the integration time), and although it depends on the overall configuration, it is possible to reflect the detection result from the fixing control of the first sheet.
[0115]
(Example 3)
FIGS. 10A and 10B are a block diagram showing the configuration of the surface roughness detection signal processing system in the “laser beam printer” which is Embodiment 3, and an identification signal level and fixing temperature correlation graph.
[0116]
In this embodiment, all the preconditions are the same as those in the above-described embodiment, and as can be seen from FIG. 10A, a new A / D conversion circuit 31 is provided at the rear stage of the rear stage amplifier circuit section of the second embodiment. A configuration in which the digitized identification signal is directly taken into the CPU, and the fixing result is controlled by substituting the identification result into a fixing control type memory 32 provided in advance in the CPU without using a specific threshold or a comparator. Used.
[0117]
As this fixing control formula, for example, y = 8X + 160 having a correlation between the identification signal level and the fixing temperature as shown in FIG. 10B is used in this embodiment, and conventionally, conventional rough paper and plain paper including OHT are used. The fixing temperature for printing was 195 ° C. However, by using this embodiment, the fixing temperature is lowered to about 170 ° C. for very smooth paper having an identification signal level of about 1 v, which is compared with the conventional control. It can be reduced by about 25 ° C, and for smooth paper with an identification signal level of about 3v, the fixing temperature is about 185 ° C, which can be reduced by about 10 ° C from the conventional fixing temperature. For rough paper with a signal level of 6v or higher, the fixing temperature is controlled to rise to 205 ° C. or higher to ensure sufficient fixing performance.
[0118]
Also in this embodiment, in the initial state in which the paper type is unknown, the temperature for rough paper fixing is set, and after the detection of the sensor, the above-mentioned control finely adjusts the minimum necessary optimum fixing temperature according to the surface roughness of each paper type. Therefore, even if paper having any surface roughness is used, the minimum and sufficient amount of heat is supplied to the identification signal level corresponding to the roughness. Therefore, more efficient fixing can be realized for a wider range of paper types.
[0119]
By providing this sensor having the above signal processing functions on the paper feeding path of the paper feeding section and the transfer section inside the electrophotographic laser beam printer of this embodiment, it can be fixed at a very low temperature such as an OHT. From smooth paper to rough paper, the efficiency of saving thermal energy is further improved, and it is also possible to prevent the occurrence of harmful effects such as toner fusion between OHTs in the paper discharge section due to excessive heating. .
[0120]
In the present embodiment, as described above, the identification signal is substituted into the control equation and the control amount is calculated. However, the identification signal is classified into a plurality of predetermined stages, and is determined in advance for each stage. Even if the control is performed according to the control amount, the same result can be obtained.
[0121]
In addition, the signal level when paper is not passed by forming a discharge circuit in each integration circuit that performs the above integration processing in a hardware manner using an integration circuit and discharging the charge accumulated in the capacitor appropriately. In this embodiment, instead of this discharge circuit, a switch Sd controlled by the CPU as shown in FIG. Based on the result, the switch is turned off immediately before the surface roughness sensor unit starts scanning the paper surface and integration is performed for a desired time. Although the circuit configuration and CPU control may be slightly complicated, the integration power of the previous paper is added to the initial part of the identification signal of the subsequent paper during continuous paper feeding. Since possible to prevent the influence of remains, apparatus becomes valid configuration if wanted sequentially perform identification of each paper even during continuous printing when it is faster.
[0122]
Example 4
FIGS. 12A and 12B are a block diagram showing the configuration of the surface roughness detection signal processing system in the “laser beam printer” of Example 4, and a CPU calculation result graph of the identification signal level.
[0123]
In this embodiment, all the preconditions are the same as those in each of the above-described embodiments. As can be seen from FIG. 12A, an A / D conversion circuit 31 is provided instead of the integration circuit section of the first embodiment. The obtained identification signal is directly taken into the CPU, and the result of the integration calculation processing that takes the sum of each signal level taken every sampling period of the CPU during a predetermined period is used as the identification signal. A configuration is used in which the fixing device is controlled by using a threshold value in a threshold memory 25 ′ provided in advance in the CPU without using a fixing device.
[0124]
For example, in this embodiment, the sampling period of the CPU is 2 msec, and is input to the CPU every 2 msec just before the paper is conveyed to the surface roughness sensor unit based on the detection signal of the paper leading edge sensor. The signal addition is started, this calculation is repeated for 1 second, which is a scanning time corresponding to the scanning distance from the leading edge of the paper to the central portion of the paper, and finally the total value is used as the integrated identification signal result. Yes.
[0125]
As a result, the integration result of the identification signal is appropriately normalized so that the upper limit level of the signal is about 3.3 v, whereby the voltage integration value of the detection result for each sheet as shown in the bar graph of FIG. It was confirmed that the magnitude relation of the integration result that matches the smoothness of the paper was established.
[0126]
In this case, for example, by setting the threshold level to two types of 0.3 v and 1.3 v and storing them in the memory of the CPU, the paper having a very smoothness for signals less than 0.3 v. The paper of 0.3v or more and less than 1.3v can be identified as smooth paper, and the paper of 1.3v or more can be identified as rough paper, and the paper type can also be identified by the soft integration processing method according to this embodiment. Obviously, the integration circuit is not necessary as compared with the hardware integration method described above, and the configuration of the signal processing system can be simplified.
[0127]
Also in this embodiment, the scanning length of the paper surface does not need to be half of the paper, and almost the same identification performance can be ensured even by integration processing for a quarter of the total length of the paper. However, the reliability of the configuration of the present embodiment increases the reliability of the data as the amount of signals that can be sampled during the same scanning period is larger due to the restriction in principle, and conversely, it is necessary to process with a shorter scanning length, If the amount of signal that can be sampled during the same scanning period is insufficient due to an increase in the speed of the apparatus or the like, the detection accuracy tends to decrease.
[0128]
For this reason, it is not easy to make the sampling period shorter than 2 msec in a normal device configuration of this type. However, in the present embodiment, when it is necessary to further speed up the device or to identify the device in a shorter time, It is necessary to consider the configuration of the entire apparatus giving priority to satisfying the sampling period necessary for detecting the surface roughness.
[0129]
Using the CPU having the optimum sampling period while paying attention to the above points, the sensor having the above signal processing function is connected to the paper in the sheet feeding unit and the transfer unit in the electrophotographic laser beam printer of this embodiment. By providing it on the transport path, it is possible to save heat energy from very smooth paper such as OHT that can be fixed at low temperature to rough paper, and also the toner fusion between OHTs in the paper discharge section due to overheating. It is also possible to prevent the occurrence of harmful effects such as wearing.
[0130]
(Example 5)
13A to 13C are pre-processing signal waveforms, a signal processing block diagram, and identification signal level comparison results graphs for each paper type in the surface roughness detection signal processing system in the “laser beam printer” of Example 5. FIG. is there.
[0131]
In this embodiment, all the preconditions are the same as those in the above-described embodiments, but the number of times that a signal exceeding a predetermined threshold level is generated in the output signal before the integration processing as shown in FIG. It is characterized by identifying based on the difference between species.
[0132]
As can be seen from FIG. 13B, the sensor signal is directly input to the comparator via the amplifier circuit and compared with the first threshold value output from the threshold signal source 25, and the resulting flag is displayed on the CPU side. The CPU counts (accumulates) how many times one flag generated for a signal component equal to or greater than the threshold value is generated within a predetermined period during detection of each paper, A configuration is used in which the result of the number of times is identified by comparing with the threshold value of the number-of-times threshold value memory unit 25 ″ stored in advance to control the fixing device.
[0133]
For example, in the present embodiment, the first threshold for the signal generated by the sensor is set to 5v and compared with all the pulse signals generated on each sheet of FIG. 13A, and flag 1 is set for pulses exceeding this threshold. When the number of occurrences of flag 1 is counted by the CPU unit, a difference in the number of times as shown in FIG. As can be seen from this graph, by setting the threshold for the number of times, for example, 8 times, it is possible to realize identification that matches the smoothness of each paper, and an integration circuit is not required, so that the configuration of the signal processing system can be simplified. (Of course, if an A / D conversion circuit is used, all threshold comparisons can be processed only within the CPU).
[0134]
By providing this sensor having the above signal processing functions on the paper feeding path of the paper feeding section and the transfer section inside the electrophotographic laser beam printer of this embodiment, it can be fixed at a very low temperature such as an OHT. From smooth paper to rough paper, it is possible to save thermal energy, and it is also possible to prevent the occurrence of adverse effects such as toner fusion between OHTs at the paper discharge section due to overheating.
[0135]
In each of the above embodiments, a dedicated paper leading edge sensor is used to detect the paper leading edge position that is a reference for signal processing timing, but a signal is generated when the paper leading edge collides with the surface roughness sensor itself. Since the noise signal level during the period when the paper is not in contact with the surface roughness sensor is not 20% of the signal level when the leading edge of the smooth paper collides, the scanning information of a very small part of the leading edge of the paper is integrated. (Rather, the signal at the time of the front end collision does not reflect the surface roughness, so it is not necessary as a signal for identifying the paper type. Although it may be controlled not to capture the initial signal), it is sufficiently possible to use the surface roughness sensor itself as a paper leading edge detection sensor. The tip sensor may be omitted.
[0136]
However, in the configurations of the first to third embodiments in which a signal is input to the CPU through the integration circuit, the delay of the rising edge of the initial signal due to the integration may affect the detection accuracy. For example, in the case of the first embodiment, as shown in the example of the block diagram of FIG. 14, the amplified sensor signal is directly A / D converted and taken into the CPU. This method may be used.
[0137]
(Example 6)
FIG. 15 is a cross-sectional view illustrating a configuration of an “inkjet printer” according to the sixth embodiment.
[0138]
In the present embodiment, the S-shaped cross-sectional shape sensor 22 is used as the paper surface roughness detection sensor according to the present invention, and the configuration of the second embodiment is used as the configuration of the signal processing system of the inkjet printer 33 with a paper type detection function. It is composed. In this cross-sectional structure, the printer has a paper feed tray 34, an ink jet paper feed roller 35, a paper guide 36, a pinch roller 37, a pinch roller opposite conveying roller 37 ', a recording head 38, a platen 39, a paper discharge roller 40, and a spur 40. In general, after receiving a print signal, the paper on the paper feed tray 34 is conveyed to the pinch roller 37 by the paper feed roller 35 after receiving the print signal, and the necessary amount of paper is fed by the operation of the pinch roller 37. Is transported to 39 parts of the platen, an image is formed on the paper in the feed area by the opposing recording head 38, and then sequentially fed by the operation of the pinch roller 37 part, and the paper after recording is nipped and transported by the paper discharge roller part After the entire image formation is completed, the paper is finally discharged.
[0139]
In the present embodiment, the surface roughness sensor 22 is disposed at a position opposite to the paper guide 36 between the paper feed roller 35 and the pinch roller 37, and the paper leading edge from the initial stage of the printing operation is moved to the pinch roller. By scanning the surface of the paper until it is transported to 37 parts, the surface roughness or frictional resistance of the paper is detected to identify the paper type. For example, for smooth paper, the amount of ink protrusion is suppressed. By forming an image in this way, ink can be saved and bleeding of the ink to the unnecessary part can be suppressed. Conversely, for paper with a rough surface, the ink can penetrate into the lower layer of the paper in consideration of the ink penetration. It is possible to switch the control amount of image forming conditions such as ink discharge amount suitable for each paper type, such as by preventing the occurrence of problems such as density reduction by switching the control so as to increase the protrusion amount. There.
[0140]
In addition, as a sensor for this type of application, a device for identifying a paper type by detecting a difference in glossiness of the paper surface using an optical sensor has already been developed in some models. Requires a large number of components such as light sources, optical systems such as lenses and filters, and photoelectric conversion elements such as photodiodes and CCDs. Since the mounting accuracy is required, there is a problem that the cost is likely to be high, and further, the performance is easily influenced by dirt on the optical system.
[0141]
On the other hand, the sensor according to the present invention can be configured at a low cost with a general-purpose member in which sheet metal, piezoelectric elements, etc. are widely used. Even if dust or dirt adheres to other parts, the performance is basically not affected, and even if it happens, it will be shaken off by vibrations that occur, so there is a need to worry about performance degradation due to dirt. It is also excellent in terms of reliability.
[0142]
(Example 7)
FIG. 16 is a cross-sectional view showing a configuration of a “thermal head printer” as an embodiment.
[0143]
In the present embodiment, an S-shaped cross-sectional shape sensor 22 is used as a paper surface roughness detection sensor according to the present invention, and the configuration of the second embodiment is used as the configuration of the signal processing system thereof. Is configured. The thermal head printer 41 of this embodiment includes an ink ribbon 42, a pair of ink ribbon transport rollers 43, a thermal head 44, a head facing plate / paper transport guide 45, and the like. The paper is transported to the nip portion between the head facing plate / paper transport guide 45 and the ink ribbon transport roller 43 on the paper feed side by the paper feed roller and paper transport roller shown in the figure, and after being sandwiched between the ink ribbon 42 and the guide 45 The ink ribbon 42 is conveyed to the head 44 together with the ink ribbon 42 while being in close contact with the ink ribbon 42, and necessary power is supplied to the head 44 according to the print signal to heat and melt the ink layer 42 a on the ink ribbon 42. After the ink image 42b is formed on the paper surface by transferring it to the paper surface, And it is configured to be issued.
[0144]
In this embodiment, the sensor 22 is disposed at a position opposite to the guide portion 45, at least before the nip portion of the guide 45 portion and the ink ribbon transport roller 43 on the paper feeding side, and from the paper feeding portion in the initial printing operation to the paper leading end portion. By detecting the surface roughness or frictional resistance of the paper by scanning the surface of the paper until it is conveyed to the nip portion, the paper type is identified. Since the thermal transfer can be performed with low power to improve the quality, the control is switched to reduce the power supplied to the ink head. Conversely, when the paper has a rough surface, the thermal conductivity is reduced and the rough surface is sufficient. In order to transfer the ink, it is necessary to lower the viscosity of the ink. Therefore, it is possible to switch the control so that the viscosity of the ink is sufficiently reduced with higher power. It is possible to switch the control amount.
[0145]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a surface property identification apparatus that can reliably identify the surface roughness and the like of a recording material in a stable state with very little identification error. Further, by using this surface property identification apparatus, it is possible to provide an image forming apparatus that does not require the user to select and set the paper type, and can perform good fixing and image formation regardless of the surface roughness of the paper. .
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a signal processing system according to a first embodiment.
FIG. 2 is an explanatory diagram of a conventional image forming apparatus.
FIG. 3 is a flowchart showing a conventional fixing process.
FIG. 4 is a diagram showing a change in temperature control temperature according to a conventional paper type and the number of paper passing
FIG. 5 is a diagram showing a configuration of a conventional surface roughness detection sensor.
FIG. 6 is an explanatory diagram of detection results obtained by a conventional surface roughness detection sensor.
FIG. 7 is a diagram showing a configuration of an improved surface roughness detection sensor
8 is a view showing a detection result by the detection sensor of FIG. 7;
FIG. 9 is an explanatory diagram of a signal processing system according to the second embodiment.
FIG. 10 is an explanatory diagram of a signal processing system according to the third embodiment.
FIG. 11 is a circuit diagram showing a modification of the integrating circuit.
12 is an explanatory diagram of a signal processing system in Embodiment 4. FIG.
13 is an explanatory diagram of a signal processing system in Embodiment 5. FIG.
FIG. 14 is a block diagram showing a configuration of a signal processing system in which a paper leading edge sensor is omitted.
FIG. 15 is a sectional view showing the structure of Example 6;
FIG. 16 is a sectional view showing the structure of Example 7;
[Explanation of symbols]
19 Piezoelectric element
22 Surface roughness sensor
24 Integration circuit

Claims (9)

By scanning the tip of a probe having a piezoelectric element while contacting the surface to be measured, a pulsed electric signal is generated from the piezoelectric element, and the surface property of the surface to be measured is determined based on the intensity difference of the electric signal. A surface identification device for identifying,
Have integration processing means said pulsed electrical signal integration process occurring within a predetermined time, characterized in that the identification signal integration result of the integration process,
The probe having the piezoelectric element has a scanning direction vibrating portion that can vibrate by repeatedly deforming and restoring in the scanning direction at the tip of the contact side of the probe, and is placed on the surface of the object to be measured against the scanning direction. It is in contact with an angle and applied pressure that enables scanning while biting within an intensity range that does not hinder scanning,
The scanning direction vibration portion includes a first bent portion and a second bent portion bent in a direction opposite to the first bent portion in the order from the side close to the non-contact side end of the probe toward the contact side end. Processed so that the cross-sectional shape of the probe is S-shaped when viewed from a cross-section perpendicular to the scanning plane and parallel to the scanning direction when there are two bent portions and the upstream side in the scanning direction is set to the right side of the page. The surface property identification device characterized by the above-mentioned .   2. The surface property identification apparatus according to claim 1, wherein the probe having the piezoelectric element has a counter contact side end on a rotating shaft having an axial direction above the scanning plane and parallel to the scanning plane and having an axial direction perpendicular to the scanning direction. A surface property identification apparatus, wherein the probe tip is fixed and pressed against the surface of the object to be measured by a pressure means in a state of being rotatable about the rotation axis. 2. The surface property identification apparatus according to claim 1, wherein the integration processing means uses an amplification circuit and an integration circuit, and obtains an integration result after the signal generated by the piezoelectric element is guided to the integration circuit through the amplification circuit. The surface property identification device according to claim 1, wherein the integration circuit comprises an integration circuit unit in which an integration resistor R1 and an integration capacitor C1 are connected in series . 4. The surface property identification apparatus according to claim 3 , wherein a second amplifier circuit is provided after the integrating circuit, and the integration result is adjusted to a desired signal level by the second amplifier circuit and output. A surface identification device. 4. The surface property identification apparatus according to claim 3 , wherein a discharge resistor Rd is provided in parallel with the integration capacitor C1 of the integration circuit unit, and the integration result by the integration circuit unit is detected by setting so as to satisfy R1 <Rd. A surface identification device that self-discharges at a desired rate. 4. The surface property identification apparatus according to claim 3 , wherein a switching circuit is provided in parallel with the integration capacitor C1 of the integration circuit unit, and an integration period and a discharge period in the integration circuit unit are set at a desired timing by a CPU of the apparatus control unit. A surface property identification device characterized by being switchable. 2. The surface property identification apparatus according to claim 1, wherein an integration circuit, an A / D conversion circuit, and a CPU are used as the integration processing means, and a signal generated by the piezoelectric element is passed through the amplification circuit and the A / D conversion circuit. A surface property identification device characterized in that an integration result obtained by guiding the CPU to the CPU and performing integration calculation processing is used as an identification signal. In the surface property identification device according to any one of claims 1 to 7, as a reference signal comprising a signal processing timing reference in the identification signal processing, surface properties, which comprises using a head signal detected from the probe Identification device. And surface property identification device according to any one of claims 1 to 8, and an image forming means for forming a toner image on a recording material having passed through the surface of the identification device, a recording material on which the toner image is formed An image comprising: fixing means for fixing the toner image on the recording material by heating and pressing; and control means for controlling fixing conditions of the fixing means in accordance with an identification signal of the surface property identification device. Forming equipment.

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