JP2017173776A - Image forming apparatus and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can suppress the occurrence of an abnormal image due to adherence of toner without reducing the lives of a fixing member and a pressure member.SOLUTION: An image forming apparatus comprises: a fixing device that brings a fixing member and a pressure member into contact with each other to fix a toner to a print medium; a rotational load providing member that provides a rotational load to the fixing member or the pressure member; a data acquisition part that acquires the amount of calcium carbonate on the front face and rear face of the print medium from a database including at least the product name of plain paper and the amount of calcium carbonate on the front face and rear face of plain paper; and a condition determination part that determines the rotational load provided by the rotational load providing member according to the amount of calcium carbonate on the front face and rear face of the print medium.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an image forming apparatus and an image forming method.

  Image forming apparatuses such as copiers, printers, and facsimiles form a toner image based on image information on an image carrier, transfer the toner image onto a recording material such as paper or an OHP sheet, and carry the toner image. The recorded material is passed through a fixing device, and the toner image is fixed on the recording material by heat and pressure. One of the fixing methods is a “heat roller method”.

  The “heat roller type” fixing device forms a nip portion with a fixing roller heated by a heating source such as a halogen heater and a pressure roller, and passes a recording material carrying an image through the nip portion, thereby applying heat and pressure. To melt and fix the toner. The heat roller method is inexpensive and widely used in monochrome machines from the viewpoint of safety and compatibility with high-speed machines.

  On the other hand, the toner is melted by heat and can penetrate between the fibers of the recording paper. At the same time, it easily adheres to the fixing roller. Further, when the toner is melted and the adhesion force to the fixing roller or the fixing belt becomes larger than the adhesive force to the paper, the melted toner is transferred from the recording paper to the fixing roller or the fixing belt and becomes an offset. In the case of the heat roller system, the transferred offset toner adheres to the temperature sensor such as the surface of the fixing roller, the separation claw, and the thermistor, and the adhered toner re-adheres to the recording paper, so-called black spots are generated and the image is May be soiled.

  The difference between the toner re-adhering toner generation and the fixing property to the fixing roller or fixing belt due to the difference in toner physical properties is large, and the influence of the filler contained in the paper is also large. In particular, when a paper containing heavy calcium carbonate prepared by a pulverization method is used as a filler, the fixing of the toner and the fixed matter formed by the heavy calcium carbonate or the fixing property to the pressure roller is poor. It tends to occur as an abnormal image including the black spots. Further, as the toner, the deterioration is remarkable in the toner having poor offset property.

  As a printed image, a white background toner is poor in both offset and fixing properties. On the other hand, the pre-stage fixed toner generated on the fixing roller is discharged onto the paper together with the unfixed toner by a self-cleaning effect. The effect is greater as the image area ratio is higher, and toner sticking is less likely to occur. The precursor stage is a stage where the toner is not larger than a size that can be visually confirmed, and is a stage where, for example, toner of about 1 mm or less is fixed.

In view of such problems, for example, in Patent Document 1, the toner adhering to the fixing roller or the pressure roller is cleaned by abutting and rubbing the cleaning web against the fixing roller or the pressure roller.
In Patent Document 2, by applying a predetermined load torque to the driven rotating fixing roller, a minute speed difference is generated between the fixing roller and the pressure roller, and the wax adhering to the surface of the fixing belt is removed. A technique for preventing the occurrence of uneven glossiness by cleaning is disclosed.

  However, Patent Documents 1 and 2 do not include a mechanism for determining an operation based on paper information to be passed. For this reason, even when the calcium carbonate content of the paper to be passed is small and the possibility of toner sticking is low, the cleaning web is driven and the load applying means is operated, There is a possibility of reducing the life of the pressure member.

  The present invention has been made in view of the above, and provides an image forming apparatus capable of suppressing the occurrence of an abnormal image due to toner fixation without reducing the life of a fixing member or a pressure member. With the goal.

  In order to solve the above-described problems, an image forming apparatus according to the present invention includes a fixing device that contacts a fixing member and a pressure member to fix toner on a print medium, and a rotational load on the fixing member or the pressure member. A data acquisition unit for acquiring the amount of calcium carbonate on the front and back surfaces of the print medium from a database having at least a product name of plain paper and a calcium carbonate amount on the front and back surfaces of the plain paper; And a condition determining unit that determines a rotational load of the rotational load applying member in accordance with the amount of calcium carbonate on the front surface and the back surface of the print medium.

  According to the present invention, it is possible to suppress the occurrence of an abnormal image due to toner fixation without reducing the life of the fixing member or the pressure member.

It is a figure which shows an example of the SEM photograph in the front surface and back surface of plain paper. It is a schematic diagram for demonstrating ATR method. It is a figure for demonstrating the difference in the penetration depth of the sample by the difference in the crystal in ATR method. It is a figure which shows an example of the spectrum acquired by ATR method. FIG. 5 is a diagram illustrating an example of conditions for obtaining peak areas A and B in the spectrum of FIG. 4. FIG. 3 is a schematic diagram illustrating an example of a fixing device. FIG. 10 is a schematic diagram illustrating another example of a fixing device. It is a schematic diagram which shows an example of a rotational load provision member. 1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. It is a figure which shows an example which plotted A / B with respect to calcium carbonate / cellulose (weight ratio). It is a figure which shows an example which plotted A / B with respect to the calcium carbonate density | concentration. It is a figure which shows an example which plotted the calcium carbonate density | concentration with respect to the applied pressure in ATR method. It is a figure which shows an example which plotted calcium carbonate concentration (ATR method) and calcium carbonate concentration (JIS method).

  Hereinafter, an image forming apparatus and an image forming method according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art, and any aspect is possible. As long as the functions and effects of the present invention are exhibited, the scope of the present invention is included.

  An image forming apparatus of the present invention includes a fixing device that contacts a fixing member and a pressure member to fix toner on a print medium, and a rotation load applying member that applies a rotation load to the fixing member or the pressure member. A data acquisition unit for acquiring calcium carbonate amounts on the front and back surfaces of the print medium from a database having at least product names of plain paper and calcium carbonate amounts on the front and back surfaces of the plain paper; And a condition determining unit that determines a rotational load of the rotational load applying member in accordance with the amount of calcium carbonate.

In the following, the details will be described. However, a predetermined amount of calcium carbonate on the surface of plain paper different from the conventional one is used in the database, and the rotational load is applied to the fixing member or the pressure member according to the amount of calcium carbonate of the print medium to be passed. The inventors have found that the desired effect can be obtained by determining the rotational load of the rotational load imparting member to be imparted, and have reached the present invention.
Hereinafter, the “calcium carbonate amount” occupying the front or back surface of plain paper (solid) will be referred to as “calcium carbonate concentration”.

  First, the premise of the present invention will be described with reference to a conventional method for obtaining the amount of calcium carbonate (calcium carbonate concentration). Plain paper basically consists of cellulose and filler, which are paper fibers. The filler is incorporated into the paper in order to give whiteness to the plain paper and make it difficult to see through, and to give the smoothness and flexibility of the surface of the plain paper. As the filler, kaolin, talc, calcium carbonate, etc. are used, but recently, due to the trend of paper neutralization, calcium carbonate, which is low in cost and excellent as a filler, is mainly used.

  If plain paper is sufficient for plain paper and is not transparent, it is not necessary to use so much calcium carbonate. However, to reduce costs, plain paper with a small amount of cellulose produces a large amount of calcium carbonate. It has been inserted. In addition, plain paper made from coniferous trees is thicker and longer than hardwood, so the strength of plain paper can be increased, but the unevenness of the surface of plain paper is larger than that of hardwood, so there is much calcium carbonate. It is necessary to incorporate it.

  In image formation in the electrophotographic system, a toner image is transferred onto plain paper and the toner is fixed in a fixing process. The photoreceptor (direct rotation system), the intermediate transfer member, the conveyance belt, and the fixing member of the image forming apparatus are in contact with the plain paper every time the image is formed, and the plain paper is pressed. Since the photoconductor, intermediate transfer belt, conveyance belt and fixing member are basically organic substances, they are softer than calcium carbonate.When image formation is repeated, calcium carbonate on the surface of plain paper can damage or bite the member. May cause malfunctions. Of course, the probability of occurrence of defects is more likely to occur in plain paper with more calcium carbonate.

Image forming equipment manufacturers know that plain paper with a lot of calcium carbonate is prone to problems, so we recommend plain paper with a low calcium carbonate as the recommended paper and develop the equipment based on that plain paper. , The user was strongly requested to use the recommended paper.
However, due to the demand for cost reduction for image formation, users are increasingly using inexpensive plain paper instead of recommended paper. In particular, most inexpensive plain papers are sold for use in PPC (Plain Paper Copier) by reducing high-cost cellulose and increasing low-cost calcium carbonate. These plain papers containing a large amount of calcium carbonate are white, and since image formation is often performed without any problems at the beginning, users have come to use it favorably.

  Also, plain paper rich in calcium carbonate generally has a large difference in the amount of calcium carbonate between the front and back surfaces of plain paper. Plain paper is produced by making pulp, which is obtained by dispersing cellulose, filler, etc. in water, on a net. When the paper is drawn on the net, the calcium carbonate tends to flow down on the net side, so the amount of calcium carbonate is usually different between the front and back of the plain paper. If the total amount of calcium carbonate is large, the front and back The difference in the amount of calcium carbonate increases.

  As an example, FIG. 1 shows SEM (scanning electron microscope) photographs of the front and back of the same plain paper. FIG. 1 is an SEM image of the surface of HAMMERMILL COLOR COPY DIGITAL (plain paper, made by INTERNATIONAL PAPER). As shown in the figure, it can be seen that the amount of calcium carbonate differs greatly between the front and back of plain paper.

  The amount of calcium carbonate on the surface of plain paper greatly affects the whiteness of plain paper, and also affects the mechanical properties for the environment and the lubricity of the surface. If there is a large difference in the amount of calcium carbonate between the front and back, the plain paper after image formation may curl, and this tendency may increase when image formation is performed on both sides of the plain paper. .

  If the plain paper on which image formation is performed is constant, the manufacturer of the image forming apparatus can perform an image forming method having both quality and durability on the plain paper. However, there are many types of plain paper currently on sale, and the user uses the purchased plain paper each time, so the regular paper is not always used.

  For this reason, image forming apparatus manufacturers always collect information on plain papers on the market and accumulate information on each plain paper. In particular, as described above, since there are many cases of troubles due to calcium carbonate, data on the amount of calcium carbonate is accumulated.

  As a method for quantifying calcium carbonate in plain paper as a whole, a method of measuring the amount of ash that has been burned with ordinary JIS P 8251 and converting it to calcium carbonate is widely used. However, in this method, only the amount of calcium carbonate in the entire plain paper is known, and the amount of calcium carbonate on the front and back sides is unknown.

  As another analysis method, there is a method of quantifying Ca in plain paper by fluorescent X-ray analysis (XRF) and converting it into calcium carbonate, but the analysis area is deep and all the thickness direction of plain paper is measured. Therefore, the amount of calcium carbonate only on the plain paper surface cannot be measured.

  Another possible method is to measure the amount of Ca by energy dispersive X-ray spectroscopy (EDS / EDX) on the surface of plain paper and convert it to the amount of calcium carbonate. However, since the measurement region (area) is very narrow, the variation in the measurement values at the measurement points is extremely large, and the amount of calcium carbonate on the surface of plain paper cannot be presented.

  In the analysis by infrared spectrophotometry (IR), the ATR method (total reflection method) has been used as a surface analysis. In the ATR method, when the sample is brought into contact with the ATR crystal and the IR light entering from the crystal side is totally reflected at the crystal interface, the IR light is absorbed when the IR light slightly exudes to the sample side, and the IR spectrum is can get. FIG. 2 shows a schematic diagram for explaining the ATR method.

  In particular, when Ge is used for the crystal, since the penetration depth of IR light is only 0.2 to 0.8 μm, the deposits that are thinly attached to the sample surface can be quantified (Japanese Patent No. 5555997). No. 5470902). The ATR method is also used for measuring the abundance ratio of the wax on the toner surface (Japanese Patent No. 5546271).

JP 2010-117586 also discloses relative calcium carbonate on the paper surface from the ratio of the peak area of 1421 cm ⁻¹ of calcium carbonate and the peak height of 1036 cm ⁻¹ of cellulose in the IR spectrum measured by the ATR method. A method of evaluating automatically is disclosed.
However, the amount of calcium carbonate disclosed in Japanese Patent Application Laid-Open No. 2010-117586 is only the ratio of the respective peak heights, and specifically quantifies the amount of calcium carbonate present on the surface of plain paper. is not. Moreover, although the value of each peak height ratio disclosed in Japanese Patent Application Laid-Open No. 2010-117586 can evaluate the vertical relationship when the amount of calcium carbonate on the plain paper surface that is actually present is overwhelmingly different, Even on the same side of plain paper, the ratio of the peak height of the IR spectrum was very large and varied and did not become constant.

  This is because, as shown in FIG. 1, the surface of the plain paper is severely uneven and has no flat surface. Therefore, the area of the plain paper to be measured is shallow at the penetration depth of IR light in the ATR method. Further, in the method disclosed in Japanese Patent Application Laid-Open No. 2010-117586, the pressure applied when the plain paper and the crystal are brought into contact is not defined. There will be a gap between the crystal and the crystal. For this reason, the depth at which IR light actually enters the plain paper changes, and the ratio of peak heights varies.

In addition, since the penetration depth of IR light by the ATR method changes depending on the wave number of IR light, if the wave numbers of the two peaks of the IR spectrum of interest are separated, a gap is likely to occur between plain paper and the crystal. In some cases, the depth at which IR light actually penetrates plain paper varies greatly with each wave number. For this reason, the peak ratio varies greatly, and it cannot be used as an index of calcium carbonate on the surface of plain paper. Thus, there has been a problem in quantifying calcium carbonate on the surface of plain paper by the ATR method.
For the reasons described above, the amount of calcium carbonate on each of the front and back sides of plain paper has a great influence on image formation, but the calcium carbonate concentration has been obtained only for the whole plain paper.

On the other hand, how to obtain the amount of calcium carbonate in the present invention will be described.
In consideration of the above problems, the present inventor conducted a qualitative analysis by the ATR method using Ge as a crystal, which is commonly used as a deposit on the surface of plain paper. It was found that although the maximum absorbance of the IR spectrum varies depending on the measurement location, the overall shape does not vary greatly.

Therefore, when diamond with a deep penetration depth of IR light was used for the crystal, it was found that the variation in absorbance at each measurement was smaller than when Ge was used for the crystal.
Since diamond, which is a crystal, is overwhelmingly harder than Ge, it is possible to press the sample more strongly against the crystal than in the case of Ge. Therefore, when the pressure to press the sample against the crystal was gradually increased, it was found that the IR spectrum was almost stable at 80 N or more.
In particular, it has been found that the ratio of the peak area of 873 cm ⁻¹ as the IR peak of calcium carbonate and the peak area of 897 cm ⁻¹ as the IR peak of cellulose is almost constant as long as they are the same surface of the same paper.

Furthermore, various ratios of the peak area of peak area and 897cm ^-1 of 873cm ^-1 for plain paper, the above-mentioned (JIS P 8251) the concentration and good correlation of calcium carbonate obtained from plain paper of the combustion ash is obtained It was found that the calcium carbonate concentration on the surface of plain paper can be quantified by the ATR method. As a result, it was found that very important data such as calcium carbonate concentration on the surface of plain paper, which was not in the conventional database, can be added to the database, and the present invention has been achieved.

  That is, in the present invention, the amount of calcium carbonate on the front and back surfaces of the printing medium is obtained from a database of plain paper information having at least the product name (product name (model number)) of plain paper and the amount of calcium carbonate on the front and back surfaces of plain paper. To do. Note that the database may have other information such as a manufacturing company name as necessary, and preferably has a manufacturing company name, a lot number, a registration date, and a data registration number.

  The calcium carbonate concentration on the plain paper surface is recorded in the database on the front and back surfaces. Ordinary paper is usually packaged in many cases, and the unsealed surface when the package is unsealed is called the front surface, and the back surface is called the back surface. However, as long as the data in the database is unified, it does not matter.

  In the present invention, the calcium carbonate concentration on the surface of plain paper is determined by measuring either diamond, ZnSe, or diamond / ZnSe as a crystal in the ATR method, and bringing the crystal and plain paper into close contact at a pressure of 80 N or more. The calcium carbonate concentration on the surface of the plain paper is calculated from the peak area derived from calcium carbonate and the peak area derived from cellulose in the IR spectrum obtained thereby.

  In the method for quantifying calcium carbonate on the surface of plain paper, diamond, ZnSe, or diamond / ZnSe is used as the crystal. These crystals have a refractive index of 2.4. The penetration depth of IR light by the ATR method can be calculated from the refractive index of the sample and the incident angle of the IR light. FIG. 3 shows a graph for explaining the penetration depth of IR light. In FIG. 3, the calculation is performed assuming that the refractive index of the sample is 1.5. As shown in the figure, the penetration depth of IR light is larger in diamond and ZnSe than in Ge.

Since the surface of plain paper has no smooth surface and is very uneven, it is preferable that the penetration depth of IR light is as deep as possible in order to stably quantify the concentration of calcium carbonate. In a crystal of diamond, ZnSe, or diamond / ZnSe, the penetration depth of IR light is deeper than that of Ge, and the penetration depth is particularly preferably 2 μm or more on the lower fraction side than 1000 cm ⁻¹ . Since the thickness of plain paper is usually 90 to 180 μm, the penetration depth of the IR light is very shallow compared to the thickness of plain paper, and it can be seen that the measurement area is only on the plain paper surface.

  In the method for quantifying calcium carbonate on the surface of plain paper, the incident angle and the number of reflections of IR light in the ATR method are not particularly limited as long as the IR spectrum can be measured stably, but the incident angle of the ATR apparatus is 45 °. This is preferable because the manufacturing cost is the lowest and a stable IR spectrum can be obtained. When the number of reflections is a plurality of times, the IR spectrum may vary at the measurement location, and thus one reflection is preferable.

  In the method for quantifying calcium carbonate on the surface of plain paper, the pressure applied when pressing the plain paper against the crystal is very important. If the measurement location is exactly the same, the same IR spectrum can be obtained if the applied pressure is the same. However, even at the same measurement location, the IR spectrum changes when the applied pressure is changed, and the change is large especially when the applied pressure is weak. This is because, if the pressure is weak, a gap is generated between the plain paper surface and the crystal. Therefore, the gap between the plain paper surface and the crystal on the plain paper surface is subtracted from the penetration depth of the IR light in FIG. This is because it is possible to measure only the area.

  For this reason, the IR spectrum can be measured more stably as the pressure applied when pressing the plain paper against the crystal is stronger. However, if it is too strong, there is a risk of damaging the ATR device. Therefore, it is necessary to select a pressing force that does not break the apparatus and that provides a stable IR spectrum. A specific pressure is 80 N or more, preferably 90 to 150 N, and more preferably 95 to 120 N. If the applied pressure is weaker than 80N, the IR spectrum tends to change.

  In the quantitative method of calcium carbonate on the surface of plain paper, from the IR spectrum obtained by the ATR method, from the ratio A / B of the peak area (A) caused by calcium carbonate and the peak area (B) caused by cellulose, calcium carbonate Calcium carbonate on the surface of plain paper can be quantified.

The peak of calcium carbonate used in the method for quantifying calcium carbonate on the surface of plain paper may be any peak as long as it has a wave number with no peak in the IR spectrum of cellulose. The peak of cellulose used in the method for quantifying calcium carbonate on the surface of plain paper may be any peak as long as there is no peak in the IR spectrum of calcium carbonate.
However, since the penetration depth of IR light in the ATR method is dependent on the wave number as described above, the peak pair of calcium carbonate and cellulose used in the calcium carbonate determination method is a peak pair having a wave number close to that. It is preferable to choose. This is because the ratio A / B between the peak area (A) due to calcium carbonate and the peak area (B) due to cellulose is the ratio of the amount of calcium carbonate and cellulose in the region of the same depth. This is because B tends to be a stable value.

  An example of a spectrum obtained by the ATR method on the surface of plain paper is shown in FIG. In addition, FIG. 5 shows an example of a baseline and a region used for calculating each peak area. As the IR peak specifically used, each IR peak shown in FIG. 4 is most preferable.

4 and 5, the peak area A, an area for obtaining the B respectively, about 879～867Cm ^-1, has a 904~890cm ^-1. The method of taking the baseline and area can be changed as appropriate, but the baseline draws a common tangent near the local minimum on both sides of the peak, and the difference between the baseline and the peak drops to about half. Calculate the area until. The area shown in FIG. 5 is not changed even in another sample. Since the peak due to calcium carbonate and the peak due to cellulose appear nearby, the peak areas A and B can be obtained from one baseline.

Each peak when calculating the A / B value is close to the wave number and the penetration depth of the IR light is very close. Therefore, even for uneven plain paper, the peak area of each peak is relative A / B, which is the ratio thereof, is almost a constant value.
A / B correlates with the ratio of the weight of calcium carbonate to the weight of cellulose in the measurement region (plain paper surface). Therefore, even with only the value of A / B, a relative comparison of the plain paper surface can be performed. In order to set the A / B value to a specific calcium carbonate concentration (wt%, calcium carbonate / (calcium carbonate + cellulose) × 100), plain paper with a known weight ratio of calcium carbonate to cellulose on the surface A calibration curve is made by measuring A / B of the paper, and converted to calcium carbonate concentration, the calcium carbonate concentration on the surface of plain paper can be quantified.

  However, it is difficult to prepare plain paper with a known weight ratio of calcium carbonate to cellulose on the surface. Therefore, commercially available calcium carbonate powder and cellulose powder can be sufficiently mixed, and this mixed powder can be used as plain paper having a known weight ratio of calcium carbonate to cellulose on the surface.

  Even if the crystal and incident angle in the ATR method are the same, the IR spectrum is measured slightly differently by the measuring device. Since the measurement conditions (measurement wave number region, interval, applied pressure) cannot be made completely the same by the measurement device, it is preferable to create a calibration curve in each measurement device. Also, it is preferable to re-create a calibration curve during maintenance of the measuring apparatus. If the measurement conditions are constant, the amount of calcium carbonate is an accurate value.

  Ordinary paper is usually sold in a state of being wrapped in one wrapping paper, for example, every 500 sheets. The wrapping paper is folded and sealed with plain paper, and is bonded and sealed at the center of one side of the plain paper. The user opens the wrapping paper with the bonded side up, and sets plain paper in the image forming apparatus in that state. Therefore, the surface where the wrapping paper is bonded is defined as the front surface, and the wrapping paper is bonded. The surface that does not exist is defined as the back surface.

In the plain paper database, in addition to the calcium carbonate concentration on the plain paper surface, there are values measured by existing methods such as basic weight, thickness, density, smoothness, air permeability, static friction coefficient, etc., which are basic characteristics. While it is very useful, there is no need for all data.
In addition, as physical strength characteristics of plain paper, there are values measured by existing methods such as Clar stiffness, bending stiffness, SST longitudinal fiber orientation, lubrication tensile strength, anti-refraction, surface strength, internal bond strength, etc. Very useful, but not all data.

  Furthermore, it is very useful to have values measured by existing methods such as ISO whiteness, ISO opacity, color tone, fluorescence intensity, glossiness, haze degree, etc. as optical characteristics, but there is no data. Also good.

As electrical characteristics, if there are values measured by existing methods such as surface resistance, volume resistance, etc., it is very useful, but there is no need for all data.
The water characteristics are very useful if there are values measured by existing methods such as moisture, squeecht sizing degree, cup water supply degree, water immersion elongation, etc., but there is no need for all data.
It is very useful if there are values measured by existing methods such as ash, filler type, paper surface pH, etc. as component characteristics, but not all data is required.
It is very useful to have a value measured by an existing method such as raw curl, open curl, cut rank, dust, etc. as product characteristics, but not all data is required.
A database in which the above data is linked to one plain paper and stored in each plain paper is a database that is very useful when performing image formation using each plain paper. Become.

Even if plain paper has the same product name from the same manufacturer, the value in the database is preferably updated because it is not always constant.
By identifying the plain paper used by each user from these databases and setting image forming conditions suitable for each plain paper, a high-quality image can be formed over a long period of time.

  The plain paper database is stored in a storage device built in the image forming apparatus or an external storage device via the Internet or the like, and data is obtained and used according to the plain paper used by the user.

As a method for the image forming apparatus to recognize plain paper used by the user, a user or a service person inputs. Input can be performed by reading with a barcode, an IC chip or the like in addition to input with a touch panel or the like.
Note that if the print medium to be imaged is not in the database, it is assumed that it will not occur unless it is special plain paper. However, if data cannot be obtained from the database, for example, it can be set manually by the default value. It is preferable that the setting is applied.

(Fixing device)
<One Embodiment of Fixing Device>
Next, a fixing device included in the image forming apparatus of the present invention will be described. In the fixing device, the fixing member and the pressure member are brought into contact with each other to fix the toner to the print medium. A configuration of an embodiment of the fixing device according to the present invention will be described.
First, a configuration in which a heat roller system is adopted for the fixing device will be described. The fixing device according to the present embodiment includes a hollow cored bar and a release layer, and includes a fixing roller having a heat source therein, and an elastic layer that is disposed in pressure contact with the fixing roller and rotates by the rotation of the fixing roller. And a pressure roller.

  FIG. 6 is a schematic diagram of the fixing device according to the present embodiment. FIG. 6 is a diagram showing a configuration of the fixing device 12 adopting a heat roller system. As shown in FIG. 6, the fixing roller 28 of the fixing device 12 forms a nip with a pressure roller 30 on the outer periphery of a metal core made of stainless steel, aluminum, or the like. A release layer is provided in order to improve releasability.

  For the release layer, a material having heat resistance and low surface energy is used. For example, silicone resin, fluororesin, for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), It is used as a heat-resistant tube made of a polymer resin such as tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

  To the surface layer, 10% by mass of an anti-wear additive such as carbon or SiC is added in order to further secure the wear resistance. When the additive is added in an amount of 3% by mass or more, sufficient abrasion resistance can be obtained. On the other hand, when the additive is added in an amount of 20% by mass or more, the ratio exposed on the surface of the fixing roller 28 increases, and the toner releasability may deteriorate.

  Further, a heat source 33 such as a halogen heater for accelerating the temperature rise of the fixing roller 28 is disposed in the core of the fixing roller 28. The heat source 33 is not limited to the halogen heater, and induction heating or a planar heating element may be used.

  The pressure roller 30 has an appropriate thickness of an elastic layer made of a heat-resistant elastic material such as fluorine-based rubber or silicone rubber on the outer periphery of a metal core such as stainless steel or aluminum. A release layer made of fluorine resin or the like is provided. The pressure roller 30 is pressed against the fixing roller 28 by a pressure member such as a spring (not shown), and pressurizes the toner with the fixing roller 28 for a certain period of time by elastically deforming the elastic layer. -Form a nip portion N that can be heated.

  Further, a separation claw 34 for peeling the fixed transfer paper is installed in contact with the fixing roller. The separation claws 34 may be arranged at several places in the fixing roller axial direction as needed. The surface of the separation claw 34 is formed of a polymer resin such as PTFE, PFA, or FEP in order to suppress toner sticking.

  Further, in order to control the heaters such as the fixing roller 28 and the pressure roller 30, a temperature sensor 36 such as a thermistor is provided to detect the temperature of each member, and the temperature is controlled by a heating controller that is a heating control means. The The fixing set temperature in this embodiment is set to 160 ° C. from the results of toner viscoelasticity and fixability tests.

<Other Embodiments of Fixing Device>
Next, other embodiments of the fixing device will be described. In this embodiment, the fixing device is a belt fixing type. The fixing device according to the present embodiment includes a heating rotator that is heated by a heating source, a fixing rotator that is arranged in parallel to the heating rotator, and an endless loop that is looped between the heating rotator and the fixing rotator. And a pressure rotator that presses the fixing rotator through the fixing belt.

FIG. 7 is a schematic diagram of the fixing device according to the present embodiment. The belt fixing system includes a flexible endless fixing belt 251 and a pressure roller 252, a fixing roller 253, a heating roller 254, and a halogen heater 25.
The fixing belt 251 is supported by a fixing roller 253 and a heating roller 254.

The fixing roller 253 has an elastic layer 42 formed on a cored bar 41.
Although it does not specifically limit as a material which comprises the metal core 41, Metal materials, such as stainless steel and aluminum, are mentioned.
The material constituting the elastic layer 42 is not particularly limited, and examples thereof include rubber materials such as foamable silicone rubber, silicone rubber, and fluorine rubber.

A halogen heater 25 is provided inside the heating roller 254 (inner peripheral surface side).
In the fixing belt 251, an elastic layer and a release layer are sequentially laminated on a base material.
The total thickness of the fixing belt 251 is usually 1 mm or less.
The thickness of a base material is 20-50 micrometers normally.
Although it does not specifically limit as a material which comprises a base material, Resin materials, such as a polyimide, are mentioned.

The thickness of the elastic layer is preferably 100 μm or more. If the thickness of the elastic layer is less than 100 μm, it may not be possible to follow minute irregularities on the surface of the toner image, and the low-temperature fixability may deteriorate.
The material constituting the elastic layer is not particularly limited, and examples thereof include rubber materials such as silicone rubber, foamable silicone rubber, and fluorine rubber.

The thickness of the release layer is usually 10 to 40 μm.
The material constituting the release layer is not particularly limited, but PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyimide, polyetherimide, PES (polyether sulfide) Etc.

<Toner fixing>
Next, toner fixation will be described. As shown in FIG. 6, in the fixing device 12, the toner on the recording paper receives heat and pressure in the fixing roller or the nip between the fixing belt and the pressure roller in the fixing device 12. At this time, the toner is melted by heat and the viscoelasticity is lowered. At the same time, when the pressure is applied, the sheet spreads on the recording paper and enters into the fibers of the recording paper. Then, the recording paper comes out of the nip, and in the case of the heat roller system, it is peeled off from both rollers by the separation claw 34 and separated away.

  The toner is melted by heat and can penetrate between the fibers of the recording paper. At the same time, it easily adheres to the fixing roller. Further, when the toner melts and becomes viscous, and the adhesion force to the fixing roller or the fixing belt becomes larger than the adhesive force to the paper, the molten toner moves from the recording paper to the fixing roller or the fixing belt and becomes an offset. . In the case of the heat roller system, the transferred offset toner is accumulated on the temperature sensor 36 such as the separation claw 34 or the thermistor, and the fixing roller or the fixing belt repeatedly stops rotating, so that the accumulated toner becomes the fixing roller or the fixing belt. May fall on the recording paper and re-attach to the recording paper, so-called black spots may be generated and the image may be soiled.

  The difference between the toner re-adhering toner generation and the fixing property to the fixing roller or fixing belt due to the difference in toner physical properties is large, and the influence of the filler contained in the paper is also large. In particular, when a paper containing heavy calcium carbonate prepared by pulverization is used as a filler, fixing of the toner and the fixed matter formed by the heavy calcium carbonate or adhesion to the pressure roller is high. It tends to occur as an abnormal image including the black spots. Further, as the toner, the deterioration is remarkable in the toner having poor offset property.

  As a printed image, a white background toner is poor in both offset and fixing properties. On the other hand, the pre-stage fixed toner generated on the fixing roller is discharged onto the paper together with the unfixed toner by a self-cleaning effect. The effect is greater as the image area ratio is higher, and toner sticking is less likely to occur. The precursor stage is a stage where the toner is not larger than a size that can be visually confirmed, and is a stage where, for example, toner of about 1 mm or less is fixed.

  As described above, the factors that cause the toner to re-adhere to the fixing roller and the fixing belt to generate an abnormal image including black spots are the image area ratio indicating the ratio of the area occupied by the image to the paper, and the print image is printed in monochrome. It can be said that the frequency of occurrence depends on the printing conditions such as the monochrome printing rate indicating the ratio being printed and the amount of heavy calcium carbonate on the sheet indicating the ratio including the filler that determines the quality of the sheet. The monochrome printing rate can be considered as an index indicating the influence of the toner physical properties of black (K) on the paper. That is, the abnormal image including the black spots depends on the printing condition on the image forming side such as the image area ratio on the paper and the physical properties of the toner used when printing the image, or the printing condition on the printing medium side such as the quality of the paper. It can be said that the occurrence of is affected.

(Rotating load applying member)
In the present invention, the rotation load applying member applies a rotation load to the fixing member or the pressure member of the fixing device. And the rotational load which a rotational load provision member provides is determined according to the amount of calcium carbonate of the surface of a printing medium, and a back surface. The rotational load is determined by a condition determining unit in the image forming apparatus.

  A schematic diagram of this embodiment is shown in FIG. In the fixing device 12 employing the heat roller system, for example, a rotational load (rotational load torque) is applied to the fixing roller 28 by a rotational load applying mechanism shown in FIG. The fixing roller 28 included in the fixing device 12 usually rotates by obtaining a driving force M from a driving source 51 provided in the main body of the image forming apparatus outside the fixing device 12. In the example shown in FIG. 8, the pressure roller 30 in pressure contact with the fixing roller 28 to which the driving force from the driving source 51 is transmitted is driven to rotate.

  Conventionally, the pressure roller 30 rotates at the same rotational speed as the fixing roller 28 by a frictional force generated between the pressure roller 30 and the fixing roller 28. On the other hand, an oil damper 55 for applying a load torque for the driven rotation can be used at the end of the shaft of the pressure roller 28 shown in the present embodiment. As shown in FIG. 8, the shaft of the pressure roller 30 that is driven to rotate is connected via a gear 57 that is a driving force transmission member.

  Further, not only the type of the oil damper 55 but also the ratio of the gear 57 can be changed to adjust the rotational load torque. As the oil damper 55, for example, rotary dampers TD88 and TD62 manufactured by Tok Bearing Co., Ltd. can be used. The shafts of the oil damper 55 and the pressure roller 30 can be contacted and separated by a contact / separation mechanism (not shown).

  In addition, a torque limiter 56 can be used as the rotational load applying member, and the same usage method as that of the oil damper 55 is possible. As the torque limiter 56, for example, a magnet type torque limiter TLES1-816-40W manufactured by Tok Bearing Co. can be used.

  When the driving force from the driving source 51 is transmitted to the pressure roller 30 side, a rotational load is applied to the fixing roller 28.

The rotational load is determined according to the amount of calcium carbonate on the front and back surfaces of the print medium. Regarding the amount of calcium carbonate on the front and back surfaces of the print medium, the ratio of the amount of calcium carbonate represented by the following formula is 1.5 or more, and the amount of calcium carbonate on the surface of the print medium having a large amount of calcium carbonate is 10 wt% or more. In this case, it is preferable that the rotational load of the rotational load applying member is 0.1 to 0.6 N · m.
Formula: Ratio of the amount of calcium carbonate = amount of calcium carbonate (wt%) on the surface of the print medium having a large amount of calcium carbonate / wt% of surface of the print medium having a small amount of calcium carbonate (wt%)

  In this case, since a frictional force is generated between the fixing member or the pressure member and the surface of the printing medium, the minute fixed matter such as the fixing toner on the fixing member or the pressure member is peeled off, and the minute fixed matter is removed. Does not grow to a visible extent. Thereby, generation | occurrence | production of the abnormal image by toner adhesion can be suppressed.

  Further, in the case of the above conditions (when the ratio of the amount of calcium carbonate is 1.5 or more and the amount of calcium carbonate on the surface of the printing medium having a large amount of calcium carbonate is 10% or more), the rotation of the rotational load applying member More preferably, the load is 0.2 to 0.4 N · m. In this case, the occurrence of abnormal images due to toner fixation can be further suppressed.

  In cases other than the above conditions, that is, when the ratio of the amount of calcium carbonate is less than 1.5, or when the amount of calcium carbonate on the surface of the printing medium having a large amount of calcium carbonate is less than 10%, the rotational load may not be applied. preferable. In this case, since it is possible to prevent unnecessary rotational load, it is possible to prevent the life of the fixing member and the pressure member from being reduced.

  As described above, the rotational load application member of the present embodiment is connected to the rotation shaft of the pressure roller 30 (pressure member) via the gear 57 (driving force transmission member), and the carbon dioxide on the front and back surfaces of the print medium. Depending on the amount of calcium, the gear 57 (driving force transmission member) contacts and separates.

(Details of image forming apparatus and image forming method)
Next, details of the image forming apparatus and the image forming method of the present invention will be described.
An image forming apparatus of the present invention includes a fixing device that contacts a fixing member and a pressure member to fix toner on a print medium, and a rotation load applying member that applies a rotation load to the fixing member or the pressure member. A data acquisition unit for acquiring calcium carbonate amounts on the front and back surfaces of the print medium from a database having at least product names of plain paper and calcium carbonate amounts on the front and back surfaces of the plain paper; A condition determining unit that determines a rotational load of the rotational load applying member according to the amount of calcium carbonate.

  The image forming method of the present invention is an image forming method including a fixing step in which a fixing member and a pressure member are brought into contact with each other to fix toner on a print medium, and the fixing step includes the fixing member or the pressure member. Fixing is performed using a rotational load applying member that applies a rotational load to the member, and at least carbon dioxide on the front and back surfaces of the printing medium is obtained from a database having at least the product name of plain paper and the amount of calcium carbonate on the front and back surfaces of plain paper. The amount of calcium is acquired, and the rotational load of the rotational load applying member is determined and fixed according to the amount of calcium carbonate on the front and back surfaces of the printing medium.

  In addition to the above, the image forming apparatus of the present embodiment includes an image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, a protective layer forming unit, and a fixing unit. It preferably has a cleaning means, and further has other means appropriately selected as necessary, for example, a static elimination means, a recycling means, a control means and the like.

  In addition to the fixing step, the image forming method of the present embodiment includes an electrostatic latent image forming step, a developing step, a transfer step, and a protective layer forming step, preferably a cleaning step, and further necessary. Other processes appropriately selected according to the process, for example, a static elimination process, a recycling process, a control process, and the like are included.

  The image forming method can be suitably performed by the image forming apparatus, the electrostatic latent image forming step can be performed by the electrostatic latent image forming unit, and the developing step is performed by the developing unit. The transfer step can be performed by the transfer unit, the protective layer forming step can be performed by the protective layer forming unit, the fixing step can be performed by the fixing unit, and the other steps. Can be performed by the other means.

<Electrostatic latent image forming step and electrostatic latent image forming means>
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the image carrier.
-Image carrier-
The image carrier (sometimes referred to as “electrostatic latent image carrier” or “photoreceptor”) is not particularly limited in terms of material, shape, structure, size, etc., and is appropriately selected from known ones. The shape is preferably a drum shape, and examples of the material include inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors such as polysilane and phthalopolymethine.
An image carrier (photoreceptor) used in the image forming apparatus includes a conductive support, and at least a photosensitive layer on the conductive support, and further includes other layers as necessary.

  As the photosensitive layer, a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, and a charge generation layer is provided on the charge transport layer. There is a reverse layer type. In order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the photoreceptor, an outermost surface layer can be provided on the photosensitive layer. An undercoat layer may be provided between the photosensitive layer and the conductive support. Moreover, an appropriate amount of a plasticizer, an antioxidant, a leveling agent or the like can be added to each layer as necessary.

The conductive support is not particularly limited as long as it has a volume resistance of 1.0 × 10 ¹⁰ Ω · cm or less, and can be appropriately selected according to the purpose. For example, aluminum, Metals such as nickel, chromium, nichrome, copper, gold, silver and platinum, metal oxides such as tin oxide and indium oxide, film or cylindrical plastic, paper coated or aluminum by vapor deposition or sputtering A plate made of aluminum alloy, nickel, stainless steel or the like, and a tube processed into a drum shape by a method such as extrusion or drawing, and then subjected to surface treatment such as cutting, superfinishing, or polishing can be used.

  The drum-shaped support preferably has a diameter of 20 to 150 mm, more preferably 24 to 100 mm, and still more preferably 28 to 70 mm. When the diameter of the drum-shaped support is less than 20 mm, it may be physically difficult to arrange each step of charging, exposure, development, transfer, and cleaning around the drum. When the diameter exceeds 150 mm, The image forming apparatus may become large. In particular, when the image forming apparatus is a tandem type, since it is necessary to mount a plurality of photoconductors, the diameter is preferably 70 mm or less, and more preferably 60 mm or less. Further, an endless nickel belt or an endless stainless steel belt as disclosed in JP-A-52-36016 can also be used as the conductive support.

The undercoat layer of the photoconductor may be composed of a single layer or a plurality of layers. For example, (1) the resin is the main component, and (2) the white pigment and the resin are the main components. And (3) a metal oxide film obtained by chemically or electrochemically oxidizing the surface of a conductive substrate. Among these, those containing a white pigment and a resin as main components are preferable.
Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among these, titanium oxide is particularly preferable because it is excellent in preventing injection of charges from the conductive support.
Examples of the resin include thermoplastic resins such as polyamide, polyvinyl alcohol, casein, and methyl cellulose; thermosetting resins such as acrylic, phenol, melamine, alkyd, unsaturated polyester, and epoxy. These may be used individually by 1 type and may use 2 or more types together.
There is no restriction | limiting in particular in the thickness of the said undercoat layer, According to the objective, it can select suitably, 0.1-10 micrometers is preferable and 1-5 micrometers is more preferable.

  Examples of the charge generation material in the photosensitive layer include monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments and other azo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, Cyanine dyes, styryl dyes, pyrylium dyes, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indanthrone pigments, squarylium pigments, phthalocyanine pigments, etc. Organic pigments or dyes; selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, amorphous silicon, and other inorganic materials. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the charge transport material in the photosensitive layer include anthracene derivatives, pyrene derivatives, carbazole derivatives, tetrazole derivatives, metallocene derivatives, phenothiazine derivatives, pyrazoline compounds, hydrazone compounds, styryl compounds, styryl hydrazone compounds, enamine compounds, butadiene compounds, distyryl. Examples thereof include compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, imidazole compounds, triphenylamine derivatives, phenylenediamine derivatives, aminostilbene derivatives, and triphenylmethane derivatives. These may be used individually by 1 type and may use 2 or more types together.

  As the binder resin used to form the photosensitive layer, it is electrically insulating and may be a known thermoplastic resin, thermosetting resin, photocurable resin, photoconductive resin, or the like. it can. Examples of the binder resin include polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, ethylene-vinyl acetate copolymer, polyvinyl butyral, Polyvinyl acetal, polyester, phenoxy resin, (meth) acrylic resin, polystyrene, polycarbonate, polyarylate, polysulfone, polyethersulfone, ABS resin and other thermoplastic resins, phenol resin, epoxy resin, urethane resin, melamine resin, isocyanate resin, Examples thereof include thermosetting resins such as alkyd resins, silicon resins, and thermosetting acrylic resins, polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene. These may be used individually by 1 type and may use 2 or more types together.

Examples of the antioxidant include phenolic compounds, paraphenylenediamines, hydroquinones, organic sulfur compounds, and organic phosphorus compounds.
Examples of the phenol compound include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-ethyl- 6-t-butylphenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3 -Tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy Ben ) Benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3 ′) -T-butylphenyl) butyric acid] cricol ester, tocopherols and the like.
Examples of the paraphenylenediamines include N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl- Examples include p-phenylenediamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine, and the like.
Examples of the hydroquinones include 2,5-di-t-octyl hydroquinone, 2,6-didodecyl hydroquinone, 2-dodecyl hydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methyl. Examples include hydroquinone and 2- (2-octadecenyl) -5-methylhydroquinone.
Examples of the organic sulfur compounds include dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like. .
Examples of the organic phosphorus compounds include triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained.
The addition amount of the antioxidant is preferably 0.01 to 10% by mass with respect to the total mass of the layer to be added.

As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is about 0 to 30 parts by mass with respect to 100 parts by mass of the binder resin. Is appropriate.
Further, a leveling agent may be added to the photosensitive layer. Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil; polymers having a perfluoroalkyl group in the chain or oligomers. The amount of the leveling agent used is preferably 0 to 1 part by mass with respect to 100 parts by mass of the binder resin.

  Next, the formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the image carrier and then performing imagewise exposure, and by the electrostatic latent image forming unit. Can do. The electrostatic latent image forming unit includes, for example, at least a charger that uniformly charges the surface of the image carrier and an exposure unit that exposes the surface of the image carrier imagewise.

The charging can be performed, for example, by applying a voltage to the surface of the image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers utilizing corona discharge such as corotrons and corotrons.
The charger preferably has voltage applying means for applying a voltage having an AC component.

The exposure can be performed, for example, by exposing the surface of the image carrier imagewise using the exposure device.
The exposure device is not particularly limited as long as it can perform image-like exposure on the surface of the image carrier charged by the charger, and can be appropriately selected according to the purpose. Examples include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.
In the present invention, an optical back side system in which imagewise exposure is performed from the back side of the image carrier may be adopted.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing unit is not particularly limited as long as it can be developed using, for example, the toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated. Preferred examples include those having at least a developing unit capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image.

<Transfer process and transfer means>
The transfer step is a step of transferring the visible image onto a recording medium. If the image forming apparatus is a monochrome machine, it is directly transferred onto plain paper as a storage medium. If the image forming apparatus is a color machine, an embodiment in which an intermediate transfer member is used, a visible image is primarily transferred onto the intermediate transfer member, and then the visible image is secondarily transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer member using two or more colors, preferably full color toner, as a toner, and a first transfer step of transferring the composite transfer image onto a recording medium An embodiment including a secondary transfer step is more preferable.
The transfer can be performed, for example, by charging the image carrier (photosensitive member) with the transfer charger using the visible image, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.
The image carrier is an intermediate transfer member used for image formation by a so-called intermediate transfer method in which a toner image formed on a photosensitive member is primarily transferred to perform color superposition and further transferred to a recording medium. It may be.

  In the transfer process in which the photosensitive member or the intermediate transfer member is in contact with the plain paper, calcium carbonate is transferred from the transfer surface of the plain paper to the photosensitive member or the intermediate transfer member. Since the amount of calcium carbonate transferred increases as the amount of calcium carbonate on the surface of plain paper increases, when image formation is performed only on one side of plain paper, it is preferable to perform transfer on the side with little calcium carbonate.

  Also, at the nip between the photosensitive member or intermediate transfer member to which the transfer is performed and the plain paper, the plain paper is pressed against the photosensitive member or the intermediate transfer member, and at that time, calcium carbonate on the surface of the plain paper is transferred to the photosensitive member or the intermediate transfer member. Migrate to At the same time, calcium carbonate damages the photoconductor or intermediate transfer member, and in severe cases, the calcium carbonate may pierce the photoconductor or intermediate transfer member and cause an abnormal image. When there is a lot of calcium, it is preferable to reduce the pressure at the nip.

As the intermediate transfer member, a material exhibiting conductivity of a volume resistance of 1.0 × 10 ^{5 to} 1.0 × 10 ¹¹ Ω · cm is preferable. When the volume resistance is less than 1.0 × 10 ⁵ Ω · cm, so-called transfer dust is generated in which the toner image is disturbed due to discharge when the toner image is transferred from the photosensitive member to the intermediate transfer member. If the toner image exceeds 1.0 × 10 ¹¹ Ω · cm, the counter charge of the toner image is transferred onto the intermediate transfer member after the toner image is transferred from the intermediate transfer member to a recording medium such as paper. It may remain and appear as an afterimage on the next image.

As the intermediate transfer member, for example, a metal oxide such as tin oxide or indium oxide, a conductive particle such as carbon black, or a conductive polymer, alone or in combination, kneaded with a thermoplastic resin, and then an extrusion molded belt A cylindrical or cylindrical plastic can be used. In addition to this, the above-mentioned conductive particles and conductive polymer are added to a resin solution containing a thermally crosslinkable monomer or oligomer, if necessary, and subjected to centrifugal molding while heating to obtain an intermediate transfer member on an endless belt. You can also.
When the surface layer is provided on the intermediate transfer member, among the surface layer materials used for the surface layer of the photoreceptor described above, the composition excluding the charge transport material is appropriately adjusted in combination with a conductive substance, Can be used.

The transfer means (the primary transfer means and the secondary transfer means) includes at least a transfer device that peels and charges the visible image formed on the image carrier (photoconductor) to the recording medium side. It is preferable to have. There may be one transfer means or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper). However, in consideration of use as direct mail, the recording medium itself may be white. preferable. The recording medium surface preferably has a coating layer of a white pigment such as calcium carbonate, talc or kaolin.

The size of the white pigment is an average particle diameter of 0.1 μm or more, preferably 0.5 to 5 μm. When the average particle size of the white pigment is less than 0.1 μm, the strength of the white pigment layer (coat layer) is very weak, and the white pigment powder is crushed and the white pigment layer is severely cracked. Peeling easily occurs.
In order to maintain the appearance of the information sheet, the thickness of the white pigment layer (coat layer) is 1 μm or more, preferably 1.5 to 3 μm or more.

<Fixing process and fixing means>
The fixing step is a step of fixing the visible image transferred to the recording medium using the fixing unit, and may be performed each time the toner of each color is transferred to the recording medium, or may be applied to the toner of each color. On the other hand, it may be carried out simultaneously at the same time in a state of being laminated.
As the fixing unit, the above-described fixing device is used. As described above, examples of the heating and pressing means include a combination of a heating roller and a pressing roller, a combination of a heating roller, a pressing roller, and an endless belt, and the like. The pressure roller normally does not need to be heated, but by heating, the temperature difference between the surface of the heating roller and the endless belt can be reduced to flatten the imaged plain paper. When the plain paper is curled, it is possible to suppress the occurrence of a so-called jam that is entangled in fixing again, and it becomes possible to stack a large amount of plain paper on which images are formed in an orderly manner.

  When the pressure roller has no heating mechanism, the pressure roller comes into contact with the heated heating roller or the endless belt, and the temperature rises. Therefore, the curling of the plain paper after fixing is adjusted by adjusting the time for which the fixing device is operated without image formation when forming an image according to the amount of calcium carbonate on the front and back surfaces of the plain paper. Can be suppressed.

  In addition, since calcium carbonate on the plain paper surface is sandwiched between the heating roller or endless belt and pressure roller at the fixing nip, calcium carbonate moves to the heating roller or endless belt and pressure roller, or the calcium carbonate is damaged. It is easy to cause various troubles by putting on or piercing calcium carbonate. Therefore, it is preferable to adjust the fixing pressure according to the amount of calcium carbonate on the plain paper surface.

  Scratches on the surface of the heating roller, endless belt, and pressure roller due to calcium carbonate on the surface of plain paper cannot be prevented as long as calcium carbonate is present on the surface of plain paper. Of course, scratches are more likely to occur as the amount of calcium carbonate on the plain paper surface increases. Therefore, it is preferable to change the frequency of replacing the fixing member and the interval (number of image formations) for cleaning the surface of the heating roller or the endless belt and / or the pressure roller. Specifically, if the amount of calcium carbonate differs from the standard plain paper for the cleaning interval (number of images formed) set for the standard plain paper, the ratio to the calcium carbonate on the standard plain paper surface The corresponding coefficient is applied to the number of image forming sheets to determine the greening interval.

As cleaning of the fixing member, web cleaning is preferably performed.
In addition, a roller carrying a polishing agent such as diamond, cubic boron nitride, silicon carbide, aluminum oxide on the surface is rubbed against a heating roller or an endless belt, and / or a pressure roller, and the heating roller or the endless belt, and In addition, the surface of the pressure roller is made uniform and so-called fixing refresh is performed as a kind of fixing cleaning.

<Other processes and other means>
The neutralization step is a step of performing neutralization by applying a neutralization bias to the image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the image carrier. It is done.

The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

The control means is a process for controlling the respective steps, and can be suitably performed by the control means.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

Further, since calcium carbonate has migrated to the surface of the photoreceptor or intermediate transfer body, cleaning for removing the calcium carbonate is important.
The cleaning step is a step of removing the electrophotographic toner remaining on the image carrier and removing calcium carbonate transferred from the surface of the plain paper, and can be suitably performed by a cleaning unit.
The cleaning unit is preferably provided downstream of the transfer unit and upstream of the charger.
The cleaning means is not particularly limited, and may be appropriately selected from known cleaners as long as the toner remaining on the image carrier can be removed. For example, a magnetic brush cleaner or an electrostatic brush A cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, a web cleaner and the like are preferable. Among these, blade cleaning is most efficient and preferable for removing the transfer residual toner and calcium carbonate. In the blade cleaning, polyurethane having excellent wear resistance is generally used. Polyurethane itself may be used for blade cleaning, but since calcium carbonate is harder and squarer than toner, the surface of the polyurethane is coated with an acrylic compound, or polyurethane is impregnated with an acrylic compound or isocyanate compound. It is preferable to improve the strength.

  When the amount of calcium carbonate on the transfer surface of the plain paper on which image formation is performed is large, the amount of calcium carbonate transferred to the photosensitive member or intermediate transfer member increases, so that the amount of calcium carbonate that the blade dams up increases. Therefore, depending on the amount of calcium carbonate on the transfer surface of the plain paper on which image formation is performed, when the image formation is completed and the photosensitive member or intermediate transfer member stops, the photosensitive member or intermediate transfer member is reversed or the distance to be reversed. By changing, the calcium carbonate collected by the blade can be removed from the blade, and the durability of the blade can be greatly improved.

<One Embodiment of Image Forming Apparatus>
Next, a basic configuration of the copying machine 100B using each of the above means will be described with reference to the drawings. In the present embodiment, illustration of the database, the data acquisition unit, and the condition determination unit is omitted. As described above, the database may be provided inside the image forming apparatus or may be provided outside the image forming apparatus.

  FIG. 9 is a schematic configuration diagram showing the configuration of the copying machine 100B. The copying machine 100B is a tandem color image forming apparatus, and includes a printer unit 150, which is a main body of the image forming apparatus, a paper feeding device 200, a scanner 300, and an automatic document feeder (ADF) 400.

The printer unit 150 is provided with an endless belt-shaped intermediate transfer belt 50 at the center. The intermediate transfer belt 50 is stretched around three support rollers, that is, a belt driving roller 14, a cleaning counter roller 15, and a secondary transfer counter roller 16, and can be rotated clockwise in FIG. In the vicinity of the cleaning counter roller 15, an intermediate transfer belt cleaning device 17 that is an intermediate transfer belt cleaning unit for removing residual toner on the intermediate transfer belt 50 is disposed.
The printer unit 150 also includes four yellow, cyan, magenta, and black colors along the transport direction so as to face the stretched surface between the belt driving roller 14 and the cleaning facing roller 15 in the intermediate transfer belt 50. A tandem-type image forming unit 120 in which two image forming units 18 are arranged to face each other is arranged.

  An exposure device 21 is disposed above the tandem type image forming unit 120. The secondary transfer device 22 is disposed on the opposite side (below the intermediate transfer belt 50) to the side where the tandem image forming unit 120 is disposed with the intermediate transfer belt 50 interposed therebetween. In the secondary transfer device 22, a transfer conveyance belt 24 that is an endless belt is stretched around a pair of transfer conveyance support rollers 23, and one of the pair of transfer conveyance support rollers 23 is rotationally driven as a drive roller. The transfer conveyance belt 24 is driven to rotate counterclockwise in FIG. Further, the right transfer conveyance support roller 23 and the secondary transfer counter roller 16 in FIG. 9 are in contact with each other with the intermediate transfer belt 50 and the transfer conveyance belt 24 interposed therebetween, and the intermediate transfer belt 50 and the transfer due to this contact are in contact with each other. A contact portion with the conveyance belt 24 becomes a secondary transfer nip.

A fixing device 25 for fixing the toner image on the recording medium S is disposed on the downstream side in the conveyance direction of the recording medium S of the secondary transfer device 22 in the printer unit 150 (left side in FIG. 9). The fixing device 25 includes a heating unit 26 provided with a heater (not shown) therein, and a pressure roller 27 that is pressed by a spring (not shown) and presses against the heating unit 26 to form a nip portion as a press-contact portion. ing.
Below the secondary transfer device 22 and the fixing device 25 in the printer unit 150, a reversing device 28 for reversing the recording medium S when an image is formed on both sides of the recording medium S is disposed.

  Next, formation of a full color image (color copy) using the copying machine 100B will be described. First, a document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and a document is set on the contact glass 32 of the scanner 300. close up.

  When the user presses a start switch on an operation panel (not shown), when a document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32. As soon as the document is set on the scanner 300, the scanner 300 is driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, the light from the light source is irradiated by the first traveling body 33 so that the light is reflected by the document surface, and the reflected light is reflected by the mirrors in the first traveling body 33 and the second traveling body 34, Light is received by the reading sensor 36 through the imaging lens 35. As a result, a color original (color image) is read and used as black, yellow, magenta, and cyan image information.

  Each image information of black, yellow, magenta, and cyan is transmitted to the exposure device 21, and exposure light corresponding to each image information is directed to each photoreceptor 10 of each image forming unit 18 in the tandem type image forming unit 120. Each is irradiated. As a result, black, yellow, magenta, and cyan toner images are formed in each image forming unit 18.

  The four image forming units 18 (Y, C, M, and K) have substantially the same configuration except that the colors of the toners to be used are different. Therefore, in FIG. , M, and K are omitted. The image forming unit 18 includes a drum-shaped photoconductor 10, and around the photoconductor 10, a charging device as a charging unit, a developing device, a primary transfer roller 62 as a primary transfer unit, a photoconductor cleaning device, and a charge eliminating device. Etc.

  Each image forming unit 18 (black image forming unit, yellow image forming unit, magenta image forming unit, and cyan image forming unit) in the printer unit 150 is based on the image information of each corresponding color. Images (black image, yellow image, magenta image, and cyan image) can be formed on the surface of each photoconductor 10.

  The black image, yellow image, magenta image, and cyan image formed by each image forming unit 18 are respectively transferred onto the intermediate transfer belt 50 that is rotationally moved by the belt driving roller 14, the cleaning facing roller 15, and the secondary transfer facing roller 16. A black image formed on the black photoconductor 10K, a yellow image formed on the yellow photoconductor 10Y, a magenta image formed on the magenta photoconductor 10M, and a cyan photoconductor 10C. Cyan images are sequentially transferred (primary transfer).

  Then, a black image, a yellow image, a magenta image, and a cyan image are superimposed on the intermediate transfer belt 50 to form a composite color image (color transfer image).

On the other hand, in the paper feeding device 200, one of the paper feeding rollers 142 is selectively rotated to feed out the recording medium S from one of the paper feeding cassettes 144 provided in multiple stages in the paper bank 143, and one sheet is separated by the separation roller 145. The paper is separated and sent to the paper feed path 146, transported by the transport roller 147, guided to the main body side paper feed path 148 in the printer unit 150, and abutted against the registration roller 49 and stopped. Alternatively, the manual feed roller 51 is rotated to feed out the recording medium S on the manual tray 54, separated one by one by the manual separation roller 52, and put into the manual feed path 53, and abutted against the registration roller 49 as described above. Stop.
The registration roller 49 is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the recording medium S.

  After abutting against the registration roller 49 and stopping, the registration roller 49 is rotated in time with the synthesized color image (color transfer image) synthesized on the intermediate transfer belt 50, and the recording medium is directed toward the secondary transfer nip. S is sent out. A composite color image (color transfer image) on the intermediate transfer belt 50 is recorded by a transfer electric field formed between the transfer conveyance support roller 23 on the secondary transfer device 22 side and the secondary transfer counter roller 16 in the secondary transfer nip. Transfer (secondary transfer) is performed on the medium S, and a color image is formed on the recording medium S. The transfer residual toner on the intermediate transfer belt 50 after passing through the secondary transfer nip is cleaned by the intermediate transfer belt cleaning device 17.

  The recording medium S on which the color image is transferred is conveyed by the secondary transfer device 22 and sent to the fixing device 25. In the fixing device 25, the composite color image (color transfer image) is fixed on the recording medium S by applying heat and pressure at a nip formed by the heating unit 26 and the pressure roller 27. The

  The recording medium S that has passed through the fixing device 25 is given a conveying force by the conveying roller pair 56 after fixing and reaches the position of the switching claw 55. The recording medium S is discharged by the pair of discharge rollers when the conveyance direction is switched by the switching claw 55 and stacked on the discharge tray 57. Alternatively, the conveying direction is switched by the switching claw 55 to reach the reversing device 28, where the reversing device 28 is reversed and guided to a position where it again hits the registration roller 49, and an image is also formed on the back surface at the secondary transfer nip. After fixing at 25, the paper is discharged by a pair of discharge rollers and stacked on the paper discharge tray 57.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail by a test example, this invention is not limited to the following test example.

(Verification of ATR method)
Using a Fourier transform infrared spectroscopic analyzer Frontier MIR / FIR (manufactured by Perkin Elmer) with an ATR measuring device (crystal: diamond / ZnSe, incident angle: 45 °, single reflection), calcium carbonate powder / cellulose powder The IR spectrum of the mixed powder was measured. Table 1 shows the measurement conditions of the IR spectrum.

  In Table 1, a force gauge 100 indicates that the sample was pressurized to 100 N on the crystal.

A mixed powder of calcium carbonate powder / cellulose powder is prepared by weighing calcium carbonate powder (special grade reagent, manufactured by Wako Pure Chemical Industries) and cellulose powder (38 μm, manufactured by Wako Pure Chemical Industries), and mixing them in an agate mortar for 3 minutes. did.
From the measured IR spectrum, the ratio A / B of the peak area (A) caused by calcium carbonate and the peak area (B) caused by cellulose was calculated and plotted against calcium carbonate / (calcium carbonate + cellulose). A very good correlation was obtained. FIG. 10 shows the result of plotting A / B against calcium carbonate / (calcium carbonate + cellulose).

In FIG. 10, the peak at 873 cm ⁻¹ was adopted as the peak due to calcium carbonate, and the peak at 897 cm ⁻¹ was adopted as the peak due to cellulose. Baseline, and 916～852Cm ^-1, peak area A, an area for obtaining the B respectively, about 879～867Cm ^-1, was 904~890cm ^-1.

  Next, the horizontal axis of FIG. 10 was converted into a calcium carbonate concentration (calcium carbonate / (calcium carbonate + cellulose) × 100) to obtain a calibration curve of calcium carbonate (FIG. 11).

Next, the front and back IR spectra of plain paper HAMMERMILL COLOR COPY DIGITAL (made by INTERNATIONAL PAPER) were measured in the same manner as the calcium carbonate / cellulose mixed powder, and A / B was calculated. In addition, the area | region at the time of calculating | requiring a baseline and peak area A and B is the same as mixed powder.
As a result of obtaining A / B, the front surface was 7.31 and the back surface was 2.47. From these A / B values and the calibration curve of calcium carbonate in FIG. 11, the calcium carbonate concentration on the surface was 32.1 wt% on the front surface and 13.8 wt% on the back surface.
Here, a SEM photograph of the surface of the measured plain paper HAMMERMILL COLOR COPY DIGITAL is shown in FIG. It can be seen that the amount of calcium carbonate on the front surface (a) measured at a calcium carbonate concentration of 32.1 wt% is overwhelmingly higher than that on the back surface (b) of 13.8 wt%.

  The IR spectrum was measured on the surface of HAMMERMILL COLOR COPY DIGITAL with each pressure of 70, 80, 90, 120N, and the concentration of calcium carbonate was calculated from the A / B value and FIG. 11, as shown in FIG. An almost constant value was obtained when the applied pressure was 80 N or more.

  Next, IR spectra on both sides of various types of plain paper were measured with a pressure of 100 N, and the concentration of calcium carbonate on the plain paper surface was determined from the measured A / B value and FIG. Further, each plain paper whose IR spectrum was measured was burned with ordinary paper according to JIS P 8251, and the calcium carbonate concentration in the plain paper was determined from the ash.

The calcium carbonate concentration measured by the JIS method (JIS method) and the calcium carbonate concentration measured by the ATR method (ATR method) were plotted. The result is shown in FIG. However, since the calcium carbonate concentration on the surface of plain paper measured by the ATR method is different between the front surface and the back surface, the average value of the front surface and the back surface is defined as the calcium carbonate concentration (ATR method).
As shown in FIG. 13, the calcium carbonate concentration (JIS method) and the calcium carbonate concentration (ATR method) have a good linear relationship with a slope of approximately 1, and the calcium carbonate concentration quantified by the ATR method is a correct value. Proven to be.

(Create database)
The calcium carbonate concentration on each side was measured by ATR method for 160 types of plain paper for PP and domestic plain paper for PPC / inkjet marketed domestically and abroad.
For each plain paper, enter the registration number, product name, unified product code, lot number, country of sale, basis weight, thickness, density calcium carbonate concentration on the unsealed surface, calcium carbonate concentration on the reverse side of the unsealed surface, and remarks And created a plain paper database.
The created database is recorded in a cloud environment and can be read by an image forming apparatus connected to the Internet. Database values are added regularly.

  When the manufacturer delivers the image forming device to the user, it reads the barcode printed on the plain paper box used by the user, searches the database from the barcode value (unified product code), and uses it. The image forming apparatus can recognize the calcium carbonate concentration on the surface of plain paper. According to the calcium carbonate concentration on the surface of the plain paper, the image forming condition is set to an appropriate state, and high quality image formation can always be performed.

(Verification content)
Verification was carried out using a copying machine imgio NEO451 manufactured by Ricoh Co., Ltd. The image forming apparatus shown in FIG. 9 and the fixing device having the fixing roller shown in FIG. 6 were used.
In the verification, plain paper A (calcium carbonate amount: 3.0 wt% (front surface), 3.2 wt% (back surface)) and plain paper B (calcium carbonate amount: 1.5 wt% (different in calcium carbonate amount) are used in the image forming apparatus. (Front surface), 1.8 wt% (back surface)), plain paper C (calcium carbonate amount: 14.0 wt% (front surface), 9.0 wt% (back surface)), plain paper D (calcium carbonate amount: 24.0 wt% ( Front side), 27.1 wt% (back side)) were set with A4Y, and a printing test was performed.
The verification results are shown in Table 2. As a printing condition, an image in which a character image was randomly formed so that the image area ratio was 3% was used.

  For the paper information, the number of plain paper was read by a bar code reader connected to the copier imagio NEO 451, the plain paper database stored on the cloud was accessed, and the calcium carbonate concentration on the surface of each plain paper was recognized.

<Toner fixing property>
The toner sticking property was evaluated by confirming the fall of the sticking toner onto the white paper portion by printing the above-mentioned image at a total of 100 k sheets, intermittently every 10 seconds. Here, the evaluation criteria are as follows. In addition, "◎" was set as the pass level.
[Evaluation criteria]
◎: No sticking occurred △: Sticking occurred in 1% or less of 1k sheets ×: Fixed image occurred in 1% or more of 1k sheets

<Fusing unit durability>
Regarding the durability of the fixing unit, the sheet passing evaluation is continued up to 200k sheets, (1) the elastic layer 42 of the pressure roller 30 is damaged, (2) the release layer of the fixing roller 28 is worn (the core 41 is exposed). Was made and evaluated. Here, the evaluation criteria are as follows. In addition, "△" or more was set as the pass level.
[Evaluation criteria]
◎: No occurrence of (1), (2) up to 200k sheets, or any of (1), (2) occurs between 160k-200k sheets ○: Either of (1), (2) up to 160k sheets △: Up to 120k sheets (1) or (2) occurs x: Either 80k sheets or less (1) or (2) occurs

  The obtained results are shown in Table 2.

(Test Examples 1-8)
The image forming apparatuses of Test Examples 1 to 4 include a data acquisition unit and a condition determination unit. In the image forming apparatuses of Test Examples 5 to 8, the data acquisition unit and the condition determination unit were not provided, and the contact / separation of the rotation load applying member was set to be opposite to that of Test Examples 1 to 4.

  In Test Example 1, plain paper A was passed through, the ratio of the calcium carbonate amount between the front and back surfaces was 1.1, and the calcium carbonate amount was 10 wt% or less. The fixing unit durability was excellent.

  In Test Example 2, plain paper B was passed, the ratio of the amount of calcium carbonate on the front and back sides was 1.2, and the amount of calcium carbonate was 10 wt% or less. The fixing unit durability was excellent.

  In Test Example 3, plain paper C is passed through, the ratio of the amount of calcium carbonate between the front and back is 1.6, and the amount of calcium carbonate is 10 wt% or more. Therefore, the rotational load applying member is connected, and the load torque applying member is the oil damper. When the load torque was 0.3 N · m, the toner adhesion ◎ and the fixing unit durability ◯ were obtained.

  In Test Example 4, plain paper D is passed through, the ratio of the amount of calcium carbonate between the front and back is 1.1, and the amount of calcium carbonate is 10 wt% or more. Therefore, the rotational load applying member is connected, and the load torque applying member is the torque limiter. When the load torque was 0.5 N · m, the toner adhesion ◎ and the fixing unit durability Δ were obtained.

  In Test Example 5, plain paper A is passed through, the ratio of the amount of calcium carbonate between the front and back is 1.1, and the amount of calcium carbonate is 10 wt% or less, but the rotational load applying member is connected, and the load torque applying member is the oil damper. When the load torque was 0.3 N · m, the toner adhesion ◎ and the fixing unit durability ◯ were obtained.

  In Test Example 6, plain paper B was passed, the ratio of the amount of calcium carbonate between the front and back was 1.2, and the amount of calcium carbonate was 10 wt% or less, but the rotational load application member was connected, and the load torque application member was the torque limiter. When the load torque was 0.5 N · m, the toner adhesion ◎ and the fixing unit durability Δ were obtained.

  In Test Example 7, plain paper C was passed, the ratio of the amount of calcium carbonate between the front and back surfaces was 1.6, and the amount of calcium carbonate was 10 wt% or more. The fixing unit durability was excellent.

  In Test Example 8, plain paper D was passed through, the ratio of the amount of calcium carbonate between the front and back surfaces was 1.1, and the amount of calcium carbonate was 10 wt% or more. The fixing unit durability was excellent.

When test examples 1 and 2 are compared with test examples 5 and 6, with respect to fixing unit durability, good results are obtained in test examples 1 and 2, but test examples 5 and 6 are inferior. In Test Examples 5 and 6, since the rotational load is applied by the rotational load applying member even when the amount of calcium carbonate is small (when sticking is difficult to occur), the life of the fixing member and the pressure member is reduced.
Further, when the test examples 3 and 4 are compared with the test examples 7 and 8, good results are obtained in the test examples 3 and 4 with respect to toner fixation, but the test examples 7 and 8 are inferior. In Test Examples 7 and 8, when the amount of calcium carbonate is large (when sticking is likely to occur), the rotation load is not applied by the rotation load applying member, and thus toner sticking occurs.

(Reference numerals in FIGS. 6 to 8)
DESCRIPTION OF SYMBOLS 12 Fixing device 25 Halogen heater 28 Fixing roller 30 Pressure roller 33 Heat source 34 Separation claw 36 Temperature sensor 41 Core metal 42 Elastic layer 51 Drive source 55 Oil damper 56 Torque limiter 57 Gear 251 Fixing belt 252 Pressure roller 253 Fixing roller 254 Heating Roller (reference numeral in FIG. 9)
DESCRIPTION OF SYMBOLS 10 Photosensitive drum 10K Black photoconductor 10Y Yellow photoconductor 10M Magenta photoconductor 10C Cyan photoconductor 14,15,16 Support roller 17 Cleaning device 18 Image forming means 21 Exposure device 22 Secondary transfer device 23 Roller 24 Two Next transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Reversing device 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 49 Registration roller 50 Intermediate transfer body 53 Manual feed path 55 Switching Claw 56 Discharging roller 57 Discharging tray 58 Separating roller 60 Cleaning device 61 Developing device 62 Transfer roller 100B Image forming device 120 Tandem developing device 130 Document table 142 Paper feeding roller 143 Paper bank 144 Paper feeding cassette 145 Separating roller La 146 feeding path 147 transport rollers 148 feed path 150 copier main body 151 bypass tray 200 sheet feeding table 300 Scanner 400 automatic document feeder L exposure light

Japanese Patent No. 5495892 JP 2014-81610 A

Claims (10)

A fixing device that contacts the fixing member and the pressure member to fix the toner to the print medium; and
A rotational load applying member that applies a rotational load to the fixing member or the pressure member;
A data acquisition unit that acquires the amount of calcium carbonate on the front and back surfaces of the printing medium from a database having at least the product name of plain paper and the amount of calcium carbonate on the front and back surfaces of the plain paper;
An image forming apparatus comprising: a condition determining unit that determines a rotational load of the rotational load applying member in accordance with the amount of calcium carbonate on the front surface and the back surface of the print medium. Regarding the amount of calcium carbonate on the front and back surfaces of the print medium, the ratio of the amount of calcium carbonate represented by the following formula is 1.5 or more, and the amount of calcium carbonate on the surface of the print medium where the amount of calcium carbonate is large is 10 wt. % Or more,
The image forming apparatus according to claim 1, wherein the condition determining unit sets the rotational load of the rotational load applying member to 0.1 to 0.6 N · m.
Formula: Ratio of the amount of calcium carbonate = the amount of calcium carbonate on the surface of the printing medium having a large amount of calcium carbonate (wt%) / the amount of calcium carbonate on the surface of the printing medium having a small amount of calcium carbonate (wt%)   The image forming apparatus according to claim 2, wherein a rotation load of the rotation load applying member is 0.2 to 0.4 N · m. The amount of calcium carbonate on the front and back surfaces of the plain paper in the database is determined by measuring the ATR method (total reflection method) under the following conditions for both sides of the plain paper, and the peak area (A The image forming apparatus according to claim 1, which is obtained from a ratio (A / B) of a peak area (B) due to cellulose.
Conditions: Diamond, ZnSe, or diamond / ZnSe is used as a crystal, and the plain paper is pressed against the crystal with a pressure of 80 N or more.   The image forming apparatus according to claim 1, wherein the rotation load applying member is an oil damper.   The image forming apparatus according to claim 1, wherein the rotation load applying member is a torque limiter.   The rotational load applying member is connected to a rotating shaft of the pressure member via a driving force transmission member, and contacts and separates from the driving force transmission member according to the amount of calcium carbonate on the front surface and the back surface of the print medium. An image forming apparatus according to claim 1, wherein:   The fixing device includes a hollow cored bar and a release layer, and includes a fixing roller having a heat source therein, and an elastic layer that is disposed in pressure contact with the fixing roller and rotates as the fixing roller rotates. The image forming apparatus according to claim 1, further comprising a pressure roller. The fixing device includes a heating rotator that is heated by a heating source, a fixing rotator that is arranged in parallel with the heating rotator, and an endless loop that is looped between the heating rotator and the fixing rotator. The image forming apparatus according to claim 1, further comprising: a fixing belt having a shape, and a pressure rotating body that presses the fixing rotating body via the fixing belt.
An image forming method having a fixing step of fixing a toner to a printing medium by bringing a fixing member and a pressure member into contact with each other,
The fixing step performs fixing using a rotation load applying member that applies a rotation load to the fixing member or the pressure member, and has at least a product name of plain paper and calcium carbonate amounts on the front and back surfaces of the plain paper. The amount of calcium carbonate on the front and back surfaces of the printing medium is obtained from a database, and the rotational load of the rotational load applying member is determined and fixed according to the amount of calcium carbonate on the front and back surfaces of the printing medium. An image forming method.