JP2010181724A - Electrophotographic device and method for cooling continuous printing paper by electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic device configured by coupling two electrophotographic devices having the same paper feeding speed and using continuous printing paper, wherein the device can obtain excellent printing quality by defining cooling temperature of the paper that is about to enter the second electrophotographic device and controlling temperature of the paper that is about to enter the second electrophotographic device to be within an appropriate range with simple configuration; and to provide a method for cooling the continuous printing paper by the electrophotographic device. <P>SOLUTION: In the tandem type electrophotographic device where a plurality of electrophotographic devices are coupled, reference temperature to be a reference when the paper that is about to be supplied to the second electrophotographic device is cooled is set to lower temperature out of temperature at the time when the recovery of a photoreceptor of the second electrophotographic device becomes about 0 or temperature at the time when the recovery of toner becomes about 0. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic apparatus that performs printing using continuous printing paper and a method for cooling continuous printing paper by the electrophotographic apparatus.

  In an electrophotographic apparatus which is one of image forming apparatuses that perform image formation by an electrophotographic method, a photoconductive photosensitive member is charged and exposed to form an electrostatic charge latent image on the photosensitive member. Then, the electrostatic latent image formed on the photoreceptor is developed with a fine particle toner containing a resin as a binder and a colorant and the like, and the obtained toner image is transferred onto a recording paper and fixed to form an image. .

  In such an electrostatic image recording process, development of an electrostatic charge latent image with fine particle toner and fixing on a recording paper are particularly important processes.

  In a conventional electrophotographic apparatus, as a method for developing toner, a magnetic brush developing method using a two-component developer composed of a toner capable of high-speed and high-quality development and a magnetic carrier is often used. Further, as a method for fixing toner, a heat roller fixing method which is high in heat efficiency and capable of high-speed fixing is often used.

  In recent years, with the development of information equipment, laser beam printers have been developed that use a laser beam for exposure of a photoconductive photoreceptor and reproduce a recorded image with dots by a modulation signal instructed by a computer.

  In particular, since recent laser beam printers require higher speed, higher image quality, and colorization, it is necessary to reduce the diameter of the laser beam and reduce the dot density to 600 dpi (dots / inch) or more. In addition, an image forming process for performing color printing, double-sided printing, and the like has been studied.

  As an electrophotographic apparatus that performs color printing and double-sided printing, there is a tandem electrophotographic apparatus that uses a plurality of electrophotographic apparatuses connected together.

  For example, when two electrophotographic devices are connected, multicolor printing is performed by printing the basic color black on the first electrophotographic device and printing colors other than black on the second electrophotographic device. Realized. Double-sided printing is also possible by printing the basic color black on the surface of the paper with the first electrophotographic device, and reversing the front and back of the paper discharged from the first electrophotographic device. This is realized by printing the back side of the paper with a second electrophotographic apparatus.

  In such a tandem electrophotographic apparatus, the paper printed by the first electrophotographic apparatus is heated by the fixing device of the first electrophotographic apparatus, and the temperature is high. Therefore, when the sheet discharged from the first electrophotographic apparatus is supplied to the second electrophotographic apparatus, the sheet heats the photoreceptor of the second electrophotographic apparatus. The photoconductor heated by the paper heats the developing device and the cleaning device in contact with the photoconductor. For this reason, the temperature rises inside each of the above-mentioned devices, causing toner fusing, deteriorating the electrophotographic characteristics of the photoreceptor and the developer itself, and it is impossible to obtain good print quality.

  Therefore, various attempts have been made to solve such problems in conventional electrophotographic apparatuses. For example, in Patent Document 1, as a method of cooling the sheet after fixing of the first electrophotographic apparatus, a duct is opposed to the upper part of the side surface in the width direction of the paper accumulated by the paper folding device, and the cooling air is supplied to the side surface in the paper width direction. It is described that it is applied to the top. Further, Patent Document 2 includes a heat absorbing member that is provided in a portion that does not contact the paper as a cooling device and generates a heat absorbing action when a voltage is applied, and the air cooled by the heat absorbing action of the heat absorbing member has a hollow structure. It is described that the heat supplied to the inside of the cooling roller is removed and the heat of the sheet conveyed while contacting the cooling roller is removed. Further, Patent Document 3 includes a cooling unit that cools the heated paper, and the cooling unit is a metal cylindrical body that conveys the paper so that the outer peripheral surface of the cylindrical body is in contact with one end of the cylindrical body. Alternatively, it is described that both ends are provided with a blower that blows air into the cylindrical body.

  However, in the invention described in Patent Document 1, since the cooling air is directly applied to the paper, the cooling air flows to the paper storage unit, affects the folding of the paper, and may interfere with paper storage. Further, in the invention described in Patent Document 2, it is necessary to provide a heat absorbing member, the structure of the sheet cooling unit becomes complicated, and the cost of the product tends to increase. Furthermore, in the invention described in Patent Document 3, when the printing speed is increased, the cooling capacity by blowing is insufficient, and a sufficient cooling effect may not be obtained.

  Further, in a high-speed electrophotographic apparatus, the sheet conveyance speed is increased, so that it is difficult to secure a sufficient time for cooling the sheet. Therefore, it is necessary to control the temperature of the paper supplied to the second electrophotographic apparatus after clarifying the cooling temperature of the paper to what extent the paper should be cooled.

  The present invention has been made in view of the above circumstances, and has been made to solve this problem. The second electrophotographic apparatus having a configuration in which two electrophotographic apparatuses using continuous printing paper and having the same paper feeding speed are connected. It is possible to clarify the cooling temperature of the paper immediately before entering the electrophotographic apparatus, and to control the temperature of the paper immediately before entering the second electrophotographic apparatus to an appropriate range with a simple configuration to obtain a good print quality. It is an object of the present invention to provide an electrophotographic apparatus and a method for cooling continuous printing paper using the electrophotographic apparatus.

  The present invention employs the following configuration in order to achieve the above object.

  The present invention relates to a first electrophotographic apparatus that conveys continuous printing paper at the same paper feed speed, and the continuous printing connected to the first electrophotographic apparatus and discharged from the first electrophotographic apparatus. A second electrophotographic apparatus to which paper is supplied, and cooling for cooling the continuous printing paper before the continuous printing paper discharged from the first electrophotographic apparatus is supplied to the second electrophotographic apparatus And the temperature of the continuous printing paper immediately before being supplied to the second electrophotographic apparatus is the temperature at which the restoration rate of the photosensitive layer of the photosensitive member of the second electrophotographic apparatus becomes substantially zero or the second And a control means for controlling the cooling means so that the toner restoration rate of the electrophotographic apparatus is lower than the lower one of the temperatures at which the toner restoration rate is substantially zero.

  Further, in the electrophotographic apparatus of the present invention, the toner restoration rate of the second electrophotographic apparatus is substantially 0 at a temperature at which the restoration rate of the photosensitive layer of the photoreceptor of the second electrophotographic apparatus is substantially 0. When the temperature of the continuous printing paper immediately before being supplied to the second electrophotographic apparatus is lower than the temperature at which the endothermic peak rises in the differential heat curve of the photosensitive layer of the photoconductor Alternatively, the cooling means may be controlled to be lower.

  In the electrophotographic apparatus of the present invention, the restoration rate of the photosensitive layer of the photoreceptor of the second electrophotographic apparatus is substantially 0 at a temperature at which the toner restoration rate of the second electrophotographic apparatus is substantially 0. The temperature of the continuous printing paper immediately before being supplied to the second electrophotographic apparatus is lower than the onset temperature of the endothermic peak in the differential heat curve of the toner. It is good also as a structure which controls the said cooling means so that it may become.

  The cooling means of the electrophotographic apparatus of the present invention may be composed of a heat pipe and a fan.

  Further, in the electrophotographic apparatus of the present invention, the control means has a temperature at which the restoration rate of the photosensitive layer of the photoreceptor of the second electrophotographic apparatus is substantially zero or the restoration rate of the toner of the second electrophotographic apparatus. The temperature detected by the temperature detecting means for detecting the temperature of the continuous printing paper discharged from the first electrophotographic apparatus, having a temperature setting means in which the lower one of the temperatures that are substantially zero is set. And the temperature set in the temperature setting means may be compared to control the cooling means.

  In the electrophotographic apparatus of the present invention, the control unit may control the air volume of the fan attached to the heat pipe of the cooling unit.

  The electrophotographic apparatus of the present invention also includes a temporary storage means for temporarily storing the continuous printing paper discharged from the first electrophotographic apparatus, and a front / back conversion of the continuous printing paper discharged from the temporary storage means. The second electrophotographic apparatus may be configured to form an image on the surface of the continuous printing paper discharged from the conversion means.

  In the electrophotographic apparatus of the present invention, the conversion unit may be a heat pipe having the cooling unit.

  In the electrophotographic apparatus of the present invention, the fixing unit included in the first electrophotographic apparatus may include a contact heating fixing unit.

  The present invention provides a first electrophotographic apparatus and a second electrophotographic apparatus that convey continuous printing paper at the same paper feed speed, and the continuous printing paper discharged from the first electrophotographic apparatus is the second electrophotographic apparatus. A cooling means for cooling the continuous printing paper before being supplied to the electrophotographic apparatus, and a cooling method for the continuous printing paper by the electrophotographic apparatus, immediately before being supplied to the second electrophotographic apparatus. The temperature of the continuous printing paper is a temperature at which the restoration rate of the photosensitive layer of the photosensitive member of the second electrophotographic apparatus is substantially 0 or a temperature at which the restoration rate of the toner of the second electrophotographic apparatus is substantially 0. The method has a control procedure for controlling the cooling means so that the temperature is lower than the lower one.

  According to the present invention, the cooling temperature of the sheet immediately before entering the second electrophotographic apparatus in the electrophotographic apparatus configured to connect two electrophotographic apparatuses having the same sheet feeding speed using continuous printing paper is clarified. In addition, it is possible to obtain an image with good image quality by controlling the temperature of the sheet immediately before entering the second electrophotographic apparatus with a simple configuration within an appropriate range.

It is a figure explaining the electrophotographic apparatus of 1st embodiment. FIG. 2 is a diagram for explaining electrophotographic apparatuses 110 and 120 constituting the electrophotographic apparatus 100 of the first embodiment. It is a figure for demonstrating the turn unit 130 which performs front and back conversion of the continuous printing paper. It is a figure for demonstrating the function structure of the control part 150 of 1st embodiment. It is a figure which shows the differential thermal curve of the result of having performed the DSC measurement of the photosensitive layer of the selenium photoreceptor used for the electrophotographic apparatuses 110 and 120. FIG. It is a figure which shows the measuring system in the case of measuring the surface hardness of a selenium photoconductor with a micro indenter. It is a figure which shows the change by the temperature of the restoration rate of the selenium photoconductor by a micro indenter. It is a figure which shows the change by the temperature of the restoration rate of the toner adhering to the selenium photoconductor by a micro indenter. 3 is a flowchart for explaining the operation of a control unit 150 of the electrophotographic apparatus 100 according to the first embodiment. It is a figure which shows the change with temperature of the restoration rate of the photosensitive layer of the organic photoreceptor by a micro indenter. It is a figure which shows the change with the temperature of the restoration rate of the toner adhering to the organic photoreceptor by a micro indenter.

  In this embodiment, in a tandem type electrophotographic apparatus in which a plurality of electrophotographic apparatuses are connected, two reference temperatures serving as a reference for cooling the sheet immediately before being supplied to the second electrophotographic apparatus are The temperature is set to the lower one of the temperature at which the restoration rate of the photoreceptor of the eye electrophotographic apparatus becomes substantially zero or the temperature at which the restoration rate of the toner becomes substantially zero.

(First embodiment)
The best mode of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an electrophotographic apparatus according to a first embodiment.

  The electrophotographic apparatus 100 according to this embodiment is a tandem type electrophotographic apparatus in which two electrophotographic apparatuses 110 and 120 are connected. The electrophotographic apparatus 100 includes two electrophotographic apparatuses 110, an electrophotographic apparatus 120, and a turn unit 130.

  In the electrophotographic apparatus 100 of this embodiment, first, continuous printing paper (hereinafter, paper) is supplied to the electrophotographic apparatus 110, and the electrophotographic apparatus 110 performs printing. When printing is finished in the electrophotographic apparatus 110 and the paper is discharged, the discharged paper is turned upside down by the turn unit 130 and supplied to the electrophotographic apparatus 120.

  In the electrophotographic apparatus 100 of the present embodiment, multi-color printing on the paper surface or double-sided printing on the paper surface and the paper back surface can be performed with the above configuration. Note that the sheet feeding speed of the electrophotographic apparatus 110 of the present embodiment and the sheet feeding speed of the electrophotographic apparatus 120 are the same, for example, 7000 lpm (line / min).

  In the electrophotographic apparatus 100 of the present embodiment, the paper discharged from the electrophotographic apparatus 110 is cooled to an appropriate temperature and then supplied to the electrophotographic apparatus 120 to obtain good print quality.

  FIG. 2 is a diagram for explaining the electrophotographic apparatuses 110 and 120 constituting the electrophotographic apparatus 100 of the first embodiment. In this embodiment, since the electrophotographic apparatus 110 and the electrophotographic apparatus 120 have the same configuration, the electrophotographic apparatus 110 will be described with reference to FIG.

  The electrophotographic apparatus 110 of this embodiment includes a printing unit, and the charger 111 is disposed so as to face the surface of the photoconductor 112. The charger 111 uniformly charges the surface of the photoreceptor 112 that passes so as to face the charger 111. The uniformly charged surface of the photoconductor 112 is exposed by a laser beam 113. The laser beam 113 forms an electrostatic latent image on the surface of the photoreceptor 112 in accordance with a print information signal supplied from an information processing apparatus (not shown).

  The photosensitive member 112 is supported by a support shaft so as to rotate at a constant speed in the direction of an arrow on the paper surface, and a toner image is recorded and formed by a known electrophotographic process. In the electrophotographic apparatus 110 and the electrophotographic apparatus 120 of this embodiment, a selenium photoconductor is used as each photoconductor.

  The developing device 114 is disposed so as to face the surface of the photoreceptor 112 on which the electrostatic latent image is formed. The developing device 114 mixes and stirs the toner t with the carrier K, imparts a charge to the toner, and attaches the toner to the surface of the photosensitive member 112 with the electrostatic force of the electrostatic latent image to form a toner image 115.

  The continuous printing paper 30 sent out from a paper supply unit (not shown) comes into contact with the surface of the photoreceptor 112 so as to transfer the toner image 115 onto the surface. The transfer unit 116 applies a charge having a polarity opposite to that of the toner image to the back surface of the paper 30 that is in contact with the surface of the photoconductor 112, and transfers the toner image 115 formed on the surface of the photoconductor 112 to the paper 30. Generate electrostatic force. The toner remaining on the photoconductor 112 after the toner image 115 is transferred to the paper 30 is removed from the photoconductor by the cleaning device 117.

  The sheet 30 on which the toner image 115 has been transferred is supplied to a preheating device 118 and a contact heating and fixing device 119 that serve as fixing means. The contact-type heat fixing device 119 includes a heat roller and a backup roller that are in pressure contact with each other, and heats and presses the paper 30 to fix the toner image 115 on the surface of the paper 30. At this time, the electrophotographic apparatus 110 winds the paper 30 around the fixing roller by the winding roller 121 and earns heating time at the time of fixing. The paper 30 sent out from the fixing device is folded along the perforations of the continuous printing paper and stored in the storage unit 122.

  FIG. 3 is a diagram for explaining a turn unit 130 that performs front / back conversion of continuous printing paper.

  The turn unit 130 of this embodiment is provided between the electrophotographic apparatus 110 and the electrophotographic apparatus 120 and is included in the cooling device 140 that cools the paper 30. The sheet 30 discharged from the storage unit 122 of the electrophotographic apparatus 110 is conveyed to the turn unit 130 via the sheet buffer unit 133 including the upper bar 131 and the lower bar 132. The sheet 30 conveyed to the turn unit 130 is led to the electrophotographic apparatus 120 with its front and back reversed.

  The cooling device 140 according to the present embodiment includes a heat pipe 134, a temperature detection sensor 135, a radiation fin 136, a cooling fan 137, and a control unit 150. The heat pipe 134 constitutes a turn portion of the turn unit 130. The paper 30 is cooled by a heat pipe 134 that is in contact with the paper 30.

  The principle of cooling by the heat pipe 134 will be described below. The principle of cooling of the heat pipe 134 is that a range where the heat pipe 134 and the paper 30 abut is a heat receiving range from the paper 30 side, and an internal refrigerant is vaporized by heat transfer from the paper 30 in the heat receiving range. The refrigerant that is vaporized into gas moves from the heat receiving range to one end in the axial direction of the heat pipe 134 at a speed of about the speed of sound. A heat dissipating fin 136 is attached to the end of the heat pipe 134 in the axial direction, and the heat exchanging of the refrigerant is performed by the effect of the heat dissipating fin 136, and the heat is liquefied by being cooled. The liquefied refrigerant moves to the heat receiving range again by the capillary phenomenon, receives the heat from the paper 30 and is vaporized, and the paper 30 can be cooled by repeating the vaporization and liquefaction.

  The temperature detection sensor 135 is provided in the heat pipe 134 and detects the temperature of the paper 30. Note that the temperature detection sensor 135 of the present embodiment is provided at a position where the temperature of the heat pipe 134 can be detected.

  The radiation fins 136 are attached to the heat pipe 134. The cooling fan 137 cools the heat radiating fins 136. The control unit 150 controls the air volume output from the cooling fan 137. Hereinafter, the control unit 150 of the present embodiment will be described with reference to FIG.

  FIG. 4 is a diagram for explaining a functional configuration of the control unit 150 according to the first embodiment.

  The control unit 150 of the present embodiment includes a temperature setting unit 151, a temperature information acquisition unit 152, a temperature comparison unit 153, an air volume control unit 154, and a storage unit 155.

  In the temperature setting unit 151, a reference temperature that is a reference for cooling the paper 30 by the cooling device 140 is set. Details of the temperature set in the temperature setting unit 151 will be described later.

  The temperature information acquisition unit 152 acquires the temperature detected from the temperature detection sensor 135. The temperature comparison unit 153 compares the reference temperature set in the temperature setting unit 151 with the temperature acquired by the temperature information acquisition unit 152. The air volume control unit 154 controls the air volume of the cooling fan 137 based on the comparison result by the temperature comparison unit 153. The storage unit 155 is, for example, a memory used when executing the above processes.

  Here, the reference temperature set in the temperature setting unit 151 of the control unit 150 of the present embodiment will be described.

  In the present embodiment, the temperature setting unit 151 is preset with a reference temperature at which a good print image can be obtained. The air volume control unit 154 controls the air volume so that the temperature of the paper 30 becomes lower than the reference temperature when the paper 30 is supplied to the electrophotographic apparatus 120.

  In the electrophotographic apparatus 110 and the electrophotographic apparatus 120 of the present embodiment, a selenium photoreceptor having a photosensitive layer made of selenium or a selenium alloy is used from the viewpoint of mechanical properties such as printing durability.

In general, a photosensitive layer of a selenium photoreceptor for an electrophotographic apparatus is made of high-purity selenium on the surface of a metal drum or other conductive substrate such as aluminum or copper, as described in JP-A-59-121341. It can be obtained by depositing a selenium alloy such as selenium tellurium in a vacuum of about 10 ⁻⁵ Torr at a temperature of about 250 to 400 ° C.

  Various studies have been made on the structure of the deposited layer. This deposited layer is formed of a charge transport layer made of amorphous selenium or amorphous selenium-tellurium alloy, a charge generation layer made of amorphous selenium-tellurium alloy, an amorphous selenium-arsenic alloy on a conductive substrate. The surface protective layer may be sequentially laminated. The vapor deposition layer may not form the layer structure as described above, but may form a single layer made of amorphous selenium / tellurium / arsenic alloy. The amount of tellurium or arsenic added to selenium is usually about 0.1 to 5% by mass.

  The thermal characteristics (onset temperature (glass transition temperature), crystallization temperature, melting point, etc.) of such a selenium photoreceptor can be measured with a differential scanning calorimeter (DSC). The measurement of thermal characteristics using DSC is hereinafter referred to as DSC measurement.

  In DSC measurement, the exchange of heat such as heat absorption and heat generation of a material is measured, and its behavior is observed. The result of DSC measurement is expressed as a differential heat curve (DSC curve). FIG. 5 shows the results of DSC measurement of the photosensitive layer of the selenium photoreceptor used in the electrophotographic apparatuses 110 and 120 of this embodiment. FIG. 5 is a diagram showing a differential thermal curve as a result of performing DSC measurement of the photosensitive layer of the selenium photoreceptor used in the electrophotographic apparatuses 110 and 120. In this measurement, about 30 mg of a sample was heated from 0 ° C. to 220 ° C. at a rate of 2.5 ° C./min in an argon stream, and data was collected.

  In FIG. 5, the temperature at which the endothermic peak rises from the DSC baseline of the photosensitive layer of the selenium photosensitive member is the rising temperature, and the intersection of the baseline and the tangent on the low temperature side of the endothermic peak, that is, the shoulder value is the onset temperature (glass transition temperature). Also, hereinafter referred to as Tg), the temperature corresponding to the intersection of the baseline and the tangent at the lower part of the exothermic peak low temperature side is the crystallization temperature (hereinafter abbreviated as Tc), and the temperature corresponding to the decrease in the baseline is the melting point (hereinafter referred to as Tm). Abbreviated).

  In the photosensitive layer of the selenium photoreceptor, the arrangement of selenium atoms changes as the temperature rises, and rearrangement starts near the rising temperature. The photosensitive layer of the selenium photoreceptor becomes an aggregate of rearranged microcrystals when the crystallization temperature Tc is exceeded, and liquefies near the melting point Tm. In FIG. 5, the rising temperature is about 40 ° C., the onset temperature Tg is about 44 ° C., the crystallization temperature Tc is about 100 ° C., and the melting point Tm is about 210 ° C.

  In the photosensitive layer of the selenium photoreceptor, as described above, the physical properties change depending on the change of state, so that the mechanical strength decreases at a temperature higher than the rising temperature, and the dark resistance decreases at a temperature higher than the crystallization temperature Tc. As a result, the chargeability is lowered, and the photosensitive layer is washed away at a temperature equal to or higher than the melting point Tm. Therefore, when a selenium photoreceptor is used in an electrophotographic apparatus, it is generally recommended to use it at a low temperature lower than the onset temperature Tg.

  However, in the electrophotographic apparatus 100 that prints a large amount of data at a high speed at a time as in the present embodiment, it is necessary to supply a large amount of heat when fixing the toner on the paper 30, and the temperature inside the electrophotographic apparatus rises. Easy to do. In the tandem system in which a plurality of electrophotographic apparatuses are connected, the second electrophotographic apparatus (electrophotographic apparatus 120 of the present embodiment) is connected to the first electrophotographic apparatus (electrophotographic apparatus 110 of the present embodiment). Since heated paper is supplied, the temperature of the selenium photoreceptor of the second electrophotographic apparatus that comes into contact with the heated paper is likely to rise, and the temperature of the photosensitive layer of the selenium photoreceptor may exceed 40 ° C. is there.

  FIG. 6 is a diagram showing a measurement system in the case where the surface hardness of the selenium photoreceptor is measured with a microindenter. FIG. 7 is a diagram showing a change in the recovery rate of the selenium photoreceptor by the microindenter depending on the temperature.

  The restoration rate shown in FIG. 7 is the elastic deformation amount / total deformation amount when the selenium photoconductor is measured with the microindenter (manufactured by Shimadzu Corporation, Microindenter MTC500) shown in FIG. It can be evaluated that the larger the value of is, the harder the material is. According to FIG. 7, the recovery rate of the selenium photoreceptor greatly decreases with a temperature change of 35 to 40 ° C. The surface of the selenium photoreceptor is plasticized at a temperature around 40 ° C., and the toner tends to adhere to the toner. Aggregates of toner are easily generated on the photoreceptor and image defects are likely to occur. The temperature around 40 ° C. corresponds to the rising temperature in the DSC measurement of the selenium photoreceptor.

  Therefore, in this embodiment, in order to make it difficult for image defects to occur, the temperature of the sheet 30 immediately before entering the electrophotographic apparatus 120 is set to the rising temperature of the endothermic peak in the DSC curve of the photoreceptor (selenium photoreceptor) of the electrophotographic apparatus 120. It needs to be lower.

  On the other hand, when the change of the restoration rate by the micro indenter with respect to the temperature is similarly examined, the result is as shown in FIG.

  FIG. 8 is a graph showing a change in the restoration rate of the toner adhering to the selenium photoreceptor by the microindenter depending on the temperature. In FIG. 8, when the temperature at which the toner restoration rate is almost zero is compared with the endothermic characteristics obtained as a result of the DSC measurement of the toner, the toner has a restoration rate of almost 0 near the onset temperature (glass transition temperature). Therefore, the toner surface is plasticized near the onset temperature (glass transition temperature) and easily adheres to the photoreceptor, and toner agglomerates are generated on the photoreceptor and image defects are likely to occur.

  As a result of the above examination, the temperature of the sheet 30 immediately before entering the electrophotographic apparatus 120 is the rising temperature of the endothermic peak in the DSC curve of the photosensitive layer of the photoreceptor of the electrophotographic apparatus 120 or the DSC curve of the toner of the electrophotographic apparatus 120. It can be seen that it is necessary to lower the onset temperature of the endothermic peak at lower than the lower one.

  In other words, the temperature of the sheet 30 immediately before entering the electrophotographic apparatus 120 is the temperature at which the restoration rate of the photosensitive layer of the photoreceptor of the electrophotographic apparatus 120 becomes 0 or the temperature at which the restoration rate of the toner becomes 0. Of these, it is necessary to make the temperature lower than any lower temperature.

  In this embodiment, since the rising temperature of the endothermic peak in the DSC curve of the photosensitive layer of the selenium photoreceptor is 40 ° C. and the onset temperature of the endothermic peak in the DSC curve of the toner is 60 ° C., the electrophotographic apparatus 120 is entered. The temperature of the immediately preceding paper 30 needs to be lower than 40 ° C.

  Therefore, in the control unit 150 of the present embodiment, the reference temperature that is the reference for cooling the paper 30 set in the temperature setting unit 151 is set to 40 ° C.

  Hereinafter, the operation of the control unit 150 of the electrophotographic apparatus 100 of the present embodiment will be described with reference to FIG. FIG. 9 is a flowchart for explaining the operation of the control unit 150 of the electrophotographic apparatus 100 according to the first embodiment.

  In the electrophotographic apparatus 100, when the sheet 30 discharged from the electrophotographic apparatus 110 is conveyed to the turn unit 130 via the sheet buffer unit 133 and the sheet 30 comes into contact with the heat pipe 134, the control unit 150 causes the cooling device 140 to Start control. The control unit 150 may start the control by detecting the contact of the paper 30 based on a change in temperature detected by the temperature detection sensor 135, for example.

  When the control of the cooling device 140 by the control unit 150 is started, the control unit 150 acquires the temperature detected by the temperature detection sensor 135 by the temperature information acquisition unit 152 (step S91). Next, the control unit 150 uses the temperature comparison unit 153 to compare the acquired temperature with the reference temperature set in the temperature setting unit 151 (step S92). And the temperature comparison part 153 judges whether the acquired temperature is more than reference temperature (step S93).

  When the temperature acquired in step S93 is lower than the reference temperature, the control unit 150 ends the process without cooling the paper 30.

  When the temperature acquired in step S93 is equal to or higher than the reference temperature, the control unit 150 controls the air volume of the cooling fan 137 by the air volume control unit 154 (step S94). For example, the air volume control unit 154 of the present embodiment may blow air from the cooling fan 137 for a predetermined time set to the paper 30 and detect the temperature of the paper 30 again by the temperature detection sensor 135 when the predetermined time has elapsed. In this embodiment, the sheet 30 is cooled by the cooling fan 137 until the temperature detected by the temperature detection sensor 135 becomes lower than the reference temperature.

  In this embodiment, since the reference temperature is set to 40 ° C. in advance, the temperature of the paper 30 can be set to 40 ° C. or less immediately before the paper 30 is supplied to the electrophotographic apparatus 120 by performing the above control. .

  In this embodiment, for example, when air is blown from the cooling fan 137 by the air volume control unit 154, the speed at which the paper 30 is conveyed may be decreased. In this case, when operating the cooling fan 137, the air volume control unit 154 may instruct a sheet conveyance control unit (not shown) to reduce the conveyance speed. In this embodiment, the conveyance of the sheet 30 may be stopped when the cooling fan 137 is blowing air, and the conveyance of the sheet 30 may be resumed when the sheet 30 becomes lower than the reference temperature.

  In the example of FIG. 9, the example in which the temperature detection sensor 135 detects the temperature of the paper 30 every predetermined time has been described, but the present invention is not limited to this.

  The air volume control unit 154 according to the present embodiment may control the air volume with reference to a table indicating the relationship between the air volume and temperature stored in the storage unit 155, for example.

  For example, the storage unit 155 of the present embodiment may store a table or the like in which the air volume output from the cooling fan 137 is associated with the degree of decrease in the temperature of the paper 30. The air volume control unit 154 may control the cooling fan 137 with reference to this table, for example, so as to output the air volume necessary for lowering the temperature of the paper 30 to the target temperature. At this time, the target temperature is preferably lower than the reference temperature.

  The air volume control unit 154 according to the present embodiment has any configuration as long as it controls the air volume of the cooling fan 137 so that the temperature of the paper 30 becomes lower than the reference temperature immediately before being supplied to the electrophotographic apparatus 120. The present embodiment can be applied.

  As described above, in the present embodiment, the reference temperature used as the reference for cooling the sheet 30 is the temperature at which the restoration rate of the photosensitive layer of the photosensitive member of the electrophotographic apparatus 120 becomes substantially zero or the toner. Is set to a temperature at which the restoration rate of the photosensitive layer of the photosensitive member, which is the lower temperature, becomes substantially zero. In the present exemplary embodiment, the surface of the photosensitive layer of the photoconductor is plasticized and the toner easily adheres, and the toner aggregate is prevented from being easily generated on the photoconductor and causing an image defect. With such a configuration, the temperature of the paper 30 immediately before entering the electrophotographic apparatus 120 can be controlled within an appropriate range, and an image with good image quality can be obtained.

(Second embodiment)
A second embodiment of the present invention will be described below with reference to the drawings. The second embodiment of the present invention is different from the first embodiment in that the photoconductors of two electrophotographic apparatuses connected to each other are organic photoconductors (OPC). Therefore, in the following description of the second embodiment, only differences from the first embodiment will be described, and those having the same functional configuration as the first embodiment will be used in the description of the first embodiment. The same reference numerals as those used are assigned, and the description thereof is omitted.

  The photoconductor of the electrophotographic apparatus 110 and the photoconductor of the electrophotographic apparatus 120 of the present embodiment are organic photoconductors, respectively.

  The temperature at which the restoration rate of the photosensitive layer of the organic photoreceptor becomes substantially zero is different from the temperature at which the restoration rate of the photosensitive layer of the selenium photoreceptor described in the first embodiment becomes substantially zero.

  FIG. 10 is a diagram showing a change in the recovery rate of the photosensitive layer of the organic photoreceptor by the microindenter depending on the temperature. As shown in FIG. 10, the temperature at which the restoration rate of the photosensitive layer of the organic photoreceptor becomes approximately 0 is about 90.degree. The onset temperature Tg of the photosensitive layer of the organic photoreceptor is about 83 ° C.

  FIG. 11 is a diagram showing a change in the restoration rate of toner attached to the organic photoreceptor by the microindenter depending on the temperature. As shown in FIG. 11, the temperature at which the toner restoration rate becomes approximately 0 is about 55 ° C. The onset temperature Tg of the toner is 53 ° C.

  Therefore, when an organic photoreceptor is used in the electrophotographic apparatus 110 and the electrophotographic apparatus 120 as in the present embodiment, the temperature and toner are restored when the restoration rate of the photosensitive layer of the photoreceptor of the electrophotographic apparatus 120 is substantially zero. Of the temperatures at which the rate becomes 0, the lower temperature is the temperature at which the toner restoration rate becomes substantially 0.

  Therefore, in the control unit 150 that controls the cooling device 140 of the present embodiment, the reference temperature set in the temperature setting unit 151 may be the temperature at which the toner restoration rate becomes substantially zero. If the reference temperature is set to a temperature at which the toner restoration rate becomes substantially zero, the temperature of the paper 30 immediately before the paper 30 is supplied to the electrophotographic apparatus 120 is the same as that at which the toner restoration rate becomes substantially zero. It can be lower than the temperature. Therefore, according to this embodiment, the surface of the toner is plasticized and easily adheres to the photoconductor, and toner aggregates are prevented from being generated on the photoconductor to easily cause image defects. It is possible to obtain a good print quality by controlling the temperature of the paper 30 immediately before entering the photographic device 120 within an appropriate range.

  As mentioned above, although this invention has been demonstrated based on each embodiment, this invention is not limited to the requirements shown in the said embodiment. With respect to these points, the gist of the present invention can be changed without departing from the scope of the present invention, and can be appropriately determined according to the application form.

  The present invention is applicable to an electrophotographic apparatus in which a plurality of electrophotographic apparatuses are connected.

100, 110, 120 Electrophotographic apparatus 130 Turn unit 133 Paper buffer unit 134 Heat pipe 135 Temperature detection sensor 136 Radiation fin 137 Cooling fan 140 Cooling device 150 Control unit 151 Temperature setting unit 152 Temperature information acquisition unit 153 Temperature comparison unit 154 Air volume control Section 155 Storage section

JP-A-1-270068 JP-A-1-266557 JP 2007-65090 A

Claims (10)

A first electrophotographic apparatus that conveys continuous printing paper at the same paper feed speed;
A second electrophotographic apparatus connected to the first electrophotographic apparatus and supplied with the continuous printing paper discharged from the first electrophotographic apparatus;
Cooling means for cooling the continuous printing paper before the continuous printing paper discharged from the first electrophotographic device is supplied to the second electrophotographic device;
The temperature of the continuous printing paper immediately before being supplied to the second electrophotographic apparatus is a temperature at which the restoration rate of the photosensitive layer of the photosensitive member of the second electrophotographic apparatus becomes substantially zero, or the second electrophotographic An electrophotographic apparatus comprising: control means for controlling the cooling means so that the toner restoration rate of the apparatus is lower than the lower one of the temperatures at which the toner restoration rate is substantially zero. When the temperature at which the restoration rate of the photosensitive layer of the photoreceptor of the second electrophotographic apparatus is substantially 0 is lower than the temperature at which the toner restoration rate of the second electrophotographic apparatus is substantially 0,
The control means includes
The cooling means is controlled so that the temperature of the continuous printing paper immediately before being supplied to the second electrophotographic apparatus is lower than the rising temperature of the endothermic peak in the differential heat curve of the photosensitive layer of the photoreceptor. Item 2. The electrophotographic apparatus according to Item 1. When the temperature at which the restoration rate of the toner of the second electrophotographic apparatus is substantially 0 is lower than the temperature at which the restoration rate of the photosensitive layer of the photoreceptor of the second electrophotographic apparatus is substantially 0,
The control means includes
2. The cooling unit is controlled such that the temperature of the continuous printing paper immediately before being supplied to the second electrophotographic apparatus is lower than an onset temperature of an endothermic peak in a differential heat curve of the toner. Electrophotographic equipment.   The electrophotographic apparatus according to claim 1, wherein the cooling unit includes a heat pipe and a fan. The control means includes
The lower one of the temperature at which the restoration rate of the photosensitive layer of the photosensitive member of the second electrophotographic apparatus becomes substantially zero or the temperature at which the restoration rate of the toner of the second electrophotographic apparatus becomes substantially zero is set. Temperature setting means,
Based on the result of comparing the temperature detected by the temperature detecting means for detecting the temperature of the continuous printing paper discharged from the first electrophotographic apparatus with the temperature set in the temperature setting means, the cooling means is provided. The electrophotographic apparatus according to claim 1, which is controlled. The control means includes
6. The electrophotographic apparatus according to claim 4, wherein an air volume of the fan attached to the heat pipe of the cooling unit is controlled. Temporary storage means for temporarily storing the continuous printing paper discharged from the first electrophotographic apparatus;
Conversion means for converting the front and back of the continuous printing paper discharged from the temporary storage means,
The electrophotographic apparatus according to claim 1, wherein the second electrophotographic apparatus forms an image on a surface of the continuous printing paper discharged from the conversion unit.   The electrophotographic apparatus according to claim 7, wherein the conversion unit is a heat pipe of the cooling unit.   The electrophotographic apparatus according to claim 1, wherein the fixing unit included in the first electrophotographic apparatus includes a contact heating fixing unit. A first electrophotographic apparatus and a second electrophotographic apparatus that convey continuous printing paper at the same paper feed speed, and the continuous printing paper discharged from the first electrophotographic apparatus is transferred to the second electrophotographic apparatus. A cooling means for cooling the continuous printing paper before being supplied, and a method for cooling the continuous printing paper by an electrophotographic apparatus comprising:
The temperature of the continuous printing paper immediately before being supplied to the second electrophotographic apparatus is a temperature at which the restoration rate of the photosensitive layer of the photosensitive member of the second electrophotographic apparatus becomes substantially zero, or the second electrophotographic A method for cooling continuous printing paper, comprising: a control procedure for controlling the cooling means so that a toner restoration rate of the apparatus is lower than a lower one of the temperatures at which the toner restoration rate becomes substantially zero.

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