JPH07114291A - Electrophotographic recording device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of curling even in the case of using a recording paper with moisture adsorbed because it is left as it is for a long time, and to stabilize the quality of the recording paper by varying a fixation temperature in accordance with a recording paper feeding order, as for an electrophotographic recording device for press-contacting the recording paper with a fixing roller by heat and fixing the medium recorded on the surface to the paper. CONSTITUTION:The device is provided with a recording paper cassette 22 capable of loading the recording paper P, a paper feeding part 21 for separating and feeding the recording paper P from the cassette 22 one by one, a developing device 14 for sticking toner to an electrostatic latent image formed on a photoreceptor belt 13 and developing the image, a transfer device 15 for transferring the toner image formed on the photoreceptor belt 13 to the recording paper P and a fixing part 31 for press-contacting the fixing roller 32 with the paper P by heat and fixing the toner on the recording paper P. The device is constituted so that the temperature of the fixing roller 32 may be variable at least at two high and low stages or more stages, and the device is provided with an MPU 52 for recognizing the number of fed recording papers P and controlling the temperature of the fixing roller 32 so as to be set at a lower temperature when the 1st paper is fed and set at a higher temperature when the 2nd and succeeding recording papers P are continuously fed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording apparatus, and more particularly to an electrophotographic recording apparatus for fixing a recording medium on its surface by heating and pressing a fixing roller against recording paper.

[0002]

2. Description of the Related Art A sheet feeding section for separating and feeding recording sheets one by one from a recording sheet cassette in which recording sheets are stacked, and a toner for an electrostatic latent image formed by receiving information and a document image on a photoconductor. A developing unit that develops with a (recording medium) to form a toner image, a transfer unit that transfers the toner image onto the recording paper, and a fixing unit that heats and presses the fixing roller against the recording paper to fix the toner on the surface of the recording paper. There is known an electrophotographic recording apparatus which is provided with and which records an image on a recording sheet.

As an electrophotographic recording apparatus of this kind, there is, for example, a copying machine, a facsimile apparatus or the like, and a recording sheet for recording an image by this apparatus is stored in a recording sheet cassette. In particular, in the facsimile apparatus, the recording paper remains stored in the recording paper cassette for a long time when the reception frequency is low. Further, since the recording paper used in this electrophotographic recording apparatus is made of plain paper, it has the property of absorbing moisture when exposed to the atmosphere for a long time and being deformed (curled) into a rolled state when heat is applied.

In this electrophotographic recording apparatus, if the toner image is transferred onto the recording paper at the transfer portion, it will be destroyed by being touched. Therefore, the fixing roller is heated and brought into contact with the recording paper at the fixing portion so that the toner image is transferred to the toner. It is designed to be fixed by applying heat and pressure. Therefore, there is a problem that the recording paper is curled. In order to solve such a problem, for example, in Japanese Unexamined Patent Publication No. 4-291277, by closing the discharge port of the discharge conveyance path with a closing member, water vapor is retained in the discharge path and after fixing, An electrophotographic recording apparatus (hereinafter referred to as a first conventional example) is described which absorbs moisture again on a recording sheet to reduce curl.

Further, in Japanese Patent Laid-Open No. 3-192061, there is provided a pair of waist rollers which face each other and one outer circumference is located inside the other outer circumference, and are conveyed by one's own weight or the urging force of the urging means. There is described an electrophotographic recording apparatus (hereinafter referred to as a second conventional example) in which a recording sheet is sandwiched and attached. Further, Japanese Patent Application Laid-Open No. 4-93970 discloses an electrophotographic recording apparatus (hereinafter, referred to as a curl) which removes a curl of a recording sheet by reversing the recording sheet after transfer and fixing and passing the fixing sheet again without transferring. The third conventional example) is described.

At present, as in the second conventional example,
The mechanism that dynamically attaches the waist is widely used.

[0007]

However, in the first conventional example, it is difficult to stably retain water vapor even if the paper discharge path is closed, and furthermore, the process from fixing to paper discharge is completed in a short time. Therefore, it is difficult to make the recording paper absorb moisture again as the curl is reduced. Further, in the second conventional example, it is difficult to remove the deformation from the recording paper that has been curled once even if the waisting process is performed, and the recording is performed by the waisting roller whose one outer circumference is located inside the other outer circumference. The curl cannot be removed by sandwiching the paper.

Further, in the third conventional example, even if the curled recording paper is passed through the fixing section again, it is heated at the first fixing section to remove moisture,
It is difficult to remove the curl even if it is heated again. Therefore, according to the first aspect of the present invention, the fixing temperature is changed according to the feeding order of the recording paper to prevent the occurrence of curling even when using the recording paper that is left for a long time and absorbs moisture. The purpose is to stabilize the quality of recording paper on which an image is recorded.

According to the second aspect of the present invention, the fixing temperature is changed according to the water content of the recording paper to prevent the occurrence of curling even when the recording paper that has been left for a long time to absorb moisture is used. The purpose is to stabilize the quality of recording paper on which an image is recorded. According to the third aspect of the present invention, the fixing temperature is changed according to the thickness of the recording paper, so that the curl is prevented from occurring even when the recording paper which is easily curled is used, and the image is recorded. The purpose is to stabilize the quality of recording paper.

According to a fourth aspect of the present invention, the fixing temperature is changed according to the leaving time of the recording paper to prevent the occurrence of curling even when the recording paper that has been left for a long time and absorbs moisture is used. The purpose is to stabilize the quality of recording paper on which an image is recorded. According to the fifth aspect of the invention, by changing the fixing temperature according to the exposure time of the recording paper, curl is prevented from occurring even when the recording paper that has been left for a long time and absorbed moisture is used to record an image. The purpose is to stabilize the quality of the printed recording paper.

[0011]

In order to achieve the above object, the invention according to claim 1 is a recording paper cassette capable of accommodating a plurality of recording papers, and separating the recording papers one by one from the recording paper cassette. And a sheet feeding unit for feeding the recording medium to the recording sheet, and an image forming unit for forming an image by transferring the recording medium to the recording sheet. A fixing roller is heated and pressed against the recording sheet to fix the recording medium transferred onto the surface of the recording sheet. In the electrophotographic recording apparatus for recording an image on a recording sheet, the fixing section for fixing the recording medium on the recording sheet of the fixing roller is at least a high temperature 2
The recording sheet number recognition means for recognizing the number of recording sheets to be fed from the recording sheet cassette is configured to be variable in steps or more, and when the recording sheet recognized by the recognition means is the first sheet, the temperature is continuously low. A fixing temperature control unit for controlling the temperature of the fixing roller to a high temperature after the first sheet is provided.

According to a second aspect of the present invention, there are provided a recording paper cassette capable of accommodating a plurality of recording papers, a paper feeding means for separating and feeding the recording papers one by one from the recording paper cassette, and a recording medium. An image forming unit that transfers an image to a recording sheet to form an image and a fixing unit that heats and presses a fixing roller onto the recording sheet to fix the recording medium transferred onto the surface of the recording sheet are provided. In an electrophotographic recording apparatus for recording, a temperature of fixing a recording medium on a recording paper of a fixing roller is variable in at least two steps of high and low, and a resistance value of the recording paper fed from the recording paper cassette is set in the fixing unit. And a fixing unit for controlling the temperature of the fixing roller to a low temperature when the resistance value of the recording paper detected by the detecting unit exceeds a preset predetermined value, and to a high temperature when the resistance value is less than the predetermined value. Temperature control means, It is characterized in that the digits.

According to a third aspect of the present invention, there are provided a recording paper cassette capable of accommodating a plurality of recording papers, a paper feeding unit for separating and feeding the recording papers one by one from the recording paper cassette, and a recording medium. An image forming unit that transfers an image to a recording sheet to form an image and a fixing unit that heats and presses a fixing roller onto the recording sheet to fix the recording medium transferred onto the surface of the recording sheet are provided. In an electrophotographic recording apparatus for recording, a temperature of fixing a recording medium on a recording paper of a fixing roller is made variable in at least two steps of high and low, and a surface potential of the recording paper fed from the recording paper cassette is recorded. And a fixing temperature for controlling the temperature of the fixing roller to a low temperature when the potential of the recording paper detected by the detecting means exceeds a preset predetermined value, and to a high temperature when the potential is less than the predetermined value. Control means, It is characterized in that the digits.

According to a fourth aspect of the present invention, there are provided a recording paper cassette capable of stacking a plurality of recording papers, a paper feeding means for separating the recording papers one by one from the recording paper cassette, and a recording medium. An image forming unit that transfers an image to a recording sheet to form an image and a fixing unit that heats and presses a fixing roller onto the recording sheet to fix the recording medium transferred onto the surface of the recording sheet are provided. In an electrophotographic recording apparatus for recording, the fixing unit is configured such that a temperature for fixing a recording medium on a recording sheet of a fixing roller is variable in at least two steps of high and low, and the time when the recording sheet is stored in the recording sheet cassette is set. Storage time measuring means for measuring, and fixing temperature control means for controlling the temperature of the fixing roller to a low temperature when the storage time measured by the measuring means exceeds a preset predetermined time and to a high temperature when the storage time is shorter than the predetermined time. And It is characterized in that the digits.

According to a fifth aspect of the present invention, there are provided a recording paper cassette capable of accommodating a plurality of recording papers, a paper feeding unit for separating and feeding the recording papers one by one from the recording paper cassette, and a recording medium. An image forming unit that transfers an image to a recording sheet to form an image and a fixing unit that heats and presses a fixing roller onto the recording sheet to fix the recording medium transferred onto the surface of the recording sheet are provided. In an electrophotographic recording apparatus for recording, the fixing unit is configured such that the temperature for fixing the recording medium on the recording paper of the fixing roller is variable at least in two steps, that is, from the completion of image recording on the previous recording paper to the next image recording. The elapsed time measuring means for measuring the elapsed time until the start, and the temperature of the fixing roller to a low temperature when the elapsed time measured by the measuring means exceeds a preset predetermined time, and to a high temperature when the elapsed time is less than the predetermined time. Fixing temperature to control It is characterized in that provided as control means.

[0016]

According to the present invention, the number of recording sheets fed from the recording sheet cassette is recognized by the fed sheet number recognizing means, and when the recognition information is the first sheet, the fixing temperature control means causes the temperature of the fixing roller. Is lowered to fix the recording medium on the recording paper. When the second and subsequent sheets of the recognition information are continuous, the fixing temperature control unit raises the temperature of the fixing roller to fix the recording medium on the recording paper. Therefore, the temperature on the lower limit side of the temperature range in which the recording medium can be fixed is applied to the first exposed recording paper that is stacked on the uppermost surface and exposed. Further, the normal temperature for fixing the recording medium is applied to the second and subsequent recording sheets.

According to the second aspect of the invention, the resistance value of the recording paper fed from the recording paper cassette is detected by the resistance detecting means, and when the detected information exceeds a predetermined value, the fixing temperature control means is used to fix the fixing roller. The temperature is lowered to fix the recording medium on the recording paper. When the detection information is less than or equal to the predetermined value, the fixing temperature control means raises the temperature of the fixing roller to fix the recording medium on the recording paper. Therefore, the moisture content increases due to moisture absorption, and the temperature at the lower limit of the fixing temperature range of the recording medium is added to the recording paper having a high resistance value. In addition, a normal temperature for fixing the recording medium is applied to the recording paper that absorbs less moisture.

According to the third aspect of the invention, the surface potential of the recording paper fed from the recording paper cassette is detected by the potential detecting means, and when the detected information exceeds the predetermined value, the fixing temperature control means is used to fix the fixing roller. The temperature is lowered to fix the recording medium on the recording paper. When the detection information is less than or equal to the predetermined value, the fixing temperature control means raises the temperature of the fixing roller to fix the recording medium on the recording paper. Therefore, the temperature at the lower limit of the temperature range in which the recording medium can be fixed is applied to the recording paper having a small thickness and a high potential. In addition, a normal temperature for fixing the recording medium is applied to the recording paper having a predetermined thickness or more.

According to the present invention, the storage time of the recording paper in the recording paper cassette is measured by the storage time measuring means, and when the measured information exceeds the predetermined time, the fixing temperature control means causes the fixing roller to rotate. The temperature is lowered to fix the recording medium on the recording paper. Further, when the measured information is less than the predetermined time, the temperature of the fixing roller is raised by the fixing temperature control means to fix the recording medium on the recording paper. Therefore, the temperature on the lower limit side of the temperature range in which the recording medium can be fixed is applied to the recording paper which has been left for a long time and has absorbed moisture. Further, a normal temperature for fixing the recording medium is applied to the recording paper which has a short standing time and does not absorb moisture.

According to the fifth aspect of the invention, the elapsed time from the completion of image recording on the preceding recording paper to the start of the next image recording is measured by the elapsed time measuring means, and when the measured information exceeds the predetermined time, fixing is performed. The temperature control means lowers the temperature of the fixing roller to fix the recording medium on the recording paper. Further, when the measured information is less than the predetermined time, the temperature of the fixing roller is raised by the fixing temperature control means to fix the recording medium on the recording paper. Therefore, the temperature on the lower limit side of the temperature range in which the recording medium can be fixed is applied to the recording paper that is stacked on the uppermost surface for a long time and is exposed and absorbs moisture. Also,
A normal temperature for fixing the recording medium is applied to the recording paper having a short exposure time and no moisture absorption.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 13 are views showing an example of a facsimile apparatus to which an embodiment of the electrophotographic recording apparatus according to the invention described in any one of claims 1 to 5 is applied. First, the configuration will be described.

In FIG. 1, reference numeral 11 denotes a recording scanning unit (image forming unit). The recording scanning unit 11 is precharged by a charger 12 and then is optically written by an unillustrated exposing unit to receive an image. A photoconductor belt 13 on which an electrostatic latent image such as information is formed, a developing device 14 that adheres toner (recording medium) to the electrostatic latent image to form a toner image and develops it, and a toner image is transferred and received. Transfer device for forming image of information on recording paper P
After the toner image is transferred onto the recording paper P, the cleaning belt 16 scrapes and collects the residual toner on the photoconductor belt 13, and the residual electric charge is removed by the neutralization LED (light emission). The diode) 17 emits light and erases.

Reference numeral 21 denotes a paper feeding unit (paper feeding means)
Is the uppermost recording paper P stacked on the recording paper cassette 22.
A feed roller 23 that contacts the sheet and separates and calls it one by one; a registration roller 24 that contacts the called edge to correct the skew and feed the sheet; and a recording sheet P that has been fed.
And a paper feed roller 25 for passing the paper between the photoconductor belt 13 and the transfer unit 15, and feeds the recording paper P in synchronization with the driving of the photoconductor belt 13.

Reference numeral 31 denotes a fixing unit. The fixing unit 31 has a heater (not shown) therein, and a fixing roller 32 which is heated to and maintained at a predetermined temperature and a pressing roller 32 which comes into contact with the fixing roller 32 with a predetermined pressing force. The recording paper P is composed of a pressure roller 33, and is sandwiched by a predetermined pressing force on the recording paper P which is fed from the recording paper cassette 22 by the paper feeding unit 21 and on which an image is formed by the recording scanning unit 11 and a predetermined temperature is applied (heating pressure contact). By this, the toner adhering to the surface of the recording paper P is fixed, an image is recorded, and the paper is discharged.

Next, processing of image information transmitted and received will be described with reference to FIG. When transmitting image information, the image information exposed and read by the reading scanning unit (known exposure unit) 41 is temporarily stored in the line memory 43 via the reading processing unit 42, and then stored in the compression mode of the information compression / decompression unit 45. According to the above, the redundancy is removed and compressed while the image information is read from the line memory 43 through the line memory control unit 44, and the RAM (Random Access Memory) is sequentially accessed through the bus 46.
ry) 47 is used as a transmission buffer and stored. Then, the stored image information is read from the RAM 47, sent to the modem 49 via the communication control unit 48, modulated by the modem 49, and sent to a predetermined communication line via the network control unit 50. The bus 46 is a so-called data bus and address bus.

When the image information is received, the image information that has passed through the network control unit 50 from the communication line is demodulated by the modem 49 and then output to the bus 46 via the communication control unit 48 and the RAM 47 is used as a reception buffer. accumulate. Then, the stored image information is sequentially read from the RAM 47, input to the information compression / decompression unit 45 via the bus 46, restored, temporarily stored in the line memory 43, and then called from the line memory 43 to call the recording processing unit 51. After that, the image is recorded on the recording paper P by the recording scanning unit 11.

Although the image information simply passes through the network control unit 50 and the communication control unit 48, the communication control information is read and understood by the communication control unit 48, and transmission control, error control, etc. Execution processing is performed, and when journal information is required, it is stored in a RAM having a non-volatile function. Also,
A call signal for network control is processed by the network control unit 50. Furthermore, image information that does not require compression or decompression of information is
Image information from the reading processing unit 42 can be read out from the line memory 43 directly to the outside such as the RAM 47 via the bus 46 to perform image processing and image communication. In addition, DMA (Dire
It is also possible to directly input image-processed information and image-synthesized information using the ct Memory Access) 52, or to superimpose on image information and store it in the line memory 43 for recording / playback. is there. In addition, by using the line memory 43 separately from the information compression / decompression unit 45, the compressed information is restored regardless of the reading scan or the recording scan and is output via the line memory 43. Can also be considered.

The overall system control, information flow management, communication control, and network control are controlled by M.
The PU (Micro Processing Unite) 53 is designed so that this MPU 53 is a ROM (Read Only Memory).
Each unit is controlled according to the control program stored in 54. The main processing of the system control of the MPU 53 is control related to the man-machine interface by the panel unit 55 and control related to the mechanical configuration of the reading scanning unit 41 and the recording scanning unit 11 by the mechanism control unit 56. The panel section 55 has the number of input / output terminals and control method set according to the type and type of panel switch and panel display.
The type and quantity of drivers and sensors are set according to the system and mechanical configuration of the reading scanning unit 41 and the recording scanning unit 11, and control is set in the same manner.

Next, the structure of the invention according to claim 1 will be described. 1 and 2, when the MPU 53 receives the image information and records the image on the recording paper P, after recording one image information, the data of the received image information remains in the line memory 43 or the RAM 47. The number of recording sheets P to be fed from the recording sheet cassette 22 is recognized by confirming whether or not the recording sheets are fed. That is, the MPU 53 constitutes a sheet feed number detecting means.

Further, the MPU 53 controls the temperature of the fixing roller 32 of the fixing unit 31 according to the number of fed recording sheets P, and when the recording sheet P for recording image information is the first sheet. The temperature of the fixing roller 32 is in a low temperature fixing mode (for example, 1
The temperature of the heater is controlled so that it becomes 40 ° C., and the recording paper P
When two or more sheets are continuous, the heater temperature is controlled so that the temperature of the fixing roller 32 becomes the high temperature fixing mode (for example, 170 ° C.). That is, MPU53
It constitutes a fixing temperature control means.

Next, the operation of the invention according to claim 1 will be described with reference to FIG. First, when in the standby state, the temperature of the fixing roller 32 is in the low temperature fixing mode. Then, when the image information is received, the first sheet of recording paper P is fed from the recording sheet cassette 22 by the sheet feeding section 21, and the image information of one sheet is transferred to the recording sheet P by the recording scanning section 11. Then, the temperature of the fixing roller 32 is set to the low temperature fixing mode, the toner is fixed by the fixing unit 31, and the image is recorded (step Sa1). Therefore, it is necessary to fix the toner to the first recording paper P that has been exposed to the uppermost surface of the recording paper P loaded in the recording paper cassette 22 and has absorbed moisture after a lapse of a predetermined time. The lower limit temperature is applied, and image information is recorded without curling.

Next, it is confirmed by the MPU 53 whether the received image information data remains (step Sa2),
When there are no more than two pieces of received image information and no data remains, the image recording operation is completed (completed). Also, when it is recognized that there are two or more pieces of image information and data remains, the fixing mode for fixing the toner is switched,
The temperature of the fixing roller 32 of the fixing unit 31 is set to the high temperature fixing mode by controlling the heating temperature of the heater by the MPU 53 (step Sa3).

Next, the recording paper cassette is fed by the paper feeding unit 21.
A second recording sheet P is fed from within 22, and the image information for one sheet is transferred to the recording sheet P by the recording scanning unit 11, and the temperature of the fixing roller 32 is in the high temperature fixing mode. The toner is fixed by the fixing unit 31 and the image is recorded (step Sa4). Therefore, the recording paper cassette 22
The normal temperature for fixing the toner is applied to the second and subsequent recording sheets P, which absorb less moisture within a predetermined time at the uppermost surface of the recording sheets P stacked therein, and the image is generated without curling. Information is recorded.

As described above, according to this embodiment, when the image information is recorded on the recording paper P, the lower limit temperature required for fixing the toner is added to the recording paper P which has absorbed moisture,
Further, since the normal temperature is applied to the recording paper P that has not absorbed moisture, the fixing temperature of the toner is switched according to the absorption of moisture of the recording paper P to prevent curling and reduce the fixing rate of the toner. Information can be recorded on the recording paper P.

Next, the structure of the invention according to claim 2 will be described. 1, 2, and 4, the paper feed roller 23 of the paper feed unit 21 is rotatably supported by the chassis 61 of the apparatus main body and is rotated by the power transmitted to the drive gear 62, as shown in FIG. A corner claw 64 is provided which is fixed to the rotating shaft 63 and abuts on the leading end of the recording paper P stacked in the recording paper cassette 22 in the paper feeding direction.
The recording paper P is fed one by one by a so-called corner claw separation method in which the uppermost recording paper P is bent by the corner claws 64 by rotating 23 and bent.

The paper feeding section 21 comprises a paper feeding roller 23 made of a conductive rubber mixed with a conductive material and a rotary shaft.
An electrode 65 is provided on the drive gear 62 side of 63, and the electrode 65 and the corner pawl 64 are electrically connected to the mechanism control unit 56 so that the resistance of the recording paper P is detected between the paper feed roller 23 and the corner pawl 64. It has become. That is, the paper feed roller 23, the corner claw 64, the electrode 65, and the mechanism control unit 56 constitute resistance detecting means.

Further, the MPU 53 controls the temperature of the fixing roller 32 in accordance with the resistance value of the recording paper P detected by the mechanism control section 56. Since it contains water (moisture absorption), the resistance value when not containing water is preset as a set value, and when the resistance value detected by the mechanism control unit 56 exceeds this set value, the fixing roller 23 The temperature of is switched from the high temperature fixing mode to the low temperature fixing mode. That is, MP
U53 constitutes a fixing temperature control means.

Next, the operation of the invention according to claim 2 will be described with reference to FIGS. The temperature of the fixing roller 32 is initially set to the high temperature fixing mode. When the image information is received, as shown in FIG. 5, first, the fixing mode is switched (step Sb1). In step Sb1, as shown in FIG.
The resistance value of the uppermost recording paper P in 22 is detected (step S
b1-1), it is confirmed whether or not the resistance value is larger (exceeds) than the set value (step Sb1-2). If smaller, the process proceeds to step Sb2, and if larger, the mode switching signal causes the fixing roller 32 of the fixing unit 32 to rotate. The heating temperature of the heater is controlled by the MPU 53, and the high temperature fixing mode is changed to the low temperature fixing mode (step S
b1-3).

Next, the recording paper P is fed from the recording paper cassette 22 by the paper feeding unit 21, one sheet of image information is transferred to the recording paper P by the recording scanning unit 11, and the temperature of the fixing roller 32 is increased. The toner is fixed by the fixing unit 31 in the fixing mode according to the resistance value of the recording paper P, and the image is recorded (step Sb2). Then, it is confirmed by the MPU 53 whether or not the received image information data remains (step S
b3) When there are no more than two pieces of received image information and no data remains, the image recording operation is ended (completed).
When it is recognized that there are two or more pieces of image information and data remains, the process returns to step Sb1 (step Sb1).
3), the same operation is repeated.

Therefore, the recording paper P for recording the image information
When the recording paper P has a resistance value larger than the set value due to water absorption (moisture absorption), the lower limit temperature necessary for fixing the toner is added to record image information, and the recording paper P does not absorb moisture and resistance On the recording paper P whose value is smaller than the set value, the normal temperature for fixing the toner is applied and the image is recorded. Therefore, the image information is recorded on the recording paper P without curling.

As described above, also in this embodiment, it is possible to obtain the same effect as that of the above-mentioned embodiment. Next, the configuration of the invention according to claim 3 will be described. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.
1, FIG. 2, and FIG. 7, reference numeral 71 is a potential sensor, and the potential sensor 71 is attached above the registration roller 24 and the corner claw 64 of the sheet feeding section 21 as shown in FIG. The potential sensor 71 measures the surface potential of the recording paper P that is separated and fed one by one by the paper feed roller 23 and the corner claws 64 while the recording paper P is rushing into the registration roller 24, and the potential data is measured. The control unit 56 is adapted to detect it.
That is, the potential sensor 71 and the mechanism control unit 56 form a potential detecting means.

In the MPU 53, the higher the surface potential of the recording paper P is, the thinner the thickness of the recording paper P is, and the more easily it is deformed when heated and pressed, so that the electric potential of the recording paper P having a relatively large thickness is set in advance. When the detected potential exceeds this set value, the temperature of the fixing roller 23 is switched from the high temperature fixing mode to the low temperature fixing mode. That is, MPU
53 constitutes a fixing temperature control means.

Next, the operation of the invention described in claim 3 will be described with reference to FIGS. 8 and 9. The temperature of the fixing roller 32 is initially set to the high temperature fixing mode. When the image information is received, as shown in FIG. 8, first, the fixing mode is switched (step Sc1). In step Sc1, as shown in FIG.
The surface potential of the uppermost recording paper P in 22 is detected (step Sc1-1), and it is confirmed whether or not the potential is larger (exceeds) than the set value (step Sc1-2). If smaller, the process proceeds to step Sc2. If the temperature is high, the temperature of the fixing roller 32 of the fixing unit 31 is controlled by the MPU 53 to change the temperature of the fixing roller 32 of the fixing unit 31 from the high temperature fixing mode to the low temperature fixing mode by the mode switching signal (step Sc1-3).

Next, the recording paper P is fed from the recording paper cassette 22 by the paper feed section 21, one sheet of image information is transferred to the recording paper P by the recording scanning section 11, and the temperature of the fixing roller 32 is increased. The toner is fixed by the fixing unit 31 in the fixing mode according to the surface potential of the recording paper P, and the image is recorded (step Sc2). Next, it is confirmed by the MPU 53 whether or not the received image information data remains (step Sc3), and when the received image information has two or more sheets and no data remains, the image recording operation is ended (completed). When it is recognized that there are two or more pieces of image information and data remains, the process returns to step Sc1 (step Sc3), and the same operation is repeated.

Therefore, the recording paper P for recording the image information
Since the electric potential of is higher than the set value and the thickness is thin, it contains water
The recording paper P, which is easy to perform, is subjected to the lower limit temperature necessary for fixing the toner to record image information, and the potential thereof is lower than the set value and is relatively thick, so that the recording paper is hard to be deformed. An ordinary temperature for fixing the toner is applied to P to record an image. Therefore, the image information is recorded on the recording paper P without curling.

As described above, also in this embodiment, it is possible to obtain the same effect as that of the above-mentioned embodiment. Next, the configuration of the invention according to claim 4 will be described. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.
1, 2, and 10, the recording paper cassette 22
As shown in FIG. 10, the lower surface side is supported by a spring 81 so that the uppermost recording paper P abuts on a corner claw 64, and above the recording paper P is rotatably supported by a rotating shaft 82a. A filler 82 that is supported and that comes into contact with and separates from the recording paper end sensor 83 is attached. This filler 82 is a recording paper cassette
When the recording paper P is stacked on the sheet 22, it is in contact with the upper surface of the sheet 22 and is separated from the end sensor 83, but when the recording sheet P is no longer in the recording sheet cassette 22, it rotates to come into contact with the end sensor 83. Thus, the presence or absence of the recording paper P is detected. The mechanism control unit 56 takes in the detection information of the end sensor 83 and causes the panel unit 55 to display “no recording paper”.

The MPU 53 detects the presence / absence of the recording paper P detected by the end sensor 83 via the mechanism control unit 56, and after the recording paper P is replenished in the recording paper cassette 22 until the recording paper P runs out. It is designed to measure stack time (storage time). That is, the MPU 53 constitutes storage time measuring means. Further, the MPU 53 controls the temperature of the fixing roller 32 according to the stack time of the recording paper P, and the longer the stack time of the recording paper P, the more the recording paper P changes with time and absorbs moisture. Set an arbitrary time with little moisture absorption as a set value in advance,
If the detected stack time exceeds this setting,
The temperature of the fixing roller 23 is switched from the high temperature fixing mode to the low temperature fixing mode. That is, MPU53
Constitutes a fixing temperature control means.

Next, the operation of the invention according to claim 4 will be described with reference to FIG.
This will be described with reference to FIG. The temperature of the fixing roller 32 is initially set to the high temperature fixing mode. When the image information is received, as shown in FIG. 11, first, the fixing mode is switched (step Sd1). Step Sd
In step 1, as shown in FIG. 12, first, the measured stack time of the recording paper P is read (step Sd1-
1).

In step Sd1-1, as shown in FIG. 13, the presence or absence of the recording paper P is first confirmed (step Sd1).
-1-1), if it is confirmed that there is no recording paper P, "no recording paper" is displayed on the panel (step Sd1-1).
2). Then, when the recording paper P is replenished in the recording paper cassette 22, the filler 82 is rotated by the recording paper P and is separated from the end sensor 83 and the recording paper P is confirmed, the time count is started and the stack time is measured. Is started (step Sd1-1-3).

Then, it is confirmed whether the stack time of the recording paper P is longer (longer) than the set value (step S).
d1-2), if small (short), the process proceeds to step Sd2, and if large, the fixing unit 31 is activated by the mode switching signal.
The temperature of the fixing roller 32 is changed from the high temperature fixing mode to the low temperature fixing mode (step Sd1-3). Then, the recording paper P is fed to the recording paper cassette 22 by the paper feeding unit 21.
The image information for one sheet is transferred to the recording paper P by the recording scanning unit 11, and the temperature of the fixing roller 32 is set to the fixing mode corresponding to the stack time of the recording paper P by the fixing unit 31. Is fixed and an image is recorded (step Sd2).

Next, it is confirmed by the MPU 53 whether the received image information data remains (step Sd3),
When there are no more than two pieces of received image information and no data remains, the image recording operation is completed (completed). When it is recognized that there are two or more pieces of image information and data remains, the process returns to step Sd1 (step Sd3), and the same operation is repeated.

Therefore, the recording paper P for recording the image information
The stack time is longer than the set value and has absorbed moisture, and the lower limit temperature necessary for fixing the toner is added to the recording paper P to record the image information, and the stack time is less than the set value. An ordinary temperature for fixing the toner is applied to the recording paper P, which is short and has little moisture absorption, to record an image. Therefore, the image information is recorded on the recording paper P without curling.

As described above, also in this embodiment, it is possible to obtain the same effect as that of the above-mentioned embodiment. Next, the configuration of the invention according to claim 5 will be described. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.
1, 2, and 14, 92 is a filler, 93 is a paper ejection sensor, and the filler 92 and the paper ejection sensor 93 are shown in FIG.
As shown in 14, the filler is provided on the downstream side of the fixing unit 31 in the paper feeding
A fixing shaft 93a is rotatably supported by a rotating shaft 92a and is attached to the discharging sensor 93 so as to come in contact with and separate from the discharging sensor 93. After the fixing unit 31 fixes the image information, the discharging port of the main body of the apparatus.
The recording paper P ejected from 94 is pushed up and rotated to come into contact with and separate from the paper ejection sensor 93 so that the ejection of the recording paper P is detected. The mechanism control unit 56 takes in the detection information of the paper discharge sensor 93.

The MPU 53 detects the discharge of the recording paper P detected by the paper discharge sensor 93 via the mechanism control unit 56 and the elapsed time from the completion of recording the previous image information to the start of recording the next image information. Is designed to measure. That is, M
The PU 53 constitutes an elapsed time measuring means. Also, MP
U53 controls the temperature of the fixing roller 32 according to the elapsed time from the discharge of the recording paper P. The longer the elapsed time, the more the recording paper P changes with time and absorbs moisture. Is set in advance as a set value, and when the detected elapsed time exceeds this set value, the temperature of the fixing roller 23 is switched from the high temperature fixing mode to the low temperature fixing mode. . That is,
The MPU 53 constitutes a fixing temperature control means. next,
The operation of the invention according to claim 5 will be described with reference to FIGS.

The temperature of the fixing roller 32 is initially in the high temperature fixing mode. Then, when the image information is received, as shown in FIG. 15, first, the fixing mode switching is started (step Se1). In step Se1,
As shown in FIG. 16, first, the elapsed time after the completion of the discharge of the recording paper P is read (step Se1-1).

Next, it is confirmed whether the elapsed time of the recording paper P is larger (longer) than the set value (step Se1-
2) If it is small (short), proceed to Step Se2,
When the temperature is high, the temperature of the fixing roller 32 is changed from the high temperature fixing mode to the low temperature fixing mode by the mode switching signal (step Se1-3). Next, the recording paper P is fed from the recording paper cassette 22 by the paper feeding unit 21, one sheet of image information is transferred to the recording paper P by the recording scanning unit 11, and the temperature of the fixing roller 32 is changed to the recording paper P. The toner is fixed and the image is recorded by the fixing unit 31 which is set in the fixing mode according to the elapsed time of (step Se2).

Then, it is confirmed by the MPU 53 whether the received image information data remains (step Se3),
When there are no more than two pieces of received image information and no data remains, the image recording operation is completed (completed). When it is recognized that there are two or more pieces of image information and data remains, the process returns to step Se1 (step Se3), and the same operation is repeated.

Therefore, the recording paper P for recording the image information
The recording paper P that has absorbed moisture due to the elapsed time from the previous recording of the image information being longer than the set value is added with the lower limit temperature necessary for fixing the toner, and the image information is recorded, An image is recorded on the recording paper P whose elapsed time is shorter than the set value and less moisture is absorbed, by applying a normal temperature applied to fix the toner. Therefore, the recording paper P
Image information is recorded without curling.

As described above, also in this embodiment, it is possible to obtain the same effects as the above-mentioned embodiment.

[0060]

According to the first aspect of the invention, when the first recording sheet fed from the recording sheet cassette is the first sheet, the temperature of the fixing roller is lowered to fix the recording medium, and the recording sheet is continuous. After the 2nd sheet, the temperature of the fixing roller is raised to fix the recording medium, so the temperature of the lower limit side of the temperature range where the recording medium can be fixed on the 1st sheet of the recording paper exposed to the uppermost surface and absorbing moisture. It is possible to fix the image on the recording paper and prevent curling of the recording paper. As a result, it is possible to stabilize the quality of the recording paper on which the image is recorded while suppressing the decrease in the fixing rate of the image.

According to the second aspect of the invention, when the resistance value of the recording paper exceeds the predetermined value, the temperature of the fixing roller is lowered to fix the recording medium, and when the resistance value is less than the predetermined value. Since the recording medium is fixed to the recording paper by raising the temperature of the fixing roller to a high value, it is possible to fix the recording medium having a high resistance value by absorbing moisture at the lower limit temperature of the fixing range of the recording medium. It is possible to prevent curling of the recording paper. as a result,
It is possible to stabilize the quality of the recording paper on which an image is recorded while suppressing a decrease in the fixing rate of the image.

According to the third aspect of the invention, when the surface potential of the recording paper is detected and exceeds the predetermined value, the temperature of the fixing roller is lowered to fix the recording medium on the recording paper, and the surface potential is predetermined. When the value is less than the value, the temperature of the fixing roller is raised to fix the recording medium on the recording paper, so the lower limit of the temperature range where the recording medium can be fixed on the recording paper that is easily deformed by moisture absorption with high surface potential due to its thin thickness. The fixing can be performed at the temperature on the side, and curling of the recording paper can be prevented. As a result, it is possible to stabilize the quality of the recording paper on which the image is recorded while suppressing the decrease in the fixing rate of the image.

According to the fourth aspect of the present invention, the temperature of the fixing roller is lowered to fix the recording medium to the recording sheet stored in the recording sheet cassette for a predetermined time, and the recording sheet storage time is set. When the value is less than a predetermined time, the temperature of the fixing roller is raised to fix the recording medium.Therefore, for recording paper that has been left for a long time and exposed to the outside air to absorb moisture, the temperature at the lower limit side of the fixing range of the recording medium It can be fixed and curling of the recording paper can be prevented. As a result, it is possible to stabilize the quality of the recording paper on which the image is recorded while suppressing the decrease in the fixing rate of the image.

According to the fifth aspect of the present invention, when the elapsed time from the completion of the previous image recording to the start of the next image exceeds the predetermined time, the temperature of the fixing roller is lowered to set the recording medium on the recording paper. When the time from the completion of image recording to the start is fixed time or less, the recording medium is fixed on the recording paper by raising the temperature of the fixing roller to a high temperature. It can be fixed at the lower limit temperature of the temperature range where the medium can be fixed,
Curling of the recording paper can be prevented in advance.
As a result, it is possible to stabilize the quality of the recording paper on which the image is recorded while suppressing the decrease in the fixing rate of the image.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a facsimile apparatus to which an embodiment of an electrophotographic recording apparatus according to any one of claims 1 to 5 is applied, and an internal configuration diagram thereof.

FIG. 2 is a block diagram showing an overall configuration thereof.

FIG. 3 is a flowchart for explaining the operation of the invention described in claim 1.

FIG. 4 is an enlarged view showing a configuration of a main part of the invention according to claim 2;

FIG. 5 is a flowchart explaining the operation.

FIG. 6 is a flowchart illustrating a process in steps of the flowchart of FIG.

FIG. 7 is an enlarged view showing a configuration of a main part of the invention according to claim 3;

FIG. 8 is a flowchart illustrating the operation thereof.

9 is a flowchart illustrating a process in steps of the flowchart of FIG.

FIG. 10 is an enlarged view showing a configuration of a main part of the invention according to claim 4 thereof.

FIG. 11 is a flowchart explaining the operation.

FIG. 12 is a flowchart illustrating processing in steps of the flowchart in FIG. 11.

FIG. 13 is a flowchart illustrating processing in steps of the flowchart in FIG. 12.

FIG. 14 is an enlarged view showing a configuration of a main part of the invention according to claim 5;

FIG. 15 is a flowchart illustrating the operation thereof.

16 is a flowchart illustrating a process in steps of the flowchart of FIG. 15.

[Explanation of symbols]

11 Recording / scanning part (image forming part) 13 Photoconductor belt 14 Developing device 15 Transfer device 21 Paper feeding part (paper feeding means) 22 Recording paper cassette 23 Paper feeding roller (resistance detection means) 24 Registration roller 25 Paper feeding roller 31 Fixing Part 32 Fixing roller 33 Pressure roller 53 MPU (paper feed number detection means, storage time measurement means,
Elapsed time measuring device, fixing temperature control device) 56 Mechanism control unit (resistance detection device, potential detection device) 64 Corner claw (resistance detection device) 65 Electrode (resistance detection device) 71 Potential sensor (potential detection device) 82, 92 Filler 83 End sensor 93 Paper ejection sensor P Recording paper

Claims (5)

[Claims] 1. A recording paper cassette capable of stacking a plurality of recording papers, a paper feed means for separating and feeding the recording papers one by one from the recording paper cassette, and a recording medium transferred to the recording papers. An electrophotographic recording apparatus for recording an image on a recording sheet, which includes an image forming section for forming an image and a fixing section for fixing a recording medium transferred to the surface of the recording sheet by heating and fixing a fixing roller to the recording sheet. In the above, the fixing unit is configured to change the temperature for fixing the recording medium on the recording paper of the fixing roller to at least two levels, high and low, and recognizes the number of recording papers fed from the recording paper cassette. And a fixing temperature control means for controlling the temperature of the fixing roller to a low temperature when the first recording sheet recognized by the recognition means is set to a high temperature and a high temperature when the second and subsequent sheets are continuous. Electrophotographic record Location. 2. A recording paper cassette capable of stacking a plurality of recording papers, a paper feed means for separating and feeding the recording papers one by one from the recording paper cassette, and a recording medium transferred to the recording papers. An electrophotographic recording apparatus for recording an image on a recording sheet, which includes an image forming section for forming an image and a fixing section for fixing a recording medium transferred to the surface of the recording sheet by heating and fixing a fixing roller to the recording sheet. The resistance detecting means for detecting the resistance value of the recording paper fed from the recording paper cassette, wherein the fixing unit is configured so that the temperature for fixing the recording medium on the recording paper of the fixing roller can be changed in at least two steps of high and low. And a fixing temperature control means for controlling the temperature of the fixing roller to a low temperature when the resistance value of the recording paper detected by the detection means exceeds a preset predetermined value, and to a high temperature when the resistance value is equal to or lower than the predetermined value. Characterized by the provision Electrophotographic recording apparatus. 3. A recording paper cassette capable of stacking a plurality of recording papers, a paper feeding means for separating and feeding the recording papers one by one from the recording paper cassette, and a recording medium transferred to the recording papers. An electrophotographic recording apparatus for recording an image on a recording sheet, which includes an image forming section for forming an image and a fixing section for fixing a recording medium transferred to the surface of the recording sheet by heating and fixing a fixing roller to the recording sheet. In the fixing roller, the temperature for fixing the recording medium on the recording paper of the fixing roller can be changed at least in two steps of high and low, and a potential detecting means for detecting the surface potential of the recording paper fed from the recording paper cassette. And a fixing temperature control means for controlling the temperature of the fixing roller to a low temperature when the potential of the recording paper detected by the detection means exceeds a preset predetermined value, and to a high temperature when the potential is equal to or lower than the predetermined value. Characterized by Electrophotographic recording apparatus. 4. A recording paper cassette capable of stacking a plurality of recording papers, a paper feeding means for separating and feeding the recording papers one by one from the recording paper cassette, and a recording medium transferred to the recording papers. An electrophotographic recording apparatus for recording an image on a recording sheet, which includes an image forming section for forming an image and a fixing section for fixing a recording medium transferred to the surface of the recording sheet by heating and fixing a fixing roller to the recording sheet. In the storage time measuring means, the fixing unit is configured to change the temperature for fixing the recording medium on the recording paper of the fixing roller in at least two steps of high and low, and measures the time when the recording paper is stored in the recording paper cassette. And a fixing temperature control means for controlling the temperature of the fixing roller to a low temperature when the storage time measured by the measuring means exceeds a preset predetermined time and to a high temperature when the storage time is equal to or shorter than the predetermined time. Characterized by Electrophotographic recording apparatus. 5. A recording paper cassette capable of stacking a plurality of recording papers, a paper feeding means for separating and feeding the recording papers one by one from the recording paper cassette, and a recording medium transferred to the recording papers. An electrophotographic recording apparatus for recording an image on a recording sheet, which includes an image forming section for forming an image and a fixing section for fixing a recording medium transferred to the surface of the recording sheet by heating and fixing a fixing roller to the recording sheet. In the above, in the fixing unit, the temperature for fixing the recording medium on the recording paper of the fixing roller is configured to be variable in at least two steps of high and low, and the elapsed time from the completion of image recording on the previous recording paper to the start of the next image recording is Elapsed time measuring means for measuring, and fixing temperature control means for controlling the temperature of the fixing roller to a low temperature when the elapsed time measured by the measuring means exceeds a preset predetermined time and to a high temperature when the elapsed time is less than the predetermined time And, Electrophotographic recording apparatus characterized by.