JP2010026449A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of preventing thermal deterioration of a fixing device and improving throughput when uneven passing of paper occurs. <P>SOLUTION: This image forming apparatus includes an image forming means for forming an image on a recording material and a fixing means for fixing an image on the recording material by pressurization and heat fusing. The image forming apparatus further includes: first and second temperature detecting means for detecting the temperature of the fixing means; first and second recording material detecting means for detecting the presence/absence of the recording material; and a carrying means having a recording material discrimination means for detecting the type of the recording material to control the temperature for heating the fixing means and carrying of the recording material based on the detection information detected by the first recording material detecting means and the determination result of the recording material discrimination means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a laser printer having a recording material discriminating means for discriminating the basis weight of a recording material by detecting the glossiness or transparency of the recording material and a film heating type fixing means. Is. More specifically, the present invention relates to fixing control of the image forming apparatus.

  An image forming apparatus such as a copying machine or a laser printer includes a latent image carrier that carries a latent image, and a developing device that visualizes the latent image as a developer image by applying a developer to the latent image carrier. A transfer unit that transfers the developer image by the developing device to a recording material conveyed in a predetermined direction, and the recording material that has received the transfer of the developer image by the transfer unit is heated under predetermined fixing processing conditions. A fixing device for fixing the developer image on the recording material by applying pressure is provided.

<Film heating type fixing device>
In the image forming apparatus, a film heating type fixing device (a heating device, an image heating device) is often used in recent years.

  A film heating type fixing device is disclosed in Patent Documents 1 to 4. This fixing device has a function of applying heat of a heating body to a recording material through a film to heat and fix an unfixed image on the recording material as a permanent image.

  Compared with other known image heating and fixing devices such as the heat roller method, hot plate method, and heat chamber method, the film heating type fixing device uses a heating element or thin film with a low heat capacity that is faster in temperature. Since it can be used, it is possible to save power and shorten the wait time (quick start).

  An example of a film heating type fixing device is shown in FIG.

  A heating body 23 (hereinafter referred to as a heater) is supported by a heater holder 26. The heater is in pressure contact with the pressure roller 22 via the fixing film 21 by pressure means (not shown).

  Further, the fixing film is driven to rotate by the rotational driving of the pressure roller.

  Therefore, the recording material P fed to the nip N is conveyed while applying heat and pressure, so that a permanent image is formed on the recording material P.

  The first temperature detection means 24 (hereinafter referred to as a main thermistor) detects the temperature of the heater and transmits it to the temperature control circuit (27, 28, 29). The temperature control circuit performs feedback control using temperature information from the main thermistor in order to give optimum heat to the recording material, and maintains the heater at a predetermined temperature.

<Non-sheet-passing temperature rise and conventional non-sheet-passing temperature solution>
Incidentally, recording materials having various widths and lengths are passed through the image forming apparatus. When a small-sized recording material such as B5 is continuously fed, the temperature rises in the heater heating element area and the non-sheet passing area. So-called “non-sheet passing portion temperature rise” occurs.

  A mechanism for raising the temperature of the non-sheet passing portion will be described. First, since heat is taken away by the recording material in the paper passing portion, the temperature of the paper passing portion becomes constant by supplying heat from the heater. However, in the non-sheet passing portion, although the heat is not taken away by the recording material, the temperature of the non-sheet passing portion rises because heat is supplied from the heater.

  When the temperature of the non-sheet passing portion rises, the thermal expansion of the pressure roller of the fixing device becomes uneven, and in the film heating type fixing device, there is a difference in the film feed speed, which may cause twisting. . If the heat resistance temperature of the fixing device is exceeded, the pressure roller surface and the heater holder are damaged.

  Here, the film heating type fixing device is a fixing device in which the temperature rise in the non-sheet-passing portion appears remarkably because the film and the pressure roller are configured with members having a small heat capacity in order to enable quick start. .

  For the above non-sheet passing portion temperature rise, apart from the above-mentioned main thermistor, a second temperature detecting means (hereinafter referred to as a sub-thermistor) is arranged in a region where the small size paper becomes a non-sheet passing portion, Patent Document 5 proposes a configuration for detecting the temperature of the paper passing portion.

  A configuration having two temperature detecting means will be described with reference to FIG. FIG. 2 is a cross-sectional view of the fixing device shown in FIG. 1, and more specifically, a cross-sectional view cut in a direction perpendicular to the recording material conveyance direction.

  In FIG. 2, the main thermistor 24 is arranged at the center of the recording material sheet passing portion so that the temperature of the recording material of any size can be detected. The sub thermistor 25 is arranged at the end of the heater which is a small size paper and is a non-sheet passing portion.

  Here, for example, when a B5 size recording material is continuously passed, the fixing temperature adjustment control is performed based on the temperature of the main thermistor. Therefore, in the non-sheet passing portion, there is no cooling action of the heater by the recording material. Instead, electric power is supplied to the heater. Therefore, the heater temperature continues to rise. That is, the non-sheet passing portion temperature rises.

  Therefore, when a non-sheet passing portion temperature rise occurs in continuous printing of B5 size, the temperature of the non-sheet passing portion is detected by the sub-thermistor. The temperature of the non-sheet passing portion is lowered by reducing the throughput of printing the material.

<Temperature increase at non-sheet passing section during unaligned sheet feeding and conventional solution>
However, in the configuration shown in FIG. 2, for example, as shown in FIG. 3, when the B5 recording material is moved toward the sub-thermistor 25, the temperature continues to rise in the non-sheet passing portion. . A so-called “temperature increase during sheet feeding” occurs.

  As shown in FIG. 3, the conventional solution to the temperature increase during this misalignment passing is to count the number of sheets of the recording material passed by the misalignment detection flag 30, and to pass a predetermined sheet within a certain time. When the number of sheets is reached, the temperature of the non-sheet passing portion is lowered by reducing the throughput of printing the recording material.

<Recording material discrimination means>
Patent Document 6 discloses a recording material determination unit that determines the type of recording material and changes the fixing processing conditions (for example, the fixing temperature and the conveyance speed of the recording paper passing through the fixing device) according to the type of recording material. Yes.
JP-A-63-313182 Japanese Patent Laid-Open No. 2-157878 JP-A-4-44075 JP-A-4-204980 JP 2002-169413 A JP 2001-139189 A

  However, the conventional measures for raising the temperature of the non-sheet passing portion at the time of the side-by-side feeding have the following problems.

  The temperature rise in the non-sheet passing portion varies depending on the heat capacity of the recording material. Specifically, the temperature rise of the non-sheet passing portion increases as the recording material has a larger heat capacity. This is because the recording material having a larger heat capacity takes away the amount of heat from the heater in the sheet passing portion, and therefore, the electric power supplied to the heater is increased by the constant temperature control.

  In the conventional temperature rise countermeasure at the time of the one-sided sheet passing, the number of sheets of recording material to be passed is counted, and the throughput is reduced when the predetermined number of sheets is reached within a predetermined time. For this reason, it is necessary to set the number of sheets of recording material to start the through-put-down to the number of sheets to be passed when the recording material having the largest heat capacity among the recording materials that may be passed is passed.

  For this reason, when a recording material having a small heat capacity passes through the paper, the throughput is reduced unnecessarily quickly.

  For example, as shown in FIG. 4, when the time for starting throughput reduction is determined using thick paper and plain paper, the throughput reduction must be started when the number of sheets A passes through. On the other hand, it is usually sufficient to start throughput reduction with the number B of sheets to be passed. However, in the conventional temperature rise countermeasure, it is necessary to start the throughput reduction with the sheet passing number A regardless of the paper type. In other words, it can be seen that the throughput of plain paper is reduced unnecessarily quickly.

In order to achieve the above object, an image forming apparatus according to claim 1 of the present application is provided.
In an image forming apparatus having an image forming unit that forms an image on a recording material, and a fixing unit that presses, heat-melts and fixes an image on the recording material,
The image forming apparatus includes first and second temperature detecting means for detecting the temperature of the fixing means;
First and second recording material detecting means for detecting the presence or absence of the recording material;
It has a recording material discrimination means for detecting the type of recording material,
And a conveying means for controlling the heating temperature of the fixing means and the conveyance of the recording material based on the detection information detected by the first recording material detection means and the determination result of the recording material determination means. Features.

The image forming apparatus according to claim 2,
The first recording material detecting means detects the recording material;
The second recording material detection means does not detect the recording material,
When the second temperature detection means detects a temperature that has risen above the fixing target temperature,
When the determination results of the recording material determination means are integrated and the integrated value exceeds a predetermined threshold value,
It is characterized by carrying control that widens the printing interval.

The image forming apparatus according to claim 3,
The first temperature detection means is disposed inside the minimum width of the recording material that can be conveyed in the longitudinal direction perpendicular to the direction in which the recording material is conveyed,
The second temperature detection means is arranged at one of the positions outside the minimum width of the recording material that can be conveyed in the longitudinal direction perpendicular to the direction in which the recording material is conveyed,
The first recording material detection means is disposed inside the minimum width of the recording material that can be conveyed in the longitudinal direction perpendicular to the direction in which the recording material is conveyed,
The second recording material detection means is outside the minimum width of the recording material that can be conveyed by the image forming apparatus in the longitudinal direction orthogonal to the direction in which the recording material is conveyed, and the second temperature detection means. It is characterized by being arranged at a position opposite to that.

The image forming apparatus according to claim 4,
The integrated value is reduced when carrying control is performed to increase the printing interval.

The image forming apparatus according to claim 5,
In the case of non-sorting paper, the integrated value is reduced.

The image forming apparatus according to claim 6,
The recording material discriminating means emits light for reflecting on the surface of the recording material, first light receiving means for receiving specularly reflected light reflected on the surface of the recording material, and reflected on the surface of the recording material Means for receiving the irregularly reflected light, and comparing the output of the first light receiving means and the output of the second light receiving means with a predetermined threshold to determine the type of the recording material It is characterized by being.

The image forming apparatus according to claim 7,
The recording material discriminating means includes a light emitting means for emitting light for transmitting the recording material, and at least one light receiving means for receiving the light transmitted through the recording material, the output of the light receiving means and a predetermined threshold value, And a means for discriminating the type of recording material.

The image forming apparatus according to claim 8,
The light emitting means is an LED.

An image forming apparatus according to claim 9 is provided.
The first light receiving means and the second light receiving means are phototransistors.

The image forming apparatus according to claim 10,
An information transmission means for the user is provided, and when the misaligned paper is generated, the user is notified of the misaligned paper.

  In this proposal, it is not necessary to detect the type of recording material brought to one side by the recording material discriminating means, and to change the throughput reduction start timing at the time of one-sided feeding according to the passed recording material. To prevent a significant decrease in throughput.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

<Image forming apparatus>
An image forming apparatus according to the present embodiment is shown in FIG.

  As shown in FIG. 5, the image forming apparatus 101 includes a cassette tray 102, a paper feed roller 103, a transfer belt driving roller 104, a transfer belt 105, photosensitive drums 106 to 109 as latent image carriers, and transfer rollers 110 to 110 as transfer means. 113, cartridges 114 to 117, optical units 118 to 121, a fixing unit 20 as fixing means, and the like.

  In the image forming apparatus 101, an electrophotographic process is used to superimpose and transfer yellow, magenta, cyan, and black toner images on a recording material as a recording material. Then, the toner image is fixed on the recording material by heating and pressing the recording material at a predetermined temperature by a fixing roller (not shown) of the fixing unit 20.

  Each color optical unit 118 to 121 is configured to form a latent image by exposing and scanning the surface of each photosensitive drum 106 to 109 with a laser beam, and a series of these image forming operations is predetermined on the recording material to be conveyed. The scanning is controlled in synchronization so that the image is transferred from the selected position. The latent images formed on the surfaces of the photosensitive drums 106 to 109 are visualized as toner images by toners as developers of the respective colors by a developing device (not shown) provided in the cartridges 114 to 117.

  In addition, the image forming apparatus 101 includes a conveying unit that conveys the recording material. Specifically, a paper feed motor (not shown) that feeds and conveys the recording material, a transfer belt drive motor (not shown) that drives the transfer belt drive roller 104, each color photosensitive drum 106 to 109, and the transfer A photosensitive drum driving motor (not shown) for driving the rollers 110 to 113 and a fixing driving motor (not shown) for driving the fixing roller are provided.

  The image forming apparatus 101 also includes a cassette tray 102 (hereinafter referred to as CST), a multi-tray (hereinafter referred to as MPT) 123, and a plurality of trays capable of feeding paper.

  Further, the image forming apparatus 101 includes one recording material determination sensor 300 on a conveyance path that is merged by being fed from a plurality of paper feed ports and conveyed.

  Here, the operation of the control CPU of the image forming apparatus will be described with reference to FIG.

  The CPU 201 determines the side-by-side feeding in the fixing device 204 described later.

  Further, the CPU 201 controls a recording material determination unit which will be described later. Specifically, the light emitting means 205 is controlled to emit light to the recording material, and the light changed by the recording material is read by the light receiving means 206.

  Then, in a sequence for preventing an unnecessary throughput reduction described later, the recording material conveying unit 203 is controlled by the ASIC as necessary.

<Film heating type fixing device>
A film heating type fixing device 20 shown in the image forming apparatus (FIG. 5) is shown in FIG.

  The heater 23 is supported by a heater holder 26. The heater is in pressure contact with the pressure roller 22 via the fixing film 21 by pressure means (not shown).

  Further, the fixing film is driven to rotate by the rotational driving of the pressure roller.

  Therefore, the recording material P fed to the nip N is conveyed while applying heat and pressure, so that a permanent image is formed on the recording material P.

  The main thermistor 24 as the first temperature detecting means is arranged at the center of the recording material passing portion so that the temperature of the recording material of any size can be detected.

  The sub-thermistor 25 as the second temperature detecting means is disposed at the end of the heater which is a small size paper and is a non-sheet passing portion.

  The sheet passing number detection flag 32, which is the first recording material detecting means, is arranged at the center of the recording material passing portion so that it can detect the passing of recording materials of any size.

The misalignment detection flag 30 as the second recording material detecting means is arranged at a position satisfying the following 1 and 2 and 3 in order to detect that the small size recording material has been misaligned.
1: The flag moves when the small-size recording paper is justified.
2: The flag does not move when the small-size recording paper is non-sorting paper.
3: Located at the heater end opposite to the sub-thermistor.

<Recording material discrimination means>
A recording material discriminating means 300 shown in the image forming apparatus (FIG. 5) is shown in FIG.

  As shown in FIG. 8, the recording material discriminating means 300 is an LED 301 that is a first light emitting means, an LED 304 that is a second light emitting means, a phototransistor 302 that is a first light receiving means, and a second light receiving means. A phototransistor 303 is included.

  Light using the LED 301 as a light source is emitted to the surface of the recording material P on the recording material conveyance guide 305 through the slit 311. Further, the recording material conveyance guide 305 is provided with a window for emitting light from the back side of the recording material in this embodiment. The reflected light from the recording material P is collected through the slits 312 and 313 and received by the phototransistors 302 and 303. Thereby, the glossiness of the recording material P is detected.

  Light using the LED 304 as a light source is emitted to the back surface of the recording material P through a light collecting guide 314 for condensing the light. The transmitted light from the recording material P is received by the phototransistors 302 and 303 through the slits 312 and 313. As a result, the amount of light transmitted from the recording material P is detected. In the present embodiment, the LED 301 is arranged so that the LED light is emitted obliquely with a predetermined angle with respect to the surface of the recording material P as shown in FIG. Further, the LED 304 is disposed so that the LED light is emitted from the position directly below the phototransistor 302 as shown in FIG.

  Next, a control flow for recording material discrimination will be described. The image forming apparatus 101 starts printing upon receiving a print start command. When the recording material reaches the position of the recording material discriminating means, the LED 301 of the recording material discriminating means emits light with a predetermined light emission quantity value, and the phototransistors 302 and 303 receive the reflected light quantity of the recording material. The LED 304 emits light with a predetermined light emission amount value after the LED 301 is turned off, and the phototransistor 302 receives the transmitted light amount of the recording material. A comparison calculation is performed between the glossiness calculated from the reflected light amount, the transmitted light amount, and the recording material discrimination threshold. From the calculation result, the type of recording material is determined.

  The procedure for determining the type of recording material by comparison operation will be described with reference to FIG.

  The glossiness a of the recording material obtained from the output values of the phototransistors 302 and 303 is compared with the glossiness determination threshold value α. If a> α, it is determined as gloss paper. In the case of a ≦ α, a comparison operation is performed between the transmittance b of the recording material obtained from the output value of the phototransistor 302 and the determination threshold value β of the transmittance. If b> β, it is determined to be cardboard. If b ≦ β, it is determined as plain paper.

Therefore, it is possible to determine the heat capacity of the recording material. (For example, the heat capacity of plain paper is smaller than the heat capacity of cardboard)
<Sequence to prevent unnecessary throughput reduction>
A sequence for preventing unnecessary throughput reduction at the time of one-sided sheet passing will be described with reference to FIG.

  In S101, a print job is started.

  In S102, the integrated value of the recording material heat capacity is reset (C = 0), and in S103, the scheduled print number R is stored.

In S104, the heat capacity of the recording material is determined using the recording material determination means. Discriminated heat capacity is referred to as the C _n.

  In step S105, it is determined whether the recording material is justified paper or non-justified paper.

  Here, the side-by-side sheet detection unit will be described in detail.

  In order to realize the one-sided sheet passing detection, a flag for detecting the conveyance of the recording material is arranged at 30 in FIG.

  That is, the recording material rotates the misalignment detection flag 30 when the sheet is not misaligned.

  On the other hand, at the time of side-by-side feeding, since the recording material does not contact the side-by-side detection flag 30, the flag does not move.

  Further, a recording material detection flag for counting the number of passing sheets of recording material is arranged at 31 in FIG. 3, and is arranged at a position where the number of passing sheets can be counted with recording materials of all sizes that can be conveyed. . That is, the sheet passing count flag 31 operates when the recording material passes through the fixing device regardless of whether the recording material is passing or not.

  Further, when the paper is not separated, the temperature of the sub-thermistor 25 is raised because the sub-thermistor 25 is located in the non-paper passing portion (see FIG. 2).

  On the other hand, at the time of one-sided paper passing, the sub-thermistor 25 is located at the paper passing portion, so the temperature does not rise (see FIG. 3).

  Therefore, when the sheet passing count flag 32 operates, the misalignment detection flag 30 does not operate, and the sub-thermistor 25 does not rise in temperature, it can be determined that the misaligned sheet has occurred.

  If it is determined that the paper is not separated, printing is performed at a normal paper feed interval in S106.

If it is determined that the sheets are just-sorted, the heat capacity is integrated in S107 (C = C _n-1 + C _n ).

  In S108, the heat capacity integrated value C is compared with the heat capacity threshold value S.

  Here, the threshold value S of the heat capacity is a value set in advance so that the non-sheet passing portion temperature at the time of small size shifting does not reach the heat deterioration temperature of the fixing device.

  If the integrated value C of heat capacity <the threshold value S of heat capacity, printing is performed at a normal paper feed interval in S106.

  If the integrated value C of the heat capacity ≧ the threshold value S of the heat capacity, printing is performed with the recording material feeding interval widened in S109.

  When the number of sheets to be passed in one print job reaches the scheduled print number R in S110, the print job is ended in S111.

  If the number of sheets to be passed in one print job does not reach the scheduled print number R in S110, the thermal capacity C of the recording material to be printed next is determined (S104). Thereafter, the sequence from S104 to S110 is repeated until the number of sheets to be printed in one print job reaches the scheduled number of prints.

  As described above, in the first embodiment, the recording material determination unit determines the heat capacity of the recording material to be passed, integrates the heat capacity of the recording material to be continuously passed, and reaches a predetermined heat capacity (integrated value). In this case, since the throughput reduction is started, it is possible to set the optimum throughput reduction start timing according to the type of the recording material.

  In other words, in the first embodiment, it is possible to prevent unnecessary throughput reduction during the misalignment feeding.

  Next, a second embodiment of the present invention will be described. The description of the same configuration as that of the first embodiment is omitted.

  In the first embodiment, unnecessary throughput reduction is prevented by making the throughput reduction start timing variable in accordance with the heat capacity of the recording material during the period from the start of printing until the throughput is reduced.

  However, after the throughput is reduced, when the sheets are further continuously fed and the throughput reduction mode is continued, the condition for continuing the throughput reduction is determined regardless of the type of the recording material.

  For this reason, unnecessary throughput reduction may occur.

  FIG. 11 shows the “non-sheet-passing portion temperature at the time of small size shifting” after the throughput is reduced.

  From FIG. 11, when plain paper is being justified, the non-sheet passing temperature at the time of small size is reduced.

  Therefore, the feature of the present embodiment is that, even after the throughput is reduced, the heat capacity of the recording material is integrated to determine whether to interrupt or restart the throughput reduction, thereby preventing unnecessary throughput reduction.

  FIG. 12 shows “non-sheet passing portion temperature at the time of small size shifting” representing the characteristics of the present embodiment.

  As shown in FIG. 12, by making the throughput down start timing variable according to the heat capacity of the recording material, the throughput down start timing for plain paper can be delayed from the throughput down start timing for thick paper. As a result, unnecessary throughput reduction can be prevented.

<Sequence to prevent unnecessary throughput reduction>
A sequence for preventing unnecessary throughput reduction at the time of one-sided sheet passing will be described with reference to FIG.

  In step S201, a print job is started.

  In S202, the integrated value of the recording material heat capacity is reset (C = 0).

  In S203, the scheduled print number R is stored.

In S204, the recording material discrimination means is used to discriminate the heat capacity of the recording material. Discriminated heat capacity is referred to as the C _n.

  In step S205, it is determined whether the recording material is a piece-by-sheet passing sheet or a non-sheet-fed sheet.

  If it is determined that the paper is not separated, printing is performed at a normal paper feed interval in S206.

If it is determined that the sheet is just one-sided, the heat capacity of the recording material is integrated in S209 (C = C _n-1 + C _n ).

  In S210, the heat capacity integrated value C is compared with the heat capacity threshold value S.

  Here, the threshold value S of the heat capacity is a value set in advance so that the non-sheet passing portion temperature at the time of small size shifting does not reach the heat deterioration temperature of the fixing device.

  If the integrated value of heat capacity C <threshold weight threshold value S, printing is performed at a normal paper feed interval in S208.

  If the integrated value C of the heat capacity is equal to or greater than the basis weight threshold value S, printing is performed with the recording material feeding interval widened in S211.

  In S207, the end of the fixing device is cooled by non-sorting paper-feed printing. Here, assuming that the heat capacity B is taken away from the fixing device by cooling, the integrated value of the heat capacity is C = C−B (however, when the integrated value C becomes a negative value, the integrated value C is set to 0. To do).

  In S212, the end of the fixing device is cooled due to the throughput reduction. Here, assuming that the heat capacity A is taken away from the fixing device by cooling, the integrated value of the heat capacity is C = C−A (however, when the integrated value C becomes a negative value, the integrated value C is set to 0). To do).

  Here, the cooling of S207 and S212 will be described more specifically with reference to FIG.

  FIG. 14 is a diagram illustrating transition of the fixing device end temperature (integrated value C) when seven recording materials are printed as an example.

  If it is assumed that misaligned paper is generated from the first print to the third print, the end temperature of the fixing device increases for each print.

  Here, the integrated value C and the threshold value S are C ≧ S, and the throughput reduction is started. Since the fixing device end is cooled between the recording materials whose throughput is reduced, the fixing value end temperature is lowered by A.

  On the fourth print, a side-by-side sheet occurs, and the fixing value end temperature rises again.

  It is assumed that the 7th sheet from the print 5 has non-sorting paper. The fixing device end is cooled by the recording material, and the fixing end temperature is lowered by B.

  That is, by adding and subtracting the integrated value C in the same manner as the fixing device end temperature, the integrated value C can be treated as equivalent to the fixing device end temperature.

  As a result, unnecessary throughput reduction can be prevented.

  When the number of sheets to be printed in one print job reaches the scheduled print number R in S213, the print job is terminated in S214.

  If the number of sheets to be passed in one print job does not reach the scheduled print number R in S213, the thermal capacity C of the recording material to be printed next is determined (S204). Thereafter, the sequence from S204 to S213 is repeated until the number of sheets to be printed in one print job reaches the scheduled number of prints.

  Next, a third embodiment of the present invention will be described. Note that a description of the same configurations as those in the first and second embodiments is omitted.

  The feature of this embodiment is that, in an image forming apparatus having a CST, there is a high possibility that the recording material in the CST is the same. Therefore, if the CST is not opened or closed, the recording material in the CST may not change. It is considered high.

  Therefore, the recording material determination result determined in the previous print job is used as the first recording material determination result of the next print job, thereby omitting the detection of the first recording material.

  As a result, the first printout time can be shortened.

  Therefore, a sequence for improving the first printout at the time of one-sided paper passing will be described below with reference to FIG.

  In step S301, a print job is started.

  In S302, the paper feed port of the recording material to be printed is determined.

  When the paper feed port is MPT, the flow (F1) described in the first embodiment is performed.

  If the paper feed port is CST, it is determined whether CST is opened or closed (S303).

  Here, as shown in FIG. 6, as the cassette opening / closing detection means 207, a method of recognizing the cassette opening / closing signal 201 by the CPU using a sensor such as a photo interrupter is conceivable.

  When the CST is opened and closed, the flow (F1) described in the first embodiment is performed.

  When the CST is not opened and closed, the basis weight based on the determined recording material discrimination result is used in the print job immediately before the main print job (S306).

  Thereafter, the sequence from S309 to S315 is repeated.

  As described above, since there is a high possibility that the recording materials in the CST are the same, if there is no opening / closing of the CST, there is a high possibility that the recording materials in the CST will not change. Therefore, by using the recording material determination result determined in the previous print job as the first recording material determination result of the next print job, it is possible to omit detection of the first recording material of the print job. Become. That is, the first printout time can be shortened.

  As a result, the first printout can be shortened compared to the first embodiment and the second embodiment.

  In the present embodiment, MPT and CST have been described. However, the same control as in the present embodiment CST can be performed for the option feeder.

  Next, a fourth embodiment of the present invention will be described. Note that a description of the same configurations as those of the first to third embodiments is omitted.

  When the misaligned paper is generated, the position of the print image and the recording material is not aligned, so that a defective image may be generated.

  Therefore, a feature of the present embodiment is that it is possible to prevent unnecessary printing by asking the user whether or not to continue printing when misaligned paper is generated. As a result, usability can be improved.

  A sequence for improving usability will be described below with reference to FIG.

  If it is determined in S405 that the sheets are just-aligned, and if the number of sheets to be printed is greater than one in S407, first the first sheet is printed in S409, and then the print job is temporarily interrupted.

  Next, in step S410, the user is notified that the sheet is justified, and in step S411, the user is asked whether to continue printing.

  In the case of continuing printing, printing is performed without asking the user whether or not to continue printing until the print job is completed (S408) (S404 to S416).

  If printing is stopped, the print job is interrupted and terminated (S417).

  Here, FIG. 17 shows information transmission means for requesting the user to continue printing.

  When the misalignment paper is generated, the engine controller 401 recognizes the misalignment paper based on a signal from the misalignment detection unit 400.

  Then, the engine controller informs the image forming apparatus controller 402 of the information on the one-sided paper passing.

  Finally, the image forming apparatus controller displays the information on the justified sheet on the display unit 403 of the image forming apparatus and the display unit 404 of the PC, and asks the user whether to continue printing.

  As described above, according to the present exemplary embodiment, it is possible to prevent unnecessary printing by asking the user whether or not to continue printing when the misaligned paper is generated. As a result, usability can be improved.

1 is a diagram illustrating a fixing device according to a background art of the present invention. 1 is a diagram illustrating a fixing device according to a background art of the present invention. 1 is a diagram illustrating a fixing device according to a background art of the present invention. It is a figure which shows the start timing of the throughput fall concerning the background art of this invention. 1 is a schematic cross-sectional view illustrating a schematic configuration of an image forming apparatus that is an example of a color image forming apparatus according to a first embodiment of the present invention. It is a figure which shows the control structure concerning 1st Example of this invention. 1 is a diagram illustrating a fixing device according to a first embodiment of the present invention. FIG. It is a figure which shows the structure of the recording material discrimination | determination sensor concerning 1st Example of this invention. It is a figure which shows the discrimination method of the recording material discrimination sensor concerning 1st Example of this invention. It is a figure which shows the control sequence concerning 1st Example of this invention. It is a figure which shows the fixing device edge part temperature of the throughput down period concerning 2nd Example of this invention. It is a figure which shows the fixing device edge part temperature of the throughput down period concerning 2nd Example of this invention. It is a figure which shows the control sequence concerning 2nd Example of this invention. It is a figure which shows the fixing device edge part temperature concerning 2nd Example of this invention. It is a figure which shows the control sequence concerning 3rd Example of this invention. It is a figure which shows the control sequence concerning 4th Example of this invention. It is a figure which shows the information transmission means concerning 4th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Fixing device 21 Fixing film 22 Pressure roller 23 Heater 24 Main thermistor 25 Sub thermistor 26 Heater holder 27 A / D converter 28 CPU
29 AC Driver 30 Alignment Detection Flag 31 Recording Material Detection Flag 32 Number of Passed Papers Detection Flag 101 Image Forming Apparatus 102 Cassette Paper Tray 103 Paper Feed Roller 104 Transfer Belt Drive Roller 105 Transfer Belt 106, 107, 108, 109 Photosensitive Drum 110, 111, 112, 113 Transfer roller 114, 115, 116, 117 Cartridge 118, 119, 120, 121 Optical unit 123 Multi paper tray 124 Multi paper feed roller 201 CPU
202 ASIC
203 Recording material conveying means 204 Fixing means 205 Light emitting means 206 Light receiving means 207 Cassette open / close detection means 300 Recording material discrimination sensor 301, 304 LED
302, 303 Phototransistor 305 Recording material conveyance guides 311, 312, 313 Slit 314 Condensing guide 400 Misalignment detecting means 401 Engine controller 402 Image forming apparatus controller 403 Display section of image forming apparatus 404 Display section of PC

Claims (10)

In an image forming apparatus having an image forming unit that forms an image on a recording material, and a fixing unit that presses, heat-melts and fixes an image on the recording material,
The image forming apparatus includes first and second temperature detecting means for detecting the temperature of the fixing means;
First and second recording material detecting means for detecting the presence or absence of the recording material;
It has a recording material discrimination means for detecting the type of recording material,
And a conveying means for controlling the heating temperature of the fixing means and the conveyance of the recording material based on the detection information detected by the first recording material detection means and the determination result of the recording material determination means. An image forming apparatus. The first recording material detecting means detects the recording material;
The second recording material detection means does not detect the recording material,
When the second temperature detection means detects a temperature that has risen above the fixing target temperature,
When the determination results of the recording material determination means are integrated and the integrated value exceeds a predetermined threshold value,
The image forming apparatus according to claim 1, wherein conveyance control for increasing a printing interval is performed. The first temperature detection means is disposed inside the minimum width of the recording material that can be conveyed in the longitudinal direction perpendicular to the direction in which the recording material is conveyed,
The second temperature detection means is arranged at one of the positions outside the minimum width of the recording material that can be conveyed in the longitudinal direction perpendicular to the direction in which the recording material is conveyed,
The first recording material detection means is disposed inside the minimum width of the recording material that can be conveyed in the longitudinal direction perpendicular to the direction in which the recording material is conveyed,
The second recording material detection means is outside the minimum width of the recording material that can be conveyed by the image forming apparatus in the longitudinal direction orthogonal to the direction in which the recording material is conveyed, and the second temperature detection means. The image forming apparatus according to claim 1, wherein the image forming apparatus is disposed at a position opposite to the image forming apparatus.   The image forming apparatus according to claim 2, wherein the integrated value is decreased when carrying control for increasing a printing interval is performed.   4. The image forming apparatus according to claim 2, wherein the integrated value is decreased in the case of non-sorting paper passing. 5.   The recording material discriminating means includes a light emitting means for emitting light for reflection on the surface of the recording material, a first light receiving means for receiving specularly reflected light reflected on the surface of the recording material, and a reflection on the surface of the recording material. Means for receiving the irregularly reflected light, and comparing the output of the first light receiving means and the output of the second light receiving means with a predetermined threshold to determine the type of the recording material The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The recording material determining means includes a light emitting means for emitting light for transmitting the recording material, and at least one light receiving means for receiving the light transmitted through the recording material, the output of the light receiving means and a predetermined threshold value, 6. The image forming apparatus according to claim 1, wherein the image forming apparatus is a means for discriminating the type of the recording material by comparing the two.   The image forming apparatus according to claim 1, wherein the light emitting unit is an LED.   The image forming apparatus according to claim 1, wherein the first light receiving unit and the second light receiving unit are phototransistors.   10. The image forming apparatus according to claim 1, further comprising an information transmission unit for a user, wherein when the misaligned paper is generated, the user is notified of the misaligned paper.

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