JP2005075602A - Medium identification method and image recording apparatus - Google Patents

Abstract

To accurately identify a medium.
A medium transported by a transport mechanism is identified. Then, a predetermined heat is applied to the medium 12, and the medium 12 is identified based on the temperature of the medium 12 that rises as the heat is applied. In this case, since the medium 12 is identified based on the temperature of the medium 12 that rises as a predetermined heat is applied to the medium 12, the medium 12 can be accurately identified. Optimal temperature control can be performed.
[Selection] Figure 1

Description

  The present invention relates to a medium identification method and an image recording apparatus.

  Conventionally, in an image recording apparatus such as a printer, a copying machine, or a facsimile machine, the thickness of a medium such as paper or an OHP sheet is detected, the medium is identified based on the thickness of the medium, and the fixing is performed based on the identification result. The fixing temperature in the apparatus is adjusted to record a good image.

  FIG. 2 is a conceptual diagram of a conventional color printer.

  In the figure, reference numeral 12 denotes a medium, and 17Y, 17M, 17C, and 17BK denote image forming units of yellow, magenta, cyan, and black, which are sequentially arranged along the conveyance direction of the medium 12, and each of the image forming units 17Y. , 17M, 17C, and 17BK are provided with photosensitive drums 20Y, 20M, 20C, and 20BK, respectively. Transfer rollers 21Y, 21M, 21C, and 21BK are arranged to face the respective photosensitive drums 20Y, 20M, 20C, and 20BK, and a transfer belt (not shown) is interposed therebetween. The medium 12 is conveyed by the transfer belt, and When the photosensitive drums 20Y, 20M, 20C, and 20BK are fed between the transfer rollers 21Y, 21M, 21C, and 21BK, the toner images of the respective colors on the photosensitive drums 20Y, 20M, 20C, and 20BK are sequentially transferred to the transfer rollers. 21Y, 21M, 21C, and 21BK are transferred onto the medium 12 to form a color toner image. The image forming units 17Y, 17M, 17C, and 17BK, the transfer rollers 21Y, 21M, 21C, and 21BK, and the LED heads (not shown) disposed corresponding to the image forming units 17Y, 17M, 17C, and 17BK are used. An image forming unit is configured.

  Subsequently, the medium 12 is sent to the fixing device 18, where the medium 12 is sent between the heating roller 18a and the pressure roller 18b, and the color toner image is fixed to form a color image. In this way, an image can be recorded, that is, printing can be performed.

  By the way, in order to detect the thickness of the medium 12 supplied to the yellow image forming unit, the medium thickness detecting device 10 is disposed upstream of the image forming unit 17Y in the conveyance direction of the medium 12. The medium thickness detecting device 10 includes a roller pair 16 and a displacement sensor 31. The roller pair 16 is brought into contact with a first roller 16a that is rotatably arranged at a predetermined position, and the first roller 16a. In addition, the second roller 16b is provided so as to be movable in the vertical direction and rotatably, and the second roller 16b is tensioned with a predetermined urging force toward the first roller 16a. .

  The medium 12 is fed to the roller pair 16, and when the roller pair 16 is sandwiched between the first and second rollers 16a and 16b, the second roller 16b is displaced in the vertical direction according to the thickness of the medium 12. . Therefore, the thickness of the medium 12 is detected by detecting the displacement amount of the second roller 16b by the displacement sensor 31, and the medium 12 is identified.

A control unit (not shown) receives the thickness of the medium 12 represented by the sensor output of the displacement sensor 31 and adjusts and controls the fixing temperature of the fixing device 18 in accordance with the thickness of the medium 12 ( For example, see Patent Document 1.)
JP 2003-149887 A

  However, in the conventional image recording apparatus, the displacement amount of the second roller 16b fluctuates due to manufacturing errors such as cylindricity and eccentricity of the first and second rollers 16a and 16b, or the medium 12 has the first, As the second roller 16b is sandwiched between the second rollers 16a and 16b, the second roller 16b is bent (bent), the displacement amount of the second roller 16b varies, and the detection error of the displacement sensor 31 is increased. If there is, the thickness of the medium 12 cannot be detected accurately. Therefore, the medium 12 cannot be accurately identified, and optimal temperature control cannot be performed.

  It is an object of the present invention to provide a medium identification method and an image recording apparatus that can solve the problems of the conventional image recording apparatus and can accurately identify a medium.

  Therefore, in the medium identification method of the present invention, the medium conveyed by the conveyance mechanism is identified.

  Then, a predetermined heat is applied to the medium, and the medium is identified based on the temperature of the medium that rises as the heat is applied.

  According to the present invention, in the medium identification method, the medium conveyed by the conveyance mechanism is identified.

  Then, a predetermined heat is applied to the medium, and the medium is identified based on the temperature of the medium that rises as the heat is applied.

  In this case, since the predetermined heat is applied to the medium and the medium is identified based on the temperature of the medium that increases as the heat is applied, the medium can be accurately identified. As a result, optimal temperature control can be performed, so that the quality of an image recorded by the image recording apparatus can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a case will be described in which printing is performed (images are recorded) using a printer among image recording apparatuses such as a printer, a copying machine, and a facsimile apparatus.

  FIG. 1 is a conceptual diagram of a color printer according to a first embodiment of the present invention.

  In the figure, reference numeral 12 denotes a medium such as paper, and 17Y, 17M, 17C, and 17BK are image forming units of yellow, magenta, cyan, and black, which are arranged in order along the conveyance direction of the medium 12, The forming units 17Y, 17M, 17C, and 17BK are provided with photosensitive drums 20Y, 20M, 20C, and 20BK, respectively, as image carriers. Each of the image forming units 17Y, 17M, 17C, and 17BK is arranged to face the photosensitive drums 20Y, 20M, 20C, and 20BK, and each of them is a charging roller as a charging device (not shown) and a developing device. A developing roller, a cleaning roller as a cleaning device, and the like are provided, adjacent to the cartridges constituting the image forming units 17Y, 17M, 17C, and 17BK, and opposed to the photosensitive drums 20Y, 20M, 20C, and 20BK. An LED head as an exposure apparatus is disposed.

  A transport mechanism (not shown) is disposed below each of the image forming units 17Y, 17M, 17C, and 17BK. The transport mechanism includes a driving roller as a first roller and a driven roller as a second roller. And a transfer belt composed of a belt as a conveying member stretched between the first and second rollers, and driving the driving roller by driving a conveying motor (not shown) as a driving unit. Can be run. Further, transfer rollers 21Y, 21M, 21C, and 21BK are disposed so as to face the respective photosensitive drums 20Y, 20M, 20C, and 20BK and sandwich the transfer belt. The image forming units 17Y, 17M, 17C, and 17BK, the LED heads, and the transfer rollers 21Y, 21M, 21C, and 21BK form an image forming unit for each color.

  Then, the surfaces of the photosensitive drums 20Y, 20M, 20C, and 20BK are uniformly and uniformly charged by the charging rollers, and the surfaces of the photosensitive drums 20Y, 20M, 20C, and 20BK are exposed by the LED heads. An electrostatic latent image is formed. The electrostatic latent image is developed by each developing roller to become a toner image of each color. On the other hand, when the medium 12 is conveyed by the transfer belt and is sent between the photosensitive drums 20Y, 20M, 20C, 20BK and the transfer rollers 21Y, 21M, 21C, 21BK, the photosensitive drums 20Y, 20M, The toner images of the respective colors on 20C and 20BK are sequentially transferred onto the medium 12 by the transfer rollers 21Y, 21M, 21C, and 21BK, and a color toner image is formed.

  Subsequently, the medium 12 is sent to the fixing device 18, where the medium 12 is sent between a heating roller 18 a as a first fixing element and a pressure roller 18 b as a second fixing element. The toner constituting the image is heated and melted by the heating roller 18a, and is pressed against the medium 12 by the pressure roller 18b. As a result, the color toner image is fixed and becomes a color image. In this way, printing is performed. The heating roller 18a incorporates a heater (not shown) as a heating element, and the heater is energized by a control unit (not shown) to control the temperature of the fixing device 18.

  By the way, in order to detect the thickness of the medium 12 supplied to the yellow image forming unit, a medium thickness detecting device 40 is disposed upstream of the image forming unit 17Y in the conveyance direction of the medium 12. The medium thickness detection device 40 is disposed below the medium conveyance path of the medium 12 so as to face the medium conveyance path, and is opposed to the stage 43 and the stage 43 as a medium holding member that maintains the conveyance position of the medium 12. The heating element 41 as a heating member disposed and biased toward the stage 43 by a spring sp1 as a first biasing member, and the stage downstream of the heating element 41 in the conveyance direction of the medium 12 43, and a thermistor 44 having a small heat capacity as a first temperature detecting portion urged toward the stage 43 by a spring sp2 as a second urging member.

  The temperature of the heating element 41 can be controlled. As the heating element 41 is urged toward the stage 43, the heating element 41 moves to the medium 12 conveyed between the heating element 41 and the stage 43. It is pressed with a predetermined pressing force.

  The medium 12 is transported by a transport device (not shown) from a paper feed unit (not shown), the front end of the medium 12 is detected by a medium travel sensor sr serving as a medium detector disposed facing the medium transport path, and the medium The temperature (normal temperature) of the medium 12 is detected by a temperature sensor hs serving as a second temperature detection unit disposed facing the conveyance path.

  Subsequently, the medium 12 is sent to the medium thickness detection device 40, and is slid and conveyed while being pressed against the stage 43 by the heating element 41. At that time, when the front end of the medium 12 is detected by the medium running sensor sr, the heating element 41 starts to generate heat. Therefore, when the medium 12 enters between the heating element 41 and the stage 43, the heating element 41 Heat is generated to a certain temperature, a predetermined heat is applied to the medium 12, and the medium 12 is immediately heated.

  Then, the medium 12 is conveyed as it is, and the temperature of the medium 12 is detected by the thermistor 44. The heat capacity calculation processing means of the control unit performs heat capacity calculation processing and is expressed by the temperature of the medium 12 before heating represented by the sensor output of the temperature sensor hs, that is, the temperature before heating and the sensor output of the heating element 41. The temperature of the medium 12 after heating, that is, the temperature after heating is received, the temperature rise of the heated portion of the medium 12 is calculated based on the temperature before heating and the temperature after heating, and the heat capacity of the medium 12 is calculated. calculate.

  By the way, since the heat capacity represents the relationship between the temperature and the thickness of the medium 12, when the heat capacity is calculated, the thickness of the medium 12 can be detected. Therefore, the medium identification processing unit of the control unit performs the medium identification process, detects the thickness of the medium 12 based on the heat capacity of the medium 12, and identifies the medium 12.

  Then, the setting value determination processing unit of the control unit performs setting value determination processing, determines a setting value related to heat applied to the medium 12 in fixing the toner image, and the temperature control processing unit of the control unit A control process is performed, the heater of the heating roller 18a is energized, and the fixing temperature of the fixing device 18 is controlled based on the set value. In the present embodiment, the set value includes a fixing temperature represented by the temperature of the heating roller 18a, a conveyance speed of the medium 12 in the fixing device 18, and a heating in the fixing device 18 that are suitable for fixing a toner image. The distance between the roller 18a and the medium 12, that is, at least one of the contact distances is included.

  In the present embodiment, the thickness of the medium 12 is detected in order to perform temperature control in the fixing device 18, but the parameter for performing other control of the thickness of the medium 12. It can also be used as

  Thus, since the thickness of the medium 12 is detected based on the pre-heating temperature and the post-heating temperature of the medium 12, the thickness of the medium 12 can be accurately detected. Therefore, since the medium 12 can be accurately identified and optimal temperature control can be performed, the quality of the image recorded by the printer can be improved.

  Next, a second embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol.

  FIG. 3 is a conceptual diagram of a color printer according to the second embodiment of the present invention.

  In this case, the thermistor 48 as a temperature detection unit is built in a stage 43 as a medium holding member and is urged toward the heating element 41 as a heating member by a spring sp2 as a second urging member.

  In the printer having the above-described configuration, the medium 12 such as paper is sent to the medium thickness detection device 40, and is slid and conveyed while being pressed against the stage 43 by the heating element 41. At this time, when the front end of the medium 12 is detected by the medium traveling sensor sr, the heating element 41 starts to generate heat. Therefore, when the medium 12 enters between the heating element 41 and the stage 43, the heating element 41 Heat is generated to a certain temperature, a predetermined heat is applied to the medium 12, and the medium 12 is immediately heated, and then the heat is transferred to the back surface of the medium 12.

  By the way, in this case, when the medium 12 enters between the heating element 41 and the stage 43, the temperature before heating of the back surface of the medium 12 is detected by the thermistor 48, and then the heat is transferred to the back surface of the medium 12. The thermistor 48 detects the temperature of the medium 12 after heating.

  The heat transfer rate calculation processing means of the control unit performs heat transfer rate calculation processing, receives the pre-heating temperature and the post-heating temperature represented by the sensor output of the thermistor 48, and based on the pre-heating temperature and the post-heating temperature, The temperature rise of the heated portion of the medium 12 is calculated, and the heat transfer rate of the medium 12 is calculated.

  By the way, the heat transfer rate represents the relationship between the temperature and the thickness of the back surface of the medium 12 and represents the necessary amount of heating as viewed from the back surface of the medium 12. Can be detected. Therefore, the medium identification processing unit of the control unit performs medium identification processing, detects the thickness of the medium 12 based on the heat transfer speed of the medium 12, and identifies the medium 12.

  Then, the setting value determination processing unit of the control unit performs setting value determination processing, determines a setting value related to heat applied to the medium 12 in fixing the toner image, and the temperature control processing unit of the control unit A control process is performed, the heater of the heating roller 18a is energized, and the fixing temperature of the fixing device 18 is controlled based on the set value.

  Next, a third embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol.

  FIG. 4 is a conceptual diagram of a color printer according to the third embodiment of the present invention.

  In this case, instead of the stage 43 (FIG. 1), a roller 50 which is a rotating body as a rotatable medium holding member is used, and the roller 50 is connected to a drive system (not shown).

  Since the roller 50 is disposed and rotated as the medium 12 is conveyed, the thickness of the medium 12 can be detected without applying a load to the conveyance of the medium 12, and color misregistration or the like occurs. Can be prevented, and the image quality can be improved.

  Next, a fourth embodiment of the present invention will be described. In addition, about the thing which has the same structure as 3rd Embodiment, the description is abbreviate | omitted by providing the same code | symbol.

  FIG. 5 is a conceptual diagram of a color printer according to the fourth embodiment of the present invention.

  In this case, a belt unit 51 is used as a medium holding member, and the belt unit 51 is separated from a driving roller 55 as a first rotating body connected to a driving system (not shown) and a predetermined distance from the driving roller 55. A driven roller as a second rotating body provided, and a seamless belt 57 as a running member stretched between the first and second rotating bodies 55 and 56 with a predetermined tension. The medium 12 is sandwiched between the heating element 41 and the belt unit 51 and conveyed on the medium conveyance path. The traveling speed of the belt 57 and the conveyance speed of the medium 12 are equalized. Accordingly, since the thickness of the medium 12 can be detected without applying a load to the conveyance of the medium 12, it is possible to prevent color misregistration and the like and improve the image quality.

  Further, since the receiving surface of the medium 12 is a flat surface, the contact pressure of the heating element 41 as the heating member and the thermistor 44 as the temperature detection unit on the medium 12 can be stably maintained. Therefore, the heat capacity of the medium 12 can be accurately detected.

  Next, a fifth embodiment of the present invention capable of recording a monochrome image will be described.

  FIG. 6 is a conceptual diagram of a printer according to the fifth embodiment of the present invention.

  As shown in the figure, the printer 11 is detachably mounted with a paper feed cassette 13 as a medium storage section for storing a medium 12 such as paper, and the paper feed cassette 13 can be pulled out in the direction of the arrow. ing. A paper feed roller 14 as a paper feed member is rotatably disposed above the feeding portion of the medium 12 of the paper feed cassette 13, and is provided as a transport member downstream of the paper feed roller 14 in the transport direction of the medium 12. The conveying roller pairs 15 and 16 are rotatably disposed, and an image forming unit 17 and a transfer roller 21 as a transfer device are disposed on the downstream side of the conveying roller pair 16.

  The image forming unit 17 includes a toner container 22 and a photosensitive drum 20 as an image carrier, and is adjacent to the image forming unit 17 and faces the LED head 19 and the photosensitive drum 20 as an exposure device. Thus, the transfer roller 21 is disposed. Then, the toner image is transferred to the conveyed medium 12. The image forming unit 17, the transfer roller 21, the LED head 19, and the like constitute an image forming unit.

  Further, a fixing device 18 as a heating member is disposed downstream from the image forming unit, and the medium 12 on which the toner image has been transferred is interposed between the heating roller 18a and the pressure roller 18b in the fixing device 18. The toner image is fixed and becomes a black and white image. In this way, monochrome printing can be performed on the medium 12.

  Further, a conveyance roller pair 23 as a conveyance member is rotatably disposed on the downstream side of the fixing device 18, and a switching blade 24 as a switching member is centered on the shaft 24a further downstream of the conveyance roller pair 23. As shown in FIG. The switching blade 24 switches the conveyance direction of the medium 12 and switches between a path rt1 for conveying the medium 12 on which printing has been completed to the discharge unit 25 and a path rt2 for inverting the medium 12. A pair of transport rollers 26 and 27 as transport members are rotatably disposed in the path rt1.

  Further, a reversing roller pair 28 as a reversing member is disposed substantially below the switching blade 24 so as to be rotatable in the forward direction and the reverse direction. The first retraction path 29 is formed as a part of the paper feed cassette 13, and the second retraction path 30 is formed between the paper feed cassette 13 and the bottom 11 a of the printer 11.

  The first and second evacuation paths 29 and 30 are for temporarily accommodating the medium 12 when the medium 12 is reversed, and guide the medium 12 to both sides of the first evacuation path 29. Guide portions 31 and 32 are formed. The guide portion 31 is formed integrally with the paper feed cassette 13 so as to be curved so that the medium 12 can be gently guided to the second retreat path 30. The second retreat path 30 has a space for at least one medium 12 to enter. The reversing portion of the medium 12 is configured by the reversing roller pair 28 and the first and second retreat paths 29 and 30. A reversing path rt3 is formed on the left side of the reversing roller pair 28, and conveying roller pairs 33 and 34 as conveying members are rotatably disposed on the reversing path rt3.

  The paper feed roller 14 and the transport roller pairs 15, 16, 23, 26, 27, 33, 34, etc. constitute a transport mechanism for transporting the medium 12.

  In the printer configured as described above, when printing is performed on one side of the medium 12, the medium 12 that has passed through the fixing device 18 is sent to the path rt 1 by the switching blade 24 and discharged to the discharge unit 25. When printing on both sides of the medium 12, the toner image is transferred to the surface of the medium 12, and the medium 12 that has passed through the fixing device 18 is sent to the path rt2 by the switching blade 24 and rotated in the forward direction. The reversing roller pair 28 is retracted into the first and second retreat paths 29 and 30, and then the reversing roller pair 28 is rotated in the reverse direction, so that the first and second retreat paths 29 and 30 are retreated. The medium 12 that has been retracted into the medium 30 is sent to a reversing path rt3 as a medium conveying path, sent to the conveying roller pair 15 by the conveying roller pair 33, 34, reversed, and transferred again to the image forming unit 17 and the transfer. The toner image is transferred between the roller 21 and the back surface of the medium 12. Then, the medium 12 that has passed through the fixing device 18 is sent to the path rt1 by the switching blade 24 and discharged to the discharge unit 25. Note that the medium transport path is configured by the path rt2, the first and second retreat paths 29 and 30, the reversing path rt3, and the like.

  By the way, temperature sensors 35 and 36 as first and second temperature detectors are provided between the image forming unit 17 and the transfer roller 21 and the fixing device 18 and between the fixing device 18 and the conveying roller pair 23. The temperature sensor 35 detects the pre-heating temperature of the medium 12, and the temperature sensor 36 detects the post-heating temperature of the medium 12.

  Before printing, the medium 12 is passed between the photosensitive drum 20 and the transfer roller 21 without transferring the toner image, and the temperature before the heating is detected by the temperature sensor 35, and then the fixing is performed. Predetermined heat is applied through the device 18 and heated, and the temperature after heating is detected by the temperature sensor 36.

  The heat capacity calculation processing means of the control unit (not shown) performs the heat capacity calculation processing, receives the pre-heating temperature and the post-heating temperature, and based on the pre-heating temperature and the post-heating temperature, the temperature increase of the heated portion of the medium 12 And the heat capacity of the medium 12 is calculated.

  Then, the medium identification processing unit of the control unit performs medium identification processing, detects the thickness of the medium 12 based on the heat capacity of the medium 12, and identifies the medium 12. In this case, the medium thickness detection device 40 is configured by the fixing device 18 and the temperature sensors 35 and 36.

  The medium 12 after the post-heating temperature is detected is sent to the path rt2 by the switching blade 24, and the first and second retraction paths 29 and 30 are passed through the reverse roller pair 28 rotated in the forward direction. Then, the reversing roller pair 28 is rotated in the reverse direction, and the medium 12 that has been retreated in the first and second retreat paths 29 and 30 is sent to the reversing path rt3 and conveyed. The pair of rollers 33 and 34 are sent to the pair of conveying rollers 15 and reversed, and are sent again between the image forming unit 17 and the transfer roller 21, and the toner image is transferred to the back surface of the medium 12.

  Thus, in order to detect the temperature after heating, the heating roller 18a of the fixing device 18 can be used as a heating member, and it is not necessary to provide a heating element, so that the cost of the printer 11 can be reduced. it can.

  By the way, in each of the above-described embodiments, the case where a sheet is used as the medium 12 has been described. However, when an OHP sheet is used as the medium 12, the medium determination unit is illustrated upstream of the medium thickness detection device 40. An optical sensor that is not used is arranged. The sensor output of the optical sensor is sent to the control unit, and the medium determination processing unit of the control unit performs medium determination processing, determines whether the medium 12 is an OHP sheet based on the sensor output, When the medium 12 is an OHP sheet, the medium thickness detection device 40 does not detect the thickness of the medium 12, and the medium identification processing unit recognizes the OHP sheet. In this case, if necessary, the thickness of the medium 12 is detected by another method, and the medium 12 is recognized based on the detected thickness. Therefore, the medium 12 can be recognized without heating for a special medium such as an OHP sheet, which is likely to be distorted by heating.

  In each of the above embodiments, the medium 12 discharged from the medium thickness detection device 40 is supplied to the image forming unit, but after being heated downstream from the medium thickness detection device 40. A cooling device (not shown) for cooling the medium 12 can be provided, and the medium 12 after being cooled by the cooling device can be supplied to the image forming unit.

  As the cooling device, for example, an air injection device for injecting air, a heat sink, or the like disposed so as to face the medium conveyance path can be used.

  In this case, since the temperature of the medium 21 can be made lower than the temperature at which the printing such as the melting point of the toner is hindered, the printing can be started early after the medium 12 is heated.

  In each of the above embodiments, the temperature sensor hs, the temperature sensor 35, and the like are provided to detect the temperature before heating, and the thermistor 44, the temperature sensor 36, and the like are provided to detect the temperature after heating. Although necessary, the thermistor 44, the temperature sensor 36, etc. can simultaneously detect the temperature of the unheated portion of the medium 12, that is, the temperature of the non-heated portion. In this case, since it is not necessary to provide a temperature sensor for detecting the pre-heating temperature, the cost of the printer can be reduced.

  In addition, when the range in which the temperature of the medium 21 can be detected is specified by the temperature sensor, the heating temperature of the medium 21 is changed (that is, lowered or increased from a predetermined temperature) to detect the specific temperature. Then, the thickness of the medium 21 can be detected from the detected temperature, that is, the relationship between the detected temperature and the heating temperature.

  In this case, since the detected temperature is limited to a predetermined value, the sensitivity characteristic of the temperature sensor can be adjusted to the vicinity of the predetermined temperature, and the detection accuracy of the thickness of the medium 12 can be increased. Furthermore, when the temperature is increased, it is possible to prevent the medium 21 from being deteriorated due to excessively high temperature.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

1 is a conceptual diagram of a color printer according to a first embodiment of the present invention. It is a conceptual diagram of a conventional color printer. It is a conceptual diagram of the color printer in the 2nd Embodiment of this invention. FIG. 10 is a conceptual diagram of a color printer according to a third embodiment of the present invention. It is a conceptual diagram of the color printer in the 4th Embodiment of this invention. It is a conceptual diagram of the printer in the 5th Embodiment of this invention.

Explanation of symbols

11 Printer 12 Medium 14 Paper feed roller 15, 16, 23, 26, 27, 33, 34 Conveying roller pair 17Y, 17M, 17C, 17BK Image forming unit 18 Fixing device 19 LED head 21, 21Y, 21M, 21C, 21BK Transfer Rollers 29, 30 First and second retraction paths 41 Heating element 43 Stage 44 Thermistor 50 Roller 51 Belt unit hs Temperature sensor rt2 Path rt3 Reverse path

Claims (12)

In a medium identification method for identifying a medium conveyed by a conveyance mechanism,
(A) Apply predetermined heat to the medium,
(B) A medium identifying method characterized by identifying a medium based on the temperature of the medium that rises as heat is applied. (A) detecting the temperature before heating before applying heat to the medium;
(B) measuring the temperature after heating after applying heat to the medium,
(C) The medium identification method according to claim 1, wherein the temperature of the medium that rises as heat is applied is calculated based on the pre-heating temperature and the post-heating temperature. An image recording apparatus including a conveyance mechanism that conveys a medium, an image forming unit that forms an image including a toner image on the medium, and a fixing device that fixes the toner image to the medium
(A) a heating member that applies predetermined heat to the medium;
(B) a temperature detector for detecting the temperature of the medium;
(C) An image recording apparatus comprising: medium identification processing means for identifying a medium based on the temperature of the medium that rises as heat is applied. The image recording apparatus according to claim 3, further comprising a set value determination processing unit that determines a set value related to heat applied to the medium in the fixing device based on a post-heating temperature after the heat is applied to the medium. The image recording apparatus according to claim 4, wherein the set value includes at least one of a fixing temperature suitable for fixing a toner image on the medium, a medium conveyance speed in the fixing apparatus, and a contact distance in the fixing apparatus. (A) a medium determination unit disposed upstream of the heating member;
(B) having a medium determination processing means for determining whether the medium is an OHP sheet based on the determination result by the medium determination unit;
(C) The image recording apparatus according to claim 3, wherein when the medium is an OHP sheet, the medium identification processing unit recognizes the OHP sheet without being heated by the heating member. The image recording apparatus according to claim 3, wherein a cooling device that cools the medium is disposed downstream of the heating member. (A) the heating member is a fixing device;
(B) The image recording apparatus according to claim 3, wherein the medium identification processing unit identifies the medium based on a temperature of the medium that rises as heat is applied in the fixing device. The image recording apparatus according to claim 8, further comprising a medium conveyance path for supplying the identified medium to the image forming unit. The image recording apparatus according to claim 3, further comprising a medium holding member that is disposed to face the heating member and holds a medium. The image recording apparatus according to claim 10, wherein the medium holding member is a rotating body. The image recording apparatus according to claim 10, wherein the medium holding member is a belt unit.

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