JP6904701B2 - Image forming device, image forming method - Google Patents

Description

The present invention relates to an image forming apparatus that forms an image on a recording material such as a sheet.

The image forming apparatus performs an image forming process by transferring, for example, a toner image formed on a photoconductor to a recording material such as a sheet, and heat-fixing the toner image transferred to the recording material. In such an image forming apparatus, image forming conditions for image forming are set according to media characteristics such as the thickness and surface properties of the recording material. The image formation conditions include the image formation rate, the fixing temperature at the time of heat fixing, and the like. The image forming speed is the speed of each part at the time of forming a toner image on the photoconductor, the speed of each part at the time of transfer, the transport speed of the recording material, and the like. The media characteristics are set by a user interface provided in the image forming apparatus or a user operation from an external device equipped with a printer driver. In addition to this, some image forming devices in recent years are equipped with a sensor (hereinafter, referred to as "media sensor") for detecting the media characteristics of the recording material. The media sensor detects media characteristics from the recording material being conveyed.

An image forming apparatus equipped with a media sensor may detect recording materials having different media characteristics when continuously forming an image on the recording material. In this case, since the media characteristics are different, the image is formed under the image forming conditions that do not correspond to the media characteristics. The image forming apparatus of Patent Document 1 is provided with a media sensor that detects media characteristics on a transport path, and detects the media characteristics of a plurality of recording materials that are continuously transported. When the media characteristics of the recording material already detected and the media characteristics of the newly detected recording material are different, the image forming apparatus stops the image forming operation. As a result, the image forming apparatus stops the image forming operation under the image forming conditions that do not correspond to the media characteristics.

Japanese Unexamined Patent Publication No. 2010-211062

However, recording materials having various media characteristics are used for image formation, and in some recording materials, the detection result by the media sensor varies near the threshold value for determining the media characteristics. When image formation is continuously performed using such a bundle of recording materials, the media characteristics of the recording material detected by the media sensor may change for each recording material, for example, plain paper and thick paper. In this case, in the image forming apparatus of Patent Document 1, the image forming operation is stopped every time the detected media characteristics change, and the convenience of the user is greatly impaired.

The image forming apparatus can also perform an image forming operation under new image forming conditions according to the detected media characteristics without stopping the image forming operation. In this case, a waiting time occurs due to the switching of the image formation conditions. For example, plain paper and thick paper have different image formation speeds and fixing temperatures. When the media characteristics change, it takes time to switch between them. Such switching of image formation conditions leads to a decrease in productivity.

In view of the above problems, it is a main object of the present invention to provide an image forming apparatus that maintains user convenience and productivity even when the media characteristics of a recording material change.

The image forming apparatus of the present invention includes an image forming means for forming an image on a recording material based on a predetermined image forming condition, a conveying means for conveying the recording material to the image forming means via a conveying path, and the conveying means. provided the road, the media detection means for detecting the media characteristics of the recording material conveyed to the image forming unit, and storing media characteristics of the recording medium detected by the medium detecting unit, a storage media characteristics comprising a storage unit that has also retained during the next image formation, and control means for controlling said conveying means and said image forming means, a recording material conveyed by said conveying means is detected by the medium detection means When the media characteristics are the first type of recording material that can be detected by varying between the first media characteristics and the second media characteristics, and the first type of recording material is continuously conveyed. In addition, in the control means, the media characteristic detected by the media detecting means for the newly conveyed recording material is the first media characteristic, and the image is stored in the storage means at the time of forming the previous image. When the media characteristic of is the second media characteristic, if the image formation speed corresponding to the first media characteristic and the image formation speed corresponding to the second media characteristic are the same, image formation is continued. If the image forming speed corresponding to the first media characteristic and the image forming speed corresponding to the second media characteristic are different, the image forming by the image forming means and the conveying of the recording material by the conveying means are interrupted. It is characterized by doing.

According to the present invention, by stopping the image forming process when the media characteristics of the recording material and the image forming conditions are different from those at the time of the previous image forming, the image forming process can be performed by changing the media characteristics of the recording material as compared with the conventional case. Reduce the frequency of outages. This ensures user convenience and productivity.

The block diagram of the image forming apparatus. Configuration diagram of the control unit. Explanatory drawing of the fuser. Explanatory drawing of the media sensor. (A) to (d) are explanatory views of a state when a media sensor detects a recording material. (A) and (b) are explanatory views of the amount of reflected light according to the type of recording material. (A) and (b) are timing charts showing operation timings during image formation processing. A flowchart showing an image forming process. Illustrative diagram of the message. An explanatory diagram of the relationship between the image formation conditions and the media characteristics of the recording material.

Hereinafter, embodiments will be described in detail with reference to the drawings.

(Constitution)
FIG. 1 is a configuration diagram of an image forming apparatus of the present embodiment. The image forming apparatus 100 includes a plurality of image forming units 120a to 120d, laser scanners 122a to 122d, primary transfer units 123a to 123d, an intermediate transfer belt 130, a secondary transfer unit 140, a fuser 170, and a paper feed cassette 220. .. Further, the image forming apparatus 100 includes an operation unit 13 as a user interface.

The image forming units 120a to 120d each include a charging roller, a photoconductor, and a developing device. The image forming units 120a to 120d are configured to be removable from the main body of the image forming apparatus 100 by the user. The surface of each photoconductor is charged by a charging roller and irradiated with laser light by the corresponding laser scanners 122a to 122d to form an electrostatic latent image. The developing device forms a toner image on the photoconductor by developing the electrostatic latent image with toner. One of the image forming units 120a to 120d forms a black toner image, and the other forms a chromatic toner image. For example, a yellow toner image is formed on the photoconductor of the image forming unit 120a. A magenta toner image is formed on the photoconductor of the image forming unit 120b. A cyan toner image is formed on the photoconductor of the image forming unit 120c. A black toner image is formed on the photoconductor of the image forming unit 120d.

The primary transfer units 123a to 123d transfer the toner images formed on the photoconductors of the corresponding image forming units 120a to 120d so as to overlap the intermediate transfer belt 130. The intermediate transfer belt 130 rotates clockwise in the drawing, and the toner image is transferred in the order of yellow, magenta, cyan, and black. The intermediate transfer belt 130 is an intermediate transfer body that transfers the transferred toner image to the secondary transfer unit 140 by rotating it.

The paper cassette 220 accommodates a recording material S such as a sheet on which an image is formed. The paper cassette 220 may contain the same type of recording material S, or may contain recording materials S having different types such as material, thickness, and size. The recording material S is fed from the paper feed cassette 220 and is conveyed to the secondary transfer unit 140 along the transfer path. A pickup roller 151, a pickup sensor 152, a transport roller 154, 155, a media sensor 14, a transport sensor 160, and a resist roller 161 are provided in a transport path from the paper cassette 220 to the secondary transfer unit 140.

The recording material S housed in the paper feed cassette 220 is fed one by one by the pickup roller 151. The pickup sensor 152 monitors whether or not the paper-fed recording material S has been fed one by one. The recording material S is conveyed to the transfer rollers 154 and 155 by the pickup roller 151. The transport rollers 154 and 155 transport the recording material S to the resist roller 161. When the resist roller 161 detects the recording material S that has been transported by the transport sensor 160, the resist roller 161 temporarily stops the transport of the recording material S and performs skew correction or the like. The resist roller 161 conveys the recording material S to the secondary transfer unit 140 at the timing when the intermediate transfer belt 130 conveys the toner image to the secondary transfer unit 140.

The secondary transfer unit 140 transfers the toner image formed on the intermediate transfer belt 130 to the recording material S conveyed by the resist roller 161. The fuser 170 heat-fixes the toner image on the recording material S. A paper transport sensor 171 that detects the recording material S that has passed through the fuser 170 is provided in the subsequent stage of the fuser 170. The recording material S on which the toner image is fixed by the fuser 170 is conveyed to the double-sided transfer path 230 in the case of double-sided printing, and is conveyed to the paper discharge transfer path 231 when the image formation is completed. The transport flapper 172 operates when the paper transport sensor 171 detects the recording material S, and distributes the recording material S to either the double-sided transport path 230 or the paper discharge transport path 231. The recording material S transported to the double-sided transport path 230 is transported from the transport roller 155 to the resist roller 161 after the front and back sides are reversed, and is transported from the resist roller 161 to the secondary transfer unit 140 to obtain a toner image for the back surface. Transfer is performed.

The image forming apparatus 100 includes a paper ejection tray 196 and a paper ejection tray 200. The recording material S conveyed to the paper discharge transfer path 231 is conveyed to either the paper transfer path 180 or the paper transfer path 181 by the transfer roller 232. The transport flapper 190 distributes the recording material S to either the paper transport path 180 or the paper transport path 181. The recording material S distributed to the paper transport path 180 is discharged to the paper discharge tray 200. The recording material S distributed to the paper transport path 181 is discharged to the paper discharge tray 196.

The operation unit 13 is an input / output device including a touch panel, key buttons, and the like composed of a display and a touch pad. The user uses the operation unit 13 to input various information related to the image forming process (number of sheets, image quality, double-sided / single-sided printing, black-and-white printing, color printing, etc.), an instruction to start the image forming process, media characteristics of the recording material S, and the like. be able to.

The media sensor 14 is provided in the middle of the transport path from the paper feed cassette 220 to the secondary transfer unit 140, and detects media characteristics such as the type of recording material S (thin paper, plain paper, thick paper) and surface properties. In the present embodiment, the media sensor 14 is provided between the transfer roller 154 and the transfer roller 155.

FIG. 2 is a configuration diagram of a control unit that controls the operation of such an image forming apparatus 100. The control unit 20 is built in the image forming apparatus 100. The control unit 20 is a computer including a CPU (Central Processing Unit) 10, a ROM (Read Only Memory) 11, and a RAM (Random Access Memory) 12. The control unit 20 is connected to an image forming unit 17, an operation unit 13, a media sensor 14, a paper feed transfer motor 150, a pickup sensor 152, and a fuser 170.

The CPU 10 controls the operation of the image forming apparatus 100 by reading a computer program from the ROM 11 and executing the RAM 12 in the work area. In the present embodiment, the CPU 10 detects the media characteristics of the recording material S from the detection result of the media sensor 14, and controls the image forming operation according to the media characteristics. For example, the CPU 10 of the image forming unit 17, the paper feed transfer motor 150, and the fuser 170 according to the detection results of various sensors including the media sensor 14 and the input of various information and instructions from the operation unit 13 by the user. Image formation processing is performed by controlling the operation.

The image forming unit 17 controls the operations of the image forming units 120a to 120d, the laser scanners 122a to 122d, the intermediate transfer belt 130, the primary transfer units 123a to 123d, and the secondary transfer unit 140 under the control of the control unit 20. The paper feed transfer motor 150 is a drive source for various rollers for transporting the recording material S provided on the transport path.

The control unit 20 detects that the recording material S has started to be conveyed by the pickup sensor 152 detecting the recording material S. After that, the recording material S is conveyed, so that the media sensor 14 detects the recording material S. The control unit 20 detects the media characteristics of the recording material S based on the detection result of the media sensor 14. The media characteristics include the thickness, surface properties, and basis weight of the recording material S, but in the present embodiment, the media characteristics are selected according to the thickness of the recording material S (thin paper, plain paper, thick paper, etc.). An example of detection will be described. The control unit 20 determines image formation conditions such as an image formation speed and a fixing temperature of the fixing device 170 according to the media characteristics. For example, the control unit 20 determines the rotation speed of the photoconductor, the scanning speed of the laser scanners 122a to 122d, the rotation speed of the intermediate transfer belt 130, the transport speed of the recording material S, and the fixing temperature according to the media characteristics. .. The control unit 20 controls the operation of the drive unit such as the paper feed transfer motor 150 and the fuser 170 based on the determined image formation conditions.

For example, when the recording material S is plain paper or thin paper, the image formation speed is set to 1/1 times the reference image formation speed, and when the recording material S is thick paper, the image formation speed is set to 1/1 the reference image formation speed. Is set to 1/2x speed. The fixing temperature is set to, for example, a temperature according to the thickness and material of the recording material S. For example, if the recording material S is thick paper, the fixing temperature is set higher than that of plain paper, and if the recording material S is thin paper, it is set lower than that of plain paper.

(Fixer)
FIG. 3 is an explanatory diagram of the fuser 170. The fuser 170 includes a heating roller 201 and a pressure roller 205. The fuser 170 heats the toner image T by transporting the recording material S on which the toner image T is transferred while sandwiching it between the fixing nip portions 206 formed between the heating roller 201 and the pressure roller 205. It is melted and pressed against the recording material S.

The heating roller 201 is an assembly composed of a heater holder 207, a fixing heater 204 fixedly arranged on the lower surface of the heater holder 207 along the longitudinal direction of the heater holder (depth direction in the drawing), a fixing film 203 of an elastic layer, and the like. The fixing heater 204 is configured by forming a resistance heating element on a ceramic substrate. The temperature detection sensor 208 comes into contact with the fixing heater 204. The temperature detection sensor 208 detects the temperature of the fixing heater 204. The pressure roller 205 is arranged so that both ends of the core metal are rotatably bearing between the side plates of the fuser 170.

The heating rollers 201 are arranged in parallel with the pressurizing roller 205 so that the fixing heater 204 side is in contact with the pressurizing roller 205, and the both end sides of the heater holder 207 are pressed with a predetermined pressing force. As a result, the surface of the fixing heater 204 is pressed against the elastic layer of the pressure roller 205 with the fixing film 203 interposed therebetween, and the fixing nip portion 206 having a predetermined width is formed. The pressure roller 205 is rotationally driven at a predetermined peripheral speed in the counterclockwise direction by a drive mechanism (not shown).

The control unit 20 detects the temperature of the fixing heater 204 from the detection result of the temperature detection sensor 208, and controls the amount of electric power supplied to the fixing heater 204 so that the fixing heater 204 reaches the target fixing temperature (target temperature). do. The control unit 20 determines the target temperature of the fixing heater 204 based on the media characteristics of the recording material S on which the image is formed, the environmental temperature, and the like. The environmental temperature is detected by, for example, a temperature sensor arranged in the vicinity of the fuser 170. The control unit 20 corrects the temperature, which is an image forming condition determined based on the type of the recording material S, by the environmental temperature, and determines the target temperature of the fixing heater 204.

(Media sensor)
FIG. 4 is an explanatory diagram of the media sensor 14. The media sensor 14 includes a light emitting unit 481 and a light receiving unit 480. The light emitting unit 481 includes a light emitting element such as an LED (Light Emitting Diode). The light receiving unit 480 includes a light receiving element such as a photodiode. The light emitting unit 481 irradiates the conveyed recording material S with light. The light receiving unit 480 receives the reflected light from the recording material S of the light emitted from the light emitting unit 481. The light receiving unit 480 outputs a detection result according to the amount of the received reflected light.

The media sensor 14 includes an elastic member 482, a guide portion 483, and a cam 484. The elastic member 482 presses the guide portion 483 in the recording material S direction with a pressing force corresponding to the rotation of the cam 484. The pressing force of the elastic member 482 changes according to the rotation of the cam 484. When the cam 484 rotates in the direction in which the execution length of the elastic member 482 is short, the pressing force becomes weak, and when the cam 484 rotates in the direction in which the execution length of the elastic member 482 is long, the pressing force becomes strong. While the media sensor 14 detects the media characteristics of the recording material S, here the type (thickness) of the recording material S, the cam 484 rotates and the pressing force of the elastic member 482 changes. The elastic member 482 is, for example, a spring, but is not limited to a spring as long as it is a member that presses the guide portion 483 in the recording material S direction by the rotation of the cam 484.

FIG. 5 is an explanatory diagram of a state when the media sensor 14 detects the recording material S. FIG. 5 shows a paper passing state when the recording material S is of two types, thin paper and thick paper. FIG. 5A shows a thin paper passing state when the pressing force of the elastic member 482 is weak. FIG. 5B shows a thin paper passing state when the pressing force of the elastic member 482 is strong. FIG. 5C shows a cardboard passing state when the pressing force of the elastic member 482 is weak. FIG. 5D shows a cardboard passing state when the pressing force of the elastic member 482 is strong. When the recording material S is thin paper, the recording material S is conveyed in a stable state with respect to the guide portion 483 regardless of the pressing force. When the recording material S is thick paper, if the pressing pressure is weak, the recording material S is conveyed in a state where the guide portion 483 is pushed up. When the recording material S is thick paper, if the pressing force is strong, the recording material S is conveyed in a stable state with respect to the guide portion 483.

When the recording material S is thick paper in this way, the recording material S may push up the guide portion 483, so that the amount of reflected light received by the light receiving portion 480 of the media sensor 14 changes. FIG. 6 is an explanatory diagram of the amount of reflected light according to the type of such recording material S. FIG. 6A shows a change in the amount of reflected light when the recording material S is thin paper. FIG. 6B shows a change in the amount of reflected light when the recording material S is thick paper.

When the recording material S is thin paper, the reflected light amount 250 received by the light receiving unit 480 is averaged because the recording material S is conveyed to the guide unit 483 in a stable state regardless of the pressing force of the elastic member 482. Both the value and the magnitude of the variation are constant. When the recording material S is thick paper, the reflected light amount 255 received by the light receiving unit 480 has a large variation when the pressing force of the elastic member 482 is weak, and an average value becomes large when the pressing force of the elastic member 482 is strong. The variation becomes smaller. As described above, when the recording material S is thick paper, the amount of reflected light differs due to the change in the transport state due to the pressing force.

The control unit 20 acquires a detection result according to the amount of reflected light from the light receiving unit 480 of the media sensor 14. Based on the difference in the amount of reflected light (detection result) as shown in FIG. 6, the control unit 20 can determine the type (material, thickness) as the media characteristic of the recording material S. The control unit 20 optimally controls the image forming speed and the fixing temperature of the fixing device 170 according to the type of the recording material S. Further, the control unit 20 stores the discriminated media characteristics (type) of the recording material S in the RAM 12. When a plurality of paper feed cassettes are provided in the image forming apparatus 100, the control unit 20 may store the media characteristics (type) of the recording material S for each paper feed cassette in the RAM 12.

The media sensor 14 is provided on the transport path and is a media detection means for detecting the recording material S passing through the detection range on the transport path. Therefore, the detection itself is performed during the transportation of the recording material S. The media characteristics (type) of the recording material S according to the detection result by the media sensor 14 are different from the media characteristics (type) of the recording material S that has already been conveyed and stored in the RAM 12, and it is necessary to change the image formation conditions. If this occurs, the control unit 20 temporarily stops the transport of the recording material S. The control unit 20 changes the image formation conditions after the transfer of the recording material S is stopped, and restarts the transfer of the recording material S after the image formation conditions are changed. Therefore, in this case, downtime occurs.

The media sensor 14 may be configured by combining an ultrasonic sensor such as a piezoelectric element with a light emitting unit 481 and a light receiving unit 480. In this case, the media sensor 14 can detect the basis weight and the like of the recording material S by using the reception signal of the ultrasonic sensor, and can further discriminate the media characteristics (type) of the recording material S with high accuracy. Become.

(Operation timing of image formation processing)
FIG. 7 is a timing chart showing the operation timing during the image forming process by the image forming apparatus 100. The image forming apparatus 100 operates in a media automatic detection mode in which the media characteristics of the recording material S are detected by the media sensor 14, and a user instruction mode in which the media characteristics of the recording material S are set by the operation unit 13. Which mode to operate is set by an instruction from the operation unit 13 or an external device equipped with a printer driver. In FIG. 7, the horizontal axis shows the event occurrence timing by the image forming apparatus 100. Events include the start of image formation operation (start of printing operation), the detection of recording material S by the media sensor 14, the completion of switching of the image formation speed, and the arrival of the recording material S at the fixing device 170. The vertical axis of FIG. 7 shows the control target. Control targets include fixing control, image formation control, transfer control, and the like.

FIG. 7A is a timing chart in the media automatic detection mode.

When the control unit 20 acquires the print operation start instruction, the control unit 20 starts the transfer operation of the recording material S. In this case, since the media characteristics of the recording material S at the start of operation are unknown, the control unit 20 starts conveying the recording material S at a speed corresponding to the media characteristics of the recording material S at the time of the previous image formation. , The operation of the fuser 170 is not started. The control unit 20 monitors the pickup sensor 152 and the like, and waits until the recording material S reaches the media sensor 14. When the recording material S reaches the detection range of the media sensor 14, the control unit 20 acquires the detection result by the media sensor 14 and detects the media characteristics of the recording material S. Here, the control unit 20 detects the type (thickness) of the recording material S. When the media sensor 14 finishes detecting the media characteristics of the recording material S, the control unit 20 sets the target temperature of the fixing temperature and starts the start-up control of the fixing device 170.

When the control unit 20 determines that the media characteristics of the recording material S are different from the media characteristics of the recording material detected last time and it is necessary to switch the image formation speed, the control unit 20 stops the transport of the recording material S. The control unit 20 stops the operation and waits for the waiting time X until the switching of the image forming speed is completed. When the switching of the image formation speed is completed, the control unit 20 drives the paper feed transfer motor 150 to restart the transfer of the recording material S, and performs the image formation process. When it is determined that it is not necessary to switch the image forming speed, the control unit 20 performs the image forming process without stopping the transportation of the recording material S. That is, the waiting time X becomes "0". The same process is performed when the image is formed on the recording material thereafter.

In the media automatic detection mode, each operation is performed at the above timing. In the media automatic detection mode, the user does not need to set the media characteristics of the recording material by the operation unit 13. However, when it is necessary to switch the image formation speed, downtime (standby time X) occurs. Since the image forming apparatus 100 forms an image on various types of recording materials, the productivity is lowered when the image forming speed is frequently switched.

FIG. 7B is a timing chart in the user instruction mode.

When the media characteristics of the recording material are set from the operation unit 13 and the control unit 20 receives an instruction to start the printing operation, the control unit 20 starts the transport operation of the recording material S. In this case, since the media characteristics of the recording material S at the start of operation are known, the image forming conditions (image forming speed and target temperature of fixing temperature) are determined. Therefore, the control unit 20 starts the transfer of the recording material S, and at the same time, starts the image formation preparation and the start-up control of the fixing device 170 according to the set media characteristics of the recording material S. Further, the control unit 20 monitors the pickup sensor 152 and the like.

In FIG. 7B, the control unit 20 detects that the fixing temperature has reached the target temperature by the temperature detection sensor 208, and then shows that the recording material S has reached the fixing device 170. The control unit 20 does not need to switch the image formation speed according to the detection of the media characteristics of the recording material S by using the media sensor 14. Therefore, the control unit 20 continues the operation without stopping the transportation of the recording material S. Therefore, in the user instruction mode, the standby time X does not occur, and the process from the start of the printing operation to the ejection of the recording material S can be executed in the shortest time. Since it is not necessary to switch the image formation speed even during continuous printing, no downtime occurs.

In the user instruction mode, each operation is performed at the above timing. In the user instruction mode, the user needs to set the media characteristics of the recording material by the operation unit 13, but the productivity can be maintained because the image formation speed is not switched.

The image forming apparatus 100 of the present embodiment operates in the media automatic detection mode and the user instruction mode, and is either a user who does not want to set the media characteristics of the recording material S or a user who wants to set the media characteristics. Can also be supported. In the user instruction mode, the media characteristics of the recording material S may be set by an external device equipped with a printer driver.

(Image formation processing)
FIG. 8 is a flowchart showing an image forming process by the image forming apparatus 100. The image forming apparatus 100 performs this process according to the print job regardless of which of the media automatic detection mode and the user instruction mode is set.

The control unit 20 waits until it receives a print job from the operation unit 13 or an external device equipped with a printer driver (S801). The control unit 20 that has received the print job starts conveying the recording material S from the paper cassette instructed by the print job (S801: Y, S802). In the user instruction mode, the control unit 20 receives the media characteristics of the recording material S together with the print job. The control unit 20 that has started transporting the recording material S determines whether or not the media automatic detection mode is set (S803).

When the media automatic detection mode is set (S803: Y), the control unit 20 acquires the detection result of the media sensor 14 when the recording material S reaches the detection range of the media sensor 14. The control unit 20 detects the media characteristics of the recording material S according to the detection result of the media sensor 14 (S804). As a result, the control unit 20 detects, for example, the type of recording material S (thin paper, plain paper, thick paper, etc.). The control unit 20 determines whether or not the type of the detected recording material S is the same as the type of the recording material at the time of the previous image formation (S805). The control unit 20 stores the type of recording material (media characteristics) at the time of the previous image formation in the RAM 12, and makes this determination by comparing the type of the recording material S detected this time with the contents of the RAM 12. ..

When the type of the recording material S at the time of the previous image formation and the type of the recording material S this time are the same (S805: Y), the control unit 20 sets the type (media characteristics) of the recording material S this time to the RAM 12. Remember (S806). When the user instruction mode is selected (S803: N), the control unit 20 stores the type (media characteristics) of the current recording material S input together with the print job in the RAM 12 (S806). The control unit 20 forms an image on the recording material S according to the image forming conditions (target temperature of the image forming speed and the fixing temperature) according to the type (media characteristics) of the recording material S (S807). The control unit 20 that has formed an image on the recording material S determines whether or not the image of the final page has been formed (S808). When the image of the final page is not formed (S808: N), the control unit 20 repeats the processes after S802 until the final page. When the image of the final page is formed (S808: Y), the control unit 20 stops the operation of the image forming apparatus 100 and ends the image forming process (S809).

When the type of the recording material S at the time of the previous image formation is different from the type of the recording material S this time (S805: N), the control unit 20 determines that the image formation speed corresponding to the type of the recording material S detected this time is increased. It is determined whether or not it is the same as when the previous image was formed (S810). When the image formation speed corresponding to the type of the recording material S detected this time is the same as that at the time of the previous image formation (S810: Y), the control unit 20 performs image formation by the processing after S806.

When the image forming speed corresponding to the type of the recording material S detected this time is different from the image forming speed at the time of the previous image forming (S810: N), the control unit 20 interrupts the image forming process (S811). The control unit 20 stops the transfer of the recording material S, for example. The control unit 20 that interrupts the image formation process displays a message on the display of the operation unit 13 or the display of the external device equipped with the device driver that the recording material S does not support automatic detection by the media sensor 14. (S812). By responding to the message, the user can instruct the processing after the interruption of the image formation processing.

FIG. 9 is an exemplary diagram of such a message. This message prompts the user to enter media characteristics. In response to such a message, the user presses the "setting" button 901 when switching to the user instruction mode and setting the media characteristics of the recording material S. In this case, the media characteristics of the recording material are not automatically detected until the end of the print job, and the image is formed under the image formation conditions according to the set media characteristics. When the user wants to continue the media automatic detection mode as it is, the user presses the "continue" button 902.

When the user selects the user instruction mode by pressing the "setting" button 901 for the message (S813: Y), the control unit 20 continues to acquire the media characteristics set by the operation unit 13, and S806 or later. Is processed. When the user presses the "continue" button 902 in response to the message (S813: N), the control unit 20 repeats the processes after S802. In this case, the control unit 20 discharges the recording material S whose transportation has been stopped to the outside of the image forming apparatus 100 as it is without performing image forming.

As described above, the image forming process is performed according to the media characteristics.

FIG. 10 is an explanatory diagram of the relationship between the image forming conditions and the media characteristics of the recording material. Here, the image forming condition is the image forming speed 1001 (1/1 times speed, 1/2 times speed), and the media characteristic is the type 1002 (thin paper, plain paper, thick paper) of the recording material. The detection result in the media automatic detection mode is classified into one of thin paper, plain paper, and thick paper. In the user instruction mode, one of thin paper, plain paper, and thick paper is set as the media characteristic. When the type 1002 of the recording material is thin paper or plain paper, the image forming speed 1001 is 1/1 times faster. When the type 1002 of the recording material is thick paper, the image forming speed 1001 becomes 1/2 times faster.

The detection result 1003 of the media sensor 14 varies when repeatedly detecting the media characteristics of a plurality of recording materials. In FIG. 10, the recording material A has a range of variation within the range of plain paper. In the recording material B, the range of variation extends over the range of plain paper and the range of thick paper. That is, in the recording material B, the image forming speed 1001 changes to 1/1 times speed and 1/2 times speed according to the detection result of the media sensor 14. In the recording material C, the range of variation extends over the range of thin paper and the range of plain paper. The image forming speed 1001 of the recording material C is 1/1 times faster regardless of the variation in the detection result.

A case where an image is formed by such recording materials A, B, and C will be described. When image formation is performed on the recording material A in the media automatic detection mode, the control unit 20 does not change the image formation speed 1001 because the type 1002 of the recording material does not change depending on the detection result.

When image formation is performed on the recording material B in the media automatic detection mode, the detection result varies between plain paper and thick paper. When the type of the recording material at the time of the previous image formation is different from the type of the recording material this time, the control unit 20 determines whether or not the image forming speed needs to be changed (process of S810 in FIG. 8). Since the image formation speeds are different, the control unit 20 displays the message of FIG. When the user presses the "setting" button 901 and selects either plain paper or thick paper, the control unit 20 does not automatically detect the recording material thereafter, and corresponds to the type of the selected recording material. The image formation process is performed under the image formation conditions.

When image formation is performed on the recording material C in the media automatic detection mode, the detection result varies between thin paper and plain paper. When the type of the recording material at the time of the previous image formation is different from the type of the recording material this time, the control unit 20 determines whether or not the image forming speed needs to be changed (process of S810 in FIG. 8). Since the image forming speed is the same, the control unit 20 continuously performs the image forming process.

As described above, the image forming apparatus 100 of the present embodiment confirms the image forming conditions according to the media characteristics when the media characteristics of the recording material change according to the detection result of the media sensor 14. When it is necessary to change the image forming conditions, the image forming apparatus 100 temporarily interrupts the image forming process and prompts the user to input the media characteristics. When the media characteristics are input by the user, the image forming apparatus 100 performs an image forming process according to the image forming conditions according to the input media characteristics. If it is not necessary to change the image forming conditions even when the media characteristics change, the image forming apparatus 100 continues the image forming process without interruption. Such an image forming apparatus 100 can improve the convenience of the user.

In the above description, the image formation speed has been described as an example of the image formation condition, but the same processing can be performed for the fixing temperature. For example, the control unit 20 determines in the process of S810 of FIG. 8 whether or not the fixing temperature corresponding to the type of the recording material S detected this time is the same as that at the time of the previous image formation. When the fixing temperatures are different, the control unit 20 interrupts the image forming process and displays the message of FIG. 9 (S811, S812). The control unit 20 that receives the input of the media characteristics from the user will perform the image formation at the fixing temperature corresponding to the media characteristics.

Claims (7)

An image forming means for forming an image on a recording material based on predetermined image forming conditions, and an image forming means.
A transport means for transporting the recording material to the image forming means via a transport path, and a transport means.
A media detecting means provided in the transport path and detecting the media characteristics of the recording material transported to the image forming means, and a media detecting means.
A storage unit said medium detecting unit by storing the media characteristics of the detected said recording medium, a storage media characteristics that are also held during the next image formation,
The image forming means and the control means for controlling the transporting means are provided.
The recording material conveyed by the conveying means is a recording medium of a first type of media properties that will be detected by the media detecting unit may be detected fluctuates in a first media characteristics of the second media characteristics, Moreover, when the first type of recording material is continuously conveyed, the control means has the media characteristic detected by the media detecting means for the newly conveyed recording material as the first media characteristic. When the media characteristic at the time of the previous image formation stored in the storage means is the second media characteristic, the image formation speed corresponding to the first media characteristic and the second media characteristic If the image formation speed corresponding to the media characteristic is the same, image formation is continued, and if the image formation speed corresponding to the first media characteristic and the image formation speed corresponding to the second media characteristic are different, the above. It is characterized in that image formation by the image forming means and transportation of the recording material by the conveying means are interrupted.
Image forming device. It also has an input means that allows the user to input media characteristics.
The control means is used to form an image by the image forming means and the recording material by the conveying means because the image forming rate corresponding to the first media characteristic and the image forming rate corresponding to the second media characteristic are different. After the transfer is interrupted, the media characteristics are acquired from the input means, and the image formation by the image forming means and the transfer of the recording material by the transfer means are restarted under the image formation conditions including the image formation speed corresponding to the media characteristics. Characterized by that
The image forming apparatus according to claim 1. The control unit, when the image forming speed corresponding to the second media characteristics and image forming speed corresponding to the first media characteristics are different, in response to a predetermined user instruction, a given display, the It is characterized by displaying a message prompting the input of media characteristics by an input means.
The image forming apparatus according to claim 2. The control means is characterized in that the media characteristics acquired from the input means are stored in the storage means.
The image forming apparatus according to claim 3. Before SL control means, the conveying speed based on the image forming speed corresponding to the media characteristics inputted from said input means and to resume the conveyance of the recording material by said conveying means,
The image forming apparatus according to claim 3 or 4. The image forming means includes a fixing means for fixing an image on the recording material at a predetermined fixing temperature.
Before SL control means is a fixing temperature in accordance with the media characteristic inputted from said input means, characterized in that to resume the image formation by said image forming means,
The image forming apparatus according to any one of claims 3 to 5. Image forming means for forming an image on a recording material based on a predetermined image forming condition, a conveying means for conveying the recording material to the image forming means through the conveying path, provided in the conveying path, the image forming The media detection means for detecting the media characteristics of the recording material conveyed to the means and the media characteristics of the recording material detected by the media detection means are stored, and the stored media characteristics are retained at the time of the next image formation. A method performed by an image forming apparatus equipped with a storage means that is used.
The recording material conveyed by the conveying means is a first type of recording material in which the media characteristics detected by the media detecting means can be detected by varying between the first media characteristics and the second media characteristics. Moreover, when the first type of recording material is continuously conveyed, the media characteristic detected by the media detecting means for the newly conveyed recording material is the first media characteristic, and the storage When the media characteristic at the time of the previous image formation stored in the means is the second media characteristic, the image formation speed corresponding to the first media characteristic and the second media characteristic correspond to the second media characteristic. If the image formation speed is the same, image formation is continued, and if the image formation speed corresponding to the first media characteristic and the image formation speed corresponding to the second media characteristic are different, the image by the image forming means is used. It is characterized in that the formation and the transfer of the recording material by the transfer means are interrupted.
Image formation method.

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