JP2024029615A - image forming device - Google Patents

Abstract

An object of the present invention is to prevent printing efficiency from decreasing due to paper type discrimination and to reduce the number of media sensors installed. An image forming apparatus 1 includes an image forming section 12 that forms an image on paper and performs printing, a paper feeding section 14 having a paper feeding cassette that stores the paper, and the image forming section 12 and the paper feeding section 14. a media sensor disposed at a position on the conveyance path between The control unit 100 controls the forming unit 12 and performs image formation according to the type of paper. The control unit 100 transports the paper stored in the paper feed cassette 141 to the detection position of the media sensor during a predetermined period when no image forming operation is performed, and causes the type discrimination unit 102 to discriminate the type. [Selection diagram] Figure 3

Description

The present invention relates to an image forming apparatus, and particularly to an image forming apparatus including a media sensor that detects physical properties of paper.

In image forming apparatuses such as copying machines and multifunction peripherals, the physical properties (thickness, smoothness, etc.) of paper on which images are formed may affect image forming output. In particular, in the case of an inkjet method, the influence is significant.

Japanese Patent Application Publication No. 2010-189137 JP2003-305923A

To solve this problem, for example, as described in Patent Documents 1 and 2, a sensor called a media sensor that detects the physical properties of paper is used to determine the type of paper from the detected value of the media sensor. A possible method is to perform image formation according to the type of paper.

However, in the inventions described in Patent Documents 1 and 2, since each paper feed cassette that stores paper is provided with a media sensor, there is a problem that the number of installed media sensors increases and the cost increases.

Furthermore, although it takes a certain amount of time to obtain the detection value of the media sensor and determine the type of paper, in the inventions described in Patent Documents 1 and 2, the type of paper is determined during printing processing ( In other words, since the type of paper on which the image is to be formed is determined, image formation cannot be performed until the determination is completed, resulting in time loss and deterioration of printing performance.

The present invention has been made in view of the above-mentioned circumstances, and aims to prevent printing efficiency from decreasing due to paper type discrimination and to suppress the number of media sensors installed.

An image forming apparatus according to one aspect of the present invention includes an image forming unit that forms an image on paper and performs printing, and a plurality of paper feed cassettes that store paper, each of which is housed in the paper feed cassette. a paper feed section that feeds paper, an ejection port that ejects the paper, a conveyance path that leads the paper from the paper feed cassette to the ejection port via the image forming section, and paper in the conveyance path. between the image forming unit and the paper feed unit, and located on the transport path where all sheets fed from the paper feed cassettes are commonly transported. a media sensor that detects the physical properties of the paper; a type discrimination section that discriminates the type of paper based on the detected value of the media sensor; and a control of the image forming section based on the discrimination result by the type discrimination section. and a control unit that performs image formation according to the type of paper, and the control unit controls the paper feeding unit and the transport unit to The paper stored in the cassette is conveyed to the detection position of the media sensor and stopped, and the type of paper is discriminated by the type discrimination section.

According to the present invention, during a predetermined period when no image forming operation is performed (for example, a period for performing calibration, a period for cleaning the image forming section), the paper stored in the paper feed cassette is transferred to the media sensor. The paper is conveyed to the detection position and stopped, and the type of paper is discriminated by the type discrimination section. That is, since the paper type is determined in advance rather than during printing processing, it is possible to prevent printing efficiency from decreasing.

In addition, since the media sensor is placed at a position on the conveyance path where all paper fed from each paper cassette is commonly transported, the same media sensor allows the paper to be fed from each paper cassette. It is possible to determine the type of any paper, and the number of media sensors installed can be minimized.

1 is a schematic partial front view showing the structure of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram for explaining the configuration of a media sensor and its positional relationship with a sheet of paper being conveyed. 1 is a functional block diagram schematically showing the main internal configuration of an image forming apparatus. (A) is a diagram showing an example of a judgment table for a reflective sensor, (B) is a diagram showing an example of a judgment table for a transmission sensor, and (C) is a diagram showing an example of a judgment table for a thickness sensor. It is a diagram. It is a figure showing an example of a type table. 3 is a flowchart illustrating an example of a process for determining the type of paper P performed by a control unit of the image forming apparatus. 7 is a flowchart illustrating an example of paper type information reset processing performed by a control unit of an image forming apparatus. 3 is a flowchart illustrating an example of image forming processing performed by a control unit of an image forming apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic partial front view showing the structure of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 is a multifunction device that has multiple functions such as a copy function, a printer function, a scanner function, and a facsimile function, and includes an image forming section 12, a paper feeding section 14, and a conveying section 19. It consists of

The image forming unit 12 forms and prints an image on paper P using an inkjet method. The image forming section 12 includes line heads (an example of an ink head) 120 that eject ink droplets of four colors (black, cyan, magenta, and yellow). Each line head 120 forms a color image on the paper P by discharging ink droplets of respective colors onto the paper P that has been transported from the paper feed section 14 to the transport unit 121 through the transport path 15.

The conveyance path 15 guides the paper P from paper feed cassettes 141A to 141D (hereinafter also simply referred to as "paper feed cassette 141") via the image forming section 12 to the discharge port 16.

The transport unit 121 includes a drive roller 122, a driven roller 123, a tension roller 124, and a transport belt 125. The conveyor belt 125 is an endless belt, and spans the drive roller 122, the driven roller 123, and the tension roller 124. The drive roller 122 is a roller that is rotated counterclockwise in FIG. 1 by a motor (not shown), and when the drive roller 122 is rotationally driven, the conveyor belt 125 rotates counterclockwise in FIG. While being moved, the driven roller 123 and the tension roller 124 are driven to rotate counterclockwise in FIG.

Tension roller 124 is a roller for maintaining appropriate tension on conveyor belt 125. The suction roller 126 is in contact with the conveyor belt 125 , and charges the conveyor belt 125 to electrostatically attract the paper P conveyed from the paper feed section 14 to the conveyor belt 125 .

The paper P on which the image has been formed by the image forming section 12 is conveyed to the discharge port 16, and is discharged from the discharge port 16 to a discharge tray (not shown).

The transport unit 19 includes a pair of registration rollers 191 provided along the transport path 15 upstream of the image forming unit 12 in the paper transport direction, and a pair of registration rollers 191 provided upstream of the pair of registration rollers 191 in the paper transport direction. It includes a registration sensor 192, a pair of intermediate rollers 193 provided between the pair of registration rollers 191 and the paper feed section 14, and a media sensor 20.

The pair of registration rollers 191 is for temporarily stopping the paper P that has been conveyed at the nip formed by the pair of registration rollers 191 and for conveying the paper P again toward the image forming section 12 .

The registration sensor 192 is provided to adjust the timing at which the paper P stops. The registration sensor 192 is, for example, a known reflective photoelectric sensor that includes a light emitting element and a light receiving element that detects the reflected light from the paper P that is emitted from the light emitting element, and detects the leading edge of the paper P. .

The intermediate roller pair 193 is for conveying the paper P toward the registration roller pair 191.

The media sensor 20 is disposed at a position on the transport path 15 between the image forming unit 12 and the paper feed unit 14 (that is, a position where the paper P always passes), and is Detect physical properties (reflectivity, transparency, thickness, etc.). Note that in FIG. 1, the media sensor 20 is provided immediately before the registration sensor 192.

As the media sensor 20, a reflection sensor that detects the reflectivity of the paper P, a transmission sensor that detects the transparency of the paper P, a thickness sensor that detects the thickness of the paper P, a CCD (Charge Coupled Device) camera, etc. can be used. It is possible, and the media sensor 20 is configured by one or more combinations of these.

FIG. 2 is a diagram for explaining the configuration of the media sensor 20 and its positional relationship with the transported paper P. The media sensor 20 includes a reflection sensor 21, a transmission sensor 22, and a thickness sensor 23.

The paper feed section 14 includes a plurality of paper feed cassettes 141A to 141D. Each of the paper feed cassettes 141A to 141D includes a pickup roller 142, a pair of paper feed rollers 143, and a pair of transport rollers 144.

The paper feed cassette 141 accommodates a plurality of sheets P, which are recording media. The pickup roller 142 is for picking up the paper P stored in the paper feed cassette 141. The pair of paper feed rollers 143 is for sandwiching the paper P picked up by the pickup roller 142, separating the sheets one by one, and transporting them toward the pair of transport rollers 144. The transport roller pair 144 is for transporting the paper P toward the transport section 19 .

The media sensor 20 is disposed between the image forming section 12 and the paper feed section 14 at a position on the conveyance path along which all sheets fed from each paper feed cassette are commonly conveyed.

FIG. 3 is a functional block diagram schematically showing the main internal configuration of the image forming apparatus 1. As shown in FIG. The image forming apparatus 1 includes a control unit 10, a document feeding section 6, a document reading section 5, an image forming section 12, a paper feeding section 14, an operation section 47, a transport section 19, a storage section 8, and open/close detection sensors 9A to 9D. (hereinafter also simply referred to as "opening/closing detection sensor 9"). Note that the same components as those of the image forming apparatus 1 shown in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted here.

The document feeding section 6 is configured to be openable and closable by a hinge (not shown) on the top surface of the document reading section 5, and the document feeding section 6 is configured to be able to open and close the document placed on a platen glass (not shown). Functions as a holding cover.

A case where the image forming apparatus 1 performs a document reading operation will be described. The original reading unit 5 optically reads the image of the original supplied to the original reading unit 5 by the original feeding unit 6 or placed on the platen glass, and generates image data. The image data generated by the document reading section 5 is stored in an unillustrated image memory or the like. Note that image formation by the image forming section 12 is also referred to as printing.

A case where an image forming operation is performed in the image forming apparatus 1 will be described. The image forming section 12 feeds paper from the paper feeding section 14 based on image data generated by the document reading operation, image data stored in an image memory, etc., image data received from a computer connected to a network, etc. Then, an image is formed on the paper P conveyed through the conveyance path 15.

The paper feed section 14 includes a media sensor 20 (FIG. 1), and the transport section 19 includes a registration sensor 192 (FIG. 1). Then, the detected values (voltage values) of the media sensor 20 and the registration sensor 192 are output to the control unit 10.

The operation unit 47 receives instructions from an operator regarding various operations and processes that can be executed by the image forming apparatus 1, such as an instruction to execute an image forming operation. The operation unit 47 includes a display unit 473 that displays operation guidance for the operator. Further, the operation unit 47 receives instructions from the user via the touch panel included in the display unit 473 based on the user's operation (touch operation) on the operation screen displayed on the display unit 473.

The display section 473 is composed of an LCD (Liquid Crystal Display) or the like. The display section 473 includes a touch panel. When the operator performs an operation of touching a button or key displayed on the screen, the touch panel receives an instruction associated with the position of the touch operation.

The storage unit 8 is a large capacity storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive), and stores various control programs and the like.

The opening/closing detection sensors 9A to 9D each detect the opening/closing of a corresponding one of the paper feed cassettes 141A to 141D. Opening/closing detection sensors 9A to 9D detect opening/closing of all paper feed cassettes. A detection signal output from the opening/closing detection sensor 9 to the control unit 10 indicates whether the paper feed cassette 141 is in an open state or a closed state.

The control unit 10 includes a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), and a dedicated hardware circuit. The processor is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an MPU (Micro Processing Unit). The control unit 10 includes a control section 100 and a type discrimination section 102.

The control unit 10 functions as a control section 100 and a type discrimination section 102 by the operation of the processor according to a control program stored in the storage section 8. However, the control section 100 and the like may be configured by hardware circuits without depending on the operation according to the control program by the control unit 10. Hereinafter, the same applies to each embodiment unless otherwise mentioned.

Control unit 100 controls the overall operation of image forming apparatus 1 . The control section 100 is connected to the document feeding section 6, the document reading section 5, the image forming section 12, the paper feeding section 14, the operation section 47, the transport section 19, the storage section 8, and the opening/closing detection sensor 9, and controls each of these sections. Performs drive control, etc. For example, the control unit 100 executes various processes necessary for image formation by the image forming apparatus 1.

The type determination unit 102 determines the type of paper P based on the detection values of the media sensor 20 (reflection sensor 21, transmission sensor 22, and thickness sensor 23), and stores determination result information in a nonvolatile memory included in the control unit 10. (Paper type information). Based on this, the control unit 100 stores determination result information (paper type information) in association with the paper feed cassette 141. For example, the type determining unit 102 determines the physical property level of the paper P based on the detection value of the media sensor 20 based on determination tables TL1 to TL3 (hereinafter also simply referred to as "determination table TL"). The determination tables TL1 to TL3 show the ranges in which the detected values of the media sensor 20 (reflection sensor 21, transmission sensor 22, and thickness sensor 23) can be distributed, divided into a plurality of ranges, and the physical property level corresponding to each range. is predetermined.

FIG. 4(A) is a diagram showing an example of the determination table TL1 for the reflection sensor 21. FIG. 4(B) is a diagram showing an example of the determination table TL2 for the transmission sensor 22. FIG. 4C is a diagram showing an example of the determination table TL3 for the thickness sensor 23. The determination table TL is stored in the storage unit 8 in advance.

For example, when the detection value of the reflection sensor 21 is "0.26V", the type discrimination unit 102 determines the physical property level of the reflectivity obtained from the reflection sensor 21 based on the determination table TL1 (FIG. 4(A)). It is judged as "A". When the detection value of the transmission sensor 22 is "2.11V", the type discrimination unit 102 sets the physical property level of the transmission obtained from the transmission sensor 22 to "b" based on the determination table TL2 (FIG. 4(B)). It is determined that Then, when the detected value of the thickness sensor 23 is "0.34V", the type discrimination unit 102 sets the physical property level of the thickness obtained from the thickness sensor 23 to "1" based on the determination table TL3 (FIG. 4(C)). ”.

Further, the type determining unit 102 determines the type of the paper P by reading out the type corresponding to the combination of physical property levels of the paper P determined above from the type table TL4.

FIG. 5 is a diagram showing an example of the type table TL4. For example, the reflective physical property level obtained from the reflective sensor 21 is "A", the transparent physical property level obtained from the transmissive sensor 22 is "b", and the physical property level of thickness obtained from the thickness sensor 23 is "1". If so, the type determining unit 102 determines the type of paper P as "media 4" based on the type table TL4.

The control unit 100 controls the image forming unit 12 based on the determination result by the type determining unit 102 to form an image according to the type of paper P. For example, the control unit 100 performs ink ejection amount adjustment processing, color tone adjustment processing, etc. according to the type of paper P. This achieves optimal image quality depending on the paper type.

Furthermore, when the control unit 100 does not receive a print request (such as an instruction from a user input to the operation unit 47 or an instruction transmitted from another PC connected to the network), the control unit 100 controls the transport unit 19 and Controls the paper feed unit 14, transports the paper P stored in the paper cassette 141 to the detection position of the media sensor 2, stops it, causes the type discrimination unit 102 to discriminate the paper type, and then accepts a new paper. The printer is placed on standby in a state where image formation is possible according to a print request. The control unit 100 stores the paper type determined by the type determination unit 102 in association with the paper feed cassette 141.

Here, the type determining unit 102 determines the type of paper P stored in the paper feed cassette 141 using the predetermined period. Note that the predetermined period is a period during which calibration is performed or a period during which cleaning of the image forming section 12 is performed.

Next, an example of the process of determining the type of paper P performed by the control unit 10 of the image forming apparatus 1 will be described with reference to the flowchart shown in FIG. Note that this process is performed when the power of the image forming apparatus 1 is turned on.

The control unit 100 resets the paper type information stored in each paper feed cassette 141, which is stored in the nonvolatile memory (S1). That is, the control unit 100 makes the type of paper P stored in the paper feed cassette 141 unknown.

Next, the control unit 100 determines whether or not the user's operation allows the paper type to be pre-determined (S2), and allows the user to perform the paper type pre-determination based on the operation on the operation unit 47. If it is determined that a permission instruction to do so has been input (YES in S2), it is determined whether there is a paper feed cassette 141 in which the type of paper P contained therein is unknown (S3). Immediately after the image forming apparatus 1 is powered on, there is no paper feed cassette 141 in which the type of paper P is known, but by repeating the processes from S8 to S12, which will be described later, the type of paper P becomes gradually clear. .

Furthermore, even if the type of paper P stored in the paper feed cassette 141 is known, when the paper feed cassette 141 is opened, the paper P may be replaced and the type of paper P may be changed. Therefore, the type is treated as unknown. Processing in this case will be explained later using the flowchart of FIG.

When the control unit 100 determines that there is a paper feed cassette 141 in which the type of paper P is unknown (YES in S3), the control unit 100 determines whether it is time to perform calibration or cleaning the image forming unit 12 ( S4).

When the control unit 100 determines that it is time to start calibration or cleaning (YES in S4), it starts calibration or cleaning (S5). Then, the control unit 100 calculates the number T of paper feed cassettes 141 (hereinafter referred to as the distinguishable number T) of paper feed cassettes 141 for which the type of paper P can be discriminated within the execution period of calibration or cleaning (S6). For example, the control unit 100 determines a predetermined period (e.g., 120 seconds) required to perform calibration and a time (e.g., 50 seconds) required to determine the type of paper P per paper cassette 141. I remember. If the calibration execution period is 120 seconds and the time required to determine the type of paper P is 50 seconds, the control unit 100 calculates the calibration execution period 120 seconds/required time 50 seconds = 2.4, and calculates the calculation result below. The integer (2 in this example) that is closest to the calculation result is calculated as the discriminable number T.

The control unit 100 determines whether or not the distinguishable number T is "1" or more (S7), and if it is determined that the distinguishable number T is "1" or more (YES in S7), the paper feed unit 14 and the transport section 19 to rotate the pickup roller 142, the pair of paper feed rollers 143, the pair of transport rollers 144, and the pair of intermediate rollers 193, the paper P stored in the specified paper feed cassette 141 is (S8), and when the paper P is transported to the detection position of the media sensor 20 (for example, until the leading edge of the paper P is detected by the registration sensor 192), the pickup roller 142 and the paper feed roller pair 143 , the conveying roller pair 144, and the intermediate roller pair 193 stop rotating, thereby stopping the paper P (S9). Then, the control unit 100 causes the media sensor 20 to perform detection, and acquires the detection value of the media sensor 20 (S10).

The type determination unit 102 determines the physical property level of the paper P based on the detection value of the media sensor 20 acquired by the control unit 100 (S11), and the type determination unit 102 determines the physical property level of the paper P based on the determination result by the type determination unit 102. , the type of paper P is determined (S12). That is, the control unit 100 causes the type determining unit 102 to determine the type of paper. The control unit 100 stores determination result information (paper type information) (S12).

The control unit 100 controls the transport unit 19, the paper feed unit 14, etc. to resume transport of the paper P, and discharges the paper P from the discharge port 16 (S13). Further, the control unit 100 subtracts "1" from the discriminable number T (S14). After this, the process returns to S7. Then, the control unit 100 repeats the processes of S8 to S14 while the discriminable number T is equal to or greater than "1" (YES in S7). When the control unit 100 determines that the discriminable number T is not greater than or equal to "1" (NO in S7), the process returns to S2.

By the way, during one calibration or cleaning execution period, the type of paper P is determined for all the paper feed cassettes 141 in which the type of paper P stored therein is unknown among the plurality of paper feed cassettes 141. It is assumed that this cannot be done.

Therefore, as another embodiment, when the control unit 100 conveys the paper P to the detection position of the media sensor 20 during the predetermined period (calibration or cleaning execution period), the control unit 100 controls the The priorities may be stored in advance, and the type of paper P may be determined starting from the paper feed cassette 141 with the highest paper feed priority.

Further, in S2, if the control unit 100 determines that the permission instruction has not been input (NO in S2), in S3, the control unit 100 determines that there is no paper feed cassette 141 in which the type of paper P is unknown. (NO in S3), in S4, the control unit 100 determines that it is not the timing to start calibration and cleaning (NO in S4), and in S7, the control unit 100 If it is determined that T is not greater than "1" (NO in S7), the process returns to S2.

Note that during one calibration or cleaning execution period, the control unit 100 controls all the paper feed cassettes 141 in which the type of paper P stored therein is unknown in the plurality of paper feed cassettes 141. If the type of paper P could not be determined, the next time the calibration or cleaning execution period arrives, the paper stored in the paper feed cassette 141 for which the type of paper P could not be determined P is fed and conveyed, the media sensor 20 performs detection, and the detection value of the media sensor 20 is acquired.

Next, an example of the paper type information reset process performed by the control unit 10 of the image forming apparatus 1 will be described with reference to the flowchart shown in FIG. Note that this process is performed for each of the paper feed cassettes 141A to 141D.

The control unit 100 determines whether the paper feed cassette 141 is opened based on the output signal from the open/close detection sensor 9 (S21), and if it is determined that the paper feed cassette 141 is opened (S21). (YES), the paper type information indicating the type of paper P stored in the paper feed cassette 141, which is stored in the nonvolatile memory, is reset (S22). That is, the control unit 100 makes the type of paper P stored in the paper feed cassette 141 unknown. This is because, as described above, when the paper feed cassette 141 is opened, the paper P may be replaced and the type of the paper P may be changed.

Next, the control unit 100 determines whether or not the paper feed cassette 141 is closed based on the output signal from the open/close detection sensor 9 (S23), and determines that the paper feed cassette 141 is closed. If so (YES in S23), the process returns to S21.

Next, an example of the image forming process performed by the control unit 10 of the image forming apparatus 1 will be described with reference to the flowchart shown in FIG. Note that this process is performed when the control unit 100 receives a print request from the user (for example, a copy execution instruction via the operation unit 47).

The control unit 100 determines whether the type of paper P stored in the paper feed cassette 141 (paper feed cassette 141 that feeds the paper P used for image formation) indicated by the print request is known ( S31). Here, if the control unit 100 determines that the type of the paper P is known (the paper type information of the paper feed cassette 141 containing the paper P of the paper P is stored) (in S31), YES), by controlling the paper feed unit 14 and the like to rotate the pickup roller 142, the pair of paper feed rollers 143, the pair of transport rollers 144, the pair of intermediate rollers 193, and the pair of registration rollers 191, the type indicated by the print request is The paper P is fed from the paper feed cassette 141 containing the paper P and transported (S32). The control unit 100 controls the image forming unit 12 and the like to form an image according to the type of paper P (S33), and discharges the paper P on which the image has been formed from the discharge port 16 (S34). After this, the process ends.

On the other hand, if the control unit 100 determines that the type of paper P stored in the paper cassette 141 indicated by the print instruction is unknown (NO in S31), the cassette designation instruction is input by the user to the operation unit 47. It is determined whether image formation using the paper P stored in yet another paper feed cassette 141 indicated by is permitted (S35). The permission is set based on a permission instruction inputted in advance to the operation unit 47 by the user, and the control unit 100 stores whether permission is granted or not.

If the control unit 100 determines that the above permission has not been granted (NO in S35), the control unit 100 controls the paper feed unit 14, etc., and controls the pickup roller 142, the paper feed roller pair 143, the conveyance roller pair 144, and the intermediate By rotating the roller pair 193, the paper P is fed and conveyed from the paper feed cassette 141 indicated by the print request (S36). After conveying the paper P to the detection position of the media sensor 20, the control unit 100 temporarily stops the paper P by stopping the rotation of the pickup roller 142, the paper feed roller pair 143, the conveyance roller pair 144, and the intermediate roller pair 193. It is stopped (S37), the media sensor 20 is caused to perform detection, and the detection value of the media sensor 20 is acquired (S38).

The type determination unit 102 determines the physical property level of the paper P based on the detection value of the media sensor 20 acquired by the control unit 100 (S39), and determines the type of the paper P based on the determination result (S40). .

The control unit 100 controls the paper feed unit 14 and the like to restart the conveyance of the paper P whose conveyance was once stopped and convey the paper P toward the image forming unit 12 (S41). etc., to perform image formation according to the type of paper P indicated by the discrimination result by the type discrimination unit 102 (S42), and to discharge the paper P on which the image has been formed from the discharge port 16 (S43). After this, the process ends.

On the other hand, if the control unit 100 determines that it is permitted to perform image formation using paper P from another paper feed cassette 141 indicated by the cassette designation instruction (YES in S35), the control unit 100 determines that the paper feed unit 14, etc. By controlling the pickup roller 142, paper feed roller pair 143, transport roller pair 144, intermediate roller pair 193, and registration roller pair 191 to rotate the paper from another paper feed cassette 141 indicated by the cassette designation instruction, P is fed and transported (S44), and an image is formed according to the paper type stored in association with the paper feed cassette 141 indicated by the cassette designation instruction (S45), and the paper P on which the image has been formed is is discharged from the discharge port 16 (S46). After this, the process ends.

Note that when performing the process of S45, if the control unit 100 does not store the paper type in association with the paper feed cassette 141 indicated by the cassette designation instruction, the process of S36 to S43 may be performed.

According to the above embodiment, during a predetermined period in which no image forming operation is performed (for example, a period in which calibration is performed, a period in which the image forming unit is cleaned), the paper stored in the paper feed cassette is transferred to the media sensor. The paper is conveyed to the detection position No. 20 and stopped, and the type discrimination unit 102 discriminates the type of paper. That is, since the paper type is determined in advance rather than during printing processing, it is possible to prevent printing efficiency from decreasing.

Furthermore, since the media sensor 20 is disposed at a position on the conveyance path where all sheets fed from each paper cassette 141 are commonly conveyed, It is possible to determine the type of any paper being fed, and the number of media sensors 20 to be installed can be minimized.

The present invention is not limited to the configuration of the above embodiments, and various modifications are possible. Furthermore, in the embodiment described above, the configuration and processing shown in the embodiment using FIGS. 1 to 8 are merely one embodiment of the present invention, and the present invention is not intended to be limited to the configuration and processing.

1 Image forming device 9 Opening/closing detection sensor 12 Image forming section 14 Paper feeding section 15 Conveying path 16 Ejection port 20 Media sensor 21 Reflection sensor 22 Transmission sensor 23 Thickness sensor 100 Control section 102 Type discrimination section 141 Paper cassette

Claims (6)

an image forming unit that forms an image on paper and prints;
a paper feeding section having a plurality of paper feeding cassettes for storing paper, and feeding paper stored in each paper feeding cassette;
an ejection port from which paper is ejected;
a conveyance path that guides paper from the paper feed cassette to the discharge port via the image forming section;
a transport unit that transports the paper in the transport path;
The device is disposed between the image forming unit and the paper feeding unit at a position on the conveyance path along which all the sheets fed from the paper feed cassettes are commonly conveyed, and detects the physical properties of the paper. A media sensor that
a type determination unit that determines the type of paper based on the detected value of the media sensor;
a control unit that controls the image forming unit based on the determination result by the type determining unit to form an image according to the type of paper;
The control unit causes the paper feed unit and the transport path to transport the paper stored in the paper feed cassette to a detection position of the media sensor, and then stops the paper during a predetermined period when no image forming operation is performed. The image forming apparatus causes the type determining section to determine the type of paper. The image forming apparatus according to claim 1, wherein the predetermined period is a period during which calibration is performed or a period during which cleaning of the image forming section is performed. When conveying the paper to the detection position of the media sensor during the predetermined period, the control unit selects the paper feed cassette having a higher paper feed priority based on the paper feed priority order of the paper feed cassette that is set in advance. 1 or 2 , wherein the paper stored in the paper feed cassette is transported by the paper feed section and the transport section to a detection position of the media sensor and stopped, and the type of paper is discriminated by the type discrimination section. 2. The image forming apparatus according to 2. The control unit includes:
Each time the type determination unit determines the type of paper, it stores the paper in association with the paper feed cassette in which the paper is stored;
If a print request is received for paper in the paper feed cassette whose type of paper is unknown,
The paper feed unit and the transport unit transport the paper stored in the paper feed cassette, the paper type of which is unknown, to the detection position of the media sensor and stop the paper, and the type discrimination unit determines the paper type. The image forming apparatus according to claim 1, wherein the image forming section performs image formation according to the paper type indicated by the result of the discrimination. When the control unit receives a print request for paper in the paper feed cassette in which the type of paper contained therein is unknown, the control unit performs image formation according to the paper type indicated by paper type information included in the print request. The image forming apparatus according to claim 1, wherein the image forming unit performs the image forming process. It further includes an operation section that accepts input instructions from the user,
The control unit includes:
If the instruction to determine the type of paper is received by the operation unit during the predetermined period, the paper is stored in the paper feed cassette by the paper feed unit and the transport unit during the predetermined period. transporting the paper to a detection position of the media sensor, stopping the paper, and causing the type discrimination unit to discriminate the type of paper;
If the operation unit receives an instruction not to perform paper type discrimination during the predetermined period, the paper stored in the paper feed cassette is moved to the detection position of the media sensor during the predetermined period. 3. The image forming apparatus according to claim 1, wherein the image forming apparatus does not carry out control to determine the type of paper by conveying the paper to a certain point and stopping the image forming apparatus.