JP7444301B2 - Image forming device, medium discrimination method, and program - Google Patents

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, or a multifunctional digital complex machine called an MFP (Multifunction Peripheral), and a medium discrimination method and program executed in the image forming apparatus.

2. Description of the Related Art There is a known technique for automatically determining the type of medium, such as paper, on which an image is formed, used in the above-mentioned image forming apparatus, using a sensor serving as a detection means. On the other hand, in recent years, special media such as envelopes and OHPs have been increasing.

Therefore, Patent Document 1 discloses a CMOS that detects the surface condition of a recording material in order to accurately determine the type of recording material when the type of recording material is determined using a plurality of recording material discrimination methods. A method is disclosed that uses an area sensor and an ultrasonic sensor that detects the basis weight of the recording material, and comprehensively determines the type of recording material from the detection results of these sensors.

JP2009-29622A

However, if a special medium such as an envelope is comprehensively determined from the detection results of a plurality of sensors as described in Patent Document 1, there is a risk that the medium will be determined to be a different medium due to erroneous detection.

The present invention was made in view of the above technical background, and is intended to prevent an envelope, which is a special medium, from being mistakenly detected as a different medium when a medium is detected by a plurality of detection means. An object of the present invention is to provide an image forming apparatus, a medium discrimination method, and a program that can perform efficient discrimination while preventing the above.

The above object is achieved by the following means.
(1) an image forming means for forming an image on a medium;
a first detection means for detecting the basis weight of the medium;
a second detection means for detecting that there is an air layer in the medium;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming means. a means of determining whether or not to apply;
An image forming apparatus comprising:
(2) When the second detection means detects that there is no air layer in the medium, the judgment means detects the basis weight by the first detection means, or the first detection means detects the basis weight. The image forming apparatus according to item 1 above, wherein the image forming apparatus determines to use the detection result by the means.
(3) If the second detecting means detects that the medium has an air layer, the determining means does not detect the basis weight by the first detecting means, or the first detecting means does not detect the basis weight. The image forming apparatus according to item 1 above, wherein the image forming apparatus determines not to use the detection result by the detection means.
(4) an image forming means for forming an image on a medium;
a first detection means for detecting the basis weight of the medium;
second detection means for detecting that the medium is an envelope;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming means. a means of determining whether or not to apply;
An image forming apparatus comprising:
(5) When the second detecting means detects that the type of the medium is not an envelope, the determining means causes the first detecting means to detect the basis weight, or the first detecting means detects the basis weight. 4. The image forming apparatus according to item 4, wherein the image forming apparatus determines to use the detection result by the detection means.
(6) When the second detecting means detects that the type of the medium is an envelope, the determining means does not detect the basis weight by the first detecting means, or the first detecting means does not detect the basis weight. 4. The image forming apparatus according to item 4, wherein the image forming apparatus determines not to use the detection result by the detection means.
( 7 ) The image forming apparatus according to any one of items 1 to 6 , wherein the first detection means is an optical sensor.
( 8 ) The image forming apparatus according to any one of items 1 to 6 , wherein the second detection means is an ultrasonic sensor.
( 9 ) The image forming apparatus according to item 8 , wherein the ultrasonic sensor includes a pair of transmitting section and receiving section that are disposed diagonally opposite each other at a predetermined angle with respect to the medium passage direction with the medium conveyance path in between. .
( 10 ) If the second detection means detects that the type of medium fed from a paper feed slot that cannot feed envelopes is an envelope, envelopes are fed from a paper feed slot that cannot feed envelopes. 7. The image forming apparatus according to any one of items 1 to 6 , further comprising a notification means for notifying a user that the image forming apparatus has been used.
( 11 ) A fixing unit that performs fixing by passing a medium between a pair of heating and pressurizing bodies whose position can be adjusted in the approaching and separating directions;
a control means for adjusting the position of the heating/pressure body of the fixing unit in a separating direction when the second detection means detects that the type of the medium is an envelope;
7. The image forming apparatus according to any one of items 1 to 6 above.
( 12 ) The image forming apparatus according to item 11 , wherein the control means stops the conveyance of the medium by the conveyance means and adjusts the position of the heating/pressure body of the fixing unit in the separating direction.
( 13 ) comprising a storage means for storing the detection result by the second detection means,
During continuous printing, if the second detection means detects that the type of medium to be printed is an envelope, the storage means stores that the type of medium is an envelope, and If it is detected that the type of the medium is not an envelope, the storage means stores that the type of the medium is not an envelope;
During continuous printing, if the detection result by the second detection means is different from the previous detection result stored in the storage means, the determination means determines that an envelope and a medium other than the envelope are mixed. The image forming apparatus according to any one of items 1 to 6 above.
( 14 ) The image forming apparatus according to item 13 , further comprising a notification means for notifying a user of the mixed loading when the determining means determines that an envelope and a medium other than the envelope are mixed.
( 15 ) Any one of the preceding items 1 to 6 , wherein the first detection means starts detecting the basis weight of the medium before the second detection means starts detecting that the type of medium is an envelope. The image forming apparatus described in .
( 16 ) comprising a transfer means for transferring an image to the medium, and a timing roller for conveying the paper to the transfer means in accordance with the timing at which the image is transferred to the medium by the transfer means,
16. The image forming apparatus according to item 15 , wherein the second detection means is disposed between the timing roller and the first detection means.
( 17 ) an image forming step of forming an image on the medium;
detecting the basis weight of the medium by a first detection means;
detecting by a second detection means that there is an air layer in the medium;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming step. a determination step for determining whether to apply;
A medium discrimination method performed by an image forming apparatus.
( 18 ) an image forming step of forming an image on the medium;
detecting the basis weight of the medium by a first detection means;
detecting by a second detection means that the medium is an envelope;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming step. a determination step for determining whether to apply;
A medium discrimination method performed by an image forming apparatus.
( 19 ) an image forming step of forming an image on the medium;
detecting the basis weight of the medium by a first detection means;
detecting by a second detection means that there is an air layer in the medium;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming step. a determination step for determining whether to apply;
A program that causes the image forming apparatus's computer to execute.
( 20 ) an image forming step of forming an image on the medium;
detecting the basis weight of the medium by a first detection means;
detecting by a second detection means that the medium is an envelope;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming step. a determination step for determining whether to apply;
A program that causes the image forming apparatus's computer to execute.

According to the image forming apparatus and medium discrimination method according to the present invention, the detection result of the second detection means is first obtained, and based on the detection result, the basis weight of the medium is detected by the first detection means. Since it is determined whether or not the detection result by the first detection means should be applied to the printing conditions, it is possible to perform processing such as not performing detection by the first detection means depending on the detection result of the second detection means. Therefore, efficient discrimination can be performed.

According to the program according to the present invention, the detection result of the second detection means is first obtained, and based on the detection result, it is determined whether or not the basis weight of the medium is detected by the first detection means, or whether the first detection It is possible to cause the computer of the image forming apparatus to execute a process of determining whether or not to apply the detection result by the means to the printing conditions.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 1 is a block diagram showing the electrical configuration of an image forming apparatus. It is an explanatory view of the arrangement state of an optical sensor. FIG. 2 is an explanatory diagram of an ultrasonic sensor and its arrangement state. (A) is a diagram schematically showing the arrangement positions of the optical sensor and the ultrasonic sensor, (B) is a diagram showing the detection voltage (output voltage) of the sensor after the leading edge of the medium reaches the timing roller, (C ) is a diagram showing the voltage detected by the sensor before the leading edge of the medium reaches the timing roller. It is a table showing characteristics of an optical sensor and an ultrasonic sensor. 2 is a flowchart illustrating an example of a medium discrimination process executed by the image forming apparatus of FIG. 1. FIG. 2 is a flowchart illustrating another example of medium discrimination processing executed by the image forming apparatus of FIG. 1. FIG.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 according to an embodiment of the present invention. In this example, a tandem color printer is used as the image forming apparatus 1.

In FIG. 1, the image forming apparatus 1 is configured such that a paper feed section 20 is disposed at the bottom of an apparatus main body 1A, an image forming section 10 is disposed at the center, and a paper discharge section 60 is disposed at the top. A medium transport path 22 is formed extending from the paper feed section 20 to the paper discharge section 60 to transport the medium S, such as paper or envelopes, fed out from the paper feed section 20 upward.

The image forming section 10 includes a driving roller 16 and a driven roller 15 arranged substantially in the vertical center of the apparatus main body 1A, and an intermediate roller horizontally suspended between the driving and driven rollers 16 and 15 and running in the direction of the arrow. A transfer belt 14 and photoreceptor units 12Y, 12M, 12C, which are image forming units for each color of yellow (Y), magenta (M), cyan (C), and black (K), arranged along the traveling direction of the transfer belt 14. It is equipped with 12K.

The toner images created by each of the photoreceptor units 12Y, 12M, 12C, and 12K are superimposed and transferred to the transfer belt 14, and the conveyance end of the transfer belt 14 (Fig. Secondary transfer is performed by a transfer roller (corresponding to a transfer means) 17 at the middle right end), and the paper S is fed to a fixing unit 30 to fix the toner image.

In this embodiment, the fixing unit 30 includes a heating roller 31 equipped with a heater (not shown) and a pressure roller 32 disposed in contact with the heating roller 31. The toner image is fixed on the medium S by passing the medium S through a nip formed in the nip and applying heat and pressure. Furthermore, in this embodiment, in order to adjust the pressing force according to the thickness of the medium S, at least one of the heating roller 31 and the pressing roller 32 can be moved in the approaching/separating direction. Note that the movement in the approaching and separating directions is not limited to movement that allows the user to visually confirm that the user is moving away. It is good if the nip pressure is weakened and the envelope can be passed through.

Each photoreceptor unit 12Y, 12M, 12C, 12K forms an image using an electrostatic copying method, and includes a charger disposed around them, a developing device 11Y, 11M, 11C, 11K, and a photoreceptor drum. It is equipped with 13Y, 13M, 13C, 13K, a transfer device, etc. Each photoreceptor drum 13Y is charged by a charger by each laser diode of an exposure section 40, which includes a print head 41 having four laser diodes, a polygon mirror, a scanning lens, etc., and four reflection mirrors 42, etc. , 13M, 13C, and 13K are exposed, and an electrostatic latent image is formed on the surfaces.

In addition, toner cartridges 70Y, 70M, 70C, 70K and sub-hoppers 80Y, 80M, 80C, 80K are used as a replenishment mechanism for replenishing toner to the developing devices 11Y, 11M, 11C, 11K of each photoreceptor unit 12Y, 12M, 12C, 12K. are arranged above the photoreceptor units 12Y, 12M, 12C, and 12K.

In FIG. 1, reference numeral 50 is an operation panel section including a key section and a display section.

The paper feeding section 20 includes one or more stages (two stages in the example of FIG. 1) of paper feeding cassettes 21. Further, a paper feed roller 23 is provided on the exit side of each paper feed cassette 21, and the medium S accommodated in each paper feed cassette 21 is pulled out by the paper feed roller 23, and a paper feed roller 23 is provided along the conveyance path 22. The sheet is transported to a secondary transfer position by a secondary transfer roller 17 by one or more sets of transport rollers 24 and 25. Note that the image forming apparatus 1 may be equipped with a manual feed tray. In this embodiment, the feeding roller 23, the conveying rollers 24, 25, and the like constitute a conveying means for conveying the medium S. Further, in this embodiment, the conveyance roller 25 near the secondary transfer roller 17 conveys the medium S to the transfer roller 17 in accordance with the timing at which the secondary transfer roller 17 transfers the toner image onto the medium S. It also serves as a timing roller for adjustment.

A plurality of sensors 91 and 92 for detecting paper types are arranged in the transport path 22 between the lower transport roller 24 and the upper transport roller (timing roller) 25. In this embodiment, an optical sensor 91 as a first detection means is arranged on the lower side, and an ultrasonic sensor 92 is arranged above the optical sensor 91, in other words, between the timing roller 25 and the optical sensor 91. ing. Note that between the secondary transfer roller 17 and the timing roller 25, an optical sensor 91 may be disposed on the upstream side, and an ultrasonic sensor 92 may be disposed on the downstream side. These optical sensors 91 and ultrasonic sensors 92 will be described later.

FIG. 2 is a block diagram showing the electrical configuration of the image forming apparatus 1. As shown in FIG. As shown in FIG. 2, the image forming apparatus 1 includes a control section 100, a fixed storage device 110, an image reading device 120, the above-mentioned operation panel section 50, an image forming section 10, a paper feed section 20, an optical sensor 91, It includes an ultrasonic sensor 92, a printer controller 150, a network interface (network I/F) 160, and the like, and are connected to each other via a system bus 175.

The control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, an S-RAM (Static Random Access Memory) 103, an NV-RAM (Non Volatile RAM) 104, a clock IC 105, and the like.

The CPU 101 centrally controls the entire image forming apparatus 1 by executing an operation program stored in the ROM 102 or the like. For example, in addition to executable control of the copy function, printer function, scan function, etc., in particular, in this embodiment, an output mode suitable for the paper type is set based on the paper type detection result of the paper S by the paper type detection sensor 90 during printing. Controls such as automatically setting (print mode) and executing printing are performed, details of which will be described later.

The ROM 102 stores programs executed by the CPU 101 and other data.

The S-RAM 103 serves as a work area when the CPU 101 executes a program, and temporarily stores programs and data used when executing the program.

The NV-RAM 104 is a nonvolatile memory backed up by a battery, and stores various settings related to image formation, the number of pixels of the display section 54, data of various screens displayed on the display section 54, etc. .

The clock IC 105 not only keeps time, but also functions as an internal timer to measure processing time and the like.

The fixed storage device 110 is composed of a hard disk or the like, and stores programs, various data, and the like.

The image reading device 120 includes a scanner or the like, reads an original set on a platen glass by scanning it, and converts the read original into image data.

The operation panel unit 50 is used when the user instructs the image forming apparatus 1 to perform jobs, etc., and makes various settings, and includes a reset key 51, a start key 52, a stop key 53, a display unit 54, a touch panel 55, etc. We are prepared.

The reset key 51 is used to reset settings, the start key 52 is used to start operations such as scanning, and the stop key 53 is pressed to interrupt operation. It is.

The display section 54 is made of, for example, a liquid crystal display device and displays messages, various operation screens, etc. The touch panel 55 is formed on the screen of the display section 54 and detects touch operations by the user.

The image forming unit 10 prints on paper a copy image generated from the image data of the original read by the image reading device 120 or the print data sent from an external terminal device, etc. The above-mentioned fixing unit 30 and the like are provided.

The print engine 18 refers to a hardware part related to image formation, and includes, for example, photoconductor units 12Y, 12M, 12C, and 12K, developing devices 11Y, 11M, 11C, and 11K, photoconductor drums 13Y, 13M, 13C, and 13K, and a charging unit. It consists of a printer, a transfer device, a laser diode, a polygon mirror, a print head 41, a motor for driving these, and the like.

Printer controller 150 generates a copy image from print data received by network interface 160.

A network interface (network I/F) 160 functions as a communication means for transmitting and receiving data with an external terminal device and the like.

FIG. 3 is an explanatory diagram of the optical sensor 91 and its arrangement state. The optical sensor 91 includes a pair of light emitting parts 91a and light receiving parts 91b which are arranged opposite to each other with the medium transport path 22 in between. The light receiving section 91b is provided with a light receiving element (not shown) such as a photodiode. The medium S pulled out from the paper feed cassette 21 by the paper feed roller 23 is passed from the bottom to the top while the gap between the roller 24a and the guide 24b that constitute the transport roller 24 is regulated so that there is no variation in the transport position. . A plurality of sets (two sets in FIG. 3) of the rollers 24a and the guides 24b are provided in the direction perpendicular to the transport direction (the width direction of the medium), and the light emitting section 91a and the light receiving section 91b move the rollers 24a and the guides 24b toward the medium S. The tip of the roller 24a and the guide 24b are located at a position immediately after passing through the roller 24a and the guide 24b. Although there are no limitations on the placement requirements for the optical sensor 91, in order to suppress a decrease in sensitivity due to flapping of the medium S, the distance from the medium S to the light emitting part 91a and from the medium S to the light receiving part 91b is set to about 6:4, and the paper passing width is set to ± It is desirable that it be within 1 to 2 mm.

The optical sensor 91 irradiates light from the light emitting element of the light emitting part 91a onto the medium S passing through the optical sensor 91, detects the transmitted light by the light receiving element of the light receiving part 91b, and the detected light amount is This is a known sensor that measures the basis weight of the medium S based on the amount of light transmitted through the medium S. In this embodiment, in order to stabilize detection variations, the amount of transmitted light is detected multiple times, for example, 10 times at a pitch of 5 mm, while the medium S is passing, and these are averaged to measure the basis weight of the medium S. It looks like this.

FIG. 4 is an explanatory diagram of the ultrasonic sensor 92 and its arrangement state. As described above, the ultrasonic sensor 92 is located between the optical sensor 91 and the timing roller 25, and faces diagonally at an angle of about 38° to 45° with respect to the passing direction of the medium S with the medium transport path 22 in between. A pair of transmitting section 92a and receiving section 92b are provided. Although there are no restrictions on the placement requirements for the ultrasonic sensor 92, it is desirable that the sheet passing width be within about 2.4 mm in order to stabilize detection variations, similar to the optical sensor 91.

This ultrasonic sensor 92 transmits an ultrasonic wave from a transmitter 92a to a medium S passing through the ultrasonic sensor 92, receives the ultrasonic wave that has passed through the medium S at a receiver 92b, and This is a known sensor that measures the basis weight of the medium S based on the following. In this embodiment, the basis weight is detected based on the attenuation rate (A'/A) when the peak value A of the ultrasonic wave is attenuated to the peak value A' of the wavelength when passing through the medium S, and the envelope is determined from the basis weight value. It is detected whether or not.

5(A) is a diagram schematically showing the arrangement positions of the optical sensor 91 and the ultrasonic sensor 92, and FIG. 5(B) is a diagram showing the detection voltage (output voltage) of the sensor after the leading edge of the medium S reaches the timing roller 25. (C) is a diagram showing the voltage detected by the sensor before the leading edge of the medium S reaches the timing roller 25.

As described above, the optical sensor 91 is arranged near the downstream side of the conveyance roller 24, and the ultrasonic sensor 92 is arranged between the optical sensor 91 and the timing roller 25. As shown in the detection voltage diagrams in FIGS. 10B and 1C, the detection voltage of each sensor is not constant, so the medium S is sampled several times and their average value is used. Furthermore, the behavior of the medium S increases the detection variation of the sensor. In particular, in the case of the ultrasonic sensor 92, detection variations increase when the medium S vibrates, so it is desirable to perform measurement while the medium S is caught in both the conveyance roller 24 and the timing roller 25. Therefore, in this embodiment, the ultrasonic sensor 92 for determining whether it is an envelope is placed between the optical sensor 91 and the timing roller 25 to improve the detection accuracy of the sensor.

Furthermore, in general, when considering the usage ratio of envelopes and printing paper (plain paper, thick paper, thin paper, etc.), printing paper is used more often. The faster the measurement result of the optical sensor 91 that measures the basis weight is, the faster the first copy time becomes. It is preferable to arrange it on the upstream side, since the total operating time of the image forming apparatus 1 is shortened, which leads to suppressing a decrease in productivity.

Further, measurements by the optical sensor 91 and the ultrasonic sensor 92 are performed when there is a possibility that a new medium S has been placed on the paper feed cassette 21 or the manual feed tray, that is, when the paper feed cassette 21 is opened or closed. It is desirable to do this for the first sheet when using a manual feed tray or when using a manual feed tray.

FIG. 6 is a table showing the characteristics of the optical sensor 91 and the ultrasonic sensor 92. The optical sensor 91 is capable of accurately detecting basis weight regardless of thickness, but is not suitable for detecting envelopes. On the other hand, the ultrasonic sensor 92 is unstable in terms of basis weight accuracy, and although the accuracy is high for thin paper with a basis weight of 150 g/mm ² or less, the accuracy decreases particularly for thick paper with a basis weight of 150 g/mm ² or more. However, it is possible to accurately identify envelopes.

To explain the reason for this, since the optical sensor 91 is a transmission type sensor, the basis weight corresponding to the amount of transmitted light transmitted through the medium S is discriminated and determined based on a preset correspondence relationship between the amount of transmitted light and the basis weight. . In principle, the thicker the paper, the lower the amount of transmission. Here, when the optical sensor 91 tries to detect an envelope, since the envelope is as thick as two sheets of paper, the amount of transmission is small, and it is mistakenly determined to be cardboard. On the other hand, the ultrasonic sensor 92 can detect an envelope based on the amount of attenuation because the ultrasonic waves are attenuated by the air layer inside the envelope. For this reason, if medium discrimination is performed using simultaneously the result of measuring the basis weight of the medium S to be transported by the optical sensor 91 and the measurement result by the ultrasonic sensor 92, a misjudgment or a contradiction error will occur.

Therefore, in this embodiment, the ultrasonic sensor 92 first detects whether or not it is an envelope, and when it is detected that it is not an envelope, the detection result of the optical sensor 91 is used or the detection result of the optical sensor 91 is not used. By continuing to perform this process, it becomes possible to accurately detect the basis weights of the envelope and the printing paper. When the ultrasonic sensor 92 detects that it is not an envelope, if the detection by the optical sensor 91 has finished, the detection result of the optical sensor 91 is used, and the ultrasonic sensor 92 detects that it is not an envelope. If the detection by the optical sensor 91 is not completed when the detection is detected, the detection by the optical sensor 91 is continued.

FIG. 7 is a flowchart illustrating an example of medium discrimination processing executed by the image forming apparatus of FIG. This medium discrimination process and the medium discrimination process shown in the flowchart of FIG. It is executed by moving.

When paper feeding is started in step S01, the medium S is conveyed along the medium conveyance path 22 by the conveyance rollers 24 and the like. When the medium S is conveyed to the position of the optical sensor 91, the optical sensor 91 starts to detect the basis weight in step S02, and when the medium S is further conveyed to the position of the ultrasonic sensor 92, the basis weight is detected by the ultrasonic sensor 92 in step S03. Start detecting whether it is an envelope.

Next, in step S04, it is determined whether the detection by the ultrasonic sensor 92 has been completed. If the detection has not been completed (NO in step S04), wait until the detection is completed. When the process ends (YES in step S04), it is checked in step S05 whether the medium S is determined to be an envelope based on the detection result of the ultrasonic sensor 92. If it is determined that the medium S is an envelope (YES in step S05), it is determined in step S06 that the medium S is an envelope, and then it is determined that the detection result of the optical sensor 91 is not used, and in step S07, the detection result of the optical sensor 91 ( (including basis weight calculation) has not been completed, the detection is stopped. If the detection by the optical sensor 91 has been completed, the detection result is not used.

Next, in step S08, the conveyance of the envelope, which is the medium S, is stopped, and in step S09, the envelope, which is the medium S, is fed from the paper feed slot (including the paper feed cassette 21) where feeding of envelopes is prohibited. Determine whether it was paper. The paper feed slots from which feeding of envelopes is prohibited are set in advance. If the paper is fed from a paper feed port for which paper feeding is prohibited (YES in step S09), in step S15, this fact is displayed on the display section 54 of the operation panel section 50 to notify the user. This notification allows the user to take measures such as resetting the envelope to another paper feed slot that can feed the envelope.

In step S09, if the envelope is not fed from a prohibited paper feed port (NO in step S09), in step S10, the fixing unit 30 In order to adjust the pressing force, at least one of the heating roller 31 and the pressure roller 32 is moved in the direction of separation. If the object has already been moved in the separating direction, this step is not performed.

Thereafter, in step S11, conveyance of the envelope, which is the medium S, is restarted, and then, in step S12, printing processing is executed under printing conditions according to the envelope.

If it is not determined to be an envelope in step S05 (NO in step S05), it is determined to use the basis weight detection result by the optical sensor 91, and in step S13, it is determined whether or not the basis weight detection by the optical sensor 91 has been completed. do. If the process has not ended (NO in step S13), wait until the process ends. When the process is completed (YES in step S13), the basis weight of the medium S is determined in step S14, and then the process proceeds to step S12, where printing processing is executed under printing conditions according to the basis weight of the medium S.

As described above, in this embodiment, the detection result of the ultrasonic sensor 92 that detects that the type of medium S to be transported by the transport roller 24 etc. is an envelope is first obtained, and based on the detection result, the optical sensor 91 It is determined whether or not to use the detection results. In other words, since the single ultrasonic sensor 92 determines whether the medium S is an envelope, the envelope is more It is possible to reliably determine whether Further, if the ultrasonic sensor 92 detects that the type of medium S is not an envelope, it is determined that the detection result by the optical sensor 91 is to be used, so the detection of basis weight by the optical sensor 91 is wasted. Therefore, efficient discrimination can be performed. Furthermore, if the ultrasonic sensor 92 detects that the type of medium S is an envelope, it is determined that the detection result by the optical sensor 91 is not used, so it is not necessary to wait for the basis weight to be detected by the optical sensor 91. It becomes possible to quickly identify the medium without any trouble.

Moreover, since the optical sensor 91 starts detecting the basis weight of the medium S before the ultrasonic sensor 92 starts detecting that the type of the medium S is an envelope, the ultrasonic sensor 92 detects the type of the medium S. If it is detected that the envelope is not an envelope, the detection result by the optical sensor 91 can be obtained and used at an early stage. As a result, in the case of printing paper that is used many times, the printing process can be started earlier, and the overall printing process time can be shortened.

FIG. 8 is a flowchart showing another example of the medium discrimination process performed by the image forming apparatus shown in FIG. This example is medium discrimination processing in continuous printing processing.

When paper feeding is started in step S21, the medium S is conveyed along the medium conveyance path 22 by the conveyance rollers 24 and the like. When the medium S is conveyed to the position of the optical sensor 91, the optical sensor 91 starts to detect the basis weight in step S22, and when the medium S is further conveyed to the position of the ultrasonic sensor 92, the basis weight is detected by the ultrasonic sensor 92 in step S23. Start detecting whether it is an envelope.

Next, in step S24, it is determined whether detection by the ultrasonic sensor has ended. If the detection has not been completed (NO in step S24), wait until the detection is completed. When the process ends (YES in step S24), it is checked in step S25 whether the medium S is determined to be an envelope based on the detection result of the ultrasonic sensor 92. If it is determined that the medium S is an envelope (YES in step S25), it is determined in step S26 that the medium S is an envelope, and then it is determined that the detection result of the optical sensor 91 is not used, and in step S27, the detection result of the optical sensor 91 ( (including calculation of basis weight) has not been completed, the detection is stopped and the process proceeds to step S28.

On the other hand, if it is not determined that it is an envelope in step S25 (NO in step S25), it is determined to use the basis weight detection result by the optical sensor 91, and in step S33, it is determined whether the detection by the optical sensor 91 is completed. do. If the process has not ended (NO in step S33), wait until the process ends. When the process is completed (YES in step S33), the basis weight of the medium S is determined in step S34, and then the process proceeds to step S28.

In step S28, the result as to whether it is an envelope or not is stored in the S-RAM 103 or the like. If the ultrasonic sensor 92 detects that it is an envelope, it is stored as an envelope; if it is detected that it is not an envelope, the optical sensor 91 determines the basis weight, and then it is stored as not an envelope.

Next, in step S29, it is determined whether the stored result is the same as the previous stored result. If they are the same (YES in step S29), the printing process is performed on the medium S in step S35, and then the process proceeds to step S36. Note that if there is no previous storage result, such as for the first medium S, the determination in step S29 is set to YES, and the process directly proceeds to steps S35 and S36.

In step S36, the presence or absence of the next medium S is checked, and if there is (YES in step S36), the process returns to step S21 to feed the next medium S. If there is no next medium S (NO in step S36), the process ends.

If the memorized result is different from the previous result in step S29 (NO in step S29), it is determined in step S30 that the medium S is mixed with envelopes and other paper, and the printing process is canceled in step S31. Then, in step S32, the display unit 54 displays the fact that it is mixed and notifies the user. This notification allows users to take necessary measures to avoid mixed loading.

In this manner, in this embodiment, it is possible to detect that envelopes and other paper are mixedly loaded on the medium S, and to avoid printing in a mixedly loaded state.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in addition to the optical sensor 91 and the ultrasonic sensor 92, other sensors for detecting the characteristics of the medium S may be arranged.

Furthermore, although a case has been shown in which the optical sensor 91 is placed upstream of the ultrasonic sensor 92 in the transport direction of the medium S, the ultrasonic sensor 92 may be placed upstream of the optical sensor 91. In this case, when the ultrasonic sensor 92 detects that the medium S is an envelope, it is determined that the optical sensor 91 does not detect the basis weight unless the optical sensor 91 has started detecting the basis weight. The basis weight detection is not started, and if the basis weight detection has already been started, it is determined that the basis weight detection result by the optical sensor 91 is not used, and the detection is stopped. On the other hand, when the ultrasonic sensor 92 detects that the medium S is not an envelope, if the optical sensor 91 has not started to detect the basis weight, it is determined that the optical sensor 91 should detect the basis weight, and the basis weight detection begins. If the basis weight detection has already started, it is determined that the basis weight detection result by the optical sensor 91 is to be used.

1 Image forming apparatus 1A Apparatus body 10 Image forming section 17 Secondary transfer roller 20 Paper feeding section 21 Paper feeding tray 22 Medium conveying path 23 Paper feeding roller 24 Conveying roller 24a Roller 24b Guide 25 Conveying roller (timing roller)
30 Fixing unit 31 Heating roller 32 Pressure roller 50 Operation panel section 54 Display section 91 Optical sensor (first detection means)
91a Light emitting section 91b Light receiving section 92 Ultrasonic sensor (second detection means)
92a Transmitter 92b Receiver S Medium

Claims (20)

an image forming means for forming an image on a medium;
a first detection means for detecting the basis weight of the medium;
a second detection means for detecting that there is an air layer in the medium;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming means. a means of determining whether or not to apply;
An image forming apparatus comprising: When the second detecting means detects that there is no air layer in the medium, the determining means detects the basis weight by the first detecting means, or detects the basis weight by the first detecting means. The image forming apparatus according to claim 1, wherein the image forming apparatus determines to use the result. When the second detection means detects that there is an air layer in the medium, the judgment means does not detect the basis weight by the first detection means, or the determination means does not detect the basis weight by the first detection means. The image forming apparatus according to claim 1, wherein the image forming apparatus determines not to use the detection result. an image forming means for forming an image on a medium;
a first detection means for detecting the basis weight of the medium;
second detection means for detecting that the medium is an envelope;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming means. a means of determining whether or not to apply;
An image forming apparatus comprising: When the second detecting means detects that the type of the medium is not an envelope, the determining means detects the basis weight by the first detecting means, or detects the basis weight by the first detecting means. The image forming apparatus according to claim 4, wherein the image forming apparatus determines to use the detection result. When the second detecting means detects that the type of the medium is an envelope, the determining means does not detect the basis weight by the first detecting means, or the first detecting means does not detect the basis weight. The image forming apparatus according to claim 4, wherein the image forming apparatus determines not to use the detection result obtained by the method. The image forming apparatus according to claim 1, wherein the first detection means is an optical sensor. The image forming apparatus according to claim 1 , wherein the second detection means is an ultrasonic sensor. 9. The image forming apparatus according to claim 8 , wherein the ultrasonic sensor includes a pair of transmitting section and receiving section that are disposed diagonally opposite each other at a predetermined angle with respect to the medium passage direction with the medium conveyance path in between. If the second detection means detects that the type of medium fed from a paper feed slot that cannot feed envelopes is an envelope, it is determined that the envelope was fed from a paper feed slot that cannot feed envelopes. The image forming apparatus according to any one of claims 1 to 6 , further comprising a notification means for notifying a user. a fixing unit that performs fixing by passing a medium between a pair of heating and pressurizing bodies whose position can be adjusted in the approaching and separating directions;
a control means for adjusting the position of the heating/pressure body of the fixing unit in a separating direction when the second detection means detects that the type of the medium is an envelope;
The image forming apparatus according to any one of claims 1 to 6 , comprising: 12. The image forming apparatus according to claim 11 , wherein the control means stops conveyance of the medium by the conveyance means and adjusts the position of the heating/pressure body of the fixing unit in the separating direction. comprising a storage means for storing the detection result by the second detection means,
During continuous printing, if the second detection means detects that the type of medium to be printed is an envelope, the storage means stores that the type of medium is an envelope, and If it is detected that the type of the medium is not an envelope, the storage means stores that the type of the medium is not an envelope;
During continuous printing, if the detection result by the second detection means is different from the previous detection result stored in the storage means, the determination means determines that an envelope and a medium other than the envelope are mixed. The image forming apparatus according to any one of claims 1 to 6 . 14. The image forming apparatus according to claim 13 , further comprising a notification means for notifying a user of the mixed loading when the determining means determines that an envelope and a medium other than the envelope are mixed. According to any one of claims 1 to 6 , the first detecting means starts detecting the basis weight of the medium before the second detecting means starts detecting that the type of medium is an envelope. image forming device. comprising a transfer means for transferring an image to the medium, and a timing roller for conveying the paper to the transfer means in accordance with the timing at which the image is transferred to the medium by the transfer means,
The image forming apparatus according to claim 15 , wherein the second detection means is arranged between the timing roller and the first detection means. an image forming step of forming an image on the medium;
detecting the basis weight of the medium by a first detection means;
detecting by a second detection means that there is an air layer in the medium;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming step. a determination step for determining whether to apply;
A medium discrimination method performed by an image forming apparatus. an image forming step of forming an image on the medium;
detecting the basis weight of the medium by a first detection means;
detecting by a second detection means that the medium is an envelope;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming step. a determination step for determining whether to apply;
A medium discrimination method performed by an image forming apparatus. an image forming step of forming an image on the medium;
detecting the basis weight of the medium by a first detection means;
detecting by a second detection means that there is an air layer in the medium;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming step. a determination step for determining whether to apply;
A program that causes the image forming apparatus's computer to execute. an image forming step of forming an image on the medium;
detecting the basis weight of the medium by a first detection means;
detecting by a second detection means that the medium is an envelope;
Based on the detection result of the second detection means, it is determined whether or not the basis weight of the medium is detected by the first detection means, or the detection result of the first detection means is used as the printing condition in the image forming step. a determination step for determining whether to apply;
A program that causes the image forming apparatus's computer to execute.

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