JP2023038272A - Image formation device, medium discrimination method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device which enables efficient discrimination while preventing an envelope that is a special medium from being discriminated as a different medium by erroneous detection, when detecting the medium by a plurality of detection means.

SOLUTION: An image formation device includes: image formation means 10 for forming an image on a medium S; first detection means 91 for detecting a basis weight of the medium S; second detection means 92 for detecting that the kind of the medium is an envelope; and determination means 101 for determining whether or not the basis weight of the medium is detected by the first detection means 91 or the detection result by the first detection means 91 is applied to a printing condition in the image formation means 10, on the basis of the detection result of the second detection means 92.

SELECTED DRAWING: Figure 7

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to an image forming apparatus such as a copier, a printer, or a multi-function digital composite machine called an MFP (Multifunction Peripheral), and a medium identification method and program executed by the image forming apparatus.

2. Description of the Related Art There is known a technique of automatically determining the type of a medium such as a sheet of paper on which an image is to be formed in an image forming apparatus such as the one described above, using a sensor, which is a detecting means. On the other hand, in recent years, as media, special media such as envelopes and OHPs have been increasing.

Therefore, Japanese Patent Application Laid-Open No. 2002-300000 discloses a CMOS for detecting the surface state of a recording material, with the aim of accurately determining the type of recording material when using a plurality of recording material determination methods. A method is disclosed in which an area sensor and an ultrasonic sensor for detecting the basis weight of the recording material are used, and the type of the recording material is comprehensively discriminated from the results of detection by these sensors.

JP 2009-29622 A

However, if a special medium such as an envelope is comprehensively discriminated from the detection results of a plurality of sensors as described in Japanese Patent Application Laid-Open No. 2002-200013, there is a risk that the medium may be discriminated as a different medium due to erroneous detection.

The present invention has been made in view of such a technical background, and is intended to prevent an envelope, which is a special medium, from being discriminated as a different medium due to erroneous detection when a plurality of detecting means detect a medium. It is an object of the present invention to provide an image forming apparatus, a medium discrimination method, and a program capable of efficiently discriminating while preventing such a problem.

The above object is achieved by the following means.
(1) 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 the medium has an air layer;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means; a judgment means for judging whether to apply;
An image forming apparatus comprising:
(2) When the second detection means detects that there is no air layer in the medium, the determination means detects the basis weight by the first detection means, or performs the first detection. 2. The image forming apparatus according to the preceding item 1, which determines to use the detection result by means.
(3) When the second detection means detects that there is an air layer in the medium, the determination means does not detect the basis weight by the first detection means, or the first detection means detects the basis weight. 2. The image forming apparatus according to 1 above, which determines not to use the detection result of the detection means.
(4) 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 the medium is an envelope;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means; a judgment means for judging whether 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 detects the grammage by the first detecting means, or 5. The image forming apparatus according to 4 above, which determines to use the detection result of 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 5. The image forming apparatus according to the preceding item 4, wherein the image forming apparatus determines that the detection result by the detecting means is not used.
(7) 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 information about the medium with ultrasonic waves;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means; a judgment means for judging whether to apply;
An image forming apparatus comprising:
(8) When the second detection means detects that the information regarding the attenuation of the ultrasonic wave is equal to or greater than a predetermined value, the determination means detects the basis weight by the first detection means, or 8. The image forming apparatus according to the preceding item 7, which determines to use the detection result of the first detection means.
(9) when the second detecting means detects that the information regarding the attenuation of the ultrasonic wave is equal to or less than a predetermined value, the determining means does not detect the basis weight by the first detecting means, or 8. The image forming apparatus according to the preceding item 7, which determines not to use the detection result of the first detection means.
(10) The image forming apparatus according to any one of (1) to (9) above, wherein the first detection means is an optical sensor.
(11) The image forming apparatus according to any one of (1) to (10) above, wherein the second detection means is an ultrasonic sensor.
(12) The image forming apparatus according to (11) above, wherein the ultrasonic sensor includes a pair of a transmitting unit and a receiving unit obliquely arranged to face each other at a predetermined angle with respect to the medium passage direction across the medium transport path. .
(13) If the second detecting means detects that the type of medium fed from the paper feed port that cannot feed envelopes is an envelope, the envelope is fed from the paper feed port that cannot feed envelopes. 13. The image forming apparatus according to any one of the preceding items 1 to 12, further comprising notifying means for notifying a user of the fact that the image forming apparatus.
(14) a fixing unit that performs fixing by passing a medium between a pair of heating/pressurizing bodies whose position can be adjusted in the contact/separation direction;
control means for adjusting the position of the heating/pressurizing body of the fixing unit in the separation direction when the second detection means detects that the type of the medium is an envelope;
14. The image forming apparatus according to any one of 1 to 13 above, comprising:
(15) The image forming apparatus according to (14) above, wherein the control means stops the conveyance of the medium by the conveyance means and adjusts the position of the heating/pressurizing member of the fixing unit in the separation direction.
(16) comprising storage means for storing detection results by the second detection means;
During continuous printing, when 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 the medium is when 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, when the detection result by the second detection means differs from the previous detection result stored in the storage means, the determination means determines that envelopes and media other than envelopes are mixed. 16. The image forming apparatus according to any one of 1 to 15 above.
(17) The image forming apparatus according to (16) above, further comprising notification means for notifying a user that envelopes and media other than envelopes are mixed when the determination means determines that envelopes and media other than envelopes are mixed.
(18) Any one of the preceding items 1 to 17, wherein the detection of the basis weight of the medium by the first detection means is started before the detection of the medium type being an envelope is started by the second detection means. The image forming apparatus according to .
(19) transfer means for transferring the image onto the medium; and a timing roller for conveying the paper to the transfer means in synchronization with the timing of transfer of the image to the medium by the transfer means,
19. The image forming apparatus according to Item 18, wherein the second detection means is arranged between the timing roller and the first detection means.
(20) an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
detecting by a second detection means that there is an air layer in the medium;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
A medium discrimination method executed by an image forming apparatus.
(21) an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
detecting by a second detection means that the medium is an envelope;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
A medium discrimination method executed by an image forming apparatus.
(22) an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
ultrasonically detecting information about the medium by a second detection means;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
A medium discrimination method executed by an image forming apparatus.
(23) an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
detecting by a second detection means that there is an air layer in the medium;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
is executed by the computer of the image forming apparatus.
(24) an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
detecting by a second detection means that the medium is an envelope;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
is executed by the computer of the image forming apparatus.
(25) an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
ultrasonically detecting information about the medium by a second detection means;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
is executed by the computer of the image forming apparatus.

According to the image forming apparatus and medium discrimination method according to the present invention, the detection result of the second detection means is obtained first, and based on the detection result, the basis weight of the medium is detected by the first detection means. or whether to apply the detection result of the first detection means to the printing condition, 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 obtained first, and based on the detection result, whether or not the detection of the basis weight of the medium by the first detection means is performed, or the first detection is performed. A computer of the image forming apparatus can be caused to determine 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 one embodiment of the present invention; FIG. 2 is a block diagram showing the electrical configuration of the image forming apparatus; FIG. FIG. 4 is an explanatory diagram of an 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) ) shows the voltage detected by the sensor before the leading edge of the medium reaches the timing roller. 4 is a table showing characteristics of an optical sensor and an ultrasonic sensor; 2 is a flowchart showing an example of medium discrimination processing executed by the image forming apparatus of FIG. 1; 4 is a flowchart showing another example of medium discrimination processing executed by the image forming apparatus of FIG. 1;

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 according to one embodiment of the 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 constructed by disposing a paper feed section 20 at the bottom of an apparatus body 1A, an image forming section 10 at the center, and a paper discharge section 60 at the top. A medium transport path 22 is formed extending from the paper feeding unit 20 to the paper discharging unit 60 for upwardly transporting a medium S such as a paper sheet or an envelope fed from the paper feeding unit 20 .

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

The toner images formed by the photoreceptor units 12Y, 12M, 12C, and 12K are superimposed and transferred onto the transfer belt 14, and the transfer belt 14 is transferred to the medium S conveyed along the medium conveyance path 22. At the middle right end), secondary transfer is performed by a transfer roller (corresponding to transfer means) 17, and the sheet S is fed to the 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 arranged in contact with the heating roller 31 . The medium S is passed through the nip portion formed in , and is heated and pressurized to fix the toner image on the medium S. As shown in FIG. Furthermore, in this embodiment, in order to adjust the pressure according to the thickness of the medium S, at least one of the heating roller 31 and the pressure roller 32 can be moved in the contact and separation directions. In addition, the movement in the contact/separation direction is not limited to movement to the extent that the user can visually confirm the separation. It is good if the nip pressure is weakened and the envelope can be fed.

Each of the photoreceptor units 12Y, 12M, 12C, and 12K forms an image by an electrostatic copying method. 13Y, 13M, 13C, 13K, a transfer unit, etc. are provided. Also, each photosensitive drum 13Y is charged by a charger by each laser diode of an exposure unit 40 having 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 to form an electrostatic latent image thereon.

Toner cartridges 70Y, 70M, 70C and 70K and sub hoppers 80Y, 80M, 80C and 80K are provided as replenishing mechanisms for replenishing toner to the developing devices 11Y, 11M, 11C and 11K of the photosensitive units 12Y, 12M, 12C and 12K. are arranged above the photoreceptor units 12Y, 12M, 12C and 12K.

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

The paper feed unit 20 includes a paper feed cassette 21 of one stage or a plurality of stages (two stages in the example of FIG. 1). In addition, a paper feed roller 23 is provided on the output 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 provided along the transport path 22 . The sheet is conveyed to a secondary transfer position by a secondary transfer roller 17 by one or a plurality of sets of conveying rollers 24 and 25 . Note that the image forming apparatus 1 may be provided with a manual feed tray. In this embodiment, the paper feed roller 23, the transport rollers 24 and 25, and the like constitute transport means for transporting the medium S. As shown in FIG. Further, in this embodiment, the conveying roller 25 near the secondary transfer roller 17 conveys the medium S to the transfer roller 17 in synchronization with the transfer timing of the toner image onto the medium S by the secondary transfer roller 17. It also serves as a timing roller for adjustment.

Between the lower transport roller 24 and the upper transport roller (timing roller) 25 , a plurality of sensors 91 and 92 for detecting paper types are arranged on the transport path 22 . In this embodiment, an optical sensor 91 as 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. Between the secondary transfer roller 17 and the timing roller 25, the optical sensor 91 may be arranged on the upstream side and the ultrasonic sensor 92 may be arranged on the downstream side. These optical sensor 91 and ultrasonic sensor 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 unit 100, a fixed storage device 110, an image reading device 120, as well as the above-described operation panel unit 50, image forming unit 10, paper feeding unit 20, optical sensor 91, It includes an ultrasonic sensor 92 , a printer controller 150 , a network interface (network I/F) 160 and the like, which 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 comprehensively 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 enabling execution of a copy function, a printer function, a scan function, etc., particularly in this embodiment, an output mode suitable for the paper type is selected based on the paper type detection result of the paper S by the paper type detection sensor 90 at the time of printing. (Print mode) is automatically set and control such as execution of printing is performed, the details of which will be described later.

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

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

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

The clock IC 105 measures time and functions as an internal timer to measure processing time.

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 has a scanner or the like, reads an original set on a platen glass by scanning, and converts the read original into image data.

The operation panel unit 50 is used when a user instructs a job or the like to the image forming apparatus 1 or performs various settings, and has a reset key 51, a start key 52, a stop key 53, a display unit 54, a touch panel 55, and the like. I have.

A reset key 51 is used to reset settings, a start key 52 is used to start operations such as scanning, and a stop key 53 is pressed to interrupt an operation. is.

The display unit 54 is composed of, for example, a liquid crystal display device, and displays messages, various operation screens, etc. A touch panel 55 is formed on the screen of the display unit 54 and detects user's touch operation.

The image forming unit 10 prints on paper a copied image generated from image data of a document read by the image reading device 120 or print data transmitted from an external terminal device or the like. and the above-described fixing unit 30 and the like.

The print engine 18 is a hardware portion related to image formation, and includes, for example, photoreceptor units 12Y, 12M, 12C, and 12K, developing devices 11Y, 11M, 11C, and 11K, photoreceptor drums 13Y, 13M, 13C, and 13K, and a charging unit. , a transfer device, a laser diode, a polygon mirror, a print head 41, and a motor for driving them.

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

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

FIG. 3 is an explanatory diagram of the optical sensor 91 and its arrangement. The optical sensor 91 includes a pair of a light-emitting portion 91a and a light-receiving portion 91b that are opposed to each other with the medium transport path 22 interposed therebetween. A light-receiving element (not shown) such as a photodiode is provided in the light-receiving portion 91b. The medium S pulled out from the paper feeding cassette 21 by the paper feeding roller 23 is passed from below to above while being regulated by the gap between the roller 24a and the guide 24b that constitute the carrying roller 24 so that there is no variation in the carrying position. . A plurality of sets (two sets in FIG. 3) of the rollers 24a and the guides 24b are provided in the direction orthogonal to the transport direction (the width direction of the medium). is positioned between adjacent rollers 24a and guides 24b at a position immediately after passing. Arrangement requirements for the optical sensor 91 are not limited. It is desirable to make it within 1 to 2 mm.

The optical sensor 91 irradiates the medium S passing through the optical sensor 91 with light from the light-emitting element of the light-emitting portion 91a, and detects the transmitted light with the light-receiving element of the light-receiving portion 91b. 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. FIG. In this embodiment, in order to stabilize detection variations, the amount of transmitted light is detected a plurality of times, for example, 10 times at a pitch of 5 mm while the medium S passes through, and these are averaged to measure the basis weight of the medium S. It's like

FIG. 4 is an explanatory diagram of the ultrasonic sensor 92 and its arrangement. As described above, the ultrasonic sensor 92 is positioned between the optical sensor 91 and the timing roller 25, and is obliquely opposed to the passing direction of the medium S at an angle of about 38° to 45° across the medium transport path 22. It has a pair of transmitting section 92a and receiving section 92b arranged. Although the arrangement of the ultrasonic sensor 92 is not limited, it is desirable that the width of the paper passing is within about 2.4 mm in order to stabilize the detection variation as with the optical sensor 91 .

The ultrasonic sensor 92 transmits an ultrasonic wave from the transmitting section 92a to the medium S passing through the ultrasonic sensor 92, and receives the ultrasonic wave transmitted through the medium S at the receiving section 92b. It is a known sensor that measures the basis weight of the medium S based on. In this embodiment, the basis weight is detected by 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 detected from the value of the basis weight. It detects whether or not

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

As described above, the optical sensor 91 is arranged near the downstream side of the conveying roller 24 , and the ultrasonic sensor 92 is arranged between the optical sensor 91 and the timing roller 25 . As shown in the detected voltage diagrams of (B) and (C) of the same figure, since the detected voltage of each sensor is not constant, the medium S is sampled several times and the average value thereof 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. For this reason, in the present embodiment, the ultrasonic sensor 92 for determining whether or not the document is an envelope is arranged between the optical sensor 91 and the timing roller 25, thereby increasing the detection accuracy of the sensor.

In general, considering the usage ratio of envelopes and printing paper (plain paper, thick paper, thin paper, etc.), the number of times printing paper is used is greater. The faster the measurement result of the optical sensor 91 for measuring the basis weight, the faster the first copy time. Arranging it on the upstream side is desirable from the viewpoint that the total operating time of the image forming apparatus 1 is shortened, leading to suppression of a decrease in productivity.

Further, the measurement by the optical sensor 91 and the ultrasonic sensor 92 is performed when there is a possibility that a new medium S is 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 when the first sheet is loaded or when using the manual feed tray.

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

The reason for this is that since the optical sensor 91 is a transmissive sensor, the grammage 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 grammage. . In principle, the thicker the paper, the smaller the permeation amount. Here, when the optical sensor 91 attempts to detect an envelope, it is erroneously discriminated as thick paper because the thickness of the envelope is the same as that of two sheets of paper. On the other hand, since the ultrasonic wave is attenuated by the air layer inside the envelope, the ultrasonic sensor 92 can detect the envelope from the amount of attenuation. Therefore, if the media are discriminated by simultaneously using the measurement result of the basis weight of the medium S to be conveyed by the optical sensor 91 and the measurement result of the ultrasonic sensor 92, erroneous discrimination or contradictory error will occur.

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

FIG. 7 is a flowchart showing 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 acting.

When paper feeding is started in step S01, the medium S is conveyed along the medium conveying path 22 by the conveying rollers 24 and the like. When the medium S is transported to the position of the optical sensor 91, the detection of the basis weight by the optical sensor 91 is started in step S02. Start detecting whether it is an envelope or not.

Next, in step S04, it is determined whether the detection by the ultrasonic sensor 92 has ended. If not finished (NO in step S04), wait until detection is finished. When the processing ends (YES in step S04), it is checked in step S05 whether or not the medium S is determined to be an envelope based on the detection result of the ultrasonic sensor 92. FIG. If the medium S is determined to be an envelope (YES in step S05), after determining that the medium S is an envelope in step S06, it is determined that the detection result of the optical sensor 91 is not used. (including calculation of basis weight) is not completed, the detection is stopped. If the detection by the optical sensor 91 is finished, 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 a paper feed port (including the paper feed cassette 21) where feeding of envelopes is prohibited. to determine whether it has been papered. A paper feed slot for which paper feeding of envelopes is prohibited is set in advance. If the paper has been fed from a paper feed slot where paper feeding is prohibited (YES in step S09), that fact is displayed on the display section 54 of the operation panel section 50 to notify the user in step S15. With this notification, the user can take measures such as resetting the envelope to another paper feed slot that can feed the envelope.

In step S09, if the paper is not fed from a paper feed slot where paper feeding of envelopes is prohibited (NO in step S09), in step S10, the fixing unit 30 At least one of the heating roller 31 and the pressure roller 32 is moved in the separating direction in order to adjust the pressing force of . If the movement has already been completed in the separating direction, the processing of this step is not performed.

After that, in step S11, the conveyance of the envelope, which is the medium S, is restarted, and in step S12, the printing process is executed under the printing conditions corresponding to the envelope.

If it is determined not to be an envelope in step S05 (NO in step S05), it is determined that the basis weight detection result by the optical sensor 91 is to be used, and in step S13, it is determined whether or not the detection of the basis weight by the optical sensor 91 has ended. do. If not finished (NO in step S13), wait until finished. Upon completion (YES in step S13), the basis weight of the medium S is determined in step S14, and the process advances to step S12 to execute print processing under printing conditions corresponding to the basis weight of the medium S. FIG.

As described above, in this embodiment, the detection result of the ultrasonic sensor 92 for detecting that the type of the medium S conveyed by the conveying roller 24 or the like is an envelope is obtained first, and based on the detection result, the optical sensor 91 It is determined whether to use the detection result by That is, since the single ultrasonic sensor 92 determines whether or not the medium S is an envelope, compared with the case of comprehensively determining the detection results of a plurality of sensors, the optical sensor 91 and the ultrasonic sensor 92, the envelope can be determined with certainty. Further, when the ultrasonic sensor 92 detects that the type of the medium S is not an envelope, it is determined that the detection result of the optical sensor 91 is to be used. and efficient discrimination can be performed. Furthermore, when the ultrasonic sensor 92 detects that the type of the medium S is an envelope, it is determined that the detection result of the optical sensor 91 is not used. It is possible to discriminate the medium quickly 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. is not an envelope, the detection result by the optical sensor 91 can be obtained early and used. As a result, in the case of printing paper that is used many times, the start of print processing can be advanced, and the entire print processing time can be shortened.

FIG. 8 is a flow chart showing another example of medium discrimination processing performed by the image forming apparatus of 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 conveying path 22 by the conveying rollers 24 and the like. When the medium S is transported to the position of the optical sensor 91, the detection of the basis weight by the optical sensor 91 is started in step S22. Start detecting whether it is an envelope or not.

Next, in step S24, it is determined whether the detection by the ultrasonic sensor has ended. If not finished (NO in step S24), wait until detection is finished. 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. FIG. If the medium S is determined to be an envelope (YES in step S25), it is determined that the medium S is an envelope in step S26, and then the detection result of the optical sensor 91 is determined not to be used. (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 to be an envelope in step S25 (NO in step S25), it is determined that the basis weight detection result by the optical sensor 91 is to be used, and in step S33 it is determined whether or not the detection by the optical sensor 91 has ended. do. If not finished (NO in step S33), wait until finished. When finished (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 of whether or not it is an envelope is stored in the S-RAM 103 or the like. When an ultrasonic sensor 92 detects an envelope, it is stored as an envelope, and when a non-envelope is detected, the basis weight is determined by an optical sensor 91, and then the non-envelope is stored.

Next, in step S29, it is determined whether or not the stored result is the same as the previous stored result. If they are the same (YES in step S29), the print process is executed for the medium S in step S35, and then the process proceeds to step S36. If the previous storage result does not exist like the first medium S, the determination in step S29 is set to YES, and the process proceeds directly 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 and the medium S is fed. If there is no next medium S (NO in step S36), the process ends.

If the stored 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 stopped in step S31. Then, in step S32, the user is notified by displaying on the display unit 54 that they are mixed. This notification allows the User to take necessary measures to avoid mixed shipments.

As described above, in this embodiment, it is possible to detect that an envelope and another sheet are mixed on the medium S, and to avoid printing in the mixed 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.

Further, although the optical sensor 91 is arranged upstream of the ultrasonic sensor 92 in the transport direction of the medium S, the ultrasonic sensor 92 may be arranged upstream of the optical sensor 91 . In this case, when the ultrasonic sensor 92 detects that the medium S is an envelope, if the optical sensor 91 does not start detecting the basis weight, it is determined that the optical sensor 91 does not detect the basis weight. The basis weight detection is not started, and if the basis weight detection has already started, it is determined that the detection result of the basis weight by the optical sensor 91 is not to be 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 does not start detecting the basis weight, it is determined that the optical sensor 91 detects the basis weight. detection is started. 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 Main Body 10 Image Forming Section 17 Secondary Transfer Roller 20 Paper Feed Section 21 Paper Feed Tray 22 Medium Conveyance Path 23 Paper Feed Roller 24 Conveyance Roller 24a Roller 24b Guide 25 Conveyance 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 portion 91b Light-receiving portion 92 Ultrasonic sensor (second detection means)
92a transmitter 92b receiver S medium

Claims (25)

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 the medium has an air layer;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means; a judgment means for judging whether 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 by the first detecting means. 2. The image forming apparatus according to claim 1, wherein the determination is to use the result. When the second detecting means detects that there is an air layer in the medium, the determining means does not detect the basis weight by the first detecting means, or the first detecting means detects the basis weight. 2. The image forming apparatus according to claim 1, wherein it is determined that the detection result is not used. 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 the medium is an envelope;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means; a judgment means for judging whether 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. 5. The image forming apparatus according to claim 4, which 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 grammage by the first detecting means, or the first detecting means does not detect the basis weight. 5. The image forming apparatus according to claim 4, wherein the image forming apparatus determines not to use the detection result obtained by. 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 information about the medium with ultrasonic waves;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means; a judgment means for judging whether to apply;
An image forming apparatus comprising: When the second detection means detects that the information regarding the attenuation of the ultrasonic wave is equal to or greater than a predetermined value, the determination means detects the basis weight by the first detection means, or detects the basis weight by the first detection means. 8. The image forming apparatus according to claim 7, wherein the detection result by the detection means is used. When the second detection means detects that the information about the attenuation of the ultrasonic wave is equal to or less than a predetermined value, the determination means does not detect the basis weight by the first detection means, or the first detection means detects the basis weight. 8. The image forming apparatus according to claim 7, wherein it is determined that the detection result by the detecting means is not used. 10. The image forming apparatus according to claim 1, wherein said first detection means is an optical sensor. 11. The image forming apparatus according to claim 1, wherein said second detection means is an ultrasonic sensor. 12. The image forming apparatus according to claim 11, wherein the ultrasonic sensor includes a pair of transmitting section and receiving section obliquely arranged to face each other at a predetermined angle with respect to the direction of passage of the medium across the medium conveying path. When the type of the medium fed from the paper feed port that cannot feed envelopes is detected to be an envelope by the second detection means, the envelope is fed from the paper feed port that cannot feed envelopes. 13. The image forming apparatus according to any one of claims 1 to 12, further comprising notification means for notifying the user of. a fixing unit that performs fixing by passing a medium between a pair of heating/pressurizing bodies whose position can be adjusted in the direction of contact and separation;
control means for adjusting the position of the heating/pressurizing body of the fixing unit in the separation 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 13, comprising: 15. The image forming apparatus according to claim 14, wherein the control means stops the transportation of the medium by the transportation means and adjusts the position of the heating/pressurizing member of the fixing unit in the separating direction. A storage means for storing the detection result by the second detection means,
During continuous printing, when 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 the medium is when 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, when the detection result by the second detection means differs from the previous detection result stored in the storage means, the determination means determines that envelopes and media other than envelopes are mixed. The image forming apparatus according to any one of claims 1 to 15. 17. The image forming apparatus according to claim 16, further comprising notifying means for notifying a user of mixed loading when said determining means determines that envelopes and media other than envelopes are mixed. 18. The method according to any one of claims 1 to 17, wherein the detection of the basis weight of the medium by the first detection means is started before the detection of the medium type being an envelope is started by the second detection means. image forming device. a transfer unit for transferring an image onto the medium; and a timing roller for conveying the paper to the transfer unit in synchronization with the transfer timing of the image onto the medium by the transfer unit,
19. The image forming apparatus according to claim 18, wherein said second detection means is arranged between said timing roller and said first detection means. an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
detecting by a second detection means that there is an air layer in the medium;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
A medium discrimination method executed by an image forming apparatus. an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
detecting by a second detection means that the medium is an envelope;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
A medium discrimination method executed by an image forming apparatus. an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
ultrasonically detecting information about the medium by a second detection means;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
A medium discrimination method executed by an image forming apparatus. an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
detecting by a second detection means that there is an air layer in the medium;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
is executed by the computer of the image forming apparatus. an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
detecting by a second detection means that the medium is an envelope;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
is executed by the computer of the image forming apparatus. an imaging step of forming an image on a medium;
detecting the basis weight of the medium with a first detecting means;
ultrasonically detecting information about the medium by a second detection means;
whether to detect the basis weight of the medium by the first detection means based on the detection result of the second detection means, or whether the detection result by the first detection means is used as the printing condition in the image forming step; a decision step to determine whether to apply;
is executed by the computer of the image forming apparatus.

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