Image forming apparatus, method of processing information related to recording medium, and computer program product

Abstract

The invention provides an image forming apparatus capable of detecting addition of a recording medium without reducing productivity, a processing method of information related to the recording medium, and a computer program product. An image forming apparatus (1) includes: a conveyance unit (71a, 71b) that continuously conveys a recording medium; an acquisition unit (91, 92) that acquires numerical value information relating to the recording medium conveyed by the conveyance unit; and a control unit (100) that compares the first numerical value information acquired by the acquisition unit with second numerical value information acquired earlier than the first numerical value information.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus such as a copier, a printer, or a multifunction digital machine called an MFP (Multi Function Peripheral), and further relates to a method for processing information related to a recording medium and a computer program product. Background Art

[0002] In an office environment where multiple users use the image forming apparatus, a user may randomly add a different type of recording medium to a paper feed tray. When adding, the information of the recording medium on the paper feed tray becomes out of date.

[0003] Therefore, it is conceivable to perform paper type determination every time a recording medium is conveyed, and detect a change in paper type due to addition.

[0004] In addition, there has been proposed an image forming apparatus that expands the criteria for determining the paper type for the second and subsequent detections within a range that does not cause problems with paper passing based on the initial paper type detection results (for example, Patent Documents 1 and 2).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-12069

[0008] Patent Document 2: Japanese Patent Application Publication No. 2021-031200 Summary of the invention

[0009] However, the determination of the paper type requires a corresponding number of data, and it takes time to determine the paper type based on these data. For example, there is a case where the first sheet of paper in the task is determined to be a recording medium that can be transported at high speed, and high-speed transport is set for the second and subsequent recording media. In this case, there is a possibility that the number of data obtained is insufficient, the paper type cannot be determined, and the addition of the recording medium cannot be detected. In addition, if the transport speed of the second and subsequent recording media is reduced in order to detect the addition, the productivity will also be reduced.

[0010] This problem cannot be solved simply by expanding the range of the determination criteria for the second and subsequent paper types as in the image forming apparatuses described in Patent Documents 1 and 2.

[0011] An object of the present invention is to provide an image forming apparatus, a method for processing information related to a recording medium, and a computer program product that can detect the addition of a recording medium without reducing productivity.

[0012] The above-mentioned object is achieved by the following means.

[0013] (1) An image forming apparatus comprising:

[0014] A conveying unit that continuously conveys the recording medium;

[0015] an acquiring unit that acquires numerical information related to the recording medium transported by the transport unit; and

[0016] The control unit compares the first numerical information acquired by the acquisition unit with the second numerical information acquired before the first numerical information.

[0017] (2) In the image forming apparatus described in the above item 1,

[0018] The control unit compares the first numerical information acquired by the acquisition unit for the first recording medium and the second numerical information acquired by the acquisition unit for the second recording medium transported before the first recording medium, and determines whether a change rate of the first numerical information relative to the second numerical information is within a predetermined range.

[0019] (3) In the image forming apparatus described in the above item 1,

[0020] The control unit compares the first numerical information acquired by the acquisition unit for the first recording medium with the second numerical information acquired by the acquisition unit for the second recording medium transported before the first recording medium, and determines whether a difference between the first numerical information and the second numerical information is within a predetermined range.

[0021] (4) In the image forming apparatus described in any one of the preceding items 1 to 3,

[0022] When comparing the first numerical information and the second numerical information, the control unit determines whether the approximate information of the first numerical information acquired by the acquisition unit and the approximate information of the second numerical information acquired before the first numerical information are consistent.

[0023] (5) In the image forming apparatus described in the above item 1,

[0024] The method comprises: a first action mode for determining the type of recording medium based on second numerical information obtained about the first recording medium of the task; and a second action mode for obtaining first numerical information about the second and subsequent recording media of the task, and obtaining a change amount of the obtained first numerical information relative to the second numerical information,

[0025] The control unit:

[0026] According to the type of recording medium determined by the first operation mode for the first recording medium of the task, the conveying speed / image forming conditions for the second and subsequent recording media of the task are set, and the allowable change amount of the first numerical information obtained in the second operation mode relative to the second numerical information is determined, and then

[0027] When the change in the first numerical information obtained in the second action mode for the second and subsequent recording media of the task exceeds the allowable change, it is determined that the type of the recording medium has changed, and the type of the recording medium is determined by obtaining the second numerical information by implementing the first action mode at a predetermined timing.

[0028] (6) In the image forming apparatus described in the above 5,

[0029] An image quality priority mode and a speed priority mode are provided, and the control unit changes the execution timing of the first operation mode in the image quality priority mode and the speed priority mode.

[0030] (7) In the image forming apparatus described in the above 5,

[0031] An image quality priority mode and a speed priority mode are provided, and the control unit changes the allowable change amount in the image quality priority mode and the speed priority mode.

[0032] (8) In the image forming apparatus described in the above 5,

[0033] The control unit changes the allowable change amount according to a conveyance speed of a recording medium, wherein the conveyance speed of the recording medium is set according to second numerical value information acquired in the first operation mode.

[0034] (9) In the image forming apparatus described in the above 5,

[0035] The control unit makes the recording medium wait temporarily and restarts the conveyance after changing the speed / image forming conditions when it is determined that the type of the second and subsequent recording media of the job has changed and it is too late to change the conveyance speed / image forming conditions if the recording medium is conveyed as it is.

[0036] (10) In the image forming apparatus described in any one of the preceding items 5 to 8,

[0037] The control unit has an image quality priority mode and a speed priority mode. When the control unit determines that the type of the recording medium after the second sheet of the task has changed, if the image quality priority mode is selected, the control unit makes the recording medium wait temporarily and starts conveying again after changing the conveying speed / image forming conditions if it determines that it is too late to change the conveying speed / image forming conditions even if the recording medium is conveyed as it is, and conveys the recording medium as it is if it is judged that it is too late to change the conveying speed / image forming conditions.

[0038] In the case of the speed priority mode, only the image forming conditions are changed.

[0039] (11) A method for processing information related to a recording medium,

[0040] An image forming apparatus including a conveying unit for continuously conveying a recording medium performs:

[0041] an acquiring step of acquiring numerical information related to the recording medium transported by the transport unit; and

[0042] The control step compares the first numerical information acquired in the acquisition step with second numerical information acquired before the first numerical information.

[0043] (12) A program for causing a computer of an image forming apparatus including a conveying unit for continuously conveying a recording medium to execute:

[0044] an acquiring step of acquiring numerical information related to the recording medium transported by the transport unit; and

[0045] The control step compares the first numerical information acquired in the acquisition step with second numerical information acquired before the first numerical information.

[0046] According to the image forming device and the method for processing information related to the recording medium involved in the present invention, numerical information related to the recording medium transported by the transport unit that continuously transports the recording medium is obtained. The first numerical information obtained is compared with the second numerical information obtained before the first numerical information. Therefore, it is possible to detect whether the recording medium has been changed, that is, whether there is any addition, based on the comparison result. Even if the number of data is small, the first numerical information and the second numerical information can be compared. In addition, the acquisition and comparison of the first and second numerical information are faster than the paper type determination process. Therefore, for the recording medium after the second sheet, the speed will not be reduced to detect the addition, that is, the productivity will not be reduced, and the addition can be detected.

[0047] According to the program of the present invention, a computer of the image forming apparatus can execute a process of acquiring numerical information about a conveyed recording medium and comparing the acquired first numerical information with second numerical information acquired before the first numerical information. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a diagram schematically showing a part of a conveyance path of a sheet on which an image is printed in an image forming apparatus.

[0049] Figure 2 (A)(B) are explanatory diagrams of optical sensors.

[0050] Figure 3 This is a diagram illustrating an ultrasonic sensor.

[0051] Figure 4 is a block diagram showing the electrical configuration of the image forming apparatus.

[0052] Figure 5 This is a block diagram for explaining the functional structure of the control section of the image forming apparatus.

[0053] Figure 6 The diagram shows a sequence example of a first detection mode for detecting and acquiring the numerical information of the first recording medium being conveyed, and a second detection mode for detecting and acquiring the numerical information of the first and subsequent recording media.

[0054] Figure 7 This is a table showing the relationship between the type of recording medium and the grammage.

[0055] Figure 8 This is a table showing the relationship between the type of recording medium and the transport speed.

[0056] Fig. 9 This is a table illustrating the relationship between the paper feed speed and the number of sampling data.

[0057] Fig.10 This is a table illustrating the relationship between the process speed and the process conditions before and after the type of recording medium is switched.

[0058] Fig.11 This is a table showing examples of change rate correction coefficients in the cases of giving priority to speed and giving priority to image quality.

[0059] Fig.12 This is a flowchart showing an example of the paper property detection operation of the image forming apparatus according to the present embodiment.

[0060] Fig.13 yes Fig.12 Continuation of the flowchart.

[0061] (Explanation of symbols)

[0062] 1: image forming device; 3: external device; 4: network; 10: image forming unit; 50: operation panel unit; 54: display unit; 60: paper feeding unit; 60a: first paper feeding tray (first-stage paper feeding box); 60b: second paper feeding tray (first-stage paper feeding box); 71a, 71b: conveying rollers (sheet conveying unit); 72: skew correction roller; 91: optical sensor (acquisition unit); 91a, 911a, 912a: light source for transmission; 91 b, 911b, 912b, 913b, 914b: light source for reflection; 91c: light receiving detection element; 92: ultrasonic sensor (acquisition unit); 91a: ultrasonic transmitting unit; 91b: ultrasonic receiving unit; 100: control unit; 100a: medium detection control unit; 100b: sheet type detection control unit; 100c: image formation control unit; 100d: storage unit; 100e: external communication control unit; 110: storage device. DETAILED DESCRIPTION

[0063] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0064] Figure 1 The diagram schematically shows a part of a conveyance path of a recording medium (hereinafter, the recording medium is also referred to as a sheet or paper) on which an image is printed in the image forming apparatus 1 according to the embodiment of the present invention.

[0065] As the image forming apparatus 1 , although not limited, a copy machine, a printer, or a multifunction digital peripheral MFP or the like is used.

[0066] exist Figure 1 In the image forming apparatus 1, a paper feed section 60 is provided at the lower part, and a first paper feed tray 60a of a first-stage paper feed cassette as an upper level and a second paper feed tray 60b of a second-stage paper feed cassette as a lower level are arranged in the paper feed section 60, and a sheet conveying path 8 is formed in the vertical direction to communicate with a paper feed port 8a of the first paper feed tray 60a and a paper feed port 8b of the second paper feed tray 60b. Furthermore, a sheet supplied to the sheet conveying path 8 from the paper feed port 8a of the first paper feed tray 60a or the paper feed port 8b of the second paper feed tray 60b is configured so that the sheet is conveyed upward on the sheet conveying path 8 as indicated by arrow A by conveying rollers (equivalent to the conveying section) 71a, 71b and the like to a pair of skew correction rollers 72 provided at an upper position of the sheet conveying path 8.

[0067] A manual feed tray (not shown) is provided on the opposite side of the first paper feed tray 60 a across the sheet feed path 8 , and a sheet placed on the manual feed tray is fed to the sheet feed path 8 through a manual paper feed port 8 c .

[0068] The user can open and close the first paper feed tray 60a, the second paper feed tray 60b, and the manual tray for the image forming apparatus 1. Opening the first paper feed tray 60a and the second paper feed tray 60b means pulling out the first paper feed tray (paper feed cassette) 60a and the second paper feed tray (paper feed cassette) 60b from the apparatus body for paper replacement, addition, etc., and opening the manual tray means taking out sheets from the manual tray and setting it to an unused state.

[0069] On the other hand, closing the first and second paper feed trays 60a, 60b means attaching the first and second paper feed trays 60a, 60b to the apparatus body, and closing the manual feed tray means setting sheets on the manual feed tray for use.

[0070] In addition, opening the first paper feed tray 60a, the second paper feed tray 60b, and the manual tray can also be referred to as opening the paper feed ports 8a, 8b, and 8c, and closing the first paper feed tray 60a, the second paper feed tray 60b, and the manual tray can also be referred to as closing the paper feed ports 8a, 8b, and 8c. The opening and closing of the first paper feed tray 60a and the second paper feed tray 60b can be detected by a sensor (not shown), and the opening and closing of the manual tray can be detected based on the presence or absence of sheets in the manual tray.

[0071] The skew correction roller 72 is a roller for correcting the skew (inclination) of the sheet conveyed on the sheet conveyance path 8 .

[0072] Between the paper feed port 8a of the upper first paper feed tray 60a and the skew correction roller 72, two medium detection sensors 91 and 92 are arranged on the upstream and downstream sides of the sheet conveying path 8 in the conveying direction. These medium detection sensors 91 and 92 detect the physical property value of the sheet as an example of information related to the sheet. The medium detection sensor 91 on the upstream side is an optical sensor that detects light irradiated to the sheet, and the medium detection sensor 92 on the downstream side is an ultrasonic sensor that detects ultrasonic waves output toward the sheet. In addition, the optical sensor 91 may be arranged on the upstream side, and the ultrasonic sensor 92 may be arranged on the downstream side.

[0073] Figure 2 (A) is an explanatory diagram of the optical sensor 91. The optical sensor 91 includes a transmission light source 91a such as an LED, a reflection light source 91b, and a light receiving element 91c composed of a photodiode or the like. The light receiving element 91c detects the amount of transmitted light 93 emitted from the transmission light source 91a and transmitted through the sheet M conveyed on the sheet conveying path 8, and the amount of reflected light 94 emitted from the reflection light source 91b and reflected by the sheet M as physical property values.

[0074] The transmission light source 91 a and the reflection light source 91 b of the optical sensor 91 may include a plurality of different light sources. Figure 2(B) shows such an optical sensor 91 having a plurality of light sources. Figure 2 The optical sensor 91 of (B) includes a blue light source 911a and an infrared light source 912a as the transmission light source 91a, and includes a red light source 911b, a blue light source 912b, a purple light source 913b, and an infrared light source 914b as the reflection light source 91b.

[0075] In this embodiment, using Figure 2 (B) The optical sensor 91. In addition, the light receiving element 91c detects the transmitted light of infrared wavelength: TIR, the transmitted light of blue wavelength: TB, the reflected light of ultraviolet wavelength: RUV, the reflected light of infrared wavelength: RIR, the reflected light of violet wavelength: RV, the reflected light of red wavelength: RR, etc. Based on the combined calculation result of the output values ​​of the detected transmitted light and reflected light, the control unit 100 described later determines the type of the sheet M (grammage, OHP, recycled paper, coated paper, etc.).

[0076] Figure 3 2 is an explanatory diagram of the ultrasonic sensor 92. The ultrasonic sensor 92 is disposed obliquely to face the sheet M across the sheet conveying path 8 (see FIG. 2 ). Figure 1 ) is provided with a pair of ultrasonic transmitting units 92a and ultrasonic receiving units 92b. In the ultrasonic sensor 92, ultrasonic waves are transmitted from the ultrasonic transmitting unit 92a to the sheet M passing through, and the ultrasonic waves transmitted through the sheet M are received by the ultrasonic receiving unit 92b. Then, the control unit 100 described later determines whether it is a single sheet of paper or two overlapping sheets of paper (envelope) based on the attenuation of the ultrasonic waves caused by the sheet M, thereby detecting the type of sheet as information related to the sheet.

[0077] In the following description, the numerical information (light receiving amount) as the detection result of the transmitted light and the reflected light by the optical sensor 91 and the numerical information (light receiving amount) as the detection result by the ultrasonic sensor 92 are also referred to as paper characteristics. In this embodiment, as described later, the paper characteristics are acquired for each sheet, and the presence or absence of addition is detected based on the amount of change in the paper characteristics.

[0078] In addition, in this embodiment, the image forming apparatus 1 has a user-specified mode and an automatic detection mode, and the user can select any one of the modes. The user-specified mode is a mode in which the user specifies the type of sheet material. When the user-specified mode is selected, the detection of the physical property values ​​of the sheet material (acquisition of paper characteristics) and the discrimination of the sheet material type by the medium detection sensors 91 and 92 are not performed. When the automatic detection mode is selected, the acquisition of paper characteristics and the discrimination of the sheet material type are performed by the medium detection sensors 91 and 92.

[0079] Figure 4 1 is a block diagram showing the electrical structure of the image forming apparatus 1. Figure 4 As shown, the image forming device 1 includes a control unit 100, a storage device 110, an image reading device 120, an operation panel unit 50, an image forming unit 10, a paper supply unit 60, the above-mentioned optical sensor 91, an ultrasonic sensor 92, and further includes a printer controller 150 and a network interface (network I / F) 160, etc., which are interconnected via a system bus 175.

[0080] 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.

[0081] The CPU 101 controls the entire image forming apparatus 1 in general by executing the action program stored in the ROM 102 or the like. For example, the copy function, the printer function, the scanning function, etc. can be controlled in an executable manner. In particular, in this embodiment, the physical property values ​​of the sheet are detected by light quantity detection using the optical sensor 91 and ultrasonic detection using the ultrasonic sensor 92. Moreover, the type of sheet is determined based on the detection result, and when printing, the image forming conditions corresponding to the type of sheet are automatically set based on the determination result to execute printing. In addition, the physical property values ​​of the sheet detected by the optical sensor 91 and the ultrasonic sensor 92, the determination results of the type of sheet, etc. are stored in the storage device 110. Furthermore, control processing output to the operation panel unit 50, external devices, etc. is executed.

[0082] ROM 102 stores programs executed by CPU 101 and other data.

[0083] The S-RAM 103 serves as a work area when the CPU 101 executes a program. The S-RAM 103 temporarily stores the program, data when the program is executed, and the like.

[0084] 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 unit 54 , data of various screens displayed on the display unit 54 , and the like.

[0085] The clock IC 105 keeps time and functions as an internal timer to measure processing time and the like.

[0086] The storage device 110 is composed of a hard disk and the like, and stores programs, various data, and the like. In particular, in this embodiment, the detection results of the paper characteristics (sheet material physical property values) detected by the optical sensor 91 and the ultrasonic sensor 92, the discrimination results of the sheet material types, and the detection history are accumulated. Furthermore, the storage device 110 stores the allowable variation of the paper characteristics of the sheets after the second sheet of the task relative to the paper characteristics of the first sheet of the task as a database. Furthermore, the change rate correction coefficient is also stored as a database. The allowable variation and the change rate correction coefficient will be described later.

[0087] The image reading device 120 includes a scanner or the like, and reads a document placed on a platen glass by scanning the document, and converts the read document into image data.

[0088] The operation panel portion 50 is used when the user issues instructions for tasks and performs various settings on the image forming apparatus 1. The operation panel portion 50 includes a reset key 51, a start key 52, a stop key 53, a display portion 54, a touch panel 55, and the like.

[0089] The reset key 51 is used to reset the settings. The start key 52 is used to start the scanning operation. The stop key 53 is pressed to interrupt the operation.

[0090] The display unit 54 is constituted by, for example, a liquid crystal display device, and outputs and displays messages, various operation screens, etc. The touch panel 55 is formed on the screen of the display unit 54, and detects a touch operation by a user.

[0091] The image forming unit 10 prints a copy image generated by the image data of the original document read by the image reading device 120 or the print data sent from the external terminal device 3 on a sheet of paper. The image forming unit 10 includes a printing engine 18 and a fixing unit 19 that heats and presses the sheet with the image formed thereon to fix the image. The printing engine 18 is composed of hardware components for image formation, such as a photosensitive drum, a charging device, an exposure device, a developing device, a transfer belt, and a transfer roller.

[0092] The network I / F 160 functions as a communication unit that transmits and receives data to and from an external device via the network 4. The external device is, for example, an external server, a cloud system, a printer driver of a user's information terminal device, another image forming device, and the like.

[0093] Figure 5 1 is a block diagram for explaining the functional configuration of the control unit 100. The control unit 100 functionally includes a medium detection control unit 100a, a sheet type detection control unit 100b, an image formation control unit 100c, a storage unit 100d, and an external communication control unit 100e.

[0094] The medium detection control unit 100a operates the optical sensor 91 and the ultrasonic sensor 92 as medium detection sensors in the first detection mode and the second detection mode described below to detect the physical properties of the sheet, etc. The sheet type detection control unit 100b detects the sheet type based on the detection results of the optical sensor 91 and the ultrasonic sensor 92.

[0095] The image formation control unit 100 c controls the image forming unit 10 under image formation conditions corresponding to each sheet type based on the sheet type detected by the sheet type detection control unit 100 b , and prints an image on the sheet.

[0096] The storage unit 100d stores the detection results of the physical property values ​​of the sheet material by the optical sensor 91 and the ultrasonic sensor 92 at one time. Furthermore, the storage unit 100d stores the detection results and detection history of the sheet material type by the sheet material type detection control unit 100b at one time. The information stored in the storage unit 100d is transferred to the Figure 4 The storage device 110 accumulates and updates.

[0097] The external communication control unit 100e is equivalent to Figure 4 The external communication control unit 100e sends and receives data to and from an external server, a management personal computer connected to a USB, or an external device 3 such as another image forming device. The information stored in the storage unit 100d can also be sent to the external device 3.

[0098] Next, the operation of the image forming apparatus 1 will be described, mainly focusing on the control performed by the control unit 100 .

[0099] In this embodiment, the control unit 100 controls the optical sensor 91 and the ultrasonic sensor 92 to detect the physical property values ​​of the sheet and the type of the sheet conveyed on the sheet conveyance path 8 in the first detection mode and the second detection mode.

[0100] The first detection mode is implemented for the first sheet conveyed. The first sheet conveyed may refer to the first sheet conveyed after the first or second paper supply tray 60a, 60b (extraction tray) is opened, the sheets are replaced, supplemented, added, etc., and the first or second paper supply tray 60a, 60b (insertion tray) is closed. Alternatively, in the case of a manual tray, it may also be the first sheet conveyed after the sheet presence detection changes from no to yes, that is, after the manual tray is closed. Alternatively, it may be the sheet conveyed first from the paper supply port that has no sheet type information because the sheet type information is reset due to power OFF / ON, sleep recovery, etc. of the image forming device 1. Alternatively, it may be the sheet conveyed first from the paper supply port after the media detection function changes from OFF to ON. Alternatively, it may be the first sheet conveyed for the print job.

[0101] The information about the first sheet is uncertain. Therefore, conveying is performed at a low speed in such a way that the detection result can be reflected in the process conditions (image forming conditions) in the first detection mode. In addition, in order to detect in detail, the number of sensor readings within the sheet surface is also increased. As a result, the number of sampling data increases, and the accuracy is improved. The type of sheet in the paper feed tray is determined by the first detection mode, and the fixing temperature and transfer current are determined by the process conditions (image forming conditions) that match the determined type of sheet. From the next sheet onwards, appropriate conditions are selected for the conveying speed to perform printing.

[0102] The media detection control unit 100 a also determines the permissible change amount (threshold value) of the paper properties acquired by the second and subsequent media detection sensors 91 , 92 in accordance with the sheet type determined based on the paper properties of the first sheet detected by the media detection sensors 91 , 92 .

[0103] On the other hand, the second detection mode is a mode in which the physical property values ​​of sheets other than the first sheet are detected until the first paper feed tray 60a, the second paper feed tray 60b, or the manual feed tray is opened after the type of the first sheet is determined in the first detection mode. The detection in the second detection mode may be performed on all sheets other than the first sheet, for example, may be performed on each plurality of sheets such as every other sheet or every fifth sheet, or may be performed at the beginning and the end of a task other than the first sheet.

[0104] In the second detection mode, the conveying speed is set to the type of sheet determined by the detection in the first detection mode. Therefore, the conveying speed becomes faster than in the first detection mode according to the type of sheet, so the time from when the sheet reaches each medium detection sensor 91, 92 to when it reaches the skew correction roller 72 becomes shorter. Therefore, the detection time is also shorter than in the first detection mode. Therefore, the number of samples of the detection results obtained by the medium detection sensors 91, 92 becomes smaller, and sufficient sampling data required for determining the type of sheet cannot be obtained.

[0105] Therefore, in this embodiment, the medium detection control unit 100a determines whether the change amount of the paper characteristics of the second and subsequent sheets detected by the medium detection sensors 91 and 92 from the paper characteristics of the first sheet is within the allowable change amount range. If it is within the allowable change amount range, the medium detection control unit 100a determines that the sheet type has not changed, that is, no sheet has been added. If it exceeds the allowable change amount, it is determined that the sheet type has changed, that is, a sheet has been added.

[0106] Figure 6 An example of a sequence related to the first detection mode and the second detection mode is shown.

[0107] In this example, the first paper feed tray 60a is loaded with thick paper 2. In this state, the first paper feed tray 60a is opened, and 10 sheets of plain paper are added to the thick paper 2. Figure 6 After the first paper feed tray 60a is inserted or removed (opened or closed) as indicated by the signal of "cassette action", four print jobs (1) to (4) consisting of four sheets each are executed as indicated by the signal of "print job".

[0108] exist Figure 6 In the example of FIG. 1 , detection in the first detection mode is performed on the first sheet fed and conveyed from the first paper feed tray 60a after the first paper feed tray 60a is inserted or removed (opened or closed). In other words, detection in the first detection mode is performed on the first sheet of the print job (1). As described above, conveyance at a low speed is performed in such a manner that the detection result can be reflected in the process condition (image forming condition) in the first detection mode.

[0109] In this embodiment, in the first detection mode, thick paper 3 is fed from the paper feed port of the first paper feed tray 60a to the media detection sensors 91 and 92 at the paper feed speed, and the paper properties are detected. The media detection control unit 100a determines the sheet type based on the paper properties.

[0110] Figure 7 The relationship between the sheet type and grammage is shown. The grammage is calculated based on the paper characteristics detected by the medium detection sensors 91 and 92, and the sheet type is determined. For example, in the grammage range of 52 to 90, it is determined to be ordinary paper. In this embodiment, 10 sheets of ordinary paper are added to the thick paper 2. Therefore, the first sheet is determined to be ordinary paper. From the skew correction roller 72, downstream, the sheet is conveyed at the process speed of the determined sheet type (here ordinary paper), and an image is formed under conditions based on the sheet type. The first sheet is conveyed at the paper feed speed of thick paper 3 because any sheet type can be fed due to the indefinite sheet type. However, as long as it is a paper feed speed at which paper can be fed, it may be a speed other than the paper feed speed of thick paper 3.

[0111] As described above, the medium detection control unit 100 a determines the permissible amount of change (threshold) of paper properties acquired by the medium detection sensors 91 and 92 for the second and subsequent sheets, according to the type of sheet determined for the first sheet.

[0112] The second and subsequent sheets are conveyed to the medium detection sensors 91 and 92 at a paper feed speed corresponding to the sheet type of the first sheet.

[0113] Figure 8 The relationship between sheet type and conveying speed is shown. Figure 8, the paper feed speed and process speed for ordinary paper, thick paper 1, thick paper 2, thick paper 3, and recycled paper are shown. The paper feed speed is the conveying speed from the paper feed ports 8a, 8b, 8c to the skew correction roller 72. The process speed is the speed from the skew correction roller 72 to image formation. For example, ordinary paper is conveyed from the paper feed ports 8a, 8b, 8c to the skew correction roller 72 at a conveying speed of 400 mm / s, and is conveyed from the skew correction roller 72 at a conveying speed of 300 mm / s. For thick paper 3, the paper feed speed and process speed are both set to the slowest. The speed increases in the order of thick paper 3, thick paper 2, thick paper 1, and ordinary paper, and ordinary paper is set to the fastest. Recycled paper is set to the same speed as ordinary paper.

[0114] The media detection sensors 91 and 92 detect the paper characteristics in the second detection mode. When the conveyance speed of the sheet increases, the number of samplings in the media detection sensors 91 and 92 decreases. Therefore, the number of sampling data obtained per one light source (LED) decreases. Fig. 9 The relationship between the paper feed speed and the number of sampling data is shown below. Fig. 9 When the maximum paper feed speed is 160 mm / s or less and the minimum paper feed speed is 121 mm / s or less, the number of sampling data is 9 / LED. When the maximum paper feed speed is 180 mm / s or more and the minimum paper feed speed is 161 mm / s or more, the number of sampling data decreases. When the maximum paper feed speed is 420 mm / s or more and the minimum paper feed speed is 306 mm / s or more, the number of sampling data becomes 4.

[0115] These multiple sampling data are averaged, for example, to determine the type of sheet. However, when the conveying speed of the sheet becomes faster, the number of data required for the high-precision determination of the type of sheet cannot be obtained. Therefore, the medium detection control unit 100a compares the paper characteristics as numerical information obtained by the medium detection sensors 91 and 92 with the paper characteristics as numerical information obtained about the first sheet for the second and subsequent sheets. Specifically, the medium detection control unit 100a calculates the change in the numerical value of the obtained paper characteristics relative to the numerical value of the paper characteristics of the first sheet. Then, the medium detection control unit 100a determines whether the change is within the range of the allowable change of the paper characteristics obtained according to the type of the first sheet (within a predetermined range). If it is within the range of the allowable change, it is determined that the sheet types are the same. If it is not within the range of the allowable change, it is determined that the addition has been made and the sheet types are different. The change can be either a rate of change or a difference. In the case where the change is a rate of change, the allowable change is also expressed as a rate of change. In the case where the change is a difference, the allowable change is also expressed as a difference.

[0116] As an example of an item of paper characteristics for which the amount of change is obtained, there is a combination of the amount of light received by the blue light source 911a and the infrared light source 912a for transmission of the optical sensor 91 and the amount of light received by the red light source 911b, the blue light source 912b, the violet light source 913b, and the infrared light source 914b for reflection. For example, the ratio of the amount of light received by the reflected light RUV of the ultraviolet wavelength to the reflected light RIR of the infrared wavelength, i.e., RUV / RIR, and the ratio of the amount of light received by the reflected light RV of the violet wavelength to the reflected light RIR of the infrared wavelength, i.e., RV / RIR, can be cited. Furthermore, the ratio of the amount of light received by the reflected light RR of the red wavelength to the reflected light RIR of the infrared wavelength, i.e., RR / RIR, and the difference in the amount of light received by the transmitted light TIR of the infrared wavelength and the transmitted light TB of the blue wavelength, i.e., (TIR-TB), can be cited.

[0117] The medium detection control unit 100a obtains, for example, RUV / RIR, RV / RIR, RR / RIR, and (TIR-TB) for each sheet after the second sheet. RUV / RIR, RV / RIR, RR / RIR, and (TIR-TB) are also obtained for the first sheet. All values ​​are obtained as approximate information obtained by averaging multiple sampling data. Moreover, the medium detection control unit 100a compares the obtained numerical values ​​of each sheet after the second sheet with the numerical value of the first sheet for each item. When the type of sheet after the second sheet is the same as the type of sheet of the first sheet, the obtained numerical values ​​for any item are consistent under the approximate calculation. That is, the rate of change is approximately 1, and in the case of a difference, it becomes approximately 0. When the rate of change exceeds (departs from) the allowable range, it is determined that the type of sheet has been changed (added). In this case, the medium detection control unit 100a may determine that the sheet type has been changed when all items of RUV / RIR, RV / RIR, RR / RIR, and (TIR-TB) exceed the permissible range. Alternatively, it may determine that the sheet type has been changed when not all but predetermined items exceed the permissible range. The medium detection control unit 100a may make the determination according to a predetermined determination method.

[0118] about Figure 6 The 2nd to 4th sheets in the printing task (1) are detected in the second detection mode.

[0119] exist Figure 6 In the example of FIG. 1 , at the stage of print job (2), the sheet type has not changed, so the medium detection sensors 91 and 92 operate in the second detection mode.

[0120] Regarding the printing task (3), the second detection mode is also used, but a sheet of a different sheet type is added to the third sheet (the 11th sheet since the first paper feed tray 60a was opened and closed). Therefore, the change in the paper characteristics is out of the range of the allowable change, so the medium detection control unit 100a determines that the sheet type is different.

[0121] However, in this embodiment, in order to maintain productivity, the remaining part of the print job (3) is printed while maintaining the conveying speed. However, the process conditions are switched according to the type of sheet estimated from the change amount.

[0122] exist Fig.10 , as an example, the relationship between the process speed and the process conditions (in this example, the fixing temperature and the transfer voltage) before and after the switching of the sheet type is shown. For example, when it is assumed that the sheet type is switched from ordinary paper to thick paper 2, the process speed is maintained at the speed of ordinary paper, and the temperature control of the fixing is changed from 180°C to 230°C. In addition, the transfer voltage setting is changed from 1400V to 1900V. In any case, the process speed is the same before and after the switching.

[0123] By changing the process conditions in this way, even if the process speed is not the optimum condition for the thick paper 2 , it is possible to suppress a decrease in image quality.

[0124] against Figure 6 The first sheet of the printing task (4) is detected in the first detection mode, and the sheet type is determined to be thick paper 2. In addition, the second and subsequent sheets of the printing task (4) are conveyed at a paper feed speed corresponding to the thick paper 2 detected in the first detection mode, and the detection action in the second detection mode is performed.

[0125] In this embodiment, when a job is transmitted from an external device, speed priority or image quality priority can be set as the paper feeding mode for the job using a printer driver or the like of the external device.

[0126] When image quality priority is set, if it is determined in the second detection mode that the sheet type is different, the conveying speed of the sheet being conveyed is reduced to the conveying speed of the thick paper 3. In addition, the paper characteristics can be obtained in the first detection mode to determine the sheet type. After the sheet is allowed to wait on the skew correction roller 72, the conveying speed is changed to the conveying speed according to the determined sheet type, and image formation and paper discharge are performed. The sheet type detected and determined in the first detection mode becomes the reference value for the next sheet. Therefore, the sheet is conveyed at the conveying speed corresponding to the sheet type, and the paper characteristics are obtained for each sheet in the second detection mode.

[0127] In addition, when image quality is prioritized, the range of the permissible variation that is judged as a different type of sheet material in the second detection mode may be changed. Specifically, the threshold value that specifies the range of the permissible variation is changed so that a small variation in the paper characteristics is judged as a different type of sheet material. In this way, sheet type discrimination can be performed with higher accuracy, and better image quality can be ensured. It is also possible to change the variation of the detected paper characteristics without changing the range of the permissible variation so that a small variation in the paper characteristics is judged as a different type of sheet material. Alternatively, when speed is prioritized, the range of the permissible variation may be changed in a gentle direction so as not to transfer to the first detection mode even if the variation is large. It is also possible to change the variation of the detected paper characteristics without changing the range of the permissible variation.

[0128] Regarding the change in the range of the allowable variation, the allowable variation itself after the change may be set in a table, depending on whether the image quality or speed is prioritized. Alternatively, the allowable variation that serves as a reference may be set in a table, and a correction coefficient that is multiplied by the allowable variation that serves as a reference may be set in another table, depending on whether the image quality or speed is prioritized. It is also possible to set the allowable variation in the case of image quality priority as the allowable variation that serves as a reference, and change the allowable variation in the case of speed priority. Alternatively, it is also possible to conversely set the allowable variation in the case of speed priority as the allowable variation that serves as a reference, and change the allowable variation in the case of image quality priority. Fig.11 An example of the rate of change correction coefficient for the cases of speed priority and image quality priority is shown. The rate of change correction coefficient is specified for each of gram weight, RUV / RIR, RV / RIR, RR / RIR, and (TIR-TB). In addition, the correction coefficient can also be calculated by an arithmetic expression. In addition, Fig.11 The reason why the grammage is shown in the figure is that when the conveying speed of the sheet is slow, the number of data sampling is large and the grammage may be calculated.

[0129] The change in the allowable change amount for determining that the sheet type is different in the second detection mode is not limited to image quality priority or speed priority. For example, the change may be made according to the sheet type determined in the first detection mode.

[0130] For example, when the sheet type is coated paper, there are many cases where high image quality is generally required, so the range of the allowable change amount is changed so that the sheet type is judged to be different under a small change amount of paper characteristics. On the other hand, when the sheet type is ordinary paper, it is highly likely that speed is prioritized over image quality, so it is changed in a manner that does not shift to the first detection mode even if the change amount is large. By changing the range of the allowable change amount according to the sheet type identified in the first detection mode, paper type changes can be detected with higher accuracy. Even in this case, the range of the allowable change amount after the change itself can be set in a table according to the sheet type identified in the first detection mode. Alternatively, the allowable change amount that serves as a reference can be set in the table, and a correction coefficient to be multiplied can be set in other tables according to the sheet type identified in the first detection mode. Alternatively, the correction coefficient can be calculated by an arithmetic expression.

[0131] Alternatively, the allowable change amount for a predetermined type of sheet may be set as the allowable change amount serving as a reference, and the allowable change amount may be increased or decreased depending on the type of sheet.

[0132] In addition, the range of the allowable variation used to judge the sheet types as different in the second detection mode can be changed when the conveying speed of the sheet in the second detection mode is fast or slow. When the conveying speed is slow, the number of sampled data is large, so a more accurate variation can be obtained. Therefore, the allowable variation is changed so that the sheet types are judged to be different under a small variation of the paper characteristics. On the other hand, when the conveying speed is fast, the allowable variation can be changed in a gentle direction so that it does not transfer to the first detection mode even if the variation is large. Even in this case, the changed allowable variation itself can be set in the table according to the conveying speed in the second detection mode. Alternatively, the range of the allowable variation that serves as a reference can be set in the table, and the correction coefficient for multiplying the allowable variation can be set in other tables according to the conveying speed in the second detection mode. Alternatively, the correction coefficient can be calculated by an arithmetic expression.

[0133] Alternatively, the allowable change amount for a case where the transport speed is fast may be set as the allowable change amount serving as a reference, and the allowable change amount may be increased or decreased according to the transport speed. Fig. 9 An example of a correction coefficient corresponding to the transport speed is shown.

[0134] Furthermore, when a plurality of correction coefficients are matched, the allowable change amount may be calculated by multiplying the allowable change amount serving as a reference by each correction coefficient.

[0135] Fig.12 as well as Fig.13 This is a flowchart showing an example of the paper property detection operation of the image forming apparatus 1 according to the present embodiment. Fig.13 yes Fig.12 The paper property detection operation is executed by the CPU 101 of the control unit 100 of the image forming apparatus 1 operating according to an operation program stored in the ROM 102 or the like. In this embodiment, sheets are supplied from the first paper supply tray 60a.

[0136] In step S01, a print instruction is waited for ("No" in step S01). When a print instruction is received ("Yes" in step S01), in step S02, whether there is information on the type of sheet material at the paper feed port is checked. In this example, the first paper feed tray 60a is opened and closed, so there is no information on the type of sheet material at the paper feed port ("No" in step S02). Therefore, in step S03, the first sheet of the first task is sent from the first paper feed tray 60a to the media detection sensors 91, 92 at the paper feed speed of thick paper 3, and the paper characteristics are detected (obtained) (first detection mode). Then, the sheet type is determined by comparing the obtained paper characteristics with the information in the paper type / variation amount database (paper type / variation amount DB) of the storage device 110.

[0137] In step S04, the paper is conveyed downstream from the skew correction roller 72 at the process speed of the determined sheet type, and an image is formed under the conditions based on the sheet type. If the sheet type information is available at the paper feed port ("Yes" in step S02), the process proceeds to step S04, and the speed and process conditions corresponding to the sheet type are set to form an image.

[0138] Next, in step S05, the permissible variation that becomes the reference of the variation of the paper characteristics acquired by the media detection sensors 91 and 92 for the second and subsequent sheets is acquired from the paper type / variation database. Furthermore, in step S06, the variation rate correction coefficient of the paper characteristics for the second and subsequent sheets is acquired from the variation correction value database of the storage device 110 in accordance with the sheet type determined based on the paper characteristics of the first sheet detected by the media sensors 91 and 92. Furthermore, in step S07, the variation rate correction value corresponding to the paper passing mode (image quality priority or speed priority) is acquired from the variation correction value database.

[0139] In step S08, the allowable change amount for the second and subsequent sheets is calculated. Specifically, the allowable change amount serving as a reference obtained from the database is multiplied by the change rate correction coefficient for the sheet type and the paper feeding mode. The obtained value is then set as the allowable change amount for the second and subsequent sheets.

[0140] Next, in step S09, the second and subsequent sheets are conveyed to the skew correction roller 72 at a paper feed speed corresponding to the sheet type determined for the first sheet. During the conveyance, the paper characteristics are detected by the medium detection sensors 91 and 92 (second detection mode).

[0141] As described above, when the transport speed increases, the number of samples in the medium detection sensors 91 and 92 decreases, so the data required for medium determination cannot be obtained. Fig.13 In step S10, it is determined whether the change in the paper characteristics of the second sheet detected by the medium detection sensors 91 and 92 relative to the paper characteristics of the first sheet is greater than the allowable change set in step S08. The change in the paper characteristics of the second sheet relative to the paper characteristics of the first sheet may also be the ratio of the paper characteristics of the second sheet to the paper characteristics of the first sheet, that is, the paper characteristics of the second sheet ÷ the paper characteristics of the first sheet. Alternatively, it may be the difference between the paper characteristics of the second sheet and the paper characteristics of the first sheet. The allowable change may also be prepared as a value corresponding to the ratio or the difference.

[0142] In step S10 , if the amount of change in the paper properties of the second sheet relative to the paper properties of the first sheet is not greater than the allowable amount of change (“No” in step S10 ), the process proceeds to step S16 .

[0143] When the change amount is greater than the allowable change amount ("Yes" in step S10), in step S11, a sheet material information deletion flag of the paper feed port is set. Next, in step S12, it is checked whether it is the image quality priority mode. If it is not the image quality priority mode ("No" in step S12), in step S13, only the process conditions are changed to the process conditions corresponding to the sheet material type estimated to be changed. The process speed is not changed.

[0144] However, in step S14, it is determined whether the process condition change is in time. If it is in time ("Yes" in step S14), the process proceeds to step S16. If it is not in time ("No" in step S14), the conveyance of the sheet is temporarily put on hold, and in step S15, the conveyance speed and process condition are changed in accordance with the type of sheet estimated to be changed. Thereafter, the conveyance is restarted, and the process proceeds to step S16.

[0145] In step S12, if the image quality priority mode is selected ("Yes" in step S12), in step S15, the conveying speed and process conditions are changed according to the type of sheet material estimated to be changed. Then, the process proceeds to step S16. In this case, if it is determined that it is too late to change the conveying speed and process conditions, the conveying of the sheet material is temporarily put on hold and changed.

[0146] After the image forming operation is executed in step S16, in step S17, it is determined whether the task is completed. If the task is not completed ("No" in step S17), the process returns to step S16. Fig.12If the task is completed ("Yes" in step S17), then in step S18, check whether there is a paper feed port sheet material information deletion flag. If there is ("Yes" in step S18), then in step S19, delete the paper feed port sheet material information and end the operation. If there is no paper feed port sheet material information deletion flag ("No" in step S18), the processing ends directly.

Claims

1. An image forming device comprising: A conveying unit that continuously conveys the recording medium; an acquiring unit that acquires numerical information related to the recording medium transported by the transport unit; and The control unit compares the first numerical information acquired by the acquisition unit with the second numerical information acquired before the first numerical information.

2. The image forming apparatus according to claim 1, wherein: The control unit compares the first numerical information acquired by the acquisition unit for the first recording medium and the second numerical information acquired by the acquisition unit for the second recording medium transported before the first recording medium, and determines whether a change rate of the first numerical information relative to the second numerical information is within a predetermined range.

3. The image forming apparatus according to claim 1, wherein: The control unit compares the first numerical information acquired by the acquisition unit for the first recording medium with the second numerical information acquired by the acquisition unit for the second recording medium transported before the first recording medium, and determines whether a difference between the first numerical information and the second numerical information is within a predetermined range.

4. The image forming apparatus according to any one of claims 1 to 3, wherein: When comparing the first numerical information and the second numerical information, the control unit determines whether the approximate information of the first numerical information acquired by the acquisition unit and the approximate information of the second numerical information acquired before the first numerical information are consistent.

5. The image forming apparatus according to claim 1, wherein: The method comprises: a first action mode for determining the type of recording medium based on second numerical information obtained about the first recording medium of the task; and a second action mode for obtaining first numerical information about the second and subsequent recording media of the task, and obtaining a change amount of the obtained first numerical information relative to the second numerical information, The control unit: According to the type of recording medium determined by the first operation mode for the first recording medium of the task, the conveying speed / image forming conditions for the second and subsequent recording media of the task are set, and the allowable change amount of the first numerical information obtained in the second operation mode relative to the second numerical information is determined, and then When the change in the first numerical information obtained in the second action mode for the second and subsequent recording media of the task exceeds the allowable change, it is determined that the type of the recording medium has changed, and the type of the recording medium is determined by obtaining the second numerical information by implementing the first action mode at a predetermined timing.

6. The image forming apparatus according to claim 5, wherein: An image quality priority mode and a speed priority mode are provided, and the control unit changes the execution timing of the first operation mode in the image quality priority mode and the speed priority mode.

7. The image forming apparatus according to claim 5, wherein: An image quality priority mode and a speed priority mode are provided, and the control unit changes the allowable change amount in the image quality priority mode and the speed priority mode.

8. The image forming apparatus according to claim 5, wherein: The control unit changes the allowable change amount according to a conveyance speed of a recording medium, and the conveyance speed of the recording medium is set according to second numerical value information acquired in the first operation mode.

9. The image forming apparatus according to claim 5, wherein: The control unit makes the recording medium wait temporarily and restarts the conveyance after changing the speed / image forming conditions when it is determined that the type of the second and subsequent recording media of the job has changed and it is too late to change the conveyance speed / image forming conditions if the recording medium is conveyed as it is.

10. The image forming apparatus according to any one of claims 5 to 8, wherein: The control unit has an image quality priority mode and a speed priority mode. When the control unit determines that the type of the recording medium after the second sheet of the task has changed, if the image quality priority mode is selected, the control unit makes the recording medium wait temporarily and starts conveying again after changing the conveying speed / image forming conditions if it determines that it is too late to change the conveying speed / image forming conditions even if the recording medium is conveyed as it is, and conveys the recording medium as it is if it is judged that it is too late to change the conveying speed / image forming conditions. In the case of the speed priority mode, only the image forming conditions are changed.

11. A method for processing information related to a recording medium, An image forming apparatus including a conveying unit for continuously conveying a recording medium performs: an acquiring step of acquiring numerical information related to the recording medium transported by the transport unit; and The control step compares the first numerical information acquired in the acquisition step with second numerical information acquired before the first numerical information.

12. A computer program product for causing a computer of an image forming apparatus having a conveying unit for continuously conveying a recording medium to execute: an acquiring step of acquiring numerical information related to the recording medium transported by the transport unit; and The control step compares the first numerical information acquired in the acquisition step with second numerical information acquired before the first numerical information.

Images