Image forming apparatus, conveyance control method for a recording medium, and program

Abstract

To provide an image forming device that can prevent productivity from declining even when a type of a recording medium is changed during printing, a method for controlling conveyance of a recording medium, and a program.SOLUTION: An image forming device 1 comprises: conveying parts 71a and 71b that convey a recording medium; recording medium sensing parts 91, 92 and 100b that sense information concerning the recording medium; and a control part 100 that makes the recording medium sensing parts sense information concerning a recording medium conveyed first by the conveying parts, makes the conveying parts operate so that the recording medium is conveyed at conveying speed based on the information concerning the recording medium conveyed first, and makes the conveying parts operate so that the recording medium is conveyed while maintaining the conveying speed, even when it is sensed that information concerning a recording medium conveyed following the recording medium conveyed first is different from the information concerning the recording medium conveyed first.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present invention relates to an image forming apparatus such as a copying machine, a printer, or a multi-function digital composite machine called an MFP (Multi Function Peripheral), a method for controlling conveyance of a recording medium, and a program.

Background Art

[0002] An image forming apparatus using a media detection sensor as means for detecting the type of a recording medium such as paper is known. Patent Document 1 discloses an image forming apparatus having control means for stopping an image forming process when the type of the recording medium detected by the media detection sensor is different from the type of the recording medium on which an image has already been formed and the corresponding image forming conditions are also different.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the image forming process is interrupted when the type of the recording medium changes during printing as in the image forming apparatus described in Patent Document 1, there is a problem that productivity decreases.

[0005] The present invention has been made in view of such a technical background, and an object thereof is to provide an image forming apparatus, a method for controlling conveyance of a recording medium, and a program capable of preventing a decrease in productivity even when the type of the recording medium changes during printing.

Means for Solving the Problems

[0006] The above object is achieved by the following means. (1) A transport unit that transports a recording medium, A recording medium detection unit that acquires information regarding the recording medium in order to set image formation conditions for forming an image on the recording medium, When the first information regarding the first recording medium acquired for the first recording medium transported by the transport unit in a job and the second information regarding the second recording medium acquired for the second recording medium transported after the first recording medium are different information, a control unit that controls so that the second recording medium is continuously transported while maintaining the transport speed during the job of forming an image on the second recording medium, When detecting information regarding the first recording medium, the control unit transports the first recording medium at a first transport speed determined in advance, and after detecting the information regarding the first recording medium, transports the recording media after the first recording medium at a second transport speed based on the information regarding the first recording medium and executes image formation under the image formation conditions based on the first information. When the recording medium detection unit detects information regarding a recording medium different from the first recording medium in the second recording medium, the recording medium detection unit is caused to perform detection at the first transport speed on the recording medium transported first in the next job of the job in which it is determined that the information regarding the recording medium is different and execute image formation under the image formation conditions based on the first information. An image forming apparatus characterized by the above. (2) The control unit causes the recording medium detection unit to detect information regarding the recording medium for a plurality of recording media transported by the transport unit. The image forming apparatus according to item (1) above. (3) The information regarding the recording medium is physical property values of the recording medium or information corresponding to the type of the recording medium. The image forming apparatus according to item (1) above. (4) Different threshold values are set for the physical property values, and when the threshold values are exceeded, it is determined as different physical property values. The image forming apparatus according to item (3) above. (5) The type of the recording medium is determined based on the physical property values. The image forming apparatus according to item (3) or (4) above. (6) The image forming apparatus according to item (1) above, wherein the recording medium includes an envelope made of at least any one of a pulp material, a resin material, and a textile material, and / or an OHP. (7) The image forming apparatus according to item (1) above, wherein when there is a change in the information regarding the recording medium detected by the recording medium detection unit, the control unit changes image forming conditions other than the conveyance speed by the conveyance unit. (8) The image forming apparatus according to item (1) above, wherein when there is a change in the information regarding the recording medium detected by the recording medium detection unit, the control unit reflects the change in the control conditions and prohibited conditions of the post-processing apparatus. (9) The image forming apparatus according to item (1) above, wherein when there is a change in the information regarding the recording medium detected by the recording medium detection unit, the control unit causes the storage unit to store at least any one of the information regarding the recording medium after the change, the information regarding the recording medium before and after the change, and the presence or absence of the change. (10) The image forming apparatus according to item (9) above, wherein when it is stored in the storage unit that there has been a change in the information regarding the recording medium, the control unit causes the recording medium detection unit to perform detection on the first recording medium of the next job of the job in which the change has occurred at the first conveyance speed. (11) The image forming apparatus according to item (1) above, wherein the control unit causes the recording medium detection unit to perform detection on at least any one of all the recording media after the first recording medium, for each arbitrary number of sheets, or the last recording medium of the job, with respect to the second recording medium. (12) The image forming apparatus according to item (1) above, wherein the conveyance unit conveys the first recording medium at a conveyance speed preset as a conveyance speed capable of feeding a thicker recording medium. (13) The image forming apparatus according to item (1) above, wherein the control unit makes a determination as to whether the information regarding the second recording medium is different from the information regarding the first recording medium based on the rate of change from the physical property value of the first recording medium or the difference in the type of recording medium. (14) When detecting information regarding the first recording medium, the control unit conveys the first recording medium at a predetermined first conveyance speed, and after detecting the information regarding the first recording medium, conveys the recording media subsequent to the first recording medium at a second conveyance speed based on the information regarding the first recording medium. At the same time, Even when it is detected that the information regarding the second recording medium is different from the information regarding the first recording medium, if there is no change in the image forming conditions, the control unit causes the recording medium detection unit to convey the recording medium to be conveyed first in the next job at the second conveyance speed. The image forming apparatus according to item 1 above. (15) The image forming apparatus according to item 1 above, wherein it is possible to set from the operation unit whether to detect the information regarding the second recording medium. (16) When it is detected that the information regarding the second recording medium is different from the information regarding the first recording medium, the image forming apparatus according to item 1 above notifies the detected information regarding the recording medium or shares it with an external device. (17) The second recording medium for which it is detected whether it is different from the information regarding the first recording medium is the last recording medium of the job. The image forming apparatus according to item 1 above. (18) A conveyance step of conveying a recording medium, A recording medium detection step of detecting information regarding the recording medium in order to set image forming conditions for forming an image on the recording medium, In a job , the When detecting information regarding one recording medium, the first recording medium is conveyed at a predetermined first conveyance speed, and after detecting the information regarding the first recording medium, the recording media subsequent to the first recording medium are conveyed at a second conveyance speed based on the information regarding the first recording medium. At the same time Regarding the first recording medium detected in the recording medium detection step A first control step of executing image formation under image forming conditions based on the first information, The When the first information and the second information regarding the second recording medium detected for the second recording medium conveyed after the first recording medium are different information, a second control step of controlling so that the second recording medium is continuously conveyed while maintaining the conveyance speed during the job of forming an image on the second recording medium; recording A third control step of causing the recording medium conveyed first in the next job of the job in which it is determined that the information regarding the recording medium is different to be detected at a first conveyance speed and executing image formation under the image formation conditions based on the first information; An image forming method including the above.

Effect of the Invention

[0007] According to the image forming apparatus and the recording medium conveyance control method according to the present invention , transfer sent First regarding the recording medium First information is acquisition and the recording medium conveyed after the first sheet Second regarding the recording medium Second information is acquisition sent . First information and second information and are different information, and even when continuously second the recording medium is conveyed. For this reason, it is possible to prevent a decrease in productivity due to a decrease in the conveyance speed.

Brief Description of the Drawings

[0009]

Figure 1

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Figure 12

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is a diagram schematically showing 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 an image forming apparatus 1 according to an embodiment of the present invention.

[0012] As the image forming apparatus 1, although not limited, a copying machine, a printer, or an MFP which is a multifunctional digital composite machine etc. are used.

[0013] In FIG. 1, a paper feeding unit 60 is provided at the lower part of the image forming apparatus 1. In this paper feeding unit 60, a first paper feeding tray 60a which is the upper first-stage paper feeding cassette and a second paper feeding tray 60b which is the lower second-stage paper feeding cassette are arranged. And a sheet conveyance path 8 is formed in the vertical direction in communication with the paper feeding port 8a of the first paper feeding tray 60a and the paper feeding port 8b of the second paper feeding tray 60b. Then, the sheet fed into the sheet conveyance path 8 from the paper feeding port 8a of the first paper feeding tray 60a or the paper feeding port 8b of the second paper feeding tray 60b is conveyed upward along the sheet conveyance path 8 as indicated by arrow A by conveyance rollers (corresponding to the sheet conveyance unit) 71a, 71b, etc. to a pair of skew correction rollers 72 installed at the upper position of the sheet conveyance path 8.

[0014] Also, a manual feed tray (not shown) is provided on the opposite side of the first paper feeding tray 60a across the sheet conveyance path 8, and the sheet set on the manual feed tray is configured to be supplied to the sheet conveyance path 8 through the manual paper feeding port 8c.

[0015] The paper feeding port 8a of the above-mentioned first paper feeding tray 60a, the second paper feeding tray 60b, and the manual feed tray all correspond to holding parts for holding the sheet, and the user can open and close the first paper feeding tray 60a, the second paper feeding tray 60b, and the manual feed tray with respect to the image forming apparatus 1. Opening the first paper feeding tray 60a and the second paper feeding tray 60b means removing the first paper feeding tray (paper feeding cassette) 60a and the second paper feeding tray (paper feeding cassette) 60b from the apparatus main body for paper replacement, addition, etc. Opening the manual feed tray means removing the sheet from the manual feed tray to make it in a non-use state.

[0016] On the other hand, closing the first paper feeding tray 60a and the second paper feeding tray 60b means mounting the first paper feeding tray 60a and the second paper feeding tray 60b on the apparatus main body. Closing the manual feed tray means setting a sheet on the manual feed tray to make it in a use state.

[0017] Also, opening the first paper feed tray 60a, the second paper feed tray 60b, and the manual feed tray is also referred to as opening the paper feed ports 8a, 8b, 8c, and closing the first paper feed tray 60a, the second paper feed tray 60b, and the manual feed tray is also referred to as closing the paper feed ports 8a, 8b, 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 feed tray can be detected by the presence or absence of a sheet in the manual feed tray.

[0018] The skew correction roller 72 is a roller for correcting the skew (tilt) of the sheet conveyed through the sheet conveyance path 8.

[0019] Between the paper feed port 8a of the upper first paper feed tray 60a and the skew correction roller 72, two media detection sensors 91, 92 are arranged on the upstream side and the downstream side in the conveyance direction of the sheet conveyance path 8. These media detection sensors 91, 92 detect physical property values of the sheet, which are an example of information regarding the sheet (hereinafter, information regarding the sheet is also referred to as sheet information). The upstream media detection sensor 91 is an optical sensor that detects light irradiated on the sheet, and the downstream media detection sensor 92 is an ultrasonic sensor that detects ultrasonic waves output toward the sheet. Note that the optical sensor 91 may be arranged on the upstream side and the ultrasonic sensor 92 may be arranged on the downstream side.

[0020] FIG. 2 is an explanatory diagram of the optical sensor 91. The optical sensor 91 includes a transmission light source 91a such as an LED and a reflection light source 91b, and a light receiving element 91c composed of a photodiode or the like. The light receiving element 91c detects, as physical property values, the amount of transmitted light 93 of the light emitted from the transmission light source 91a and transmitted through the sheet M conveyed through the sheet conveyance path 8, and the amount of reflected light 94 of the light emitted from the reflection light source 91b and reflected by the sheet M. Then, based on the levels of the detected transmitted light amount and reflected light amount, the control unit 100, which will be described later, discriminates the type of the sheet M (basis weight, OHP, recycled paper, coated paper, etc.) to detect the type of the sheet (sheet type), which is another example of the sheet information. Note that the optical sensor 91 may be composed of a plurality of sensor groups corresponding to each of colors such as red, green, and blue, for example.

[0021] FIG. 3 is an explanatory diagram of the ultrasonic sensor 92. The ultrasonic sensor 92 includes a pair of ultrasonic transmitting units 92a and ultrasonic receiving units 92b that are disposed obliquely opposite to each other with the sheet conveyance path 8 interposed therebetween with respect to the passing direction of the sheet M (see FIG. 1). This ultrasonic sensor 92 transmits ultrasonic waves from the ultrasonic transmitting unit 92a to the passing sheet M, and receives the ultrasonic waves transmitted through the sheet M by the ultrasonic receiving unit 92b. Then, a control unit 100 described later detects the sheet type as sheet information by determining whether it is a single sheet or a double-sided sheet (envelope) based on the attenuation amount of the ultrasonic waves by the sheet M.

[0022] FIG. 4 is a block diagram showing the electrical configuration of the image forming apparatus 1. As shown in FIG. 4, the image forming apparatus 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 feeding unit 60, the above-described optical sensor 91, and an ultrasonic sensor 92, and further includes a printer controller 150 and a network interface (network I / F) 160, etc., and are connected to each other via a system bus 175.

[0023] 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.

[0024] The CPU 101 comprehensively controls the entire image forming apparatus 1 by executing the operation programs stored in the ROM 102 and the like. For example, in addition to controlling the execution of functions such as a copying function, a printer function, and a scanning function, particularly in this embodiment, it causes the physical property values of the sheet to be detected based on the light amount detection by the optical sensor 91 and the ultrasonic detection by the ultrasonic sensor 92, discriminates the sheet type based on the detection results, and automatically sets the image forming conditions corresponding to the sheet type and executes printing based on the discrimination results at the time of printing. Further, it executes control processes such as storing and accumulating the physical property values of the sheet detected by the optical sensor 91 and the ultrasonic sensor 92, the discrimination results of the sheet type, etc. in the storage device 110, and outputting them to the operation panel unit 50 and an external device.

[0025] The ROM 102 stores the programs executed by the CPU 101 and other data.

[0026] The S-RAM 103 serves as a work area when the CPU 101 executes a program, and temporarily stores programs, data when executing programs, and the like.

[0027] 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 unit 54, data of various screens displayed on the display unit 54, and the like.

[0028] The clock IC 105 measures time and functions as an internal timer to measure processing time and the like.

[0029] The storage device 110 consists of a hard disk or the like and stores programs and various data. Particularly in this embodiment, it accumulates the detection results of the physical property values of the sheet by the optical sensor 91 and the ultrasonic sensor 92, the discrimination results of the sheet type, and further the detection history and the like.

[0030] The image reading device 120 includes a scanner or the like, reads a document set on the platen glass by scanning, and converts the read document into image data.

[0031] The operation panel unit 50 is used when a user gives instructions such as jobs to the image forming apparatus 1 or makes various settings, and includes a reset key 51, a start key 52, a stop key 53, a display unit 54, a touch panel 55, and the like.

[0032] The reset key 51 is used to reset settings, the start key 52 is used for start operations such as scanning, and the stop key 53 is pressed when interrupting operations.

[0033] The display unit 54 is composed of, for example, a liquid crystal display device and outputs and displays messages and various operation screens. The touch panel 55 is formed on the screen of the display unit 54 and detects the touch operations of the user.

[0034] The image forming unit 10 prints a copy image generated from the image data of the document read by the image reading device 120 or the print data transmitted from an external terminal device 3 or the like onto a sheet, and includes a printing engine 18 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, and a fixing unit 19 that heats and presses the sheet on which the image is formed to fix the image.

[0035] The network I / F 160 functions as a communication means for transmitting and receiving data between an external device, such as an external server, a cloud system, a printer driver of a user's information terminal device, and other image forming apparatuses, via the network 4.

[0036] FIG. 5 is a block diagram for explaining the functional configuration of the control unit 100. Functionally, the control unit 100 includes a media detection control unit 100a, a sheet type detection control unit 100b, an image formation control unit 100c, a storage unit 100d, an external communication control unit 100e, and a conveyance control unit 100f.

[0037] The media detection control unit 100a operates the optical sensor 91 and the ultrasonic sensor 92, which are media detection sensors, in the first detection mode and the second detection mode described later to detect the physical properties of the sheet, etc. The sheet type detection control unit 100b detects the sheet type, which is sheet information, based on the detection results of the optical sensor 91 and the ultrasonic sensor 92.

[0038] The image formation control unit 100c controls the image forming unit 10 under the image formation conditions corresponding to each sheet type based on the sheet type detected by the sheet type detection control unit 100b, and prints an image on the sheet.

[0039] The storage unit 100d temporarily stores the detection results of the physical property values of the sheet by the optical sensor 91 and the ultrasonic sensor 92, the detection results of the sheet type by the sheet type detection control unit 100b, the detection history, etc. The information stored in the storage unit 100d is transferred to the storage device 110 in FIG. 4 and accumulated and updated.

[0040] The external communication control unit 100e corresponds to the network I / F 160 in FIG. 2, and performs data transmission and reception with an external device 3 composed of a terminal device, an external server, or another image forming apparatus, etc.

[0041] The conveyance control unit 100f controls the paper feed and conveyance of the sheet.

[0042] Next, the operation of the image forming apparatus 1 will be mainly described based on the control by the control unit 100.

[0043] In this embodiment, the control unit 100 causes the physical property value detection and the sheet type detection by the optical sensor 91 and the ultrasonic sensor 92 to be performed on the sheet conveyed through the sheet conveyance path 8 in the first detection mode and the second detection mode.

[0044] The first detection mode is implemented for the sheet conveyed first. The sheet conveyed first may be the sheet conveyed first after opening the first paper feed tray 60a and the second paper feed tray 60b (removing the first paper feed tray 60a and the second paper feed tray 60b), performing sheet replacement, replenishment, addition, etc., and then closing the first paper feed tray 60a and the second paper feed tray 60b (inserting the first paper feed tray 60a and the second paper feed tray 60b). Alternatively, in the case of the manual feed tray, it may be the first sheet conveyed after the detection of the presence or absence of the sheet changes from no to yes, that is, after the manual feed tray is closed. Alternatively, it may be the first sheet conveyed from the paper feed port without sheet type information due to the reset of the sheet type information by turning off / on the power of the image forming apparatus 1, waking up from sleep, etc., or it may be the first sheet conveyed from the paper feed port when the media detection function changes from OFF to ON. Alternatively, it may be the first sheet conveyed for the first sheet of the print job.

[0045] The paper feed performance affects the basis weight of the sheet and the paper feed speed. Generally, as the basis weight increases, the paper feed performance deteriorates, so the conveyance speed is reduced to stabilize the paper feed performance. Fig. 6 shows the relationship between the sheet type and the conveyance speed. The paper feed speed shown in Fig. 6 is the conveyance speed of the sheet conveyed to the skew correction roller 72, and the process speed is the conveyance speed of the sheet during image formation. Fig. 7 shows the relationship between the sheet type and the basis weight.

[0046] Since the information regarding the first sheet detected in the first detection mode is uncertain, in the first detection mode, conveyance is performed at a low conveyance speed (paper feed speed) up to the skew correction roller 72. Specifically, it is conveyed at a paper feed speed preset in advance as a paper feed speed capable of feeding a relatively thick recording medium (for example, the paper feed speed of 150 mm / s for thick paper 3). Also, it is advisable to increase the number of sensor readings within the sheet surface for detailed detection to improve the accuracy. Downstream of the skew correction roller 72, it may be conveyed at the conveyance speed (process speed) corresponding to the sheet information detected for the sheet. For example, if it is detected that the sheet type is plain paper, it may be conveyed at the conveyance speed of plain paper.

[0047] For the image formation of the first sheet, the fixing temperature and the transfer voltage are determined according to the detected sheet information (image formation conditions), and the image formation is performed.

[0048] For the sheets after the first sheet, printing is executed by selecting an appropriate conveyance speed corresponding to the sheet information detected for the first sheet.

[0049] On the other hand, the second detection mode is a mode in which sheet information is detected for sheets other than the first sheet between the determination of the first sheet information in the first detection mode and the opening of the first paper feed tray 60a, the second paper feed tray 60b, or the manual feed tray. The detection in the second detection mode may be performed for all sheets other than the first sheet, or may be performed for every plurality of sheets, for example, every other sheet or every five sheets, or may be performed at the beginning and the end of the job excluding the first sheet.

[0050] In the second detection mode, the conveyance speed corresponds to the sheet information determined by the detection in the first detection mode. Therefore, depending on the sheet type, the conveyance speed becomes faster than in the first detection mode, so the time from when the sheet reaches each media detection sensor 91, 92 until it reaches the skew correction roller 72 becomes shorter, and thus the detection time also becomes shorter than in the first detection mode.

[0051] FIG. 8 and FIG. 9 show different sequence examples for the first detection mode and the second detection mode. In FIGS. 8 and 9, for example, after the insertion and removal (opening and closing) of the first paper feed tray 60a as indicated by the signal of "cassette operation", four print jobs (1) to (4) each consisting of 4 sheets are executed as indicated by the signal of "print job".

[0052] In both FIG. 8 and FIG. 9, in the first detection mode, detection is performed on the sheet fed and conveyed from the first paper feed tray 60a for the first sheet after the insertion and removal (opening and closing) of the first paper feed tray 60a, in other words, the first sheet of the print job (1).

[0053] On the other hand, for the second detection mode, in FIG. 8, detection is performed for all sheets except the first sheet, and in FIG. 9, detection is performed for the last sheet of each job. Also, in FIG. 8, it is shown that the change of sheet information (change of sheet information) was detected by the detection of the third sheet of the print job (3) (the 11th sheet counted from after the paper feed cassette is opened and closed), and in FIG. 9, it is shown that the change of sheet information was detected by the detection of the last sheet of the print job (3). By such detection, it is possible to detect that different types of sheets have been added in the same paper feed cassette.

[0054] In the examples of FIGS. 8 and 9, detection in the first detection mode is also performed for the first sheet of the first job (print job (4)) after the change of sheet information is detected.

[0055] The image forming apparatus 1 is configured to be able to implement both FIGS. 8 and 9 as the second detection mode, and either one may be selected according to the performance of the image forming apparatus 1 and the type of sheet to be conveyed. For example, when the processing performance of the image forming apparatus 1 is low and the conveyance speed of the sheet is high, various controls during printing may not be in time for detection of each sheet. Therefore, the physical property values and the sheet type may be detected only for the last sheet of the job as shown in FIG. 9 to reduce the control load. Also, detection may be performed not only for the last sheet of the job but also at predetermined intervals such as every two or three sheets.

[0056] Also, in this embodiment, whether or not to perform the second detection mode described above can be set by the user through the operation of the operation panel unit 50. Depending on the user, there may be a case where, during booklet printing, the cover sheet and the inner sheets are placed in the same paper feed cassette for printing. For such an image forming apparatus or paper feed cassette that is used in this way, it is necessary to provide a mechanism that does not inadvertently cause a change in the sheet type. When the setting not to perform the second detection mode is made, only the first detection mode is implemented.

[0057] In this embodiment, the sheet information detected by the media detection sensors 91 and 92 is the physical property value or sheet type of the sheet. The physical property value may include at least one of the transmittance information, reflectance information, stiffness information, thickness information, basis weight information, size information, grain direction information, color information, moisture information, smoothness information, resistance information, friction information, and sheet composition information of the sheet. The sheet composition information includes at least one of pulp material, coating agent, fluorescent agent, and filler.

[0058] The table shown in FIG. 10 summarizes the sheet information for each detection means for acquisition. For example, from the optical sensor 91, information on the sheet type, transmittance, reflectance, basis weight, coating agent, fluorescent agent, filler, color information, and pulp material determined from the optical characteristics can be obtained, and from the ultrasonic sensor 92, information on the sheet type can be obtained. Also, by measuring the displacement amount of the sheet conveyance roller with a displacement sensor, information on stiffness and sheet thickness can be obtained, information on the paper size can be obtained from the paper regulating plate position sensors of the paper feed cassettes 90a and 90b, and information on the grain direction, color, smoothness, and pulp material of the paper can be obtained from the sensor using CMOS, and information on moisture and basis weight can be obtained from the electrostatic sensor, and resistance can be obtained by detecting the transfer current.

[0059] Regarding the sheet type, by setting a threshold value for the physical property value of the detection target, for example, the transmittance, it can be determined as a different physical property value, and the sheet type from thin paper to thick paper can be detected. Also, as the sheet, those composed of at least any one of pulp material, resin material, and textile material, envelopes composed of at least any one of pulp material, resin material, and textile material, and / or overhead projectors (OHP) etc. are included.

[0060] Whether the sheet information has changed can be determined, for example, by whether the physical property value of the sheet has changed by 10% or more, or whether the sheet type itself has changed. This change rate of 10% is a value that cannot be realized for sheets of the same sheet type from the same paper feed port, but the threshold value of the change rate may be changed depending on the physical property value.

[0061] The control unit 100 of the image forming apparatus 1 controls the execution of the first detection mode and the second detection mode, and performs the following control based on the detected results.

[0062] That is, regarding the conveyance speed of the sheet, as described above, the conveyance speed corresponding to the sheet information detected in the first detection mode is applied to convey the sheet after the first sheet. Further, when the sheet information detected in the second detection mode is different from the sheet information detected in the first detection mode, that is, when a change in the sheet information is detected, even if it is printing of the same job, the conveyance speed corresponding to the sheet information detected in the first detection mode is maintained without changing the conveyance speed. By maintaining the conveyance speed, productivity can be maintained without causing a decrease in the conveyance speed or a conveyance stop. Note that the determination as to whether the sheet information detected in the second detection mode is different from the sheet information detected in the first detection mode may be made by directly comparing the sheet information detected in the second detection mode with the sheet information detected in the first detection mode. Alternatively, when the second detection mode has already been performed, it may be indirectly determined by comparison with the result of the already performed second detection mode.

[0063] However, for the process conditions, the image forming conditions corresponding to the sheet information after the change are adopted. For example, when the sheet type is switched from plain paper to thick paper 2, the conveyance speed is maintained at the conveyance speed of plain paper, and the process conditions of thick paper 2 are adopted as the process conditions.

[0064] FIG. 11 shows the relationship between the conveyance speed (process speed) before and after the change of the sheet type and the process conditions (here, the fixing temperature and the transfer voltage). In the above example, when switching from plain paper to thick paper 2, the process speed is maintained at 300 mm / s, but the fixing temperature is changed from 180°C to 230°C, and the transfer voltage is changed from 1400 V to 1900 V.

[0065] In this way, even if a change in sheet information is detected, the conveyance speed of the sheet is maintained, and the process conditions are changed to the optimal conditions for the sheet after the change. Thus, even if the conveyance speed is not optimal, it is possible to prevent a decrease in productivity and a decrease in image quality.

[0066] For the sheet conveyed first in the next job after the change in sheet information is detected, it is carried out as the detection of the first sheet by the first detection mode. In this case, the sheet conveyance speed may be the low-speed conveyance speed when the sheet information is undetermined. However, until the skew correction roller 72, it is conveyed at the conveyance speed of the sheet before the change detection in the previous job, and it may be conveyed downstream of the skew correction roller 72 at the conveyance speed corresponding to the sheet information detected during that time.

[0067] Also, even when it is detected that the sheet information after the first sheet is different from the sheet information of the first sheet, for example, when it is determined that the paper is switched from plain paper to recycled paper, if there is no change in the image formation conditions, the second detection mode may be carried out for the sheet conveyed first in the next job.

[0068] Also, in the sequence example of FIG. 8, if the original sheet information before the change is detected for the fourth sheet after the change in sheet information is detected in the third sheet of the print job (3), there may be a possibility that different types of sheets are mixed in the third sheet. In this case, it is determined whether there is a change in sheet information in the last sheet of the job, and it is determined that there is no change. Then, for the next print job (4), the detection operation is performed in the second detection mode from the first sheet.

[0069] Also, when the job is a job that performs staple processing as post-processing in the post-processing device, and a change in sheet information is detected during this staple job, while maintaining the conveyance speed, the conditions corresponding to the sheet information after the change are reflected in the control conditions and prohibited conditions of the post-processing device. For example, when the sheet type changes from plain paper to thick paper 2, without changing the conveyance speed, the number of stapled sheets is changed from 50 to 30, or the sheet alignment operation is performed under the conditions of thick paper 2.

[0070] Furthermore, when the control unit 100 of the image forming apparatus 1 detects a change in the sheet information as a result of detection in the second detection mode, the control unit 100 stores at least any one of the sheet information after the change, the sheet information before and after the change, or the presence or absence of the change in the storage unit 100d. Desirably, these pieces of information are stored in association with the information of the paper feed ports 8a, 8b, 8c or the first and second paper feed trays 60a, 60b, and the manual feed tray. Then, when a sheet is conveyed from the paper feed ports 8a, 8b, 8c associated with the information indicating that there is a change (switching) in the sheet information, it is desirable that the first detection mode is applied to the first sheet.

[0071] Furthermore, at least any one of the sheet information after the change, the sheet information before and after the change, or the presence or absence of the change when there is a change in the sheet information is displayed on the display unit 54 of the operation panel unit 50 to notify the user, or transmitted to an external device 3 such as a cloud server or the user's terminal device, or an irregular or periodic access from the external device is received, and these pieces of information are shared with the external device.

[0072] FIG. 12 is a flowchart for explaining the print process performed by the image forming apparatus 1. This print process 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 a storage unit such as the ROM 102.

[0073] Start the first sheet feeding in step S01. In step S02, determine whether it is the execution timing of the first detection mode. If it is the execution timing of the first detection mode (YES in step S02), proceed to step S03 and convey the sheet at the conveyance speed in the first detection mode.

[0074] Next, in step S04, perform media detection in the first detection mode to detect sheet information. In step S05, determine the sheet type based on the detected sheet information.

[0075] In step S06, convey the sheet at a conveyance speed corresponding to the sheet type. That is, if the conveyance speed in step S03 does not correspond to the sheet type, switch to the corresponding conveyance speed and convey. If the conveyance speed in step S03 corresponds to the sheet type, convey at that conveyance speed. Then proceed to step S13.

[0076] If it is not the execution timing of the first detection mode in step S02 (NO in step S02), in step S07, convey the sheet at a conveyance speed corresponding to the sheet type detected in the first detection mode (the sheet type determined in step S05).

[0077] Next, in step S07, determine whether it is the execution timing of the second detection mode. If it is the execution timing of the second detection mode (YES in step S08), in step S09, perform media detection in the second detection mode to detect sheet information. In step S10, determine the sheet type based on the detected sheet information. Then, in step S11, determine whether the sheet type is different from the sheet type detected in the first detection mode. Note that by determining whether it is different from the sheet type detected in the previous second detection mode, it is also possible to indirectly determine whether it is different from the sheet type detected in the first detection mode.

[0078] If it is different (YES in step S11), in step S12, maintain the conveyance speed and proceed to step S13. If it is not different (NO in step S10), proceed directly to step S13.

[0079] Even when it is not the execution timing of the second detection mode in step S08 (NO in step S08), the process proceeds to step S13.

[0080] In step S13, after forming an image under process conditions corresponding to the sheet type detected in the first detection mode or the second detection mode, in step S13, it is determined whether the print job has ended. If not (NO in step S14), the process returns to step S02 to feed the next sheet, and then the operations from step S02 to step S14 are repeated. If the print job has ended (YES in step S14), this process ends.

[0081] Note that in steps S05 and S10, the sheet type is determined, but it is also possible to determine the presence or absence of a change in the sheet based on physical property values.

Explanation of Signs

[0082] 1 Image forming apparatus 3 External device 4 Network 10 Image forming unit 50 Operation panel unit 54 Display unit 60 Sheet feeding unit 60a First sheet feeding tray (first-stage sheet feeding cassette) 60b Second sheet feeding tray (first-stage sheet feeding cassette) 71a, 71b Conveyor rollers (sheet conveyance unit) 72 Skew correction roller 91 Optical sensor (recording medium detection unit) 91a, 91b Light sources 91c Light receiving detection element 92 Ultrasonic sensor (recording medium detection unit) 91a Ultrasonic transmitter 91b Ultrasonic receiver 100 Control unit 100a Media detection control unit 100b Sheet type detection control unit (recording medium detection unit) 100c Image formation control unit 100d Memory unit 100e External communication control unit 100f Edge processing unit 110 Memory device

Claims

1. A conveying unit that conveys a recording medium, A recording medium detection unit that acquires information regarding the recording medium in order to set image formation conditions for forming an image on the recording medium, A control unit that, when the first information regarding the first recording medium acquired for the first recording medium conveyed by the conveying unit in a job and the second information regarding the second recording medium acquired for the second recording medium conveyed after the first recording medium are different information, controls so that the second recording medium is continuously conveyed while maintaining the conveyance speed during the job of forming an image on the second recording medium, The control unit conveys the first recording medium at a first conveyance speed determined in advance when detecting information regarding the first recording medium, and after detecting the information regarding the first recording medium, conveys the recording medium after the first recording medium at a second conveyance speed based on the information regarding the first recording medium and executes image formation under the image formation conditions based on the first information, When the recording medium detection unit detects information regarding a recording medium different from the first recording medium in the second recording medium, the recording medium detection unit is made to perform detection at the first conveyance speed on the recording medium conveyed first in the next job of the job in which it is determined that the information regarding the recording medium is different, and executes image formation under the image formation conditions based on the first information, An image forming apparatus characterized by the above.

2. The control unit causes the recording medium detection unit to detect information regarding the plurality of recording media conveyed by the conveying unit. The image forming apparatus according to claim 1.

3. The information regarding the recording medium is information corresponding to the physical property value of the recording medium or the type of the recording medium. The image forming apparatus according to claim 1.

4. The image forming apparatus according to claim 3, wherein different threshold values are set for the physical property values, and when the threshold values are exceeded, it is determined that the physical property values are different.

5. The type of the recording medium is determined based on the physical property value. The image forming apparatus according to claim 3 or 4.

6. The recording medium includes an envelope made of at least any one of a pulp material, a resin material, and a textile material, and / or an OHP. The image forming apparatus according to claim 1.

7. The image forming apparatus according to claim 1, wherein when there is a change in the information regarding the recording medium detected by the recording medium detection unit, the control unit changes the image forming conditions other than the conveyance speed by the conveyance unit.

8. The image forming apparatus according to claim 1, wherein when there is a change in the information regarding the recording medium detected by the recording medium detection unit, the control unit reflects the change in the control conditions and prohibited conditions of the post-processing device.

9. The image forming apparatus according to claim 1, wherein when there is a change in the information regarding the recording medium detected by the recording medium detection unit, the control unit causes the storage unit to store at least any one of the information regarding the recording medium after the change, the information regarding the recording medium before and after the change, and the presence or absence of the change.

10. The image forming apparatus according to claim 9, wherein when it is stored in the storage unit that there has been a change in the information regarding the recording medium, the control unit causes the recording medium detection unit to perform detection on the first recording medium of the next job of the job in which the change has occurred at the first conveyance speed.

11. The image forming apparatus according to claim 1, wherein the control unit causes the recording medium detection unit to perform detection on at least any one of all the recording media after the first recording medium, for each arbitrary number of sheets, or the last recording medium of the job, for the second recording medium.

12. The image forming apparatus according to claim 1, wherein the conveyance unit conveys the first recording medium at a paper feed speed preset as a paper feed speed capable of feeding a thicker recording medium.

13. The image forming apparatus according to claim 1, wherein the control unit makes a determination as to whether the information regarding the second recording medium is different from the information regarding the first recording medium based on the change rate from the physical property value of the first recording medium or the difference in the type of recording medium.

14. When detecting the information regarding the first recording medium, the control unit conveys the first recording medium at a first conveyance speed determined in advance. After detecting the information regarding the first recording medium, the control unit conveys the recording media after the first recording medium at a second conveyance speed based on the information regarding the first recording medium. Even when it is detected that the information regarding the second recording medium is different from the information regarding the first recording medium, and when there is no change in the image forming conditions, the control unit causes the recording medium detection unit to convey the recording medium conveyed first in the next job at the second conveyance speed.

15. The image forming apparatus according to claim 1, wherein it is possible to set from an operation unit whether or not to detect information regarding the second recording medium.

16. The image forming apparatus according to claim 1, wherein when it is detected that the information regarding the second recording medium is different from the information regarding the first recording medium, the information regarding the detected recording medium is notified or shared with an external device.

17. The image forming apparatus according to claim 1, wherein the second recording medium for which it is detected whether it is different from the information regarding the first recording medium is the final recording medium of a job.

18. A conveying step of conveying a recording medium, A recording medium detection step of detecting information regarding a recording medium in order to set image forming conditions for forming an image on the recording medium, In a job, when detecting information regarding a first recording medium, the first recording medium is conveyed at a first conveyance speed determined in advance, and after detecting the information regarding the first recording medium, the first recording medium and subsequent recording media are conveyed at a second conveyance speed based on the information regarding the first recording medium, and image formation is executed under image forming conditions based on the first information regarding the first recording medium detected in the recording medium detection step, a first control step; A second control step of controlling so that the second recording medium is continuously conveyed while maintaining the conveyance speed during the job of forming an image on the second recording medium when the first information and the second information regarding the second recording medium detected for the second recording medium conveyed after the first recording medium are different information; A third control step of causing detection to be performed at the first conveyance speed on the recording medium conveyed first in the next job of a job for which it is determined that the information regarding the recording medium is different, and executing image formation under image forming conditions based on the first information; An image forming method including the above.

Images