JP6020075B2 - Printing device - Google Patents

Description

  The present invention relates to a printing apparatus that prints an image on a sheet. More specifically, the present invention relates to a technique for detecting a change in the open / close state of a storage unit that stores sheets fed into the apparatus.

  2. Description of the Related Art Conventionally, as a technique related to a printing apparatus, a technique for detecting opening / closing of a storage unit that stores sheets fed into the apparatus has been proposed. For example, Patent Document 1 discloses a sheet feeding device including a plurality of storage units and a tray set sensor corresponding to each storage unit. Further, in Patent Document 1, after the storage unit is pulled out and opened, the tray set sensor corresponding to the storage unit detects that the storage unit has been returned to its original state and closed. Discloses that the storage unit is moved to a position where paper can be fed.

JP-A 62-65846

  However, the conventional technique described above has the following problems. That is, in the conventional printing apparatus, a dedicated sensor is provided in each storage unit in order to detect a change in the open / close state of the sheet storage unit. For this reason, there is room for improvement because the number of parts is large and the device configuration is complicated.

  The present invention has been made to solve the problems of the conventional printing apparatus described above. That is, an object of the present invention is to provide a printing apparatus capable of recognizing a change in the open / closed state of a sheet storage unit with a configuration having a small number of parts.

  In order to solve this problem, a printing apparatus includes a printing unit that prints an image on a sheet, a storage unit that stores the sheet, and a sheet feeding unit that feeds the sheet stored in the storage unit into the conveyance path. When the sheet is placed in the storage unit and the storage unit changes from the open state to the closed state, the sheet supply unit is in a non-feeding position where the sheet cannot be fed. A loading mechanism, a moving mechanism for moving the mounting plate from the non-feeding position to a sheet feeding position capable of feeding a sheet at the sheet feeding unit, and the presence or absence of a sheet. A detection unit that detects sheet conveyance control, a measurement unit that measures a conveyance time T from the start of sheet conveyance control until the detection unit detects a change in the presence or absence of a sheet, and the mounting plate described above at the sheet feeding position. After the sheet is fed by the sheet feeding unit in a certain state, the sheet is detected by the detection unit. A determination unit that determines that there is a change in the open / close state of the storage unit when the transport time β until reaching the device and the transport time T measured by the measurement unit satisfy a relationship of T> β; It is characterized by having.

  The printing apparatus disclosed in the present specification includes a placement plate on which a sheet is placed in a storage unit, and a moving mechanism that moves the placement plate. The mounting plate is in the non-feeding position when the storage unit changes from the open state to the closed state. The mounting plate is moved from the non-feeding position to the feeding position by the moving mechanism. Furthermore, the conveyance time β from when the sheet is fed by the sheet feeding unit to the detection position and the conveyance time from when the sheet conveyance control is started until the detection unit detects a change in the presence or absence of the sheet. When T satisfies the relationship of T> β, it is determined that the open / close state of the storage unit has changed. The closed state of the storage unit is a state set in the apparatus, and the open state is a state of not being set in the apparatus. The timing at which the mounting plate moves from the paper feeding position to the non-paper feeding position corresponds to, for example, the time when the storage unit changes from the closed state to the open state. Further, the transport time β may be stored in advance or may be acquired from an external device such as a server. The conveyance time β may be an actual measurement value measured in a test before shipment, or may be a design value calculated based on a movement speed and a movement distance.

  That is, in the printing apparatus disclosed in this specification, if the open / close state of the storage unit is not changed, the mounting plate is in the paper feeding position, and the time for moving the mounting plate is hardly included in the transport time T. . Therefore, the conveyance time T is substantially equal to the conveyance time β. On the other hand, if there is a change in the open / closed state of the storage unit, the mounting plate is in the non-feeding position, and the transfer time T includes the moving time for moving the mounting plate to the feeding position by the moving mechanism. For this reason, the transport time T becomes large and satisfies the above relationship. Therefore, according to this configuration, it is possible to recognize a change in the open / close state of the storage unit without a sensor for detecting a change in the open / close state of the storage unit.

  In addition, the determination unit includes a minimum movement time α required for the movement of the mounting plate from the non-feeding position to the feeding position by the moving mechanism, the transfer time β, and the transfer time T. When the relationship of T ≧ α + β is satisfied, it may be determined that there is a change in the open / close state of the storage unit. By considering the minimum movement time α, it is possible to more accurately recognize the change in the open / close state of the storage unit. This minimum movement time α may be stored in advance or may be acquired from an external device such as a server. The minimum movement time α may be an actual measurement value measured in a test before shipment, or may be a design value calculated from a movement speed and a movement distance.

  The minimum moving time α may be different depending on at least one of the capacity of the storage unit, the type of sheet, the temperature in the apparatus, and the humidity in the apparatus. The minimum movement time α may vary for each element listed. Therefore, it is possible to detect the open / close state of the storage unit more accurately by preparing the minimum movement time α for each of these elements, selecting the minimum movement time α suitable for the current situation, and applying it to the determination of the determination unit.

  The conveyance time β may be different according to at least one of the storage unit, the sheet type, the consumption level of the sheet feeding unit, the temperature in the apparatus, and the humidity in the apparatus. The conveyance time β may vary for each element listed. Therefore, the opening / closing state of the storage unit can be detected more accurately by preparing the transport time β for each of these elements, selecting the transport time β suitable for the current situation, and applying it to the determination of the determination unit.

  Further, the printing device disclosed in this specification includes an acquisition unit that acquires a size in the conveyance direction of the sheet based on the timing at which the detection unit detects a change in the presence or absence of the sheet, and the acquisition unit acquires A storage unit for storing the recorded size and a determination unit for determining whether or not to perform printing on the sheet, and the detection unit is located upstream of the printing unit in the sheet conveyance direction, and the printing unit The unit prints an image on the sheet when it is determined that the determination unit performs printing, and the determination unit determines (1) that the determination unit has changed the open / close state of the storage unit. (2) When the two conditions that the sheet size of the previous sheet conveyance stored in the storage unit and the sheet size set in the print data match are satisfied In addition, it is good to judge that you want to printIf there is no change in the open / close state of the storage unit, it can be estimated that a sheet having the same size as that acquired at the previous sheet conveyance is conveyed. For this reason, if the size set in the print data matches the previously acquired size, it is estimated that there is a high possibility of printing on a sheet of the target size. Therefore, it is preferable to print.

  In addition, the determination unit determines whether the determination unit has determined that the open / close state of the storage unit has changed, the size of the sheet at the time of the previous sheet conveyance stored in the storage unit, and the printing If the sheet size set in the data does not match, it may be determined not to print. If the size of the sheet at the previous sheet conveyance and the size of the sheet set in the print data do not match even though the storage unit is not opened and closed, there is a possibility that printing cannot be performed on a sheet of the target size. Therefore, it is preferable not to print.

  In addition, the determination unit determines that the size of the sheet at the time of the previous sheet conveyance stored in the storage unit is not printed when the determination unit does not determine that the open / close state of the storage unit has changed. If the sheet size is larger than the sheet size set in the data, printing is performed. If the sheet size stored in the storage unit at the previous sheet conveyance is smaller than the sheet size set in the print data, It may be determined that printing is not performed. If the size of the sheet set in the print data is larger than the size of the sheet at the previous sheet conveyance, it is estimated that the image does not protrude and can be printed on the sheet. Therefore, it may be printed.

  Further, the printing apparatus disclosed in the present specification notifies that the sheet stored in the storage unit or the print data is changed when the determination unit determines not to perform printing. A sheet change notification unit may be provided. By changing the sheet or the print data, it can be expected that the reason why it is determined not to perform printing is solved and printing is possible. Therefore, it is preferable to notify the user of the aforementioned change.

  The determination unit may determine to perform printing when the determination unit determines that the open / close state of the storage unit has changed. If there is a change in the open / close state of the storage unit, there is a possibility that the sheet stored in the storage unit has been replaced with another sheet, and the reliability of the size acquired at the previous sheet conveyance is low. Therefore, it is preferable to print in order to prevent a print avoidance determination due to erroneous recognition of the sheet size.

  Further, the printing device disclosed in this specification includes the size acquired by the acquisition unit and the sheet set in the storage unit that stores the sheet that is the acquisition target by the acquisition unit. A discrepancy notifying unit may be provided for notifying that the size of the sheet stored in the storage unit matches the size set in the storage unit when the sizes do not match. If the size acquired by the acquisition unit does not match the size of the sheet set in the storage unit, for example, when the sheet stored in the storage unit is changed, the setting of the storage unit is changed. It may not have been done. By notifying the mismatch, it can be expected that the size set in the storage unit matches the size of the sheet actually stored.

  Further, the sheet size stored in the storage unit is erased at least when the power is turned off or no sheet is detected during printing, and the determination unit stores the sheet size in the storage unit. If not, it is better to decide to print. When the power is turned off, there is a possibility that the sheet stored in the storage unit during the power-off is replaced with another sheet. Alternatively, when it is detected that there is no sheet during printing, there is a possibility that the sheet is replaced with another sheet when the sheet is stored in the storage unit. That is, in these cases, the reliability of the size acquired during the previous sheet conveyance is low. Therefore, it is preferable to print in order to prevent a print avoidance determination due to erroneous recognition of the sheet size. The size acquired during the previous sheet conveyance is preferably used only when the storage unit is not opened or closed.

  According to the present invention, a printing apparatus capable of recognizing a change in the open / close state of a sheet storage unit with a configuration having a small number of parts is realized.

1 is a perspective view showing a printer according to an embodiment. FIG. 2 is a schematic configuration diagram illustrating an internal configuration of a printer. It is explanatory drawing which shows the paper feed cassette in which a mounting board exists in a non-paper feed position. It is explanatory drawing which shows the paper feed cassette in which a mounting board exists in a paper feed position. FIG. 2 is a block diagram illustrating an electrical configuration of a printer. It is a flowchart which shows the procedure of a printing process. It is a flowchart which shows the procedure of an open / close determination process. It is explanatory drawing which shows the conveyance time T. FIG. It is explanatory drawing which shows the example of the database of minimum movement time (alpha) and conveyance time (beta). It is a flowchart which shows the procedure of a sheet size confirmation process.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of a printing apparatus according to the invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to an electrophotographic color printer.

[Entire printer configuration]
As shown in FIG. 1, the printer 100 according to the embodiment includes an image forming unit 10 that forms an image on a sheet, and an operation panel 40 that is positioned on the upper surface of the image forming unit 10. The operation panel 40 includes a display unit 41 including a liquid crystal display and a button group 42 including a start key, a stop key, a numeric keypad, and the like. With this operation panel 40, the printer 100 can display an operation status and can be input by a user. The printer 100 is an example of a printing apparatus.

  A sheet before printing is placed on the bottom of the printer 100, and a paper feed cassette 91 that can be detached from the printer 100 main body is set. On the upper surface of the printer 100, a paper discharge tray 96 for placing printed sheets is provided. The printer 100 prints an image on the sheet stored in the paper feed cassette 91 by the image forming unit 10, and discharges the printed sheet to the paper discharge tray 96.

  The paper feed cassette 91 can be in either an open state or a closed state. The closed state is the arrangement shown in FIG. 1 and is a state in which the paper feed cassette 91 is correctly set in the printer 100. When the paper feed cassette 91 is pulled out from the front side of the printer 100, the paper feed cassette 91 is opened. When printing with the printer 100, the paper feed cassette 91 is closed. When the paper feed cassette 91 is in the open state, the printer 100 cannot feed paper from the paper feed cassette 91 for printing. The paper feed cassette 91 is an example of a storage unit.

[Internal configuration of printer]
As shown in FIG. 2, the image forming unit 10 forms a toner image, transfers the toner image to a sheet, a process unit 50, a fixing unit 8 that fixes unfixed toner on the sheet, and a paper feed cassette. 91 and a paper discharge tray 96 are provided. The process unit 50 is an example of a printing unit.

  Further, in the image forming unit 10, a conveyance path 11 for conveying a sheet stored in a sheet feeding cassette 91 located at the bottom is provided. The sheet is guided along the conveyance path 11 to the upper discharge tray 96 through the sheet supply roller 71, the registration roller 74, the process unit 50, and the fixing unit 8 and through the discharge roller 77. In FIG. 2, the conveyance path 11 is indicated by a one-dot chain line. The paper feed roller 71 is an example of a paper feed unit.

  The process unit 50 can form a color image, and the components corresponding to the colors of yellow (Y), magenta (M), cyan (C), and black (K) are arranged in parallel. The process unit 50 forms a toner image by a known electrophotographic method. Further, the image forming unit 10 includes a conveyance belt 7 that is stretched by rollers 75 and 76 and conveys the sheet to the transfer position of the process unit 50.

  The image forming unit 10 takes out the sheets placed in the sheet feeding cassette 91 one by one by the sheet feeding roller 71 and conveys the sheets to the process unit 50. In the conveyance path 11, a sheet sensor 72 is provided at a position downstream from the paper feed roller 71 and upstream from the registration roller 74. The sheet sensor 72 detects the presence or absence of a sheet at the detection position. When the leading edge of the sheet fed by the sheet feeding roller 71 reaches the detection position of the sheet sensor 72, the sheet sensor 72 changes the presence / absence of a sheet, specifically, the change from absence of a sheet to presence of a sheet. To detect. When the trailing edge of the sheet being conveyed reaches the detection position of the sheet sensor 72, the sheet sensor 72 detects a change in the presence or absence of a sheet, specifically, a change from presence of a sheet to absence of a sheet. The sheet sensor 72 is an example of a detection unit.

  Then, the image forming unit 10 transfers the toner image formed by the process unit 50 onto a sheet conveyed by the conveyance belt 7. Further, the sheet on which the toner image is transferred is conveyed to the fixing unit 8 and the toner image is thermally fixed to the sheet. Then, the sheet after fixing is discharged to a paper discharge tray 96.

[Internal configuration of paper cassette]
As shown in FIGS. 3 and 4, a mounting plate 92 is provided at the bottom inside the paper feed cassette 91. A sheet bundle B in which a plurality of sheets are stacked is stored on the mounting plate 92. At least the end portion of the mounting plate 92 on the side close to the paper feed roller 71 moves in the vertical direction. The mounting plate 92 moves between the non-feeding position shown in FIG. 3 and the feeding position shown in FIG.

  For example, as shown in FIG. 3, the non-paper feeding position is an arrangement in which at least an end portion of the mounting plate 92 near the paper feeding roller 71 is lowered to the bottom of the paper feeding cassette 91. When the placing plate 92 is in the non-feeding position, the sheets in the sheet bundle B and the feeding roller 71 are not in contact with each other. Therefore, at the non-feeding position, the sheet cannot be taken out to the conveyance path 11 even if the feeding roller 71 is rotated. Even when the maximum number of sheets that can be stored in the sheet feeding cassette 91 is stored, the sheets in the sheet bundle B and the sheet feeding roller 71 do not come into contact with each other as long as the placement plate 92 is set to the non-sheet feeding position.

  As shown in FIG. 4, the sheet feeding position is an arrangement of the mounting plate 92 in which the end near the sheet feeding roller 71 is closer to the sheet feeding roller 71 than the non-sheet feeding position. The sheet feeding position is, for example, an arrangement in which the uppermost sheet of the sheet bundle B and the sheet feeding roller 71 are in contact with each other. If the sheet feeding roller 71 is rotated while the uppermost sheet of the sheet bundle B is in contact with the sheet feeding roller 71, the uppermost sheet of the sheet bundle B is fed.

  The printer 100 has a moving mechanism 93 that raises the mounting plate 92 of the closed paper feeding cassette 91. For example, a driving force of a driving motor 78 that rotationally drives the paper feed roller 71 is transmitted to the mounting plate 92 via the moving mechanism 93. That is, the drive motor 78 rotates the paper feed roller 71 and raises the mounting plate 92.

  Therefore, when the paper feed cassette 91 is pulled out from the printer 100 and is opened, the drive of the drive motor 78 and the moving mechanism 93 is cut off by a clutch mechanism (not shown). Therefore, the mounting plate 92 is disposed at the non-feeding position. In this state, the user can store sheets in the sheet feeding cassette 91 or exchange sheets. Thereafter, when the paper feed cassette 91 is set in the printer 100, the paper feed cassette 91 is closed, and the drive is coupled so that the driving force of the drive motor 78 can be transmitted to the moving mechanism 93 by a clutch mechanism (not shown). The

  However, the placement plate 92 does not move when the paper feed cassette 91 is simply closed. That is, when the paper feed cassette 91 is once opened and then changed to the closed state, the placement plate 92 is in the non-paper feed position as shown in FIG. The clutch mechanism provided between the drive motor 78 and the moving mechanism 93 is not only a cutting mechanism that cuts the drive when the paper feed cassette 91 is pulled out, but a driving force of a certain level or more is moved from the drive motor 78. A slip clutch mechanism is also provided so as not to be transmitted to the mechanism 93.

  When the paper feed cassette 91 is open, the printer 100 cannot feed paper from the paper feed cassette 91. In the closed state of the paper feed cassette 91, when the printer 100 receives print data for which paper feed is requested from the paper feed cassette 91, it starts sheet conveyance control. In the case of the first sheet feeding after the sheet feeding cassette 91 is changed from the open state to the closed state, the mounting plate 92 is in the non-sheet feeding position. Therefore, the printer 100 rotates the paper feed roller 71 and raises the mounting plate 92 by the drive motor 78. That is, when the conveyance control of the sheet from the sheet feeding cassette 91 is started in a state where the mounting plate 92 is in the non-feeding position, the printer 100 moves the mounting plate 92 upward. When the placing plate 92 is raised and the uppermost sheet of the sheet bundle B comes into contact with the sheet feeding roller 71, the sheet is conveyed. When the reaction force from the paper feed roller 71 reaches a predetermined value, the mounting plate 92 stops rising by a slip clutch mechanism (not shown) of the clutch mechanism.

  After feeding the uppermost sheet of the sheet bundle B, the placement plate 92 is appropriately raised by the drive motor 78 by the thickness of one sheet. Once the mounting plate 92 has been moved to the paper feed position, the drive connection between the drive motor 78 and the moving mechanism 93 is not cut off unless the paper feed cassette 91 is opened. Absent. That is, the printer 100 maintains the mounting plate 92 at the paper feed position even after printing as long as the paper feed cassette 91 remains closed. If the mounting plate 92 is mechanically biased toward the paper feed roller 71 by a spring or the like in addition to the moving mechanism 93, the feeding plate 92 can be fed without being raised one by one. The paper position can be maintained.

[Electrical configuration of printer]
Next, the electrical configuration of the printer 100 will be described. As shown in FIG. 5, the printer 100 includes a control unit 30 that includes a CPU 31, a ROM 32, a RAM 33, and an NVRAM (nonvolatile RAM) 34. The control unit 30 is electrically connected to the image forming unit 10, the operation panel 40, the network interface 37, the sheet sensor 72, the temperature sensor 73, the drive motor 78, and the like. The printer 100 acquires the temperature inside the printer 100 by the temperature sensor 73. The printer 100 may further include a humidity sensor.

  The ROM 32 stores various control programs for controlling the printer 100, various settings, initial values, and the like. The CPU 31 controls each component of the printer 100 according to a control program read from the ROM 32 and a signal sent from the sheet sensor 72 or the like. The CPU 31 is an example of a measurement unit, a determination unit, an acquisition unit, a determination unit, a sheet change notification unit, and a mismatch notification unit.

  The RAM 33 is used as a work area from which various control programs are read or as a storage area for temporarily storing image data. In the RAM 33, for example, previous data that is the size of the sheet acquired based on the detection result of the sheet sensor 72 is stored. The RAM 33 is an example of a storage unit. The NVRAM 34 stores various setting values. In the NVRAM 34, for example, the size of the sheet stored in the paper feed cassette 91 set by the user is stored. The user sets the size of the sheet placed on the paper feed cassette 91 by using the operation panel 40 or the like.

  The network interface 37 is connected to a network such as a LAN, and enables connection to an external device in which a printer driver for the printer 100 is incorporated. The printer 100 can transfer print data via the network interface 37.

[Print processing]
Next, a printing process for executing printing in the printer 100 will be described with reference to the flowchart of FIG. The print processing is executed by the CPU 31 when a print job is received and a printing operation is started in the image forming unit 10.

  When the printing process is started, the CPU 31 first executes an open / close determination process for determining whether or not the paper feed cassette 91 is opened / closed (S101). The open / close determination process executed in S101 will be described with reference to the flowchart of FIG.

[Paper cassette open / close judgment processing]
In the open / close determination process, first, driving by the drive motor 78 is started, and rotation of the paper feed roller 71 is started (S201). The driving force by the drive motor 78 is also transmitted to the mounting plate 92 via the moving mechanism 93, and the lifting of the mounting plate 92 is started (S202). S201 and S202 correspond to the start of sheet conveyance control. Further, a timer is started (S203). This timer is an example of a measurement unit. In order to ensure the accuracy of determination, it is desirable to start S201, S202, and S203 almost simultaneously.

  Subsequently, it is determined whether or not the leading edge of the sheet is detected by the sheet sensor 72 (S204). That is, it is determined whether or not the leading end of the sheet has reached the detection position of the sheet sensor 72. When the sheet has not reached (S204: No), the process waits until the sheet is detected by the sheet sensor 72. If a sheet is detected (S204: Yes), the timer time is acquired (S205). The time acquired in S205 is the conveyance time T.

  Here, the conveyance time T will be described in detail. The conveyance time T is the time from the start of sheet conveyance control until the sheet sensor 72 detects a change in the presence or absence of a sheet. For example, when the sheet conveyance control is started, the conveyance time T when the placement plate 92 is in the non-feeding position is the sum of the movement time T1 and the conveyance time T2, as shown in FIG. .

  FIG. 8A shows a point in time when sheet conveyance control is started, and the paper feed roller 71 is rotated. Next, the mounting plate 92 is lifted up and moved to the paper feeding position shown in FIG. When the sheet of the sheet bundle B comes into contact with the sheet feeding roller 71, the sheet is pulled out to the conveyance path 11, and the leading end of the sheet reaches the position shown in FIG. 8C, so that the sheet sensor 72 detects the sheet. To do. The time taken for the placement plate 92 to move from FIG. 8A to FIG. 8B is the movement time T1, and it takes for the sheet to be conveyed from FIG. 8B to FIG. 8C. Time is transport time T2.

  When the rotation of the paper feed roller 71 is started, if the placement plate 92 is already at the paper feed position and the sheets of the sheet bundle B stored in the paper feed cassette 91 are in contact with the paper feed roller 71, The sheet is immediately fed to the conveyance path 11. The conveyance time T in this case is a time during which the sheet is conveyed to the detection position of the sheet sensor 72 after the sheet is started to be fed by the sheet feeding roller 71. In this case, the movement time T1≈0 and the conveyance time T≈the conveyance time T2. The transport time T2 is substantially constant regardless of the size of the paper feed cassette 91 and the number of stored sheets. This is defined as a conveyance time β.

  On the other hand, when the sheet feeding roller 71 starts to rotate and the placement plate 92 is in the non-sheet feeding position, the sheets in the sheet bundle B are not in contact with the sheet feeding roller 71. Therefore, after the placement plate 92 is raised until it comes into contact, sheet feeding is started. Therefore, the movement time T1 for moving the mounting plate 92 from the non-feeding position to the feeding position is necessary. In this case, the conveyance time T = the movement time T1 + the conveyance time T2.

  The moving time T1 varies depending on the number of sheets stored in the sheet feeding cassette 91. The movement time T1 in the sheet feeding cassette 91 is minimum when the maximum number of sheets that can be stored is stored in the sheet feeding cassette 91. This minimum movement time T1 is defined as a minimum movement time α. The smaller the number of sheets stored, the longer the movement time T1. The movement time T1 is longer than the minimum movement time α.

  That is, when the sheet conveyance control is started, if the placement plate 92 is in the sheet feeding position, the movement time T1 is substantially 0, and the conveyance time T2 is substantially equal to the conveyance time β. On the other hand, when the mounting plate 92 is in the non-feeding position, the movement time T1 is a value equal to or longer than the minimum movement time α, and the conveyance time T2 is substantially equal to the conveyance time β. Therefore, if the conveyance time T acquired in S205 is compared with the conveyance time β, it can be determined whether or not the placing plate 92 is in the non-feeding position at the start of sheet conveyance control. That is, if T> β, it is determined that the placing plate 92 is in the non-feeding position, that is, the first sheet is conveyed after the sheet feeding cassette 91 is opened and closed.

  Depending on the timing of driving by the drive motor 78, when the sheet conveyance control is started, there is a possibility that the placing plate 92 is located between the paper feeding position and the non-paper feeding position. In other words, after the sheet is fed from the sheet feeding cassette 91, the sheet conveyance control is started when the movement of one sheet has not yet been completed. In this case, the movement time T1 is shorter than the minimum movement time α. Accordingly, the transport time T in this case is smaller than the sum of the minimum movement time α and the transport time β.

  If the mounting plate 92 is in the non-feed position, the movement time T1 is equal to or longer than the minimum movement time α, and the conveyance time T2 is substantially equal to the conveyance time β. Therefore, the transfer time T is equal to or longer than the minimum movement time α + the transfer time β. On the other hand, if the mounting plate 92 is not in the non-feeding position, the movement time T1 is smaller than the minimum movement time α, so the conveyance time T is smaller than the minimum movement time α + conveyance time β. Therefore, if the conveyance time T acquired in S205 is compared with the minimum movement time α + conveyance time β, it is determined whether or not the placing plate 92 is in the non-feeding position at the start of sheet conveyance control. Can also be determined accurately taking into account.

  In order to make the above-described determination, the printer 100 stores the minimum movement time α and the conveyance time β in the NVRAM 34. The minimum movement time α and the conveyance time β are stored in a database 99 as shown in FIG. 9, for example. The minimum moving time α varies depending on the type of stored sheet and the temperature in the apparatus. The sheet type is the sheet size or thickness type set for the print job being printed. The temperature is a temperature acquired by the temperature sensor 73 (see FIG. 5). Each value of the minimum movement time α and the conveyance time β may be an actual measurement value obtained by measurement before shipment from the factory, or as a design value calculated from the rotation speed and movement distance of the conveyance roller. Also good.

  The minimum movement time α may be stored separately for each capacity of the paper feed cassette 91. In the large-capacity paper feed cassette 91, the moving speed of the mounting plate 92 may be set faster because the difference in moving distance due to the number of sheets is large. FIG. 9 shows an example of the database 99 of the paper feed cassette 91 having a small capacity. Further, it is further preferable that the conveyance time β is stored with a value that varies depending on the degree of wear of the paper feed roller 71. This is because the sheet conveyance speed changes as the sheet feeding roller 71 is consumed.

  Returning to the description of FIG. 7, after acquiring the transport time T in S205, the CPU 31 reads the minimum travel time α and the transport time β from the database 99 of the NVRAM 34 (S207). In view of the capacity of the paper feed cassette 91 in use, the type of sheet being printed, the temperature in the apparatus, the degree of wear of the paper feed roller 71, etc., the most appropriate minimum movement time α and transport time β are read out. Good.

  Then, the transport time T acquired in S205 is compared with the minimum movement time α + transport time β (S208). If T ≧ α + β (S208: Yes), the mounting plate 92 is in the non-feeding position. Therefore, it can be considered that the sheet feeding cassette 91 is opened before the current sheet conveyance control. Therefore, it is determined that the paper feed cassette 91 has been opened and closed (S209).

  On the other hand, if T ≧ α + β is not satisfied (S208: No), the mounting plate 92 is not in the non-feeding position. Therefore, before the current sheet conveyance control, it can be considered that the sheet feeding cassette 91 is not opened. Therefore, it is determined that the paper feed cassette 91 has not been opened or closed (S210). Thereby, the open / close determination process is terminated.

  In addition, the printer 100 executes a process of acquiring the sheet size when conveying a sheet, separately from the open / close determination. For this purpose, the timer measures the time from when the leading edge of the sheet reaches the detection position of the sheet sensor 72 until the trailing edge of the sheet reaches the detection position of the sheet sensor 72. The sheet size is calculated from the measured time and the sheet conveyance speed. Therefore, even after the conveyance time T is acquired, the time measurement by the timer is continued. The sheet size is calculated from the measured time and the conveyance speed. Changes in the conveyance status such as the conveyance of the sheet being temporarily stopped between the time when the leading edge of the sheet reaches the detection position of the sheet sensor 72 and the time when the trailing edge of the sheet reaches the detection position of the sheet sensor 72 If there is a sheet size, the sheet size should be acquired considering that point.

[Continuation of print processing]
Next, returning to the printing process of FIG. 6, after the open / close determination process of S101, it is determined whether or not the previous data is stored in the RAM 33 (S102). The previous data is the sheet size data acquired during the previous sheet conveyance. Note that the previous data is erased from the RAM 33 when at least one of the power-off of the printer 100 and the detection of the absence of sheets in the paper feed cassette 91 occurs. When the printer 100 is new, no previous data is stored. Note that the printer 100 does not detect a sheet at the detection position of the sheet sensor 72 even after a predetermined time has elapsed since the start of sheet conveyance control from the sheet cassette 91. It is determined that there is no sheet.

  If it is determined that there is previous data (S102: Yes), it is then determined whether the paper feed cassette 91 has been opened or closed before this printing (S103). As a result of the open / close determination process in S101, when it is determined that the sheet has not been opened / closed (S103: No), it can be estimated that the sheets stored in the paper feed cassette 91 have not changed since the previous printing. That is, it is presumed that the sheet cassette 91 stores sheets of the sheet size of the previous data. Therefore, the sheet size requested by the previous data and the current print data is compared (S104).

  If the previous data and the requested size match (S104: Yes), there is a high possibility that the relationship between the print data and the sheet size is appropriate. Therefore, one page is printed (S105). That is, a toner image based on the received print data is formed and transferred to a sheet that has already started to be conveyed. The transferred toner image is fixed on the sheet by the fixing unit 8.

  If it is determined that there is no previous data (S102: No), and if it is determined that the paper feed cassette 91 is opened / closed as a result of the open / close determination process of S101 (S103: Yes), both are S105. Go to and print one page. If there is no previous data, there is no target to be compared with the sheet size requested in the current print data. If it is determined that the paper feed cassette 91 has been opened / closed (S103: Yes), there is a possibility that the sheets stored in the paper feed cassette 91 at the time of opening / closing have been replaced. In other words, there is no reliable data about the seats that are currently stored. In these cases, the process proceeds to S105, and one page is printed for the time being.

  When printing is performed, sheet size confirmation processing is further executed (S106). Next, the sheet size confirmation process will be described with reference to the flowchart of FIG.

[Sheet size confirmation process]
In the sheet size confirmation process, first, the sheet size is acquired (S301). Since the timer counts in the open / close determination process (see FIG. 7), the trailing edge of the sheet passes through the detection position of the sheet sensor 72 from the time when the leading edge of the sheet passes the detection position of the sheet sensor 72. The elapsed time up to the time can be obtained. The sheet size can be acquired based on the acquired elapsed time and the sheet conveyance speed. The sheet size acquired in S301 is the length of the conveyed sheet in the conveyance direction.

  Next, it is determined whether or not the set size set in the sheet feeding cassette 91 that has fed the current sheet matches the sheet size acquired in S301 (S302). In the printer 100, the size of the sheet stored in the paper feed cassette 91 is set. This setting is performed by the user from the operation panel 40 or the like. The set size is stored in the NVRAM 34.

  If the set size matches the sheet size acquired in S301 (S302: Yes), the sheet size acquired in S301 is stored in the RAM 33 as the previous data (S303). Then, the sheet size confirmation process ends.

  On the other hand, if the set size does not match the sheet size acquired in S301 (S302: No), a notification for prompting the user to change the setting is displayed on the display unit 41 (S304). That is, the user is notified that the size of the sheet stored in the paper cassette 91 matches the set size set in the paper cassette 91. At this time, the sheet size acquired in S301 and the size currently set in the sheet feeding cassette 91 may be displayed on the display unit 41. Thereafter, the previous data is stored (S303), and the sheet size confirmation process is terminated.

[Continuation of print processing]
Next, returning to the printing process of FIG. 6, after the sheet size confirmation process of S106, it is determined whether or not printing of all received print data has been completed (S108). If processing of all print data has been completed (S108: Yes), the print processing is terminated. If not completed (S108: No), the process returns to S101 to execute the process for the next page. For example, since there is a possibility that the paper feed cassette 91 is opened and closed after printing one page due to detection of no sheet in the paper feed cassette 91 or the like, it is desirable to perform open / close determination processing for each page.

  On the other hand, if the previous data does not match the requested size (S104: No), there is a high possibility that the relationship between the print data size and the sheet size is inappropriate. Therefore, a display prompting the user to check and change the sheet size is displayed on the display unit 41 of the operation panel 40 (S111). In other words, the user is notified to change the sheet stored in the paper feed cassette 91 or to change the print data.

  Subsequently, it is determined whether or not the previous data is larger than the requested size (S112). Even if the sizes do not match, printing is possible if the sheet is larger than the print data. Therefore, if the previous data is larger than the required size (S112: Yes), the process proceeds to S105 and one page is printed, as in the case where the sizes match.

  On the other hand, if the previous data is smaller than the required size (S112: No), the print data may be protruded from the sheet, so printing is stopped (S113). That is, a sheet that has not been formed and has already started to be conveyed is discharged to the discharge tray 96 as a blank sheet. Further, a sheet size confirmation process is executed (S114). S114 is the same process as S106 described above, and a description thereof will be omitted. Then, the printing process ends. If the previous data is smaller than the required size, it is preferable not to print even if there is another page.

  As described in detail above, in the printer 100 of this embodiment, the mounting plate 92 that moves to the non-feeding position by opening / closing the feeding cassette 91 is provided in the feeding cassette 91. Therefore, in the first print request after the paper feed cassette 91 is opened and closed, the mounting plate 92 is first moved from the non-paper feed position to the paper feed position, and then the paper feed roller 71 feeds paper. On the other hand, if the paper feed cassette 91 is not opened and closed after printing is performed, the mounting plate 92 is in a position raised from the non-paper feed position. That is, the moving time T1 for moving the mounting plate 92 hardly takes. In the printer 100, if the measured transport time T is longer than the transport time β from the start of sheet feeding to the detection position of the sheet sensor 72, it is determined that the sheet feeding cassette 91 has been opened and closed. Even without a sensor, changes in the open / closed state can be recognized. Therefore, a printing apparatus that can recognize a change in the open / close state of the sheet storage unit with a configuration having a small number of parts is realized.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the printing apparatus is not limited to the printer 100, and can be applied to any apparatus having a printing function, such as a multifunction machine, a copier, and a FAX apparatus. Further, even if a color image can be formed, it may be dedicated to a monochrome image. Further, an ink jet printing apparatus may be used.

  Further, for example, an apparatus including two or more paper feed cassettes 91 may be used. In this case, it is preferable to use a database that stores the minimum movement time α and the conveyance time β for each paper feed cassette. The minimum movement time α may be different depending on the size and depth of the paper feed cassette, that is, the size and number of sheets that can be stored. Further, the conveyance time β may be different depending on the distance between the sheet feeding roller of the sheet feeding cassette and the detection position of the sheet sensor 72, and the like.

  Further, for example, in the database 99, the minimum movement time α and the conveyance time β may be different depending on the humidity in the apparatus in addition to the sheet type and the temperature in the apparatus. For this purpose, the humidity in the apparatus is acquired, and an appropriate minimum movement time α and transport time β are read according to the acquired humidity. By selecting a value suitable for the current situation, the open / closed state can be detected more accurately.

  Further, for example, instead of storing the minimum movement time α and the conveyance time β in the database 99 of the own device, it may be acquired from an external device such as a server.

  Further, for example, there is no need to determine whether or not the previous data is larger than the requested size (S112 in FIG. 6). That is, regardless of the magnitude relationship, if the previous data and the requested size do not match (S104: No), after the size change notification (S111), the process may proceed to S113 to stop printing.

  In the above embodiment, the previous data is stored in the RAM 33. However, it may be stored in a nonvolatile storage unit such as the NVRAM 34.

  For example, if it is determined that the sheet sizes match, the remaining pages of the print data may be continuously printed without performing the open / close determination process. Further, for example, the number of sheets stored in the paper feed cassette 91 may be estimated and notified based on the measured conveyance time T.

  The processing disclosed in the embodiments may be executed by a single CPU, a plurality of CPUs, hardware such as an ASIC, or a combination thereof. Further, the processing disclosed in the embodiment can be realized in various modes such as a recording medium or a method recording a program for executing the processing.

31 CPU
33 RAM
50 Process section 71 Paper feed roller 72 Sheet sensor 91 Paper feed cassette 92 Mounting plate 100 Printer

Claims (11)

A printing section for printing an image on a sheet;
A storage section for storing the seat;
A sheet feeding unit that feeds a sheet stored in the storage unit into a conveyance path;
The sheet is placed in the storage unit and is placed at a non-feeding position where the sheet cannot be fed by the sheet feeding unit when the storage unit changes from an open state to a closed state. A board,
A moving mechanism for moving the mounting plate from the non-feeding position to a feeding position where sheets can be fed by the feeding unit;
A detection unit that is located in the conveyance path and detects the presence or absence of a sheet;
A measurement unit that measures a conveyance time T from the start of conveyance control of the sheet until the detection unit detects a change in the presence or absence of the sheet;
Measured by the measurement unit and the conveyance time β from when the sheet is fed by the sheet feeding unit with the placing plate in the sheet feeding position until the sheet reaches the detection position of the detection unit. A determination unit that determines that the open / close state of the storage unit has changed when the transport time T satisfies a relationship of T>β;
A printing apparatus comprising: The printing apparatus according to claim 1,
When the maximum number of sheets that can be stored in the storage unit is placed on the mounting plate and the mounting plate is in the non-feeding position, the determination unit performs the non-feeding position by the moving mechanism. When the minimum movement time α, which is the time taken to move the mounting plate from the paper feed position to the paper feeding position, the conveyance time β, and the conveyance time T satisfy the relationship T ≧ α + β, the storage unit It is determined that there has been a change in the open / closed state of the printer. The printing apparatus according to claim 2,
The printing apparatus according to claim 1, wherein the minimum moving time α varies depending on at least one of the capacity of the storage unit, the type of sheet, the temperature in the apparatus, and the humidity in the apparatus. In the printing apparatus according to any one of claims 1 to 3,
The printing apparatus according to claim 1, wherein the conveyance time β varies depending on at least one of the storage unit, the type of sheet, the degree of wear of the sheet feeding unit, the temperature in the apparatus, and the humidity in the apparatus. In the printing apparatus according to any one of claims 1 to 4,
An acquisition unit that acquires a size in the conveyance direction of the sheet based on a timing at which the detection unit detects a change in the presence or absence of the sheet;
A storage unit for storing the size acquired by the acquisition unit;
A determination unit for determining whether or not to print on the sheet;
With
The detection unit is located upstream of the printing unit in the sheet conveyance direction,
The printing unit prints an image on a sheet when it is determined that the determination unit performs printing;
The determination unit
(1) The determination unit does not determine that there is a change in the open / close state of the storage unit;
(2) The sheet size at the time of the previous sheet conveyance stored in the storage unit matches the sheet size set in the print data,
A printing apparatus that determines to perform printing when the two conditions are satisfied. The printing apparatus according to claim 5,
In the state where the determination unit has not determined that the opening / closing state of the storage unit has changed, the determination unit stores the size of the sheet at the time of the previous sheet conveyance stored in the storage unit and the print data. A printing apparatus that determines that printing is not performed when the set sheet size does not match. The printing apparatus according to claim 5,
In the state where the determination unit has not determined that the opening / closing state of the storage unit has changed, the determination unit stores the size of the sheet at the previous sheet conveyance stored in the storage unit in the print data. Printing is performed when the sheet size is larger than the set sheet size, and printing is performed when the sheet size at the previous sheet conveyance stored in the storage unit is smaller than the sheet size set in the print data. A printing apparatus characterized in that it is determined not to be performed. The printing apparatus according to claim 6 or 7,
A printing apparatus comprising: a sheet change notification unit for notifying that the sheet stored in the storage unit is changed or the print data is changed when the determination unit determines that printing is not performed. . The printing apparatus according to any one of claims 5 to 8,
When the determination unit determines that the opening / closing state of the storage unit has changed, the determination unit performs printing regardless of the size of the previous sheet transport stored in the storage unit. A printing apparatus characterized in that it is determined to be performed. The printing apparatus according to any one of claims 5 to 9,
When the size acquired by the acquisition unit and the size of the sheet set in the storage unit storing the sheet to be acquired by the acquisition unit do not match, stored in the storage unit A non-coincidence notifying unit that notifies that the size of the sheet that is set matches the size set in the storage unit. The printing apparatus according to any one of claims 5 to 10,
The size of the sheet stored in the storage unit is erased at least when the power is turned off or no sheet is detected during printing.
The printing apparatus according to claim 1, wherein the determination unit determines to perform printing when a sheet size is not stored in the storage unit.

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