JP2008039849A - Image forming apparatus and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of effectively suppressing photoreceptors from being optically exposed, in which a cover that can be opened/closed by a user is provided, and image formation is performed by using the photoreceptors. <P>SOLUTION: The image forming apparatus includes: the cover covering the inside of the apparatus, that can be opened/closed by the user; a detecting means for detecting whether the cover is opened/closed; and a notifying means for notifying the user that the cover is in an open state when an elapsed time after detecting by the detecting means that the cover is opened reaches a prescribed time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that includes a cover that can be opened and closed by a user, and that forms an image using a photoconductor, and more particularly to an image forming apparatus that can effectively suppress light exposure of the photoconductor.

  Usually, in an image forming apparatus such as a laser printer, printing processing is performed by performing various processes such as formation of a latent image on a photosensitive drum based on image data, development with a developer, and transfer to a printing medium such as paper. Is made. When the photoconductor in such an image forming apparatus is exposed to external light, it loses its function or shortens its life. Therefore, it is desired that the photoconductor is not exposed to external light as much as possible.

  Therefore, some conventional devices have been devised such as a structure in which the photoconductor is positioned in the back of the device, or a shutter provided for the photoconductor is closed when the cover of the device is opened (for example, , An apparatus described in Patent Document 1 below).

However, since such a conventional apparatus is mechanically complicated in structure and high in cost, some of the conventional apparatuses have a structure that does not take any defensive measures for the exposure of the photoreceptor. is there. In particular, in a tandem printer provided with a plurality of photoconductors, depending on the arrangement direction of the photoconductors, the photoconductors are easily exposed when the printer cover is opened (for example, described in Patent Document 2 below). Equipment).
JP-A-6-19226 JP 2005-331877 A

  In the case of a conventional apparatus using a photoconductor, particularly an apparatus that does not have a mechanism for guarding the photoconductor as described above, when the user opens a cover for accessing the inside of the apparatus, the photoconductor is exposed to external light. There is a high possibility of exposure, and at that time, a message notifying that printing is not possible is only displayed on the display panel or the like, so that there is a possibility that it will be exposed to external light for a long time. Such exposure of the photosensitive member is not preferable because it causes a decrease in function and shortens the service life.

  SUMMARY OF THE INVENTION An object of the present invention is an image forming apparatus that includes a cover that can be opened and closed by a user and that forms an image using a photoconductor, and that can effectively suppress light exposure of the photoconductor, etc. Is to provide.

  In order to achieve the above object, according to one aspect of the present invention, an image forming apparatus covers a cover that can be opened and closed by a user, a detection unit that detects opening and closing of the cover, and the detection unit. And a notification means for notifying a user that the cover is in an opened state when the elapsed time after it is detected that the cover has been opened reaches a predetermined time. .

  Furthermore, in the above-mentioned invention, the preferred embodiment is that the predetermined time is a first time and a second time longer than the first time, and the predetermined time is made when the first time is reached. The notification method is different from the notification method performed when the second time is reached.

  Furthermore, in the above invention, a preferred aspect is characterized in that the notification means further performs the notification when the detection means detects that the cover is opened.

  Furthermore, in the above invention, a preferred aspect is characterized in that the notification by the notification means is made by emitting a sound.

  In the invention described above, one aspect is that the image forming apparatus is a tandem printer, and includes a plurality of photoconductors arranged along an opening formed by opening the cover. Features.

  Furthermore, in the above-described invention, one aspect is characterized in that the opening is formed in a direction perpendicular to the bottom surface of the image forming apparatus.

  In order to achieve the above object, according to another aspect of the present invention, there is provided a control method for an image forming apparatus including a cover that can be opened and closed by a user, covering the inside of the apparatus, and detecting that the cover is opened. When the elapsed time after the detection reaches a predetermined time, the user is notified that the cover is open.

  Further objects and features of the present invention will become apparent from the embodiments of the invention described below.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention. In the drawings, the same or similar elements are denoted by the same reference numerals or reference symbols.

  FIG. 1 is a configuration diagram according to an embodiment of a printer which is an image forming apparatus to which the present invention is applied. The printer 2 shown in FIG. 1 is an image forming apparatus to which the present invention is applied. When the cover 3 is opened by the user, it is detected and the time after the opening is measured, and the cover 3 is not closed for a predetermined time. After the elapse of time, the buzzer informs the user that the cover 3 is in an open state (this state is referred to as a first state), and when a certain time elapses without the cover 3 being closed, the buzzer and the display panel 71 display The user is prompted to close the cover 3 (this state is referred to as a second state), and the light exposure of the photosensitive member 62 due to the opening of the cover 3 is effectively suppressed. In addition, the printer 2 can store the number of times the cover 3 is opened and the second state and the time in the second state in a nonvolatile memory so that the printer 2 can be viewed later, thereby facilitating the maintenance of the printer accurately and easily. It is what you want to go.

  A host computer 1 shown in FIG. 1 is a host device that makes a print request to the printer 2 and transmits print data including image data and control commands to the printer 2 based on a user operation or the like. The host computer 1 can be configured by a so-called personal computer.

  As shown in FIG. 1, the printer 2 includes a controller 4, an engine control unit 5, an engine 6, a user I / F 7, and the like, and includes a cover 3 that can be opened and closed by a user, and a sensor 8 that detects opening and closing thereof. This is a tandem type laser printer.

  The controller 4 receives the print data transmitted from the host computer 1, interprets the control command included in the data, performs predetermined processing on the image data included in the data, and provides the processed data to the engine side Data to be generated. As shown in FIG. 1, the controller 4 includes an I / F 41, a CPU 42, a ROM 43, a RAM 44, an engine I / F 45, and an NVRAM 46.

  The I / F 41 is a part that receives the print data transmitted from the host computer 1, and the ROM 43 is a part that stores various programs for controlling the printer 2. The RAM 44 is a memory for storing the received print data and the like, and the image data of each page on which print processing is performed on the engine side is delivered to the engine I / F 45 from here.

  Next, the NVRAM 46 is a non-volatile memory, and stores information that should remain without being erased even when the printer 2 is turned off. In the printer 2, the number of times when the cover 3 is opened and the number of times of the second state and the time when the cover 3 is in the second state can be stored.

  The CPU 42 controls various processes performed in the printer 2. In particular, the CPU 42 interprets the process for storing the image data included in the received print data in the RAM 44 and the control command included in the print data. It governs processing for instructing the engine control unit 5 to perform appropriate printing processing, processing for controlling the user I / F 7, and the like. The printer 2 is characterized by processing performed by the CPU 42 when the cover 3 is opened, and the specific contents thereof will be described later. The processing executed by the CPU 42 is mainly performed according to a program stored in the ROM 43.

  Next, when executing printing on the engine side, the engine I / F 45 reads the pixel data stored in the RAM 44 described above at a predetermined timing, performs a predetermined process on the pixel data, and delivers the pixel data to the engine side. This is the part that controls the interface between the controller 4 and the engine side. Although not shown, the engine I / F 45 includes a memory for temporarily storing data, a decompression unit, a screen processing unit, and the like. The pixel data read from the RAM 44 is compressed data. Decompression and screen processing to convert to dot data. Further, the engine I / F 45 is specifically composed of an ASIC. As described above, the printer 2 is a tandem type printer and, as an example, uses CMYK (cyan, magenta, yellow, and black) toners as developing materials. Therefore, the engine I / F 45 corresponds to each color. It consists of a system.

  The cover 3 is a cover that covers the inside of the printer 2 and is opened when the user accesses the inside of the printer 2. The cover 3 is opened when troubles such as replacement of consumables such as a toner cartridge and a photoconductor or a paper jam occur. The sensor 8 is a part that detects opening and closing of the cover 3, and for example, a contact sensor is used. The detection result by the sensor 8 is notified to the CPU 42.

  Next, although not shown, the engine control unit 5 includes a CPU, a ROM, a RAM, and the like, and controls the operation of the engine 6 described later.

  The engine 6 includes an image forming unit 61 shown in FIG. 1, a transfer unit (not shown), a fixing unit, and the like. Four image forming units 61 are provided for each color (61C, 61M, 61Y, 61K), and each image forming unit 61 has a detachable photoconductor (drum) 62 (62C, 62M, 62Y, 62K), A charging unit (not shown) for charging the photosensitive member 62, an exposure unit (not shown) for forming a latent image on the photosensitive member 62 based on data sent from the controller 4, and a developer for each color. A developing device for developing an image with (toner) is provided. Each developing device has a detachable cartridge for containing a developer, and each cartridge is provided with a nonvolatile memory 63 (63C, 63M, 63Y, 63K). The memory 63 can store the number of times when the cover 3 is opened and the number of times when the cover 3 is opened and the time when the cover 3 is in the second state. The memory 63 may be provided in the photoconductor 62 or in the image forming unit 61 itself.

  The transfer unit is provided with an intermediate transfer member to which the toner image formed on each photoconductor is transferred. The toner image formed on the intermediate transfer member is then transferred to a printing medium such as paper. The fixing unit is a portion in which the toner image transferred onto the printing medium is welded to the medium to form a permanent image. The printing medium that has passed through the fixing unit is then discharged (discharged) out of the printer 2.

  The photosensitive members 62 of the engine 6 are installed at positions where they are easily exposed to external light when the cover 3 is opened. FIG. 2 is a schematic structural diagram for explaining the positional relationship between the photoconductor 62 and the cover 3 in the printer 2. FIG. 2 is a side view of the inside of the printer 2 and shows a state in which the cover 3 (solid line in the figure) is opened. As shown in FIG. 2, the four photoconductors 62C, 62M, 62Y and 62K corresponding to the respective colors of the printer 2 are arranged in a direction perpendicular to the bottom surface B of the printer 2. Therefore, when the cover 3 is released from the closed state (dotted line in the figure), all four photoconductors 62 are exposed to external light. In other words, since the four photoconductors 62 are arranged along the opening O in the direction perpendicular to the bottom surface that can be formed on the front surface of the printer 2 by opening the cover 3, the photoconductor 62 is easily exposed. It has become. Therefore, in the printer 2, when the cover 3 is opened by the user, control is performed so that the cover 3 is quickly closed as will be described later.

  Next, the user I / F 7 is a part that controls an interface with the user, and includes a control panel, a sound generation unit 73, and the like. FIG. 3 is a diagram illustrating the control panel and the sound generation unit 73 of the printer 2. The display panel 71 in FIG. 3 is, for example, an LCD panel, and displays various messages to the user, menus for the user to operate, and the like. Also, as shown in FIG. 3, the control panel is provided with various switches and lamps 72, which are used for user operation and notification to the user. The voice generation unit 73 is a part that emits a buzzer sound or a voice message. When the cover 3, which is a feature of the printer 2, is opened, the display panel 71 and the sound generator 73 are used to notify the user.

  As described above, the printer 2 according to the present embodiment having the above-described configuration is characterized by the processing when the cover 3 is opened. The specific contents of the processing will be described below. . FIG. 4 is a flowchart illustrating a procedure of processing performed when the printer 2 is turned on. The processing shown in FIG. 4 is mainly performed by the CPU 42 according to a program stored in the ROM 43.

  When the printer 2 is powered on, first, the CPU 42 checks whether or not a cover open error has occurred (step S1). The cover open error is an error that means that the cover 3 is in an open state and printing is impossible, and the CPU 42 performs the check from the open / closed state of the cover 3 detected by the sensor 8 described above.

  As a result of the check, when the cover 3 is closed and no cover open error has occurred (No in step S1), the CPU 42 confirms that printing is possible without any other error, and then displays the display on the display panel 71. The user I / F 7 is instructed to set the message to “Ready” (step S14). And the process at the time of power-on is complete | finished.

  On the other hand, as a result of the check, when the cover 3 is opened and a cover open error has occurred (Yes in step S1), the CPU 42 instructs the user I / F 7 to display the cover open error on the display panel 71. An instruction is given (step S2). In addition, the CPU 42 instructs the user I / F 7 to sound the buzzer once (step S3). As a result, a buzzer is emitted once from the sound generating unit 73, and the user is made to recognize more firmly that the cover 3 has been opened. Further, by opening the cover 3, the photosensitive member 62 is exposed. (And so on).

  Next, the CPU 42 updates the value of Timer (step S4). “Timer” is a variable representing an elapsed time (for example, seconds) since the cover 3 was opened, and the value of the Timer is updated to the elapsed time at that time.

  Next, the CPU 42 compares the updated value of Timer with a predetermined time X (for example, seconds) until the transition to the first state (step 5). This first state is a state in which processing (first state processing) for notifying the user that the second state described later is approached, and the time X until transition to this state is, for example, 3 minutes. (180 seconds).

  In the comparison, at the stage immediately after the cover 3 is opened, naturally, since the value of the opened time Timer is smaller than X (Yes in Step S5), the first state is not changed, The CPU 42 checks whether or not the cover open error has been released after a predetermined time (step S6). That is, it is checked whether or not the cover 3 is closed. The predetermined time is set to 1 second, for example, and the check is performed at the same interval from when the cover 3 is opened until it is closed. This check is performed from the open / closed state of the cover 3 detected by the sensor 8 described above.

  As a result of the check, if the door 3 is not yet closed (No in step S6), the process proceeds to the above-described step S4, and the process is repeated from the update of the Timer value. In this way, when the processes of Step S4, Yes in Step S5, and No in Step S6 are repeated without the cover 3 being closed, the value of Timer increases sequentially, for example, by 1 second, and as a result If the value of Timer is equal to or greater than X (No in step S5), the process proceeds to step S7.

  In step S7, the CPU 42 compares the value of Timer with a predetermined time Y (for example, seconds) until the transition to the second state. The second state refers to a state in which the photoconductor 62 is continuously exposed to external light for a certain period of time and has a high risk of adversely affecting the photoconductor 62, and the time until the transition to this state is made. Y is set to 5 minutes (300 seconds), for example. This time is sufficient time until the photosensitive member 62 is actually exposed. However, if the second state is reached, the cover 3 is closed because there is a high risk of adversely affecting the photosensitive member 62. Prompt processing will be done.

  In the comparison, at the stage where the value of Timer is not less than X, it is natural that the value of Timer is smaller than Y (No in Step S7), so the process proceeds to Step S8, and the CPU 42 The first state process is executed. Specific contents of the first state process will be described later. Thereafter, the CPU 42 checks whether or not the cover open error has been released after the predetermined time described above (step S6). If the cover 3 is not closed, the process proceeds from step S4 to step S6 via step S8. This process is repeatedly executed.

  If the value of Timer is equal to or greater than Y (Yes in step S7), the CPU 42 executes the second state process (step S9). Specific contents of the second state process will be described later. Thereafter, the processing from step S4 to step S6 through step S9 is repeatedly executed until the cover 3 is closed.

  When the cover 3 is closed by the user and the cover open error is canceled (Yes in step S6), the CPU 42 first sets the buzzer in a stopped state (step S10). That is, at that time, if the buzzer is not sounding, it is left as it is, and if it is sounding, the buzzer is stopped. Subsequently, the CPU 42 sets the panel backlight not to be flashed (step S11). The panel backlight flash is the blinking of the backlight of the display panel 71 described above, and is stopped when the flash is started in the second state process described later.

  Next, the CPU 42 initializes the value of Timer described above (step S12) and initializes the value of a variable buzzerTime described later (step S13). Specifically, the value is 0 for both.

  Thereafter, after confirming that printing is possible without other errors, the CPU 42 instructs the user I / F 7 to set the display message on the display panel 71 to “Ready” (step S14).

  In this way, the process at the time of power-on is completed. Even when the power is not turned on, the same process is executed when the cover 3 is opened by the user and a cover open error occurs.

  Next, the first state process described above will be described. FIG. 5 is a flowchart illustrating the procedure of the first state process. In the processing shown in FIG. 4, when the process proceeds to step S8, the CPU 42 checks whether or not it is time to sound the buzzer (step S81). Specifically, as shown in FIG. 5, it is checked whether or not the value of (Timer-buzzerTime) is equal to or greater than the value of BuzzerOnTiming. Here, the buzzerTime is a variable representing an elapsed time (for example, seconds) after the cover 3 is opened when the buzzer is sounded last time. Note that the buzzer here means a buzzer sounding a plurality of times in step S82 to be described later. In other words, buzzerTime represents the value of Timer at the time of the previous buzzer multiple times. Further, BuzzerOnTiming is an interval at which the buzzer is sounded a plurality of times, and is a predetermined constant. For example, a value of 5 seconds is set.

  As a result of the check, if the value of (Timer-buzzerTime) is equal to or greater than the value of BuzzerOnTiming (Yes in step S81), the CPU 42 determines that it is time to sound the buzzer and sounds the buzzer multiple times. Is instructed to the user I / F 7 (step S82). When the process proceeds to step S81 for the first time after the cover 3 is opened this time, as described above, the timerTime is initialized to a value of 0, and the Timer is a value greater than X (for example, 180). The process proceeds to S82 and the buzzer is sounded a plurality of times.

  At this time, the CPU 42 updates the value of buzzerTime (step S83). That is, as described above, the value of Timer at that time is set. Thereafter, the CPU 42 ends the first state process.

  On the other hand, as a result of the check, if the value of (Timer-buzzerTime) is not equal to or greater than the value of BuzzerOnTiming (No in step S81), the CPU 42 ends this first state process without doing anything. For example, as described above, when the check in step S6 in FIG. 4 is performed at intervals of 1 second and BuzzerOnTiming is 5 seconds, the buzzer is sounded multiple times, and then the transition to S81 is 4 Until this time, since the value of (Timer-buzzerTime) does not reach 5 seconds, this processing is not performed.

  The first state process is executed in this way, and if the cover 3 is not closed and the first state is continued, the buzzer is sounded multiple times at intervals of the value of BuzzerOnTiming (for example, every 5 seconds). It will be. By this processing, the user is informed that the cover 3 is in an opened state and that the second state has been approached.

  Next, the second state process will be described. FIG. 6 is a flowchart illustrating the procedure of the second state process. In the process shown in FIG. 4, when the process proceeds to step S <b> 9, the CPU 42 first checks whether or not a message prompting the user to close the cover 3 is displayed on the display panel 71 (step S <b> 91).

  As a result of the check, if a message prompting to close the cover 3 is not displayed (No in step S91), the CPU 42 instructs the user I / F 7 to display the message (step S92). As a result, for example, a message “Please close the cover” shown on the display panel 71 of FIG. 3 is displayed, and the user is prompted to close the cover 3. At the same time, the CPU 42 instructs the user I / F 7 to flash the backlight of the display panel (step S93), and the flashing of the backlight is started. Further, the CPU 42 instructs the user I / F 7 to make the buzzer sound (step S94), and the buzzer sound is continuously generated from the sound generator 73.

  When the process proceeds to step S91 for the first time after the cover 3 is opened this time, that is, when the process proceeds to the second state, a message prompting the user to close the cover 3 is not yet displayed on the display panel 71. Message display, backlight flashing, and buzzer generation will be started.

  Then, the CPU 42 updates the value of the number of second state transitions stored in the nonvolatile memory of the printer 2 (Step S95). Specifically, since it is determined that the state has shifted to the second state at this time, a value obtained by adding 1 to the number of times of the second state transition so far is stored as a new number of second state transitions. The nonvolatile memory to be stored may be the NVRAM 46 described above or the memory 63. Thereafter, the process proceeds to step S96.

  On the other hand, after the transition to the second state, if the process returns to S91 without closing the cover 3, a message prompting to close the cover 3 has already been displayed (Yes in step S91). The process moves to step S96. That is, the message display, the backlight flash, and the buzzer sound are continuously generated.

  In step S96, the CPU 42 updates the value of the second state accumulated time stored in the nonvolatile memory (step S96). Specifically, the update is performed based on the check interval of step S6 in FIG. 4 described above. For example, when the check interval is 1 second, the update is performed every second every time the process proceeds to step S96. Two-state cumulative time is increased. Strictly speaking, it is preferable not to perform this update because there is almost no elapsed time in the second state when the process proceeds from the first state, ie, step S95. The second state accumulation time may be performed based on the value of Timer and the value of Y at the time when the second state ends.

  In this way, the second state process is executed, and once the state transitions to the second state, the message display, the flashing of the backlight, and the generation of the buzzer sound are continued until the user closes the cover 3, and the user is in an emergency situation. It is urged to close the cover 3 at an early stage by recognizing that.

  As described above, in this printer 2, when the cover 3 is opened, the buzzer sounds once, the cover 3 is in an opened state, and there is a risk that the cover 3 is opened. Informed by the user. Thereafter, when the predetermined time (X) elapses, the state is shifted to the first state, and a plurality of buzzers are sounded at predetermined intervals to notify the user that the second state with high risk is approaching. Further, when a predetermined time (Y-X) elapses, a transition is made to the second state, and a message prompting to close the cover 3 is displayed, the backlight of the display is flashed, and a continuous buzzer sound is generated. The user is visually and audibly informed that 3 is open and that it is an emergency.

  Note that the method of notifying the user and calling attention at each stage is merely an example, and other methods may be used. However, it is preferable to use a method according to the content of notification to the user at each stage.

  As described above, in the printer 2 in the present embodiment, the elapsed time after the cover 3 is opened is measured, and when the predetermined time has elapsed, the cover 3 is opened by a method such as a buzzer. Since the user is informed that there is a risk due to the presence of the image, the user is prompted to close the cover 3 at an early stage, and the exposure of the photoconductor 62 to external light can be suppressed. This is particularly effective for a printer having a structure in which all the photoconductors are arranged along the opening formed when the cover 3 is opened.

  In the printer 2, when the cover 3 is opened, the above notification is made in the first state and the second state by a method suitable for each stage, and by using a visual and auditory method. So it is more effective.

  Further, when the printer 2 is changed to the second state, the cumulative number of times of transition to the second state and the cumulative time of the second state are updated and remain in the nonvolatile memory. Sometimes it is possible to view this information. When the second state is reached, there is a high possibility that the photosensitive member 62 is affected by external light. Therefore, the cumulative number and the cumulative time are determined based on the judgment of the replacement time of the photosensitive member 62 and the image quality deterioration of the printer 2. This is effective information for determining the cause of the printer, and makes it possible to perform maintenance work of the printer more accurately and easily than before.

  In this embodiment, the image forming apparatus is a printer. However, the present invention can also be applied to other image forming apparatuses such as a copying machine and a facsimile.

  The protection scope of the present invention is not limited to the above-described embodiment, but covers the invention described in the claims and equivalents thereof.

1 is a configuration diagram according to an embodiment of a printer that is an image forming apparatus to which the present invention is applied. FIG. 2 is a schematic structural diagram for explaining the positional relationship between a photoconductor 62 and a cover 3 in the printer 2. FIG. FIG. 3 is a diagram illustrating a control panel and a sound generation unit 73 of the printer 2. 3 is a flowchart illustrating a procedure of processing performed when the printer 2 is powered on. It is the flowchart which illustrated the procedure of the 1st state process. It is the flowchart which illustrated the procedure of the 2nd state process.

Explanation of symbols

1 host computer, 2 printer, 3 cover, 4 controller, 5 engine control unit, 6 engine, 7 user I / F (notification means), 8 sensor (detection means), 41 I / F, 42 CPU (detection means, notification) Means), 43 ROM (detection means, notification means), 44 RAM, 45 engine I / F, 46 NVRAM, 61 image forming unit, 62 photoconductor, 63 memory, 71 display panel, 72 switch lamp, 73 sound generator , B bottom, O opening

Claims (7)

A user-coverable cover covering the inside of the device;
Detection means for detecting opening and closing of the cover;
Notification means for notifying the user that the cover is open when the elapsed time after the detection means detects that the cover is opened reaches a predetermined time. An image forming apparatus. In claim 1,
The predetermined time is a first time and a second time longer than the first time;
The image forming apparatus, wherein the notification method performed when the first time is reached differs from the notification method performed when the second time is reached. In claim 1 or claim 2,
The image forming apparatus, wherein the notification unit further performs the notification when the detection unit detects that the cover is opened. In any one of Claim 1 thru | or 3,
The notification by the notification means is made by emitting a sound. In any one of Claims 1 thru | or 4,
The image forming apparatus is a tandem printer,
An image forming apparatus comprising: a plurality of photoconductors arranged along an opening formed by opening the cover. In claim 5,
The image forming apparatus according to claim 1, wherein the opening is formed in a direction perpendicular to a bottom surface of the image forming apparatus. A method for controlling an image forming apparatus including a cover that can be opened and closed by a user, covering the inside of the apparatus,
Detecting that the cover has been opened,
A method for controlling an image forming apparatus, comprising: notifying a user that the cover is open when an elapsed time after the detection reaches a predetermined time.

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