JP2008176730A - Image forming device and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize power saving of a display part without causing trouble in display. <P>SOLUTION: This image forming device has: an LCD (Liquid Crystal Display) 203 displaying information; a display data memory 202a holding display data before displaying them on the LCD 203; and an LCD controller 202 driving the LCD 203 by use of the display data held in the display data memory 202a. Input frequency of the display data to the display data memory 202a is varied according to at least one of an operation state and operation environment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming apparatus control method, and more particularly to power saving of a display unit included in the image forming apparatus.

In recent years, there has been a trend toward digitization of information, and image forming apparatuses such as printers and facsimiles used for outputting digitized information have become indispensable devices. In such an image forming apparatus, for example, if it is a printer, immediate output of the image is required, and if it is a facsimile, it is necessary to always be in a receivable state, so that the power is always on. . On the other hand, these image forming apparatuses are not always in operation, and stand by with the power turned on while no instruction to be processed is given. Therefore, power saving in such a standby state is required. 2. Description of the Related Art Conventionally, a method has been proposed in which a printing operation is performed with a reduced clock signal and driving power in the apparatus when a job that does not require a printing speed in a power saving operation state of the printer, for example, a job such as printing at a specified time, is performed. (For example, refer to Patent Document 1).
JP 2002-86844 A

However, the method disclosed in Patent Document 1 is limited to a period in which the printer operation rate is low, and is not applicable to all power saving states. On the other hand, in the conventional image forming apparatus, a driver that controls the display unit from the display data generation source even in the power saving mode in order to prevent erroneous display and display disappearance of the display unit such as an LCD (Liquid Crystal Display) Data supply and clock supply to the network continue to be executed, which leads to an increase in power consumption.
The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to realize power saving of a display unit without causing a display defect in an image forming apparatus having a display unit.

In order to solve the above problems, the invention according to claim 1 is a display unit that displays information, a display data memory that holds display data before being displayed on the display unit, and a display data memory that holds the display data. A display control unit that drives the display unit using the displayed display data, and changes an input frequency of the display data to the display data memory according to at least one of an operation state and an operation environment. It is characterized by.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, display data is repeatedly input to the display data memory in at least one normal state of the operation state and the operation environment. The frequency of input of the display data to the display data memory is lowered when the normal state transitions to a predetermined state.

According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the image forming apparatus further includes a transfer circuit that inputs the generated display data to the display data memory, the transition from the normal state to a predetermined state, A clock is supplied to the transfer circuit in accordance with the timing at which the display data is transferred to the display data memory in a state where the input frequency of the display data to the display data memory is lowered.
The invention described in claim 4 is characterized in that a clock frequency supplied to the transfer circuit is changed in accordance with at least one of the operation state and the operation environment.
According to a fifth aspect of the present invention, in the image forming apparatus according to the first aspect, when at least one of the operation state and the operation environment transitions from a normal state to a predetermined state, the display data memory is supplied to the display data memory. The input of display data is stopped.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect of the present invention, the image forming apparatus further comprises a transfer circuit for inputting the generated display data to the display data memory, and according to at least one of the operation state and the operation environment. The clock supply to the transfer circuit is stopped.
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the filter removes a noise component of power supplied to at least one of the display control unit and the display unit. It is characterized by providing.
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the electrostatic shield that blocks the influence of electrostatic noise on at least one of the display control unit and the display unit. It is characterized by providing.

According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, an electrostatic film is provided on the display surface of the display section.
According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the first to ninth aspects, the input frequency of the display data to the display data memory in accordance with a traffic amount of a connected network. It is characterized by changing.
The invention according to claim 11 is a control method of an image forming apparatus equipped with a display device, wherein the first step of transferring display data before display to a display data memory temporarily stored, and the operating state And a second step of detecting a change in at least one of the operating environments, and changing a repetition frequency of the first step according to at least one of the operating state and the operating environment. .

  According to the present invention, in an image forming apparatus having a display unit, it is possible to realize power saving of the display unit without causing a display defect.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In an image forming apparatus having a display unit, after image display on the display unit is completed, the clock from the image data generation source to the control circuit that controls the display unit is stopped, thereby reducing the power consumption of the apparatus. Plan.

FIG. 1 is a block diagram illustrating an internal hardware configuration of the image forming apparatus 1 according to the present embodiment. As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment includes a CPU 101, a memory 102, a storage 103, a host I / F 105, a paper feed tray 106, a print engine 107, a paper discharge tray 108, a speaker 109, and a display panel. An I / F 110, a bus 111, and a display panel 200 are included. In FIG. 2, the electrical connection is indicated by solid arrows, and the flow of paper used for printout is indicated by broken arrows.
The memory 102 is generally constituted by a volatile memory such as a DRAM. A control program such as firmware 104 stored in the storage 103 is loaded into the memory 102, and a control unit is configured to control the operation of the image forming apparatus 1 according to the control of the CPU 101. The storage 103 includes a ROM (Read Only Memory), an EEPROM (Electronically Erasable and Programmable ROM), and a nonvolatile storage medium such as a magnetic disk or an optical disk. In addition to the control program such as the firmware 104 described above, the image forming apparatus 1 Stores various information used in the operation.

  The host I / F 105 is an interface used when the image forming apparatus 1 communicates with other devices via a network or a connection cable. A print job transmitted from an external host device is input to the control unit of the image forming apparatus 1 via the host I / F 105, and print processing is executed under the control of the control unit. In the printing process, paper is pulled out from the paper feed tray 106, an image is formed on the paper by a print engine 107 as an image forming mechanism, and the paper is discharged onto the paper discharge tray 108. The speaker 109 is a voice interface that notifies the user of the state of the image forming apparatus 1 by voice. The display panel I / F 110 is a communication interface with the display panel 200. The display panel 200 is an output interface that displays the state of the image forming apparatus 1 and has a touch panel and other operation units, and is also an input interface when the user directly operates the image forming apparatus 1. These elements shown in FIG. 1 are connected via a bus 111.

  Next, functional blocks of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. As shown in FIG. 2, in the image forming apparatus 1, the firmware 104 stored in the storage 103 is loaded into the memory 102, and a control unit that controls each operation of the image forming apparatus 1 in conjunction with the CPU 101 is configured. The The control unit includes a device I / F control unit 121, a display panel I / F control unit 122, and an engine control unit 123 that control each unit of the image forming apparatus 1 according to the control of the device control unit 120 and the device control unit 120. It is. The apparatus control unit 120 controls the operation of the entire image forming apparatus 1. As an example of the control by the apparatus control unit 120, the apparatus is started by turning on the power of the image forming layer apparatus 1, switched to the power saving mode when the non-operating state of the apparatus continues for a predetermined time, and host I / F control. Unit 121, display panel I / F control unit 122, engine control unit 123, and other control units. The host I / F control unit 121 transmits and receives data to and from the host device via the host I / F 105. The display panel I / F control unit 122 controls the display panel 200 via the display panel I / F 110. The display panel I / F control unit 122 will be described in detail later. The engine control unit 123 mainly controls the print engine 107 and executes image formation based on a print job received from the host device.

  FIG. 3 specifically shows the display panel I / F control unit 122 and the display panel 200. As shown in FIG. 3, the display panel I / F control unit 122 includes an image display control unit 122a, a clock control unit 122b, and an operation control unit 122c. The image display control unit 122a has a drawing area 122d therein, and display data displayed on the display panel 200 is first formed in the drawing area 122d. The image display control unit 122a forms (draws) display data to be displayed on the display panel 200 in the drawing region 122d according to the control of the device control unit 120, and also displays the drawing data in the drawing region 122d according to the operation of the device or the operation of the device control unit 120. Update the display data. Further, the image display control unit 122a transmits the display data formed in the drawing area 122d to the display panel 200. The clock control unit 122b controls the clock supplied to the display panel 200. The operation control unit 122 c transmits operation information on the display panel 200 by the user to the device control unit 120.

The display panel 200 according to the present embodiment includes an ASIC (Application Specific Integrated Circuit) 201, an LCD controller 202, an LCD 203, an LED (Light Emitting Diode) 204, and an operation unit 205. The ASIC 201 mainly controls the LED 204 and the operation unit 205 in accordance with a clock signal supplied from the clock control unit 122b via the display panel I / F 110. Further, it also functions as a transfer circuit that transfers display data input from the image display control unit 122 a via the display panel I / F 110 to the LCD controller 202. The LCD controller 202 has a display data memory 202a therein, stores input display data in the display data memory 202a, and drives the LCD 203 in accordance with a unique clock different from the clock supplied from the clock control unit 122b. The display data 202a stored in the data memory 202a is displayed.
The LCD 203 is a generally used liquid crystal display panel, and is a display unit that displays information. The LCD 203 is driven by the LCD controller 202. As the type of liquid crystal display panel used as the LCD 203, various types of liquid crystal panels such as a simple matrix system and an active matrix system can be used. As for the arrangement method of the liquid crystal included in the liquid crystal display panel, if it is a simple matrix method, an active matrix method such as a TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, DSTN (Dual Scan Twisted Nematic) type, etc. If so, a TN type, a VA (Vertical Alignment) type, or the like is appropriately selected. Further, regarding the light source method, a transmission type, a reflection type, a semi-transmission type, or the like is appropriately selected and used according to the application.

An LED 204 is a light emitter for indicating various states of the apparatus, such as warnings such as out of paper and paper jam, and receiving or executing a print job, and is a display unit that displays information together with the LCD 203. A plurality of LEDs 204 are provided for each apparatus state to be indicated. The LEDs 204 are arranged in the vicinity of the character information indicating the respective device states, and each LED 204 emits light according to the control of the image display control unit 122a. The operation unit 205 is an operation unit for the user to directly operate the image forming apparatus 1, and includes a touch panel that touches the screen of the LCD 203 and a switch provided separately on the display panel 200. The operation of the operation unit 205 by the user is processed by the ASIC 201, and a signal corresponding to the operation performed by the user is input to the operation control unit 122c via the display panel I / F 110.
Display data generated in the image display control unit 122 a and input to the display panel 200 via the display panel I / F 110 is input to the LCD controller 202 through the ASIC 201. The LCD controller 202 updates the display data stored in the display data memory 202a using the received display data, and drives the LCD 203 according to the display data. The refresh rate of the LCD controller 202 according to the present embodiment is 60 Hz. That is, the LCD controller 202 updates the display of the LCD 203 using the display data stored in the display data memory 202a regardless of whether or not new display data is received.

Here, the image display control unit 122a repeatedly transmits the display data to the LCD controller 202 regardless of whether or not the display data formed in the drawing area 122d is updated. That is, the transmission of display data from the drawing area 122d to the display data memory 202a is not executed only once when the display data of the drawing area 122d is updated by the image display control unit 122a, but the display data in the drawing area 122d is displayed. It is repeatedly executed even during a period in which data does not change. As a result, even when display data stored in the display data memory 202a is garbled due to electrostatic noise or transmission error, the display data is updated with correct display data. Can be solved.
In the image forming apparatus 1 having such a configuration, the gist of the present embodiment is that the display data supply from the image display control unit 122 a to the display panel 200 and the clock supply from the clock control unit 122 b to the ASIC 201 are performed by the image forming apparatus 1. By changing according to the operation state, power saving is achieved.

Hereinafter, the operation of the image forming apparatus 1 according to the present embodiment will be specifically described.
FIG. 4 is a flowchart illustrating the operation of the image forming apparatus 1 according to the present embodiment. As shown in FIG. 4, when the image forming apparatus 1 is switched to the power saving mode under the control of the apparatus control unit 120 (S401), the image display control unit 122a transmits display data of the drawing area 122d to the LCD controller 202. The clock controller 122b stops supplying the clock to the ASIC 201 (S402), and shifts the display panel 200 to the power saving state. The operation of S402 may be executed independently by the image display control unit 122a and the clock control unit 122b, or may be executed under the control of the device control unit 120. As a result, the display data update of the display data memory 202a by the image display control unit 122a is stopped, and the ASIC 201 stops its operation.

  Here, a specific mode of stopping supply of display data and a clock will be described. The supply of display data is stopped when the image display control unit 122a stops outputting display data from the drawing area 122d. As for the clock supply stop, the clock control unit 122b controls the display panel I / F 110 to block the input of the clock generated in the main body of the image forming apparatus 1 to the display panel 200. In addition, for example, the image display control unit 122a may not perform any particular processing, and may simply stop the clock supply to the ASIC 201. In this case, even if the display data is input from the drawing area 122 d to the ASIC 201, the clock is not supplied to the ASIC 201, so the display data is not transferred to the LCD controller 202, and the display data input to the LCD controller 202 is stopped. To do. The display data supplied via the display panel I / F 110 may be blocked by the display panel I / F control unit 122 controlling the ASIC 201. Here, it is preferable to stop the supply of display data and the clock by executing the display data and the clock with a higher-order configuration because signal transmission redundancy can be eliminated and more power can be saved.

  In a state where display data and clock supply to the ASIC 201 are stopped, the LCD controller 202 drives the LCD 203 using display data stored in the display data memory 202a according to a unique clock. In other words, in the power saving mode of the image forming apparatus 1, the LCD controller 202 continues to display the display data stored in the display data memory 202 a on the LCD 203. Therefore, the display on the LCD 203 does not disappear even when the supply of display data and the clock is stopped. Thus, further power saving can be achieved by stopping the clock supply to the display panel 200 and the display data supply to the LCD controller 202 in the power saving mode.

  On the other hand, when the operation unit 205 is operated, or when the power saving mode is canceled when the image forming apparatus 1 receives a new print job or the like (S403), the clock control unit 122b transfers to the ASIC 201. The image display control unit 122a resumes display data transmission of the drawing area 122d to the LCD controller 202 (S404). The display data and the clock supply may be restarted at the same time. However, when the clock supply from the clock control unit 122b to the ASIC 201 is stopped, the ASIC 201 receives the display data received from the image display control unit 122a from the LCD controller 202. Cannot transfer to. Therefore, in resuming the supply of display data and clock, it is preferable to restart the supply of display data from the image display control unit 122a after the clock supply from the clock control unit 122b is restarted first.

In the control of the display panel 200 in the power saving mode according to the present embodiment, power supply or the like is performed without changing from the normal time. Accordingly, when returning to the normal state, it is possible to return to the normal state only by restarting the supply of the clock and the supply of the display data. If power saving is achieved by stopping the supply of power or the like, it takes time to start up the apparatus by turning on the power again when returning to the normal state. Therefore, the power saving control according to the present embodiment makes it possible to quickly return to the normal state.
As described above, according to the image forming apparatus 1 according to the present embodiment, when the apparatus is switched to the power saving state, it is possible to realize power saving of the display unit without causing a display defect. It becomes possible.

In the above description, the example in which the display data and the clock supply are stopped according to the transition of the image forming apparatus 1 to the power saving mode and the display panel 200 is shifted to the power saving state has been described. Even when the apparatus 1 is in a normal state, after new display data is generated in the drawing area 122d by the image display control unit 122a, the display data is once transmitted to the LCD controller 202, and then the supply of display data is stopped. May be. Thereby, by eliminating the redundancy of data transmission from the image display control unit 122a to the LCD controller 202, further power saving of the display unit can be achieved. On the other hand, by performing the power saving control according to the present embodiment according to the transition to the power saving mode of the entire apparatus, it is possible to collectively execute the power saving control in the entire apparatus, thereby simplifying the processing. Can do.
Further, other requirements for determining the transition of the display panel 200 to the power saving state include, for example, a traffic amount of a LAN (Local Area Network) to which the image forming apparatus 1 is connected, and the image forming apparatus 1 is also connected. There is an operating environment of the image forming apparatus 1 such as the number of host devices connected to the connected LAN and time information. Based on this information, the possibility that the image forming apparatus receives a print job and the number of users who are working on the floor are predicted. Switch to power state. A specific example is shown in FIG.

  FIG. 5 is a diagram showing a time change graph of the traffic amount of the LAN to which the image forming apparatus 1 is connected and the state of the display panel 200 corresponding to the graph. As shown in the figure, the display panel 200 is normally operated when the traffic volume of the LAN to which the image forming apparatus 1 is connected is equal to or greater than a predetermined threshold value, and the power saving operation is performed when the traffic volume is equal to or smaller than the predetermined threshold value. Such control may be performed by the device control unit 120 of the image forming apparatus 1 or the host I / F control unit 121. Further, a plurality of control units may be interlocked. Further, based on the amount of traffic of the LAN to which the image forming apparatus 1 is connected, the number of connected host devices and time information, etc., it is determined whether or not the image forming apparatus 1 is shifted to the power saving state, and the display is accordingly performed. The state of the panel 200 may be changed.

In the above description, an example in which the display of the LCD 203 is continued using the display data stored in the display data memory 202a in the LCD controller 202 after the supply of the display data and the clock is stopped.
However, in the conventional image forming apparatus, there is a product in which the display on the display unit disappears in the power saving mode. In these products, display of the display unit is generally stopped by turning off the backlight of the LCD, and display data and a clock are supplied. Therefore, further power saving can be achieved by applying this embodiment to a device in which the display on the display unit disappears in the power saving mode.

In the above description, the display unit has been described as an LCD. However, the display unit need not be an LCD, and an organic EL (Eelectro Lluminescence) display, a CRT (Cathode Ray Tube) display, an FED (Field Emission Display), or the like can be displayed. Another display may be used as the unit. Even in such a case, the display control unit corresponding to the LCD controller 202 of FIG. 3 can perform screen display even when display data is not supplied to the display control unit. The same effect can be obtained.
In the above description, the example in which the display data is generated by the control unit configured in the memory 102 of the main body of the image forming apparatus 1 and the display data is input to the display panel 200 has been described. However, this embodiment can be applied even when display data is generated inside the display panel 200. For example, consider a case where a functional unit corresponding to the image display control unit 122a is configured in the ASIC 201. In such a case, a command corresponding to the print job is supplied from the device control unit 120 of the main body of the image forming apparatus 1 to the ASIC 201, and display data is generated in the image display control unit configured in the ASIC 201. In normal operation, display data generated in the ASIC 201 is supplied to the LCD controller 202. On the other hand, power saving can be achieved by stopping the supply of display data from the ASIC 201 to the LCD controller 202 during the power saving operation.

  In the above description, the example in which the clock is supplied from the main body of the image forming apparatus 1 to the display panel 200 and the ASIC 201 operates according to the clock has been described. However, even when the clock is generated inside the display panel 200, the present embodiment can be applied. For example, a clock generation unit is provided inside the display panel 200, and the ASIC 201 operates according to the clock in normal operation. On the other hand, power saving can be achieved by stopping the clock supply from the clock generator to the ASIC 201 during the power saving operation. As a specific mode of the clock supply stop, it can be performed by stopping the power supply to the clock generation unit or by blocking the signal between the clock generation unit and the ASIC 201. Further, as described in the above embodiment, the LCD controller 202 operates with its own clock. Accordingly, the LCD controller 202 and the ASIC 201 can share a clock source. As a result, an increase in the scale of the apparatus can be prevented. In such a case, the clock is supplied only to the LCD controller 202 during the power saving operation, and the clock supply to the ASIC 201 is stopped.

In the present embodiment, an example will be described in which display failure caused by the display data stored in the display data memory 202a of the LCD controller 202 not being updated in the power saving mode in the first embodiment is described. In addition, about the structure which attaches | subjects the code | symbol similar to Example 1, the same or equivalent part as Example 1 is shown, and description is abbreviate | omitted.
FIG. 6 is a block diagram showing the display panel 200 according to the present embodiment.
In FIG. 6, in addition to the functional configuration of the display panel 200, the power supply for each functional configuration is indicated by a dotted line. In addition to the example according to the first embodiment, the display panel 200 according to the present embodiment includes a noise filter 206 that cuts a noise component of the power supplied from the power circuit 112 of the image forming apparatus 1. The noise filter 206 is a filter that performs waveform shaping or the like on the power supplied from the outside to the display panel 200. Since power supply noise is generally generated mainly as a high frequency component, a low-pass filter is used as the noise filter 206, for example.

  In the power saving state of the display panel 200, that is, in the state where the display data is not supplied to the LCD controller 202 and the clock is not supplied to the ASIC 201, the LCD controller 202 has the display data memory 202a as described in the first embodiment. The LCD 203 is driven using the display data stored in. At this time, if the display data stored in the display data memory 202a changes to data different from the legitimate data due to electrostatic noise applied to the LCD controller 202 or the LCD 203, a transmission error, or the like, that is, garbled data. If this occurs, the display data in the display data memory 202a is not updated with the correct display data generated in the image display control unit 122a, so that the LCD 203 continues to be driven by the changed display data. . As shown in FIG. 6, by providing the noise filter 206, it is possible to reduce noise generated from the power source and prevent display data stored in the display data memory 202a from being garbled.

Further, as shown in FIG. 7, an electrostatic shield 207 for preventing electromagnetic wave noise or the like may be provided. Noise that contributes to garbled display data stored in the display data memory 202a can be generated not only by the power supply but also by other factors. Therefore, the display data stored in the display data memory 202a can be prevented from being garbled by providing the electrostatic shield 207 so as to cover each functional configuration included in the display panel 200. As the electrostatic shield 207, for example, a metal plate such as iron, an aluminum foil, or the like can be used.
Although FIG. 7 shows an example in which the entire display panel 206 is covered with the electrostatic shield 207, for example, only the LCD controller 202 and the LCD 203 may be covered. As a result, for example, noise generated inside the display panel 200 such as the ASIC 201 and the LED 204 can be prevented from affecting the display data memory 202a.
Further, an electrostatic film for preventing noise may be provided on the display surface of the LCD 203.

FIG. 8 is a cross-sectional view showing a state in which the display surface of the LCD 203 is cut in the vertical direction around the LCD 203 of the display panel 200.
As shown in FIG. 8, an electrostatic film 208 is provided on the display surface side of the LCD 203. In the downsized display panel 200, the LCD 203 and the LCD controller 202 are very close to each other, and noise from the display surface of the LCD may affect the display data memory 202a. Therefore, by providing an electrostatic film on the display surface of the LCD 203, noise from the display surface of the LCD 203 can be prevented. As the electrostatic film 208, for example, a transparent conductive film can be used. Specifically, Hibeam (registered trademark), which is a transparent conductive film manufactured by Toray (registered trademark), or the like is used.

In this embodiment, an example will be described in which display data supply and clock supply are not completely stopped in the power saving mode in the first embodiment. As described in the first embodiment, during the power saving operation of the image forming apparatus 1, the display data transfer from the image display control unit 122a to the LCD controller 203 and the clock supply to the ASIC 201 are stopped, thereby further saving. Electricity can be achieved. However, as described in the second embodiment, the display data stored in the LCD controller 203 is not updated. Therefore, when data in the display data memory 203a is garbled, there is a possibility that a display failure of the LCD 203 may occur. is there.
In addition, when the user performs any operation on the operation unit 205 in the power saving operation state of the display panel 200, the clock supply to the ASIC 201 is stopped and the ASIC 201 is in a non-operating state. However, it is difficult to recognize and process the type of operation that has been performed and to convey it to the operation control unit 122c.

Therefore, when the user operates the operation unit 205 in the power saving operation state of the display panel 200, the power saving operation state can be canceled and the normal state can be entered, but the user can operate the operation unit 205. It is difficult to cause the user to perform the operation, and the user needs to perform the same operation on the operation unit 205 again, which may cause confusion regarding the operation of the apparatus.
This embodiment addresses such issues and optimizes device operation while saving power by lowering the display data transfer frequency and the supply clock frequency during power-saving operation of the device than during normal operation. Plan.
In addition, about the structure which attaches | subjects the code | symbol similar to Example 1, the same or equivalent part as Example 1 is shown, and description is abbreviate | omitted. Further, the example in which the display data and the supply clock described in the first embodiment are completely stopped is an aspect of the signal input frequency reduction described in the present embodiment. This embodiment is contrary to the first embodiment. is not.

FIGS. 9A to 9E schematically show the timing of clock supply to the ASIC 201 and transfer of display data to the LCD controller 202 in the normal state and the power saving state of the image forming apparatus 1 according to the present embodiment. FIG.
FIG. 9A shows the normal state of the image forming apparatus 1. As shown in FIG. 9A, in the normal state of the image forming apparatus 1, a clock is supplied at a predetermined frequency and display data is repeatedly supplied.
FIG. 9B shows an example in which the clock frequency is lowered in the power saving state of the image forming apparatus 1. By reducing the frequency of the clock, power saving can be achieved and an operation corresponding to the operation of the operation unit 205 by the user can be performed. Further, as shown in FIG. 9B, the period required for one display data transfer becomes longer due to the decrease in the frequency of the clock supplied to the ASIC 201.
FIG. 9C shows an example in which the display data transfer interval is widened while the frequency of the clock supplied to the ASIC 201 remains unchanged. Power consumption can be reduced by reducing the display data transfer frequency. Further, since the clock is supplied in the same manner as usual, it is possible to deal with the user's operation on the operation unit 205 in the same way as usual.

FIG. 9D shows an example in which the display data transfer frequency is lowered and the clock is supplied to the ASIC 201 only when the display data is transferred, as in FIG. 9C. In the example shown in FIG. 9D, a clock is supplied to the ASIC 201 in accordance with the display data transfer timing. In addition to lowering the display data transfer frequency, the power supply can be further reduced by supplying the clock only when the display data is transferred. In addition, since a clock is supplied at the display data transfer timing, it is possible to respond to an operation on the operation unit 205 by the user at that timing.
FIG. 9E shows an example in which the display data transfer frequency and the supply clock frequency are lowered. In addition to lowering the display data transfer frequency, lowering the frequency of the supply clock can further reduce power consumption. Further, similarly to the example of FIG. 9B, an operation corresponding to an operation on the operation unit 205 by the user can be performed. As described above, according to the image forming apparatus according to the present embodiment, it is possible to realize an aspect equivalent to that during normal operation with respect to the operation aspect of the apparatus that the user feels while reducing the power consumption of the apparatus. It becomes.

1 is a block diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a functional block diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating a display device and its peripheral configuration included in an image forming apparatus according to an embodiment of the present invention. 6 is a flowchart illustrating an operation of the image forming apparatus according to the exemplary embodiment of the present invention. FIG. 6 is a diagram illustrating switching of an image forming apparatus according to another embodiment of the present invention to a power saving state. It is a block diagram which shows the display apparatus contained in the image forming apparatus which concerns on the other Example of this invention, and its periphery structure. It is a block diagram which shows the display apparatus contained in the image forming apparatus which concerns on the other Example of this invention. It is sectional drawing which shows the state which cut | disconnected the display surface of LCD of a display panel in the perpendicular direction. FIG. 10 is a diagram illustrating a display data and clock supply mode during normal operation and power saving operation of an image forming apparatus according to another embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 101 ... CPU, 102 ... Memory, 103 ... Storage, 104 ... Firmware, 105 ... Host I / F, 106 ... Paper feed tray, 107 ... Print engine, 108 ... Paper discharge tray, 109 ... Speaker, DESCRIPTION OF SYMBOLS 110 ... Display panel I / F, 111 ... System bus, 120 ... Apparatus control part, 121 ... Host I / F control part, 122 ... Display panel I / F control part, 122a ... Image display control part, 122b ... Clock control part , 122c ... operation control unit, 122d ... drawing control unit, 200 ... display panel, 201 ... ASIC, 202 ... LCD controller, 202a ... display data memory, 203 ... LCD, 204 ... LED, 205 ... operation unit, 206 ... noise filter 207: Electrostatic shield 208: Electrostatic film

Claims (11)

  A display unit for displaying information; a display data memory for holding display data before being displayed on the display unit; a display control unit for driving the display unit using display data held in the display data memory; An image forming apparatus, wherein the display data input frequency to the display data memory is changed according to at least one of an operation state and an operation environment.   In the normal state of at least one of the operation state and the operation environment, display data is repeatedly input to the display data memory, and the display on the display data memory is performed when the normal state is changed to the predetermined state. The image forming apparatus according to claim 1, wherein the data input frequency is lowered.   A transfer circuit for inputting the generated display data to the display data memory; in a state where the normal state is changed to a predetermined state and the input frequency of the display data to the display data memory is lowered; The image forming apparatus according to claim 2, wherein a clock is supplied to the transfer circuit in accordance with a transfer timing to the display data memory.   4. The image forming apparatus according to claim 1, wherein a clock frequency supplied to the transfer circuit is changed according to at least one of the operation state and the operation environment. 5.   2. The image forming apparatus according to claim 1, wherein when at least one of the operation state and the operation environment transitions from a normal state to a predetermined state, input of the display data to the display data memory is stopped. .   The transfer circuit for inputting the generated display data to the display data memory is provided, and the clock supply to the transfer circuit is stopped according to at least one of the operation state and the operation environment. Image forming apparatus.   The image forming apparatus according to claim 1, further comprising a filter that removes a noise component of power supplied to at least one of the display control unit and the display unit.   The image forming apparatus according to claim 1, further comprising an electrostatic shield that blocks an influence of electrostatic noise on at least one of the display control unit and the display unit.   The image forming apparatus according to claim 1, further comprising an electrostatic film on a display surface of the display unit.   The image forming apparatus according to claim 1, wherein an input frequency of the display data to the display data memory is changed according to a traffic amount of a connected network. A control method of an image forming apparatus equipped with a display device,
A first step of transferring display data before display to a display data memory temporarily holding, and a second step of detecting a change in at least one of the operating state and the operating environment, the operating state and A control method for an image forming apparatus, wherein the frequency of repeating the first step is changed according to at least one of operating environments.

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