JP5386649B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a printer, and more particularly to an image forming apparatus devised so as to exhibit an optimized power saving function when there is no paper to be fed. It is.

  Generally, in an electrophotographic image forming apparatus such as a copying machine, a printer, or a facsimile, if an error such as an abnormal fixing temperature or a paper jam is detected, there is a serious risk such as a fire hazard. , Processing to immediately stop the power supply to the fixing device is performed.

  Further, in the image forming apparatus disclosed in Patent Document 1, if power supply to the fixing device is stopped when an error occurs, the power supply is restored from the power supply stop state to the print state when the printing process is started. In consideration of the fact that it takes time to do so, the power supply setting in the standby state between the print state and the power supply stop state is adopted.

  Further, in a general image forming apparatus, when there is no paper to be fed to the paper feeding unit (hereinafter referred to as “paper empty”), it is uneconomical to leave the power supply to the fixing device with high power consumption as it is. For this reason, processing for shifting the power supplied to the fixing device to power supply in the standby state as described above is performed.

  The power supply in the standby state is performed with less power than the power supply amount in the normal printing state, so that power consumption is not wasted. In addition, when power supply is completely stopped, it takes time to recover from the power supply stop state to the print state when the printing process is started. It is set to intermediate power supply.

Japanese Patent Laid-Open No. 9-20047

  However, in the paper empty state as described above, unlike the error state such as failure of the fixing device or occurrence of a jam, there is no danger that the fixing device must be stopped urgently. There is plenty of room to consider.

  Also, even if it is called paper empty in a word, depending on the type of image forming apparatus such as whether the image forming apparatus is a printer, a copying machine, or a facsimile, or what type of paper has become paper empty. There are various modes such as the type of paper.

  In this way, various modes of power saving can be considered, and it is possible to select a rational power saving process by finely adjusting the power saving method according to the paper empty mode as a method of paper empty processing. It can be said that it is appropriate.

  Therefore, the present invention has been made in view of the above circumstances, and its purpose is to set an appropriate power saving mode according to the state of the paper empty when the paper empty occurs. An object of the present invention is to provide an image forming apparatus capable of achieving power saving according to the situation.

  In order to solve the problems, the present invention provides a paper feeding unit to the image forming apparatus, a paper type detecting unit for detecting the type of paper stored in the paper feeding unit, and the presence / absence of paper stored in the paper feeding unit. In the image forming apparatus provided with the detected paper empty detecting means, the effect can be exhibited without regret.

  That is, in the image forming apparatus having the above-described configuration, the paper empty detecting unit can detect that no paper is in any of the paper feeding units. It is also possible to detect whether such a type of paper is loaded in the image forming apparatus. Accordingly, the image forming apparatus can save power according to the purpose by setting the power saving mode according to the detected type of out-of-paper, and can be used for the convenience of the user.

  For this reason, the image forming apparatus according to the present invention is housed in the paper feeding means for the image forming apparatus, the paper type detecting means for detecting the type of paper stored in the paper feeding means, and the paper feeding means. A paper empty detecting means for detecting the presence or absence of a paper sheet, and the paper type detecting means when the paper empty detecting means detects that there is no paper in any of the paper feeding means. The image forming apparatus includes a power-saving mode setting unit that sets a subsequent power-saving mode according to the type of paper that is detected to be not.

  One of the modes of power saving as described above is to control power feeding to the fixing device in the direction of power saving. Another mode of power saving is to stop power feeding to the fixing device as a typical example. It is done.

  As another power saving mode, there is a power saving process in which the power supply to the fixing device is reduced to a predetermined power saving power lower than that during normal printing, that is, in the standby state.

  In order to automatically shift to such a power saving process, the type of paper to be transferred to a predetermined power saving mode is stored in advance, and the paper empty detection unit stores the above-described predetermined value. What is necessary is just to make it transfer to the said predetermined | prescribed power saving mode, when it detects that there is no paper. Such a method is very simple and easy to implement, reliable and economical.

  For example, when a paper with a remarkably large frequency of use (specified by size and feed direction) becomes paper empty, such as A4 size horizontal feed, the paper is immediately replaced and the printing process is resumed. Since it is predicted with a very high probability, it is apparent that the printing efficiency is remarkably lowered if the fixing stop process or the transition to the standby state is performed even if the A4 sheet is used up. Therefore, when such paper becomes paper empty, it can be determined that the temperature of the fixing device does not change or the amount of change is small even if it is changed so that printing can be resumed as smoothly as possible even if necessary. Should be shifted to a predetermined power saving mode.

  On the other hand, when paper becomes empty for paper that is not normally used, such as A3, the waiting time is slightly longer for the user who has become paper empty, but there is little damage for many other users. In consideration of the overall efficiency and economics of power saving, it is desirable to switch to a power saving state in which the temperature of the fixing device is set to a considerably low value even if the power supply to the fixing device is turned off or not turned off.

  Further, as means for automatically shifting to the power saving process, a paper usage frequency detecting means for automatically detecting the paper usage frequency, and the paper empty detecting means confirm that there is no paper in any of the paper feeding means. When the paper type detected by the paper type detection unit when detected is a highly used paper detected by the paper usage frequency detection unit, power is normally supplied to the fixing device. It is possible to reduce the power consumption to a predetermined power saving power lower than that at the time.

  Also, a sheet usage frequency detecting means for automatically detecting the usage frequency of the sheet, and when the paper empty detecting means detects that there is no sheet in any of the paper feeding means, the sheet type detecting means should not In the case where the type of paper detected is a paper with a high usage frequency detected by the paper usage frequency detecting means, one of the power saving modes is to gradually supply power to the fixing device every predetermined time. The power supply to the fixing device is stopped when a predetermined condition is satisfied, or the power supply to the fixing device is reduced to a predetermined power saving power lower than that during normal printing. Also good.

  Further, as one of power saving modes, it is desirable to stop the power supply to the fixing device when the image forming apparatus is a facsimile. In the case of a facsimile, since the frequency of use is relatively low and it is often unnecessary to restart printing immediately, it is desirable to perform processing that stops power supply in order to prioritize the power saving effect.

  In contrast, when the image forming apparatus is a copying machine or a printer, the power supply to the fixing device is reduced to a predetermined power saving power lower than that during normal printing (standby processing). It is desirable to adopt the embodiment. This is in line with the fact that it is often not resumed as slowly as facsimile.

  In the present invention, since the mode of subsequent power saving is set according to the type of paper that is basically detected as being unfeedable, for example, because frequently used paper is paper empty. If an early restart is anticipated, set a power saving mode that is more convenient for the early restart than the power saving effect. For example, if a large paper that is rarely used is paper empty, Since power saving priority processing such as processing or power supply stoppage is automatically set, the purposeful power saving for each paper can be achieved no matter what paper becomes paper empty.

1 is a cross-sectional view showing an entire color printer as an example of an image forming apparatus according to the present invention. It is a block diagram which shows the control system of the color printer which concerns on one Embodiment of this invention. 6 is a flowchart illustrating an example of a control procedure of the color printer according to the embodiment of the present invention. 6 is a chart showing an example of a correspondence relationship between a predetermined paper type and a use frequency in a color printer according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

  First, the outline of the image forming unit of the image forming apparatus according to the present invention will be described with reference to FIG. The present invention can be applied to various apparatuses such as a printer, a copying machine, and a facsimile apparatus as long as it is an electrophotographic image forming apparatus. In this embodiment, a color printer will be described as an example.

  First, an outline of a color printer X as an example of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG. The image forming apparatus X will be described here using a color printer as an example, but is not limited thereto, and may be a copier, a facsimile, a monochrome printer, or the like.

  As shown in FIG. 1, the image forming apparatus X includes four image forming units 101, two optical devices 102, and an intermediate transfer belt 103, as in a general intermediate transfer type image forming apparatus. . Further, a secondary transfer device 104, a paper feeding unit (an example of a paper feeding unit) 105, a fixing unit (an example of a fixing unit) 106, a paper discharge unit 107, and the like are provided.

  Here, the four image forming units 101 execute an image forming process for transferring toner images of respective colors of black, yellow, cyan, and magenta to the intermediate transfer belt 103, and the right side (intermediate transfer belt in FIG. 1). 103 in the order of black, yellow, cyan, and magenta. These image forming processes of the image forming unit 101 are not different for each color, but have the same configuration, and hence are collectively referred to as an image forming unit 101.

  The image forming unit 101 is written by irradiation (exposure) of a laser beam on the surface of the charged photosensitive drum 111, the photosensitive drum 111 that carries the toner image, a charging device that charges the surface of the photosensitive drum 111. A developing device that develops the electrostatic latent image with toner, a primary transfer device that transfers the toner image developed and formed on the photosensitive drum 111 to the intermediate transfer belt 103, and a toner remaining on the photosensitive drum 111 are removed. A cleaning device is provided.

  The two optical devices 102 are disposed below the image forming unit 101, and one of them is a laser beam L (beam light) for writing an electrostatic latent image on the photosensitive drum 111 for black and yellow. The other) outputs the laser beam L for writing the electrostatic latent image to the photosensitive drum 111 for cyan and magenta.

  The intermediate transfer belt 103 is an endless belt made of a material such as rubber or urethane, for example. The intermediate transfer belt 103 is wound around a driving roller 131 and a driven roller 132 and is driven to rotate. Pass between transfer devices.

  The image forming operation on the transfer material such as recording paper by the color printer X is not particularly different from that of the general image forming apparatus X, and the outline thereof is the photosensitive drum 111 which is first uniformly charged by the charging device. In addition, the optical device 102 irradiates the laser beam L so that the photosensitive drum 111 is exposed and an electrostatic latent image is written on the surface of the photosensitive drum 111. The electrostatic latent image is developed by a developing device, and a toner image is formed on the surface of the photosensitive drum 111. This is performed in the image forming unit 101 for each color.

  The toner images formed on the surface of the photosensitive drums 111 of the respective colors are sequentially transferred and stacked on the intermediate transfer belt 103 by the respective primary transfer devices, and a full color toner image is formed on the intermediate transfer belt 103. The full-color toner image formed on the intermediate transfer belt 103 is transferred by the secondary transfer device 104 onto a recording sheet fed one by one from the paper feeding device 105. Thereafter, the toner is fixed on the recording paper by the fixing device 106, and the recording paper on which the image is formed is discharged to the paper discharge unit 107.

  After the toner image is transferred to the intermediate transfer belt 103, the toner remaining on the surface of the photosensitive drum 111 is removed by a cleaning device.

  Thus, the color printer X forms a color image on a transfer material such as recording paper.

  FIG. 2 is a block diagram showing the control system of the color printer X described above. The control procedure of the color printer X described later is achieved by the control system shown in this block diagram.

  As shown in FIG. 2, the control system of the color printer X according to the present embodiment includes a paper feeding unit 105, an image forming unit 101, a fixing unit 106, a paper discharge unit 107, and the like as basic components. The paper feed unit 105 is provided with a plurality of paper feed cassettes (here, for convenience, it is assumed that there are two paper feed cassettes). Each paper feed cassette has a sheet in each paper feed cassette. Paper sensors 105a and 105b for detecting whether or not there are provided. Signals relating to the presence or absence of paper from the paper sensors 105a and 105b are always transmitted to the control unit 7. Also, the correspondence between each paper feed cassette and the type of paper contained therein is known, and an example is shown in FIG.

  A toner image is formed in the image forming unit 101 on a transfer material (hereinafter, simply referred to as “paper P”) such as paper or an OHP film supplied from the paper feed cassette as described above. The toner image is heated and pressed on the paper P by the fixing unit 106 and fixed, and the paper P on which the toner is fixed is discharged to the paper discharge unit 107.

  As shown in FIG. 2, the temperature of the fixing roller 106 a provided in the fixing unit 106 is constantly measured by a fixing temperature sensor 106 b provided in the vicinity of the fixing roller 106 a and is transmitted to the control unit 7.

  All operations of the color printer X as described above are controlled by the control unit 7 including a computer.

  That is, the control unit 7 receives signals from the fixing temperature sensor 106b, the paper sensors 105a and 105b, and the control unit 7 follows the control procedure (program) described later based on these signals. By controlling the temperature of the fixing roller 106a via the drive unit 106c, an appropriate temperature can be maintained and power saving can be achieved.

  Next, a procedure for controlling the temperature of the fixing roller 106a according to a signal from the paper sensor 105a or 105b of one of the paper feed cassettes in the color printer X described above will be described.

  In the following description, S1, S2,... Are identification codes of control procedures (steps).

  The process is executed when the printer X performs a printing process.

  During the printing process, the control unit 7 constantly monitors the signals from the paper sensors 105a and 105b to determine whether or not the paper in any of the paper cassettes has been exhausted (whether a paper empty signal has been received) (S1). ).

  When the paper empty signal is received (Yes in S1), the control unit 7 determines the type of paper stored in the paper empty paper cassette (S2). As described above, this determination is made based on the correspondence between the paper cassettes that are predetermined and stored and the paper (size and direction) stored therein. An example of the correspondence table is shown in FIG. The frequency of use in the correspondence table is described for reference in consideration of human judgment, and the control unit 7 itself can be used only by making the following judgment based on the position (number of stages) of the cassette. It does not judge or refer to the frequency.

  Here, it is shown that the A4 landscape paper feed cassette C1 is mounted at the top. The use frequency item indicates that the A4 landscape feeding cassette C1 has a high use frequency when viewed from the human side, and other than that, it is determined that the use frequency is low.

  When the paper empty is detected as described above, the control unit 7 controls the power supply to the fixing roller 106a in the power saving direction. That is, first, it is determined whether or not the cassette in which the paper empty is detected is the uppermost cassette. From a human sense, this means that it is determined whether the paper cassette in which the paper empty is detected is a cassette that stores frequently used paper.

  If it is determined that the cassette in which the paper empty is detected is the uppermost cassette (the paper with the highest use frequency is paper empty) (Yes in S2), the process proceeds to S3. If it is determined that the cassette is not the uppermost cassette, the process proceeds to S9.

  That is, when the paper sensor detects that there is no paper in any of the cassettes, the subsequent power saving mode changes according to the type of paper detected by the paper sensor as shown below. . The power saving mode setting means sets such a power saving mode.

  In S3, the control unit 7 starts driving the built-in timer. Here, there are two timers, timer 1 and timer 2. Timer 1 times out in a predetermined time, for example, 5 minutes, and timer 2 has a predetermined time for transition to a standby state. Time goes up with progress. The transition of the timer 2 to the standby state is a value such as 20 minutes or 30 minutes, for example.

  When the timers 1 and 2 start timing, the timer 1 waits until the value of the timer 1 elapses for 5 minutes (S4). When the value of timer 1 has elapsed 5 minutes (Yes in S4), the control unit 7 inputs a value obtained by lowering the set temperature by 5 ° C. to the fixing roller driving unit 106c, and the fixing roller driving unit 106c is based on this command. Then, the set temperature of the fixing roller 106a is lowered by 5 ° C. (S5).

  In S4, if 5 minutes have not elapsed, it is determined whether the paper has been replenished (S12). If not replenished, the process returns to S4. (S14).

  Following the processing of S5, the control unit 7 detects the time count of the timer 2 and determines whether or not the predetermined standby time has elapsed (S6).

  If the waiting time has not elapsed (No in S6), it is determined from the value of the paper sensor 105a or 105b of the cassette where paper empty has occurred whether or not paper has been supplied to the cassette.

  If the paper is not replenished, the process returns to S3b. If the paper is replenished, the process returns to the printing state (S16), and further returns to the start (S17).

  When the process is S3, the timer 1 is reset. At this time, the timer 2 is not reset and the time measurement is continued.

  Therefore, every time the timer 1 measures 5 minutes, the set temperature of the fixing roller is decreased by 5 ° C., and the temperature of the fixing roller is decreased by 5 ° C. every 5 minutes (S5). Repeat the process to determine whether the time has been counted.

  While such control is repeated, when the timer 2 measures the elapse of a predetermined standby time in S6 (Yes in S6), the control unit 7 stops the power supply to the fixing roller. At the same time as (S7), it waits for paper to be replenished for the cassette that has become paper empty.

  If the paper sensor 105a or 195b detects paper empty for a frequently used (uppermost cassette (A4 landscape feed paper)) paper by the control as described above, it is fixed at a cycle of 5 minutes or the like. While the temperature is gradually lowered, the printer returns to the printing state as soon as the paper is supplied. This state is continued for a predetermined waiting time. As a result, the fixing temperature can be quickly returned to the printing state as soon as the paper is replenished as soon as possible. If the paper is frequently used, even if paper empty occurs, it is expected that the paper will be replenished immediately. However, prioritizing the convenience of early return) waits for paper supply.

  On the other hand, if it is determined in S2 that the cassette where the paper empty is detected is not the uppermost cassette (C1), that is, it is a cassette that is relatively infrequently used in human sense (No in S2). ), The process proceeds to S9, and it is determined whether the type of printing currently being performed is facsimile, copying, or printer work. This determination can be made only in the case of a multifunction machine, but the control unit 7 can automatically determine which mode is currently used.

  If it is determined in S9 that the print type is a printer or a copy, the control unit 7 controls the fixing roller driving unit 106c to control the temperature of the fixing roller 106a to a predetermined standby temperature as usual (S10). .

  When paper empty occurs on a low-use sheet, the number of people using the cassette is small, so there is a high possibility that the printer X will be left unattended. Therefore, it is important to save power by lowering the fixing temperature in the neglected state.

  Further, if it is determined in S9 that the current print type is facsimile, the frequency of use of the facsimile is lower, so the power to the fixing roller 106a is turned off to give priority to power saving (S11).

  All of the color printers X described above handle the frequency of use of the paper as known in advance. For example, as shown in FIG. 4, the A4 horizontal feed is used frequently: high, the A4 vertical feed is used frequently, the others are low, etc. Assuming that the cassette is set in the second level, if the number of cassettes with paper empty is known, the frequency of use is also assumed. Strictly speaking, however, the frequency of use of paper may vary depending on recent results. In such a case, a method of automatically detecting the use frequency of the paper can be taken.

  Since the usage frequency of such paper is synonymous with how many cassettes are used frequently, the usage frequency of the paper used is calculated by obtaining the usage frequency of the used cassette or the data of the usage frequency and the number of days. Providing the frequency detection means is usually a well-known technical matter.

  Accordingly, in a color printer having a paper usage frequency detecting means for automatically detecting the paper usage frequency as described above, there is no paper in any cassette by signals from the paper sensors 105a, 105b,. If the detected paper type is a highly used paper detected by the paper usage frequency detecting means, the paper is immediately supplied and the printing process is resumed. Since there is a high possibility, as described in S3 to S6, as described above in S3 to S6, the power supply to the fixing roller 106a is gradually reduced every predetermined time (for example, 5 minutes), and a predetermined waiting time is set. When a predetermined condition such as is satisfied, power supply to the fixing roller 106a is stopped, or power supply to the fixing roller 106a is performed as described in S10. It is also possible to adopt a power saving process that decreases until the power-saving power lower predetermined standby state than at the time of normal printing.

7 Control unit 101 Image forming unit 105 Paper feeding unit 105a, 105b Paper sensor 106 Fixing unit 106a Fixing roller 106b Fixing temperature sensor 106c Fixing roller driving unit

Claims (1)

Paper feeding means;
Paper type detection means for detecting the type of paper stored in the paper supply means;
Paper empty detection means for detecting the presence or absence of paper stored in the paper supply means;
A fixing device having a fixing roller and fixing the toner to the paper;
When the paper empty detecting means detects that there is no paper in any of the paper feeding means during execution of the printing process , the printing process is interrupted, and the paper type detected by the paper type detecting means is not present And a power saving mode setting means for setting a subsequent power saving mode,
One of the power saving modes is to reduce the set temperature of the fixing roller every time a predetermined time elapses only when the paper type detected by the paper type detection means is a highly used paper , When the power supply to the fixing device is stopped after a lapse of a standby time longer than the predetermined time, and a high-use paper is fed before the standby time elapses, the process returns to the printing process and is not a high-use paper. in this case, the image forming apparatus is shall stop the power supply to the fixing device.