JP2010132400A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recorder for reducing noise by automatically being switched to a paper feeding speed depending on the noise of an operational environment in printing. <P>SOLUTION: When a printing job is generated, a noise level immediately before starting the printing of the operational environment is detected by a sound sensor 26 and a noise level detecting part 29 as a noise level detecting means, and when the detected noise level immediately before starting the printing is smaller than a threshold, a paper feeding mode of printing paper is switched to a silent sound paper feeding mode from an ordinary paper feeding mode by a control part 27 as a mode switching means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as an inkjet printer having a printing function in a normal paper feeding mode and a printing function in a silent paper feeding mode that has a slower paper feeding speed and a smaller generated sound. .

  Conventionally, in image forming apparatuses such as inkjet printers used in offices and homes, printing paper such as plain paper, coated paper, OHP sheets, glossy paper, glossy film, etc., laminated on the hopper, A method of feeding one sheet at a time is generally employed. A separation pad that contacts the sheet feeding roller is arranged in the feeding path, and the sheet is fed one by one using friction between the separation pad and the sheet. To do. Further, in order to prevent the next (second) and subsequent sheets from being double-fed together with the uppermost sheet, a paper return lever is generally provided for returning the double-fed paper to the hopper side. When the paper is returned, the paper feed roller is rotated in the reverse direction to rotate the paper return lever toward the hopper so as to push the double fed paper back to the hopper. In the paper returning operation, there is a configuration in which the cam mechanism works to move the hopper from the hopper up position to the hopper down position.

  In such an image forming apparatus, generally, the feeding speed of the printing paper is set so that the printing time is the shortest, and the paper feeding operation is performed by one paper feeding operation regardless of the type and printing resolution of the printing paper. Done at speed. During printing, mechanical noise is generated due to contact of a hopper, a separation pad, and a paper feed roller that feeds printing paper. The noise increases as the paper speed increases to shorten the printing time. It can become loud and annoying noise.

  In order to reduce such annoying noise, the silencer generates a sound with the same phase and the same sound pressure as the mechanical sound, and cancels the mechanical sound with the generated sound to reduce the noise. It has been proposed (see, for example, Patent Document 1).

  On the other hand, in this type of image forming apparatus, the applicant has determined that the normal paper feed mode print function in which the print paper feed speed is set so as to minimize the print time, and the print paper feed speed to be set accordingly. It has a low-noise low-noise quiet paper feed mode (noise reduction mode) printing function, switching the paper feed speed according to user settings, print paper type and print resolution, and reducing noise The invention has already been invented (see, for example, Patent Document 2).

JP 2007-171487 A (Abstract, paragraphs [0002], [0015], [0020]-[0022], FIG. 1, FIG. 4, etc.)

Japanese Unexamined Patent Publication No. 2001-97579 (abstract, paragraphs [0007], [0010], [0028]-[0033], FIG. 1, FIG. 7, etc.)

  When the silencer is separately prepared and silenced as in the above-mentioned Patent Document 1, it is costly and requires an installation space. In addition, the image recording device, the silencer, and the user are in a certain arrangement position. If not related, it is ineffective and impractical.

  By the way, whether or not the mechanical sound generated by feeding the printing paper is perceived as unpleasant noise by the user is related to the environmental sound (noise) of the operating environment of the image forming apparatus, and the operating environment is quiet. If there is, the possibility that the user will feel the paper feed sound in the normal paper feed mode as an unpleasant noise regardless of the type of printing paper or the like increases.

  However, this type of image forming apparatus has not been invented to reduce noise in consideration of noise in the operating environment.

  In the image forming apparatus disclosed in Patent Document 2, it is conceivable that the user designates (sets) the normal paper feed mode or the silent paper feed mode in consideration of the noise of the operating environment. It is necessary to specify (set) the mode every time, which is not convenient and practical. Therefore, the paper feed mode specified (selected) in consideration of noise in the operating environment at the time of initial setting or the like is saved in the nonvolatile memory, and the paper feed mode saved in the nonvolatile memory is used for subsequent printing. It is conceivable to feed the paper in the normal paper feed mode or the silent paper feed mode based on the image, but the noise state of the operating environment varies not only depending on the location of the operating environment of the image forming apparatus but also depending on the time zone, etc. However, since the change is not always regular, even if such an initial setting is made, at the time of each printing, printing is performed in an appropriate paper feeding mode according to the noise of the operating environment at that time. It is not possible to reduce noise.

  The present invention has been made in view of the above problems, and provides an image forming apparatus that automatically switches to a paper feed speed according to noise in an operating environment when printing is performed to reduce noise. With the goal.

  In order to achieve the above object, an image forming apparatus according to the present invention is an image forming apparatus having a printing function in a normal paper feeding mode and a printing function in a silent paper feeding mode having a lower paper feeding speed than that. Noise level detection means for detecting the noise level immediately before the start of printing in the operating environment due to the occurrence of, and when the noise level immediately before the start of printing detected by the noise level detection means is less than a threshold, the printing paper feed mode is set to Mode switching means for switching from the normal sheet feeding mode to the silent sheet feeding mode.

  In this case, every time a print job is generated, the noise level detection means detects the noise level of the operating environment immediately before the start of printing, and if the detected noise level immediately before the start of printing is lower than the threshold and the operating environment is quiet, the mode The switching unit switches the paper feeding mode of the printing paper from the normal paper feeding mode to the silent paper feeding mode. Therefore, it is possible to reduce the noise by automatically switching to a paper feed speed according to the noise of the operating environment when printing.

  The threshold value is a ratio of the integrated value of the print time of the noise level including the print sound of the normal paper feed mode and the integrated value of the print time of the noise level including the print sound of the silent paper feed mode ( It is preferable that the noise level before the start of printing in the operating environment is set to the magnitude of the noise level.

  In this case, pay attention to the fact that the volume of the printing sound during printing that gives the user discomfort differs depending on the noise level of the operating environment before printing, and that the discomfort given to the user depends on the total amount of noise level during printing. Based on the integrated value of the printing time of the noise level including the printing sound of the normal paper feeding mode and the integrated value of the printing time of the noise level including the printing sound of the silent paper feeding mode, the two integrated values are a constant ratio (equal to Since the threshold value is set so as to include a case, it is possible to further reduce noise.

  Further, under the condition that the noise level of the operating environment immediately before the start of printing detected by the noise level detection means does not depend on time, the fixed ratio is the feeding speed in the normal feeding mode and the feeding speed in the silent feeding mode. It is practical to be a ratio of

  An embodiment of the present invention will be described in detail with reference to FIGS.

(One embodiment)
An embodiment will be described with reference to FIGS.

  1 is a perspective view from the front of an ink jet printer 100 as an image forming apparatus of the present invention, FIG. 2 is a perspective view from the back of the printer 100, and FIG. 3 is a perspective view of a paper feeding device 1 provided in the printer 100. 4 is a cross-sectional view taken along the line II of FIG. 3, FIG. 5 is a front view showing the main configuration of the paper feed roller unit, FIGS. 6 to 8 are explanatory views of the operation of the paper feed device 1, and FIG. FIG. 10 is a flowchart for explaining the switching of the paper feed mode for reducing noise.

  A printer 100 shown in FIGS. 1 and 2 is provided with a carriage mechanism, an auto sheet feeder (ASF) sheet feeding device 1 and the like in a main body 101, a paper discharge port 102 provided on the front surface of the main body 101, and the main body 101. A manual paper feed port is provided on the rear surface. Further, a tray 104 for an auto sheet feeder is disposed above the manual sheet feeding port 103 on the rear surface of the main body 101, and a paper gap is switched beside the sheet feeding port 103 according to the thickness of the recording medium. An adjustment lever 201 for releasing the nip point of the driven roller with respect to the paper feed roller is disposed so as to protrude from the main body 101.

  The recording paper P on the tray 104 is fed and conveyed by the paper feeding roller of the paper feeding device 1 and is taken into the main body 101, and is further nipped by the conveying roller and conveyed to the print head 106. After printing with the color ink of the discharged ink cartridge 105, the ink is discharged from the paper discharge port 102. The recording paper manually fed to the paper feed port 103 is also printed by the ink cartridge 105 and then discharged from the paper discharge port 102.

  As the recording paper P of the tray 104, plain paper, special paper, recommended OHP sheet, glossy paper, glossy film, label sheet, government postcard, and the like can be used.

  The adjustment lever 201 slides stepwise in the direction of the arrow a along the slit 110 provided linearly on the main body 101 so that the paper gap can be switched and the nip point of the driven roller with respect to the paper feed roller can be released. It has become. Here, the paper gap switching is performed regardless of the distance between the paper surface and the nozzle opening surface of the print head 106, that is, the paper gap, in order to maintain the printing accuracy at a substantially constant high accuracy regardless of the thickness of the recording paper. The print head 106 is moved and adjusted so that it is always substantially constant.

  A sheet feeding device 1 shown in FIG. 3 includes a sheet feeding roller shaft 3 and a hopper 4 that are rotatably supported by a frame 2, and a pair of sheet feeding roller units 5 are attached to the sheet feeding roller shaft 3. . One paper feed roller unit 5 is disposed in the vicinity of the right frame 2 in the figure constituting the tray 104, and the other paper feed roller unit 5 is movable along the paper feed roller shaft 3. The slidable paper feed roller unit 5 is connected to an edge guide 6 that moves parallel to the paper placement surface of the hopper 4 of the tray 104 and guides one side edge of the paper, and adjusts it according to the paper width. It is possible.

  The paper feed roller shaft 3 is supported by projecting from the frame 2. A hopper cam 8 for hopper down and a roller driving gear 9 for transmitting a driving force of a motor (not shown) to the paper feed roller shaft 3 are provided at one shaft end. It is fixed. At the other end of the shaft, the sheet feeding roller 7 of each sheet feeding roller unit 5 is stopped by rotating once for each sheet feeding operation, that is, the linear portion of the side-view D-shaped sheet feeding roller 7 is separated by a separation pad. An encoder 10 is provided for extracting a signal for stopping at a position (reset position) opposed to 11. A hopper cam 8 that is paired with the hopper cam 8 is fixed to the paper feed roller shaft 3 inside the frame 2 where the encoder 10 is disposed.

  The hopper 4 is inclined as shown in FIG. 4, the upper end is pivotally supported by the frame 2 by a support shaft 4 a, and the lower end extends to the sheet feeding area of the sheet feeding roller 7. The paper P is set in a stacked state. Under the hopper 4, a hopper spring 21 is disposed between the subframe 20 and the back surface of the hopper 4, and constantly urges the lower end of the hopper 4 to the hopper up position on the paper feed roller 7 side. . As shown in FIG. 8, cam followers 22 are formed at both lower portions of the hopper 4. The hopper 4 is moved from the hopper up position to the hopper down position against the urging force of the hopper spring 21 by the contact of the hopper cam 8. To operate. When the paper feed roller 7 starts to rotate from the reset position, the contact between the hopper cam 8 and the cam follower 22 is released, and the hopper 4 is moved to the hopper up position by the hopper spring 21.

  Since the feed roller unit 5 has the same configuration except that one is fixed and the other is slidable, the description will be made here with the slide-side feed roller unit. FIG. 5 is a front view showing the main configuration of the paper feed roller unit 5.

  The paper feed roller unit 5 includes a sub-frame 20 that supports the separation pad 11 and the paper return lever 12, and the sub-frame 20 includes an inclined surface of the frame 2 where the hopper 4 is located as shown in FIG. Then, a base portion 20a facing each of the substantially horizontal surfaces extending forward, and a side portion 20b through which the paper feed roller 7 passes are extended from the base portion 20a. The paper feed roller 7 and the paper return disk 13 are formed integrally with a bush 14, and the bush 14 is attached to a side portion 20 b of the subframe 20. The bush 14 is fitted so as not to rotate with respect to the paper feed roller shaft 3 and to be slidable in the axial direction. The paper feed roller 7 is configured as a D-type in a side view, and the roller surface is formed of a high friction material such as rubber.

  As shown in FIG. 4, the separation pad 11 is fixed to a separation pad holder 15 pivotally supported by a support shaft 15a on a subframe 20 on the back side of the hopper 4, and has a friction coefficient with respect to the paper P. The material is smaller than the coefficient of friction of the paper feed roller 7. Assuming that the friction coefficient between the paper feed roller 7 and the paper P is μ1, the friction coefficient between the separation pad 11 and the paper P is μ2, and the friction coefficient between the papers is μ3, the relationship is μ1> μ2> μ3. It has become. The separation pad holder 15 is biased by the pad spring 16 so as to be rotated toward the paper feed roller 7, thereby positioning the separation pad 11 in the rotation path of the paper feed roller 7.

  The idle roller 17 is supported by a roller holder 18 movably attached along the side portion 20 b of the sub frame 20, and is disposed so as to contact the separation pad 11. The idle roller 17 can move in the direction of the separation pad 11 and can rotate with the roller shaft of the roller holder 18 as a guide. The roller holder 18 is always urged in the direction of the separation pad 11 by a roller spring 19 formed of a coil spring, and the idle roller 17 is brought into contact with the separation pad 11. The roller spring 19 is set to a biasing force smaller than the pad spring 16. A cam 23 and a cam follower 24 are provided for causing the idle roller 17 and the separation pad 11 to contact and separate in accordance with the paper feeding operation. The linking operation of the idle roller 17 and the separation pad 11 is separated when the leading edge of the paper passes, and after the leading edge of the printing paper has passed, the printing paper between the arc portion of the paper feeding roller 7 and the separation pad 11 is interposed. The idle roller 17 is brought into contact with the separation pad 11 before the released contact is released.

  The paper return lever 12 is rotatably supported by the subframe 20 and is urged toward the hopper 4 by a paper return spring (not shown). The disc 13 of the bush 14 facing the paper return lever 12 is provided with a recess 13a that acts to push the paper return lever 12 toward the hopper 4 during the paper return operation. FIG. 6 shows a separation state of the printing paper P that is double-fed when the uppermost printing paper P is fed. FIG. 6A shows the relationship between the paper feeding roller and the double-fed printing paper P, and FIG. 6B shows the relationship between the paper return lever and the double-fed printing paper. When the paper feed roller 7 is reversed from the stop position in FIG. 6 (A) in the direction of the arrow in the figure, the disk 13 simultaneously moves the paper return lever 12 into the recess 13a as shown in FIG. 6 (B). In this state, it is reversed in the direction of the arrow in the figure.

  That is, the paper return lever 12 enters the recess 13a of the disk 13 when the disc is reversed, and when the reverse rotation continues further, the paper return lever 12 is pushed by the rear wall 13b of the recess 13a and moves the paper return lever 12 toward the hopper 4. The double fed paper is pushed back into the hopper 4.

  When the sheet feeding device 1 configured as described above operates, a unique sound is generated when each section is activated (during printing). This sound includes sounds that are irrelevant to the paper feed speed (such as the sound that occurs when the motor of the paper feed roller rotates) and sounds that change the sound level according to the paper feed speed (such as the operation of the separation pad and hopper). The main sounds that change the sound level in relation to the paper feed speed are the friction sound (first generated sound) that occurs between the paper feed roller and the separation pad during the paper return operation, There is a striking sound (second generated sound) that is generated when the hopper hits the paper feed roller in the hopper up operation after the paper operation starts. These generated sounds will be described with reference to FIGS. 6 and 7 show the paper return operation, and FIG. 8 shows the hopper up operation.

  When the paper feed roller shaft 3 is reversed from the state of FIGS. 6A and 6B and the paper feed roller 7 and the disk 13 are reversed, the recess 13a of the disk 13 is formed as shown in FIG. When pushed by the rear wall, the paper return lever 12 rotates in the direction of the arrow. As the paper return lever 12 rotates, the paper P that has been double fed is pushed back to the hopper 4, and the paper P is no longer interposed between the paper feed roller 7 and the separation pad 11 as shown in FIG. Since the first generated sound is in a state where the outer peripheral surface of the paper feed roller 7 and the separation pad 11 are in contact with each other by the urging force of the pad spring 21 in the paper returning operation (FIG. 7A), the friction between both members is large. It happens.

  The second generated sound is generated in the process from the paper returning operation until the paper is picked up in the next paper feeding operation. That is, in the hopper 4, as shown in FIG. 8A, the hopper cam 8 acts on the cam follower 22 slightly before the end of one rotation of the paper feed roller 7, and the hopper down starts. Locked to the hopper 4. The locked state of the hopper 4 is maintained until immediately before the sheet feeding roller 7 picks up the sheet in the next sheet feeding operation. As shown in FIG. 8B, when the hopper cam 8 releases the locking claw 25 and the hopper 4 by the rotation of the paper feed roller 7, the hopper 4 moves from the hopper down position to the hopper up position. The urging force of the spring 21 causes the tip of the hopper 4 to hit the paper feed roller 7 and a striking sound is generated. As for the level of the second generated sound, the speed at which the hopper cam 8 moves away from the cam follower 22, that is, the higher the rotational speed of the hopper cam 8, the momentary separation occurs. As a result, the speed at which the hopper 4 hits the paper feed roller 7 is faster. Therefore, a loud hitting sound is generated.

  The printing sound accompanying the feeding of the printing paper P including the first and second generated sounds tends to increase as the feeding speed increases. For this reason, it is advantageous to perform paper feeding at a low speed in order to reduce noise.

  Next, as shown in FIG. 1, the printer 100 includes a sound sensor 26 that detects an environmental sound (noise) of the operating environment of the printer 100, for example, at an appropriate location in the main body 101. The sound sensor 26 is simply a small microphone, but may have any configuration as long as it can detect the sound of the operating environment, and may be a so-called sound level meter.

  Next, paper feed control for automatically reducing printing sounds such as the first and second generated sounds according to noises in the operating environment will be described with reference to FIGS.

  FIG. 9 is a block diagram of paper feed control of the printer 100. When a print job occurs, the control unit 27 of FIG. 9 prints from a print driver of the main control unit (host computer) or the like (not shown) of the printer 100. When the job is received, the control unit 27 selects a paper feed sequence corresponding to the paper type and resolution included in the print job from a plurality of paper feed sequences prepared in advance based on the print command of the received print job.

  Information on drive control of the paper feed roller 7 of the paper feed device 1 and the conveyance roller (not shown) for each paper feed sequence is held in a non-volatile sequence information storage unit 28. At this time, the drive control information for each paper feed sequence includes control information for the normal paper feed mode in which the paper feed roller 7 is controlled at a speed slower than the normal speed and the print paper is fed at the normal paper feed speed v0. And the control information of the silent paper feed mode in which the paper feed roller 7 is controlled at a speed slower than the normal speed to feed the printing paper at the paper feed speed v1 slower than the paper feed speed v0.

  The paper feed control block of the printer 100 includes a noise level detection unit 29 that forms the noise level detection unit of the present invention together with the sound sensor 26, and the control unit 27 forms the mode switching unit of the present invention.

  The control unit 27 that has received the print job instructs the noise level detection unit 29 to detect noise, and the noise level detection unit 29 operates when the paper feed roller 7 and the transport roller are operated from the occurrence of the print job. The latest noise level of the operating environment detected by the sound sensor 26 until the operation of the printer, that is, the noise level [dB] of the operating environment immediately before the start of printing that does not include the printing operation sound such as the paper feeding sound of the printer 100. Is detected (step S1 in FIG. 10).

  Further, the noise level immediately before the start of printing detected by the noise level detection unit 29 is sent to the control unit 27, and the mode switching means formed by the control unit 27 is, for example, a threshold [dB] held in the sequence information storage unit 28. And the detected noise level immediately before the start of printing (step S2 in FIG. 10). If the detected noise level is equal to or greater than the threshold value and the noise in the operating environment of the printer 100 is high, the selected paper feed sequence is selected. The control information for the normal paper feed mode is read from the sequence information storage unit 28 (step S3 in FIG. 10). On the other hand, when the detected noise level is smaller than the threshold value and the noise in the operating environment of the printer 100 is small, the control information of the silent sheet feeding mode of the selected sheet feeding sequence is read from the sequence information storage unit 28 (step in FIG. 10). S4).

  Then, the control unit 27 controls the paper feed roller driving unit 30 and the conveyance roller driving unit 31 according to the control information read by the mode switching unit of the control unit 27 (step S5 in FIG. 10). The paper feed roller drive unit 30 is configured by a paper feed roller motor such as a stepping motor, and drives the paper feed roller motor based on the drive control of the control unit 27 to make the paper feed roller 7 a paper feed sequence. Accordingly, the printing paper P rotates in the forward and reverse directions and feeds the printing paper P at the paper feeding speed in the normal paper feeding mode or the silent paper feeding mode. The conveyance roller drive unit 31 is configured by a conveyance roller motor such as a DC motor or a stepping motor. The conveyance roller drive unit 31 drives the conveyance roller motor based on the drive control of the control unit 27, and the conveyance roller is forward and reverse according to the conveyance sequence. The paper P that has been fed is conveyed to the print head 106.

  Therefore, when the operating environment immediately before the start of printing of the printer 100 is quiet with a noise level lower than the threshold, the feeding speed of the printing paper P is automatically changed from the feeding speed v0 in the normal feeding mode to the feeding in the noise feeding mode. By switching to the paper speed v1, the paper feeding sound can be reduced.

  By the way, the threshold value may be a default value (standard value) set at the time of manufacturing the printer 100 or the like. However, in order to set a more appropriate value according to the actual operating environment, for example, the operation unit (see FIG. By selecting a threshold setting, which is one of the operation settings of the printer 100, the noise level at that time detected by the sound sensor 26 is displayed on the liquid crystal display unit (not shown) of the main body 101 and displayed. Based on the noise level, the user can set (change) an appropriate value as the threshold value and write (rewrite) it to the sequence information storage unit 28. By doing so, the effect of noise reduction is further improved.

(Other embodiments)
Another embodiment will be described with reference to FIGS. 1, 9 and 11.

  In the present embodiment, the difference from the one embodiment is the setting of the threshold value in the noise level detection unit 29 of FIG.

  Whether or not a printing sound such as a paper feeding sound of the printer 100 gives an unpleasant feeling to the user is determined by a relative relationship between the noise level of the operating environment of the printer 100 and the volume of the printing sound.

  Therefore, in the present embodiment, the threshold value is the integrated value of the print time of the noise level including the print sound in the normal paper feed mode and the print of the noise level including the print sound in the silent paper feed mode as described below. Set the noise level of the operating environment before printing so that the integrated value of time is equal.

<Determination method of darkness value>
The method for determining the threshold will be described below.

-Superposition of two sound volumes Generally, the sound volume B ([dB]) is the sound pressure p [Pa] and the reference sound pressure p0 (generally, p0 = 20 × 10 ⁻⁶ [P] is often used). It is known that the following equation (1) is used. Here, it is known that the characteristic of the volume B is close to the auditory characteristic that humans feel with respect to the sound pressure p.

  Then, the environmental sound volume (noise) Be = Be (t) [dB] (t is time, and the environmental sound volume Be is time-dependent) before the printing sound of the printer 100 is generated. When the volume Bn [dB] (volume in the paper feeding mode n, which is a mode-specific and time-independent volume, for example, a volume measured in the environment of the sound pressure p0) is superimposed, the volume ( The environmental sound volume Be) is given by Btot (Be (t), Bn) of the following equation (2).

  Further, the ratio indicating how much the environmental volume Be of the printer 100 has changed before and after the superposition is defined and expressed by Pn (Be (t)) [%] in the following equation (3). The threshold can be set by evaluating the influence of the printing sound on the operating environment from the ratio Pn.

<Determination of threshold>
Assuming that the paper feed speed (and hence the print speed) in the paper feed mode n of the printer 100 is vn [m / s] and the length of the print paper designated by the print job is L [m], the print paper is used as the printer 100. The time tn required for printing is given by the following equation (4).

  At this time, the total volume [dB] of the sound that the user of the operating environment of the printer 100 feels by the printing of the printer 100, that is, the printing sound Bn of the printer 100 superimposed on the environmental volume Be (= Be (t)). Is obtained by integrating the equation (2) with the operation time (printing time) tn of the printer 100, and is given by In of the following equation (5).

  Then, in the two sheet feeding modes m (n ← m) and m + 1 (n ← m + 1), if the total volume In with respect to the environmental volume Be before superimposing is Im (Be) and Im + 1 (Be), the following equation 6 If the relationship of equation (6) is satisfied, the rate of change in the sound felt by the user is smaller in printing in the paper feeding mode m than in printing in the paper feeding mode m + 1 (less influence on the operating environment), and Since it can be said that no unpleasant feeling is given, it is preferable to print in the paper feed mode m.

  Further, when the relationship expressed by the following equation (7) is satisfied, the rate of change of sound felt by the user is smaller in the paper feed mode m + 1 than in the paper feed mode m (the influence on the operating environment). Therefore, it is preferable to print in the paper supply mode m + 1.

  Therefore, the threshold value for switching the paper feed mode of the printer 100 is basically determined and set to the environmental sound volume (noise level) Be [dB] immediately before the start of printing in which the following equation (8) is satisfied. can do.

  In this case, pay attention to the fact that the volume of the printing sound during printing that gives the user discomfort differs depending on the noise level of the operating environment before printing, and that the discomfort given to the user depends on the total amount of noise level during printing. Based on the integrated value Im of the noise level printing time including the printing sound in the normal paper feeding mode (mode m) and the integrated value Im + 1 of the noise level printing time including the printing sound in the silent paper feeding mode (mode m + 1). The threshold value is set to the environmental sound volume Be immediately before the start of printing in which both integral values Im and Im + 1 are equal. For this reason, the threshold is set in consideration of the influence of the magnitude of the printing sound (paper feeding sound) in the paper feeding mode of the printer 100 on the noise level of the operating environment before printing, and the integral value Im and the integral value Im + 1 are set. Since printing is performed by setting the smaller paper feeding mode, the printing sound of the printer 100 can be further reduced. Note that the threshold does not necessarily have to be set to the environmental sound volume Be immediately before the start of printing in which both the integral values Im and Im + 1 are equal, and based on experiments and the like, the print start in which both the integral values Im and Im + 1 have a constant ratio. You may set to environmental sound volume Be immediately before.

  Incidentally, the environmental volume (noise level) Be [dB] immediately before the start of printing detected by the noise level detection unit 29 is actually a volume that does not depend on the time when the detection sound of the sound sensor 26 is sampled and held. In this case, In in the equation (5) is given by the following equation (9).

  Therefore, the threshold value can be more easily set to the level of the environmental sound volume Be that satisfies the following expression (10).

  When the printing sound of the printer 100 is 40 [dB], 60 [dB], and 80 [dB], the environmental volume Btot at the time of printing (after superimposition) with respect to the environmental volume Be just before the start of printing (before superimposition) is For example, it changes with the characteristics of the solid lines a, b, and c in FIG. In FIG. 11, the horizontal axis represents the environmental volume Be before the occurrence of the printing sound (immediately before the start of printing), and the vertical axis represents the environmental volume Btot.

  When the printing sound of the printer 100 is 60 [dB] in the normal paper feeding mode (mode m) and 40 [dB] in the silent paper feeding mode (mode m + 1), the threshold value is the total volume Btot of the solid line a. How much the ratio A / B between the value A and the value B of the total volume Btot of the solid line b has changed before and after the printing sound is superimposed on the environmental volume Be of the printer 100 in the normal paper feed mode and the silent paper feed mode. The ratio P [%] indicating the above can be defined and expressed by Pn (Be (t)) [%] in the following equation (3), and the environmental volume Be of the printer 100 is superimposed on the print sound. The ratio P [%] of the silent feed mode indicating the amount of change before and after, the ratio Pm + 1 / Pm in the normal feed mode, and the environmental volume immediately before the start of printing that is equal to the feed speed ratio vm + 1 / vm Be determined to be environmental volume Be It can be constant.

  Specifically, the volume Btot when the printer 100 is operated in the normal paper feed mode (mode m) and the silent paper feed mode (mode m + 1) for the range of the environmental sound volume Be expected when the printer is manufactured. Based on the data, the environmental volume Be that satisfies A / B = vm + 1 / vm is obtained and determined, and the value [dB] is written in the sequence information storage unit 28 and set.

  In this way, based on the comparison between the optimum threshold value set in consideration of the influence of the printing sound on the environmental sound volume of the printer 100 and the environmental sound volume (noise level) immediately before the start of printing detected by the sound sensor 26. Thus, it is possible to provide a practical configuration capable of switching the printing paper feeding mode of the printer 100 from the normal feeding mode to the silent feeding mode.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the mechanism structure of the printer 100 such as paper feeding may be any. Further, the configuration of the paper feed control of the printer 100 may be any.

  The present invention can be similarly applied to image forming apparatuses of various printing methods other than the ink jet type such as a thermal transfer printer, and can be applied to various image forming apparatuses regardless of business use or home use. can do.

1 is a perspective view from the front of a printer as an image forming apparatus according to an embodiment of the present disclosure. The perspective view from the back of the printer of FIG. FIG. 2 is a perspective view of a paper feeding device provided in the printer of FIG. 1. II sectional drawing of FIG. FIG. 4 is a front view illustrating a main configuration of a paper feed roller unit in FIG. 3. FIG. 4 is an explanatory diagram of a separation state of the uppermost printing paper of the paper feeding device of FIG. 3. FIG. 4 is an explanatory diagram of a paper returning operation of the paper feeding device of FIG. 3. Explanatory drawing of the hopper up operation | movement at the time of paper feeding of the paper feeder of FIG. FIG. 2 is a block diagram of paper feed control of the printer of FIG. 1. The flowchart of operation | movement description of FIG. Explanatory drawing of the threshold value setting of other embodiment of this invention.

Explanation of symbols

  27 ... Control unit, 26 ... Sound sensor, 29 ... Noise level detection unit, 100 ... Printer

Claims (3)

An image forming apparatus having a printing function in a normal paper feeding mode and a printing function in a silent paper feeding mode having a lower paper feeding speed than the normal paper feeding mode,
Noise level detection means for detecting the noise level immediately before the start of printing in the operating environment due to the occurrence of a print job;
An image switching unit that switches a paper feeding mode of the printing paper from the normal paper feeding mode to the silent paper feeding mode when a noise level immediately before the start of printing detected by the noise level detecting unit is smaller than a threshold value; Forming equipment.   The threshold is an operation in which the integrated value of the printing time of the noise level including the printing sound in the normal paper feeding mode and the integrated value of the printing time of the noise level including the printing sound in the silent paper feeding mode have a constant ratio. The image forming apparatus according to claim 1, wherein the image forming apparatus is set to a noise level before starting printing of the environment.   The image forming apparatus according to claim 2, wherein the constant ratio is a ratio between a sheet feeding speed in a normal sheet feeding mode and a sheet feeding speed in a silent sheet feeding mode.

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