JP2005338342A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a change in a residue toner quantity by utilizing a laser beam emitted from an optical scanner. <P>SOLUTION: The action of a laser printer 11 is explained. The toner in a toner container 120 is successively consumed along with progression of image formation. The position of the top surface (water surface) of the toner lowers gradually from (1) to (6) as the toner decreases. As the top surface of the toner descends, the toner covering a light exit window 124 disposed at a slope section 120A decreases. The laser beam LB in an unshielded range is transmitted from the light exit window 124 and received by a photodetecting sensor 128. The amount of the light received of the photodetecting sensor 128 increases successively until the amount of the light of the laser beam LB in the unshielded range is attained. Accordingly, the amount of the light of the laser beam LB transmitted from the light exit window 124 is varied by the range of the toner covering the light exit window 124 and the amount of the light received of the laser beam LB received by the detecting sensor 128 is varied. Namely, the range of the toner covering the light exit window 124, i.e. the change in the residue toner quantity, can be measured by the amount of the light received of the photodetecting sensor 128. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus.

  A laser beam emitted from the optical scanning device forms a latent image on an electrophotographic photosensitive member (hereinafter referred to as “photosensitive member”), and the latent image is developed in a developing unit to form a toner image. There is known an image forming apparatus using a known electrophotographic process for recording an image by transferring the formed toner image onto a recording paper or the like, and fixing the transferred toner image onto the recording paper.

  Such an image forming apparatus is provided with a toner storage unit that stores toner to be supplied to the developing unit.

  The toner in the toner storage portion is consumed and reduced as the image is formed. When the remaining amount of toner becomes a predetermined amount or less, the toner is replenished or replaced with a new toner container filled with toner. For this reason, the image forming apparatus is provided with toner remaining amount detecting means for detecting the remaining amount of toner in the toner containing portion.

  As the toner remaining amount detecting means, various sensors such as a magnetic permeability sensor and a vibration sensor are used.

  As described below, a method for detecting the remaining amount of toner using laser light emitted from an optical scanning device has been proposed.

  As shown in FIG. 15A, an optical path of laser light emitted from an optical scanning device (not shown) is changed, and a light entrance window 822 through which the laser light LS whose optical path has been changed passes through the toner storage portion 820. A configuration has been devised in which a light exit window 824 through which the transmitted laser light LS can be transmitted is provided, and a light receiving sensor 828 for detecting the laser light LS transmitted through the light output window 824 is disposed.

  With such a configuration, when the upper surface position of the toner is (1) and (2), the laser light LS is not emitted from the light exit window 824 because the toner is blocked and the light receiving sensor 828 does not detect the laser light LS. When the toner is consumed and the upper surface position of the toner becomes (3) or less, the laser beam LS is transmitted through the light exit window 824, and the light receiving sensor 828 detects the laser beam LS.

  However, in the detection of the remaining amount of toner in such a configuration, as shown in FIG. 15B, whether or not the light receiving sensor 828 detects the laser light LS, that is, there is toner at the position (3). It can only be detected. That is, it is impossible to measure how much toner remains, in other words, a change in the remaining amount of toner. (For example, refer to Patent Document 1).

  Further, as a method for measuring the remaining amount of toner in an analog manner, the following method has been proposed.

  The side wall in contact with the toner in the toner storage portion is made of a transparent material through which light propagates. This side wall is irradiated with light by an infrared light emitting LED. The light that has entered the side wall is refracted on the outer surface of the side wall, and propagates to the end of the side wall while being reflected inside the thick part of the side wall. The reflection efficiency differs between a portion where the toner is present on the inner wall surface of the side wall in contact with the toner and a portion where the toner is not present. For this reason, when the remaining amount of toner decreases due to toner consumption, the amount of light propagating changes corresponding to the decrease. Therefore, the change in the amount of light is measured by the light receiving sensor, and the change in the remaining amount of toner is measured.

However, the measurement of the remaining amount of toner by such a method is easily affected by external light because it measures divergent light propagating through the side wall. For this reason, it is necessary to take measures against optical noise so as not to be affected by external light. Further, since divergent light propagating through the side wall has a small amount of light, it needs to be a highly sensitive sensor. In addition, a light source such as an infrared light emitting LED is separately required. For this reason, it is expensive. (For example, refer to Patent Document 2).
Japanese Patent Laid-Open No. 03-126967 Japanese Patent No. 3419136

  The present invention has been made to solve the above problem, and an object of the present invention is to measure a change in the remaining amount of toner using laser light emitted from an optical scanning device.

  The image forming apparatus according to claim 1 forms a toner image by developing an optical scanning device that emits a laser beam that forms a latent image on an electrophotographic photosensitive member, and the latent image formed on the electrophotographic photosensitive member. A developing portion, a toner containing portion that contains toner to be supplied to the developing portion, and has a slope portion formed with a slope on a part or the whole of the bottom surface; an optical path changing means that changes the optical path of the laser beam; A light incident portion that is formed in the toner accommodating portion and through which the laser light changed by the optical path changing means is transmitted, and a light incident portion that is formed in the slope portion of the toner accommodating portion and can transmit the transmitted laser light. A light exit unit, a laser beam extending unit that is disposed between the light path changing unit and the light entrance unit, and that extends the irradiation range of the laser beam with respect to the inclination direction of the inclined surface unit; A light receiving means for receiving laser light. It is characterized in.

  According to another aspect of the present invention, a laser beam is emitted from the optical scanning device to form a latent image on the electrophotographic photosensitive member. The latent image is developed in the developing unit to form a toner image on the electrophotographic photosensitive member.

The developing unit is supplied with toner from the toner storage unit. The toner storage portion includes a slope portion with a slope formed on a part of the bottom surface or the entire surface. The toner in the toner storage portion is consumed and reduced when development is performed. When the remaining amount of toner falls below a predetermined amount, it is necessary to replenish the toner or replace it with a new toner container filled with toner.

  For this reason, the change in the remaining amount of toner in the toner container is measured as follows.

The optical path of the laser beam is changed by the optical path changing means. The irradiation range of the laser beam whose optical path has been changed is expanded by the laser beam extending means with respect to the inclination direction of the inclined surface portion of the toner storage unit. The laser beam whose irradiation range has been expanded is transmitted through a light incident portion formed in the toner accommodating portion. The transmitted laser beam can be transmitted from the light exit portion provided on the slope portion. The toner container has a large amount of toner, and the toner covers the entire surface of the light exit portion provided on the slope portion. In the state, the laser light transmitted from the light incident portion formed in the toner accommodating portion is blocked by the toner and is not transmitted from the light exit portion. Therefore, the amount of light received by the light receiving means is zero.

  As the toner decreases, the upper surface (water surface) position of the toner decreases. Then, as the upper surface of the toner is lowered, the toner covering the light output portion provided on the slope portion is decreased. Therefore, the toner covering the light exit portion provided on the slope portion is reduced, and the toner covers only a part of the light exit portion. And since the irradiation range of the laser beam is extended with respect to the inclination direction of the inclined surface, only a part of the laser beam is blocked by the toner, but the laser beam in the unblocked range is transmitted from the light emitting unit, and the light receiving means Receive light. Further, the amount of light received by the light receiving means at this time is equal to the amount of laser light in a range not blocked.

  Further, when the toner is reduced and no toner is present on the entire surface of the light exiting portion, all the laser light is transmitted through the light exiting portion, and the amount of light received by the light receiving means is maximized.

  As described above, the amount of laser light transmitted from the light exiting portion varies depending on the range of the toner covering the light exiting portion provided on the slope portion, and the amount of light received by the light receiving means varies. In other words, the change in the amount of toner covering the light exiting portion provided on the slope portion, that is, the change in the remaining amount of toner is measured by the change in the amount of light received by the light receiving means.

  According to a second aspect of the present invention, in the configuration according to the first aspect, the optical path changing unit directs a laser beam outside a range for forming a latent image on the electrophotographic photosensitive member to the laser beam expanding unit. It is a mirror, and the laser beam expanding means is a beam expander.

  The image forming apparatus according to claim 2 changes the optical path of the laser beam outside the range for forming a latent image on the electrophotographic photosensitive member with a mirror and directs the beam to the beam expander. The beam expander spreads the laser beam with respect to the inclination direction of the inclined surface portion of the toner containing portion.

  The laser light is transmitted from the light incident portion formed in the toner accommodating portion, and the amount of the laser light transmitted from the light exit portion provided on the slope portion changes according to the change in the remaining amount of toner, and is received by the light receiving means. The amount of received light changes. That is, the change in the remaining amount of toner is measured by the change in the amount of light received by the light receiving means.

  Since the mirror changes the optical path of the laser beam outside the range for forming the latent image on the electrophotographic photosensitive member, it does not affect the latent image formation. Therefore, it is possible to measure a change in the remaining amount of toner even during image formation.

  In addition, since there is no mechanical drive mechanism, there are few failures.

  The image forming apparatus according to claim 3 forms a toner image by developing an optical scanning device that emits a laser beam that forms a latent image on the electrophotographic photosensitive member, and the latent image formed on the electrophotographic photosensitive member. A developing unit, a toner containing unit containing toner to be supplied to the developing unit, and a sloped part having a slope formed on a part or the whole of the bottom surface; and changing the optical path of the laser beam, A rotatable reflecting mirror that extends an irradiation range with respect to the inclination direction of the inclined surface portion, and the laser light that is formed in the toner storage portion and whose optical path is changed by the reflecting mirror and the irradiation range is extended is transparent. A light incident part, a light emitting part formed on the inclined surface part of the toner accommodating part and capable of transmitting the transmitted laser light, and a light receiving means for receiving the laser light transmitted through the light emitting part. It is characterized by providing.

  In the image forming apparatus according to the third aspect, the rotatable reflecting mirror changes the optical path of the laser beam and extends the irradiation range. Therefore, the number of parts is small and the cost is low.

  The reflection mirror expands the irradiation range by scanning the laser beam with respect to the inclination direction of the inclined surface of the toner storage unit. Then, the laser light is transmitted from the light incident portion formed in the toner accommodating portion, and the amount of the laser light transmitted from the light exit portion provided on the inclined surface portion is changed according to the change in the remaining amount of toner. The amount of received light changes. That is, the change in the remaining amount of toner is measured by the change in the amount of light received by the light receiving means.

  Further, instead of scanning the laser beam, the irradiation range may be expanded by irradiating the laser beam to a plurality of positions with respect to the inclination direction of the inclined surface portion of the toner storage unit. (Irradiated with multiple laser beams).

  In this case, as the amount of toner decreases, the number of laser beams that are transmitted from the light exit portion changes. Therefore, the light receiving means can measure the change in the remaining amount of toner by the change in the number of received laser beams. Alternatively, the change in the remaining amount of toner may be measured by detecting the position of the laser beam transmitted from the light exit portion with a light receiving means.

  According to a fourth aspect of the invention, there is provided the image forming apparatus according to the third aspect, wherein the reflection mirror also serves as a light shielding unit that shields an emission port from which the laser beam is emitted from the optical scanning device. .

  In the image forming apparatus according to the fourth aspect, since the reflection mirror also serves as a light shielding unit that shields the exit port from which the laser beam is emitted from the optical scanning device, it is not necessary to provide a separate light shielding unit. Therefore, the number of parts is small and the cost is low.

  According to a fifth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to fourth aspects, wherein the expanded laser beam is arranged between the light emitting unit and the light receiving unit. It is characterized by comprising a light collecting means.

  In the image forming apparatus according to the fifth aspect, the expanded laser light transmitted from the light output portion is condensed by the condensing unit and then received by the light receiving unit.

  Therefore, the light receiving range of the light receiving means may be narrow. That is, since a small light receiving means may be used, space is saved.

  According to a sixth aspect of the present invention, in the configuration according to any one of the first to fifth aspects, the toner storage portion is detachably mounted, and the light receiving means is mounted on the toner storage portion. It is also characterized in that it also serves as a detecting means for detecting whether or not it has been performed.

  In the image forming apparatus according to the sixth aspect, since the light receiving means also serves as a detecting means for detecting whether or not the toner accommodating portion is mounted, it is not necessary to provide a separate detecting means. Therefore, the number of parts is small and the cost is low.

  As described above, according to the present invention, the change in the remaining amount of toner can be measured using the laser light emitted from the optical scanning device.

  Hereinafter, as an example to which the image forming apparatus according to the present invention is applied, a laser printer to which a known electrophotographic process is applied will be described with reference to the drawings. The known electrophotographic process is to transfer a toner image formed on a photoconductor to a recording paper through charging of the photoconductor, formation of a latent image by exposure with a laser, etc., and development of the latent image with toner. A series of processes for recording an image by fixing a toner image on a recording sheet.

  The image forming apparatus to which the present invention is applied is not limited to a laser printer described below, and may be a copying machine, a facsimile, a multifunction machine, or the like.

  FIG. 1 shows a schematic configuration of a laser printer 11 according to a first embodiment of the present invention. The laser printer 11 forms a toner image based on image information input from an external apparatus by the known electrophotographic process described above, and records this image on the recording paper P. In the following description, detailed descriptions of those not directly related to the essence of the present invention are omitted.

  First, an outline of the configuration of the laser printer 11 and an outline of a process for forming an image on the recording paper P will be described. Note that the left side of the figure is the front side.

  As shown in FIG. 1, a photosensitive drum 20 is rotatably supported near the center inside the laser printer 11. The photosensitive drum 20 is rotated in the direction of the arrow K by driving means (not shown).

  A roller charger 22 is disposed so as to be in contact with the upper left portion of the photosensitive drum 20. The roller charger 22 is charged with a charging bias and charges the photosensitive drum 20 to a predetermined potential. After charging, exposure is performed by the laser beam LA emitted from the optical scanning device 44 disposed above the photosensitive drum 20, and a latent image corresponding to image information is formed on the surface of the photosensitive drum 20.

  In the developing device 27, a developing unit 24 including a developing roller 26 that holds toner charged to a predetermined polarity and a toner storage unit 120 that stores toner to be supplied to the developing unit 24 are integrated. .

  The latent image formed on the surface of the photoconductive drum 20 is developed by applying a developing bias to the developing roller 26 to become a toner image. The toner image is sent to the nip portion between the photosensitive drum 20 and the transfer roller 32.

  On the other hand, a paper feed cassette 48 in which the recording paper P is accommodated is disposed below the laser printer 11. The recording paper P is fed out by the pickup roller 36 and is transported by the transport roller 38. Then, it is sent to the nip portion between the transfer roller 32 and the photosensitive drum 20 by the registration roller 40 at a predetermined timing.

  A voltage having a polarity opposite to the predetermined potential of the toner described above is applied to the transfer roller 32, and the toner image on the photosensitive drum 20 is transferred to the recording paper P. The recording paper P to which the toner image has been transferred is sent to the fixing device 34. The fixing device 34 fixes the toner image on the recording paper P with heat and pressure. The recording paper P on which the toner image is fixed is discharged to a discharge tray 42 at the top of the laser printer 11.

  The toner image is not completely transferred onto the recording paper P by the transfer roller 32, and a part of the toner image remains on the photosensitive drum 20 as residual toner. Residual toner is scraped off by the cleaning blade 30 of the cleaning device 28 and collected in the interior 29 of the cleaning device 28.

  The photosensitive drum 20, the developing device 27, the cleaning device 28, and the roller charger 22 constitute an integrally supported process cartridge 100. The process cartridge 100 is detachably attached to the laser printer 11.

  An opening / closing cover 50 for attaching / detaching the process cartridge 100 is provided on the front surface of the laser printer 11. The opening / closing cover 50 is provided with a rotating shaft 52 at the lower end.

  As shown in FIG. 2, when the process cartridge 100 reaches the end of its life, the open / close cover 50 can be opened and closed and replaced with a new process cartridge 100.

  As shown in FIG. 1, in the state where the process cartridge 100 is mounted on the laser printer 11, the bottom surface of the toner storage unit 120 of the developing device 27 forms an inclined surface 120A that is lowered toward the developing unit 24 side. Yes.

  As shown in FIG. 3, a light emitting unit 202 that emits laser light, a polygon mirror 204 that scans laser light, a reflection mirror 206, a pick-off mirror 208, and the like are disposed inside the optical scanning device 44.

  The pick-off mirror 208 changes the optical path of the laser beam LB outside the scanning range IB of the area IM where a latent image is formed on the photosensitive drum 20.

  As shown in FIG. 4, the laser beam LA is emitted from the emission port 210 and is exposed to the photosensitive drum 20. The laser beam LB whose optical path has been changed by the pick-off mirror 208 is emitted from the emission port 212.

  As shown in FIGS. 1 and 4, the emitted laser beam LB is emitted from an e-beam expander 130 provided between the process cartridge 100 and the optical scanning device 44, and an inclined surface portion of the toner container 120 of the process cartridge 100. It is expanded with respect to the slope direction of 120A (the left-right direction in FIGS. 1 and 4).

  A light incident window 122 made of a transparent resin plate through which the laser beam LB expanded by the e-beam expander 130 is transmitted is provided on the upper surface of the toner container 120 of the process cartridge 100. Further, a light exit window 124 made of a transparent resin plate through which the laser light LB transmitted through the light entrance window 122 can be transmitted is provided on the inclined surface 120 </ b> A of the toner storage unit 120. In other words. The laser beam LB can be transmitted through the light entrance window 122 and the light exit window 124.

A condensing lens 126 is provided below the toner container 120, and the laser beam LB transmitted through the light exit window 124 is collected by the condensing lens 126. A light receiving sensor 128 is provided below the condensing lens 126. The laser beam LB provided and condensed by the condenser lens 126 is received. The light receiving sensor 128 can measure a change in the amount of received light.

  As shown in FIG. 2, when the process cartridge 100 is not mounted, the light receiving sensor 128 directly transmits the laser light LB without transmitting the light entrance window 122 and the light exit window 124 of the toner storage unit 120. Is received. Therefore, the amount of light received by the light receiving sensor 128 increases because the amount of light is not lost between the light entrance window 122 and the light exit window 124.

  Next, the operation of the laser printer 11 of this embodiment will be described.

  As the image is formed on the recording paper P, the toner in the toner storage unit 120 is consumed and decreased. When the amount of toner decreases and the remaining amount of toner falls below a predetermined amount, it is necessary to replace it with a new process cartridge 100. Therefore, it is necessary to detect the remaining amount of toner.

  It should be noted that if the toner runs out completely, printing failure occurs, so the apparatus must be forcibly stopped before the toner runs out completely. However, if the apparatus suddenly stops and the user does not prepare a spare new process cartridge, printing cannot be performed until the user obtains a new one.

  The method described in Japanese Patent Laid-Open No. 03-126967 can only detect whether or not there is a predetermined amount of toner. Therefore, when a toner amount equal to or less than a predetermined amount is detected, the user is notified that the process cartridge needs to be replaced. For example, when a certain number of sheets are printed, the apparatus is forcibly stopped. For this reason, the toner is wasted because the replacement is performed in a state where a certain amount of toner remains in the process cartridge.

  However, the laser printer 11 according to the present embodiment measures the change in the remaining amount of toner, notifies the user of the measurement result, and forcibly stops the apparatus when the toner remaining level is almost out of toner. . For this reason, the toner is not wasted.

  Next, a method for measuring changes in the remaining amount of toner will be described.

  As shown in FIG. 5A, as the toner decreases, the upper surface (water surface) position of the toner gradually decreases from (1) to (6).

  In the state (1) where there is a large amount of toner in the toner container 120, the toner covers the entire surface of the light exit window 124 provided on the inclined surface 120A. Therefore, the laser beam LB transmitted through the light entrance window 122 is blocked by the toner and is not transmitted through the light exit window 124.

  Therefore, as shown in the graph of FIG. 5B, the received light amount of the laser beam LB received by the light receiving sensor 128 is zero.

  However, as the toner decreases, the upper surface (water surface) position of the toner decreases, and the toner covering the light exit window 124 provided on the inclined surface 120A decreases, and the states (3) and (4) in FIG. As described above, when the toner covers only a part of the light exit window 124, the laser light LB is partially blocked by the toner, and the laser light LB in a range not blocked is transmitted from the light exit window 124. The light receiving sensor 128 receives light.

  Then, as shown in the graph of FIG. 5B, the amount of light received by the light receiving sensor 128 increases so as to be equal to the amount of light of the laser light LB in the unobstructed range.

  When the toner decreases and the toner exits from the entire surface of the light exit window 124 as shown in (5) and (6) of FIG. 5A, all the laser light LB is transmitted through the light exit portion. As shown in the graph of FIG. 5B, the amount of light received by the light receiving sensor 128 is the amount of light received through the entire surface of the light exit window 124.

  As described above, the amount of the laser light LB transmitted through the light exit window 124 varies depending on the range of the toner covering the light exit window 124, and the amount of the laser light LB received by the light receiving sensor 128 varies. That is, it is possible to measure the range of toner covering the light exit window 124, that is, the change in the remaining amount of toner, with the amount of light received by the light receiving sensor 128.

  Accordingly, since the change in the remaining amount of toner is measured using the optical scanning device 44, the cost is low.

  Further, since the light quantity of the laser beam LB is directly measured, it is not easily affected by external light. Therefore, it is not necessary to take measures against optical noise. Further, since the light is condensed by the condenser lens 126, the light receiving range of the light receiving sensor 128 may be narrow. That is, the light receiving sensor 128 is small.

  Furthermore, since the laser beam LB outside the range for forming the latent image on the photosensitive drum 20 is picked off and used, it is possible to always measure the change in the remaining amount of toner even during image formation. In addition, since there is no mechanical drive mechanism, there are few failures.

  Now, as shown in FIG. 2, when the process cartridge 100 is not mounted, the light quantity is not lost in the light entrance window 122 and the light exit window 124, so that the light received by the light receiving sensor 128 is received as shown in FIG. The amount increases. Therefore, the case where the process cartridge 100 is not attached and the case where it is attached can be detected by the difference in the amount of light received by the light receiving sensor 128.

  Therefore, the laser printer 11 detects whether or not the process cartridge 100 is mounted without separately providing detection means for detecting whether or not the process cartridge 100 is mounted. Therefore, the number of parts is small and the cost is low.

  Next, a second embodiment of the image forming apparatus according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st Embodiment, and the overlapping description is abbreviate | omitted.

  7 and 8 show the main part of the laser printer 12 according to the second embodiment of the present invention.

  As shown in FIG. 7, the reflection mirror 200 is disposed above the optical path of the laser beam LA of the optical scanning device 442 to the photosensitive drum 20. The reflection mirror 200 has a semicircular cross section and a reflection mirror surface 204 at the bottom. Further, the reflection mirror surface 204 rotates around the rotation shaft 202.

  As shown in FIG. 8, when the reflection mirror 200 is rotated, the reflection mirror surface 204 is applied to the optical path of the laser beam LA and reflects the laser beam LA. The reflected laser light LC is transmitted through the light entrance window 122 of the toner storage unit 120. Further, by rotating the reflection mirror 200, scanning is performed with respect to the inclined direction of the inclined surface portion 120A of the toner containing portion 120, and the laser light LC is expanded.

  Next, the operation of the laser printer 12 of this embodiment will be described.

  Similarly to the laser printer 11 of the first embodiment, the change in the remaining amount of toner can be measured by the change in the amount of light received by the light receiving sensor 128. (See Figure 5). Further, it is possible to detect whether or not the process cartridge 100 is mounted without separately providing detection means for detecting whether or not the process cartridge 100 is mounted. (See FIGS. 2 and 6).

  Further, the rotatable reflecting mirror 200 has both the function of changing the optical path of the laser beam LA and the function of extending the irradiation range. Therefore, the number of parts is small and the cost is low.

  Next, a third embodiment of the image forming apparatus according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st and 2nd embodiment, and the overlapping description is abbreviate | omitted.

  9 to 11 show the main part of the laser printer 13 according to the third embodiment of the present invention.

  As shown in FIG. 9, a shutter 300 is provided at the exit 210 of the laser beam LA of the optical scanning device 443. The shutter 300 rotates about the rotation shaft 302. The lower surface of the shutter 300 is a reflection mirror surface 304.

  As shown in FIG. 9, normally, even if the shutter 300 is closed and the laser beam LA is continuously irradiated for some reason, the exposure of the laser beam LA to the outside is prevented. Further, entry of dust or the like into the optical scanning device 443 is prevented.

  As shown in FIG. 10, at the time of image formation, the shutter 300 is opened, the optical path of the laser beam LA is opened, and the photosensitive drum 20 is exposed.

  As shown in FIG. 11, when the shutter 300 is rotated, the reflection mirror surface 304 enters the optical path and reflects the laser light LA. The reflected laser beam LD is transmitted through the light incident window 122 of the toner storage unit 120 as in the second embodiment. Further, by rotating the shutter 300, the laser beam LD is expanded by scanning with respect to the inclined direction of the inclined surface portion 120A of the toner containing portion 120.

  Next, the operation of the laser printer 13 of this embodiment will be described.

  As in the first and second embodiments, the change in the remaining amount of toner can be measured by the change in the amount of light received by the light receiving sensor 128. (See Figure 5). Further, it is possible to detect whether or not the process cartridge 100 is mounted without separately providing detection means for detecting whether or not the process cartridge 100 is mounted. (See FIGS. 2 and 6).

  Further, the shutter 300 has three functions, that is, a function of changing the optical path of the laser beam LA, a function of extending the irradiation range, and a shutter function of the emission port 210 of the optical scanning device 443. Therefore, the number of parts is small and the cost is low.

  Next, a fourth embodiment of the image forming apparatus according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st-3rd embodiment, and the overlapping description is abbreviate | omitted.

  FIG. 12 shows a main part of a laser printer 14 according to the fourth embodiment of the present invention.

  As in the third embodiment, as shown in FIG. 12, a shutter 300 is provided at the exit 210 of the laser beam LA of the optical scanning device 443. The shutter 300 rotates about the rotation shaft 302. The lower surface of the shutter 300 is a reflection mirror surface 304.

  Note that the condensing lens 126 (FIG. 11) is not provided below the toner container 120 in the laser printer 14 of the fourth embodiment.

  However, a light receiving sensor 400 having a wide light receiving area capable of receiving all of the laser light LD transmitted from the light exit window 124 is provided below the toner storage unit 120.

  Next, the operation of the laser printer 13 of this embodiment will be described.

  As in the first to third embodiments, the change in the remaining amount of toner can be measured by the change in the amount of light received by the light receiving sensor 400. (See Figure 5). Further, it is possible to detect whether or not the process cartridge 100 is mounted without separately providing detection means for detecting whether or not the process cartridge 100 is mounted. (See FIGS. 2 and 6).

  Now, in order to increase the accuracy of the measurement of the remaining amount of toner, it is desired to measure laser light that is transmitted over a wide range of the slope portion 120A. For this reason, it is desired to widen the light transmission range of the light exit window 124. However, if the condensing lens 126 (FIG. 11) is provided below the toner storage unit 120, it becomes a large and thick lens to condense a wide range of laser light and occupy a large space.

  However, in the case where the light receiving sensor has a wide light receiving area without providing a condensing lens as in this embodiment, even if the light transmission range of the light exit window 124 is widened, only the area of the light receiving sensor 400 is widened. Because the thickness does not change, it saves space.

  Next, a fifth embodiment of the image forming apparatus according to the invention will be described. In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st-4th embodiment, and the overlapping description is abbreviate | omitted.

  FIG. 13 shows a main part of a laser printer 15 according to the fifth embodiment of the present invention.

  As in the third and fourth embodiments, as shown in FIG. 13, the shutter 300 rotates about the rotation shaft 302. The lower surface of the shutter 300 is a reflection mirror surface 304. Similarly to the fourth embodiment, the laser printer 15 is not provided with the condenser lens 126 (FIG. 11) below the toner container 120.

  In the third and fourth embodiments, the reflecting mirror surface 304 is rotated to scan and expand the inclined direction of the inclined surface portion 120A of the toner storage unit 120 (see FIG. 11).

  On the other hand, in the fifth embodiment, the reflection mirror surface 304 is held at a predetermined angle (three levels in this embodiment), and the laser beam LA is reflected to be laser beams LE, LF, and LG. Then, the light is reflected so as to line up with respect to the inclination direction of the inclined surface portion 120 </ b> A of the toner containing portion 120.

  Each of the laser beams LE, LF, and LG is transmitted through the light incident window 122 of the toner storage unit 120. The laser beams LE, LF, LG transmitted through the light entrance window 122 can be transmitted through the light exit window 124, respectively.

  Below the toner storage unit 120, three light receiving sensors 502, 504, and 506 corresponding to the laser beams LE, LF, and LG are provided.

  Next, the operation of the laser printer 15 of the present embodiment will be described.

  When the toner covers the entire surface of the light exit window 124, the laser beams LE, LF, and LG are blocked by the toner and do not transmit light, so that the three light receiving sensors 502, 504, and 506 do not receive light. However, as shown in FIG. 14, when the toner is consumed and decreased, first, only the laser beam LE is transmitted and only the light receiving sensor 502 receives light (FIG. 14A). As it further decreases, the laser beams LE and LF are transmitted, and the light receiving sensors 502 and 504 receive the light. When the toner does not cover the light exit window 124, the laser beams LE, LF, and LG are all transmitted, and the light receiving sensors 502, 504, and 506 all receive the light.

  As described above, unlike the first to third embodiments, the laser printer 14 of the fourth embodiment is configured so that the light receiving sensors 502, 504, and 506 receive the laser beams LE, LF, and LG (in other words, the outgoing light The change in the remaining amount of toner is measured by the number of laser beams transmitted through the window 126).

  The change in the remaining amount of the toner may be measured at the position of the light receiving sensors 502, 504, and 506 that receive the light, instead of measuring the change in the remaining amount of the toner by the number of receiving the laser beams LE, LF, and LG.

  Further, in order to increase the accuracy of measurement of the remaining amount of toner, the light transmission range of the light exit window 124 may be widened, and measurement may be performed with a larger number of laser beams and corresponding light receiving sensors.

  In addition, this invention is not limited to said embodiment.

  For example, in the above embodiment, the photosensitive drum 20, the developing device 27, the cleaning device 28, and the roller charger 22 constitute an integrally supported process cartridge 100, and the process cartridge 100 is attached to and detached from the laser printer 11. Although it was mounted | worn possible, it is not limited to this.

  For example, in the developing device 27, the developing unit 24 and the toner containing unit 120 containing the toner to be supplied to the developing unit 24 are integrated, but the developing unit and the toner containing unit are separated, that is, a developing device. And the toner container, only the toner container may be detachably mounted.

  Alternatively, the toner container may be replenished from a toner replenishing port or the like when the toner is not removable and the toner runs out.

  Further, for example, the entire toner container may be formed of a transparent resin without providing the light entrance window 122 and the light exit window 124 made of a transparent resin in the toner container 120.

It is the figure which showed typically the inside of the laser printer which concerns on the 1st Embodiment of this invention. In the laser printer according to the first embodiment of the present invention, an opening / closing cover is opened and a process cartridge is taken out. It is the figure which showed typically the inside of the optical scanning device of the laser printer which concerns on the 1st Embodiment of this invention. It is the figure which showed typically the principal part of the laser printer which concerns on the 1st Embodiment of this invention. (A) is a diagram schematically showing how the toner in the toner storage portion decreases, and (B) is a graph showing how the amount of light received by the light receiving sensor changes as the toner decreases. It is the graph which showed the difference of the light reception amount of a light reception sensor with the presence or absence of mounting | wearing of a process cartridge. FIG. 6 is a diagram schematically illustrating a main part of a laser printer according to a second embodiment of the present invention, and is a diagram at the time of image formation. FIG. 6 is a diagram schematically illustrating a main part of a laser printer according to a second embodiment of the present invention, and is a diagram at the time of toner remaining amount measurement. It is a figure of the state where a principal part of a laser printer concerning a 3rd embodiment of the present invention was shown typically, and a shutter was closed. FIG. 10 is a diagram schematically illustrating a main part of a laser printer according to a third embodiment of the present invention, and is a diagram at the time of image formation. FIG. 10 is a diagram schematically illustrating a main part of a laser printer according to a third embodiment of the present invention, when a toner remaining amount is measured. FIG. 10 is a diagram schematically illustrating a main part of a laser printer according to a fourth embodiment of the present invention when a toner remaining amount is measured. FIG. 10 is a diagram schematically illustrating a main part of a laser printer according to a fifth embodiment of the present invention, and is a diagram at the time of toner remaining amount measurement. It is a graph which shows in order from (A) to (C) how each light receiving sensor receives light as the toner decreases. In the method of detecting toner using the laser beam of the conventional optical scanning device, (A) is a diagram schematically showing how the toner in the toner container is decreased, and (B) is the toner. It is the graph which showed light reception of the laser beam in a light-receiving sensor in connection with decrease of (2).

Explanation of symbols

11 Laser printer (image forming device)
20 Photosensitive drum (electrophotographic photosensitive member)
44 Optical Scanning Device 24 Developing Portion 120 Toner Storage Portion 120A Slope Portion 122 Light Entrance Window
124 Light emission window (light emission part)
126 Condensing lens (condensing means)
128 Light receiving sensor (light receiving means)
130 Beam Expander 200 Reflective Mirror 208 Pickoff Mirror 300 Shutter (Light Shielding Means)

Claims (6)

An optical scanning device that emits laser light that forms a latent image on the electrophotographic photosensitive member;
A developing unit for developing a latent image formed on the electrophotographic photosensitive member to form a toner image;
A toner containing portion that contains toner to be supplied to the developing portion, and has a sloped portion with a sloped surface formed on a part or the whole of the bottom surface;
An optical path changing means for changing an optical path of the laser beam;
A light incident portion that is formed in the toner accommodating portion and through which the laser light changed by the optical path changing means is transmitted;
A light output portion formed on the slope portion of the toner storage portion and capable of transmitting the transmitted laser light;
A laser beam extending unit that is disposed between the optical path changing unit and the light incident unit, and expands an irradiation range of the laser beam with respect to an inclination direction of the inclined surface;
A light receiving means for receiving the laser light transmitted through the light emitting section;
An image forming apparatus comprising: The optical path changing means is a mirror for directing laser light outside the range for forming a latent image on the electrophotographic photosensitive member to the laser light expanding means,
The image forming apparatus according to claim 1, wherein the laser beam expanding unit is a beam expander. An optical scanning device that emits laser light that forms a latent image on the electrophotographic photosensitive member;
A developing unit for developing a latent image formed on the electrophotographic photosensitive member to form a toner image;
A toner containing portion that contains toner to be supplied to the developing portion, and has a sloped portion with a sloped surface formed on a part or the whole of the bottom surface;
A rotatable reflecting mirror that changes an optical path of the laser beam and expands an irradiation range of the laser beam with respect to an inclination direction of the inclined surface;
A light incident portion that is formed in the toner accommodating portion and that transmits the laser light whose light path is changed by the reflection mirror and whose irradiation range is extended;
A light output portion formed on the slope portion of the toner storage portion and capable of transmitting the transmitted laser light;
A light receiving means for receiving the laser light transmitted through the light emitting section;
An image forming apparatus comprising:   The image forming apparatus according to claim 3, wherein the reflection mirror also serves as a light shielding unit that shields an emission port from which the laser beam is emitted from the optical scanning device.   5. The image forming apparatus according to claim 1, further comprising: a condensing unit that is disposed between the light output unit and the light receiving unit and condenses the expanded laser beam. apparatus.   6. The toner container according to claim 1, wherein the toner container is detachably mounted, and the light receiving unit also serves as a detecting unit that detects whether the toner container is mounted. The image forming apparatus described in 1.

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