JP2010186074A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that can properly use a developer up to its appropriate deterioration state according to an initial capacity of a cartridge. <P>SOLUTION: The image forming apparatus is configured to detachably mount therein a plurality of types of developing cartridges 5B having different initial capacities of toner T and is configured to optically detect an amount of the toner T in the developing cartridge 5B. The image forming apparatus includes a light-emitting device 81, a light-receiving device 82, a light-receiving determining means 110 configured to determine a replacement time of the developing cartridge 5B on the basis of a light reception signal of the light-emitting device 82, a detecting means 200 configured to detect the initial capacity of the mounted developing cartridge 5B, and a luminous intensity-changing part 170 configured to change luminous intensity of the light-emitting device 81 in accordance with the initial capacity of the developing cartridge 5B detected by the detecting means 200. The luminous intensity-changing part 170 changes the luminous intensity of the light-emitting device 81 such that the luminous intensity of the developing cartridge 5B is relatively smaller as the initial capacity of the developing cartridge 5B is smaller. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus capable of determining a replacement time of a cartridge to be mounted using an optical developer remaining amount detecting unit.

  2. Description of the Related Art Generally, there are electrophotographic image forming apparatuses that are detachably equipped with a cartridge containing toner and supply toner in a cartridge to a photoconductor to form an image. In such an image forming apparatus, a cartridge is provided based on a light reception signal obtained by providing a pair of light transmission windows facing the side walls of the cartridge and detecting light incident from one light transmission window from the other light transmission window. A configuration for estimating the amount of toner in the toner may be used (see Patent Document 1).

  By the way, the toner in the cartridge gradually deteriorates (charging performance is lowered) by repeated stirring, and when the number of printed sheets exceeds a predetermined number of prints, the initial charging performance cannot be obtained and the quality of the formed image is lowered. To do. Therefore, in order to form a good image, it is necessary to leave a predetermined amount without using up all the toner in the cartridge.

JP 2001-005276 A

  On the other hand, a plurality of types of cartridges having different initial capacities of toner, for example, two types of large-capacity type and small-capacity type are set and are often sold. However, in the conventional image forming apparatus, it is determined that it is time to replace the cartridge when the amount of toner falls below a certain amount regardless of the initial toner capacity.

  Since the toner deterioration state roughly depends on the usage time of the cartridge, even with the same toner remaining amount, compared with the large-capacity type, the remaining toner of the small-capacity type has deteriorated so as to lower the image quality. Absent. For this reason, if it is determined that it is time to replace the toner when the amount of toner falls below a certain amount regardless of the initial capacity of the toner, the small-capacity type may be replaced with the replacement time even though the remaining toner can still withstand use. As a result, the toner cannot be used effectively.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can use a developer to an appropriate deterioration state in accordance with an initial capacity of a cartridge.

  In order to achieve the above-described object, the image forming apparatus of the present invention is configured such that a plurality of types of cartridges having different initial capacities of the developer can be attached and detached, and the amount of the developer in the cartridge is optically detected. An image forming apparatus comprising: a light emitting element that emits light into the cartridge; a light receiving element that receives light emitted from the light emitting element and passing through the cartridge; Determination means for determining replacement time, detection means for detecting the initial capacity of the mounted cartridge, and light emission intensity changing means for changing the light emission intensity of the light emitting element according to the initial capacity of the cartridge detected by the detection means; The light emission intensity changing means adjusts the light emission intensity of the light emitting element so that the light emission intensity of the cartridge having a small initial capacity is relatively small. Characterized in that it further.

  Here, changing the light emission intensity of the light emitting element according to the initial capacity includes not only changing the light emission intensity individually according to the initial capacity but also changing the light emission intensity according to the range of the initial capacity. Specifically, for example, when there are three types of cartridges that can be mounted, two of the initial capacities that are included in one range have the same light emission intensity, and the remaining one that includes the initial capacities in another range emits light. Including the form of different strength.

  According to the image forming apparatus configured as described above, the intensity of light received by the light receiving element can be relatively reduced by changing the emission intensity of the cartridge having a small initial capacity to be relatively small. it can. In the image forming apparatus configured to optically detect the amount of developer in the cartridge, it is determined that there is sufficient developer in the cartridge when the intensity of light received by the light receiving element decreases.

  As a result, a cartridge with a small initial capacity is determined to be the replacement time compared to the conventional configuration in which it is determined that it is the replacement time when the amount of toner falls below a certain amount regardless of the initial capacity of the toner. It is possible to lengthen the time required to complete the process. As a result, the usage period of the cartridge with a small initial capacity can be extended, and therefore, the developer in the cartridge with a small initial capacity that could not be used effectively can be used to an appropriate deterioration state. .

  The image forming apparatus of the present invention is an image forming apparatus configured to detachably attach a plurality of types of cartridges having different initial capacities of the developer and to optically detect the amount of the developer in the cartridge. A light emitting element that emits light into the cartridge, a light receiving element that receives light emitted from the light emitting element and passed through the cartridge, and a ratio of a time when an output value of the light receiving element exceeds a light receiving reference value. A determination unit that determines that it is time to replace the cartridge when the determination threshold is exceeded; and a detection unit that detects an initial capacity of the mounted cartridge, wherein the determination unit detects the initial cartridge detected by the detection unit. The light receiving reference value is changed in accordance with the capacity, and the light receiving reference value is used when the light receiving element is used for determining the replacement time of a cartridge having a small initial capacity. And a difference from the output value in the state in which no light is large.

  Here, changing the light reception reference value according to the initial capacitance includes not only changing the light reception reference value individually according to the initial capacitance, but also changing the light reception reference value according to the range of the initial capacitance. Specifically, for example, when there are three types of cartridges that can be mounted, two of the initial capacities included in one range use the same light receiving reference value, and the remaining one includes the initial capacities within another range. Includes a form in which different light receiving reference values are used.

  In addition, when the output value of the light receiving element exceeds the light receiving reference value, the light receiving reference value is exceeded by a value that is smaller than the light receiving reference value, and in addition to a value that is larger than the light receiving reference value. This includes the case where it falls below the light reception reference value. That is, exceeding the light reception reference value means straddling the light reception reference value.

  According to the image forming apparatus configured as described above, when using a cartridge with a small initial capacity, the light receiving reference value is changed to a value having a large difference from the output value in a state where the light receiving element is not receiving light. It becomes difficult for the output value of the light receiving element to exceed the light receiving reference value. This is the same state as when the intensity of the light received by the light receiving element is actually reduced, making it difficult to exceed the light reception reference value.

  Thus, as described above, the use period of the cartridge having a small initial capacity can be extended, so that the developer in the cartridge having a small initial capacity that could not be used effectively can be used to an appropriate deterioration state. Can be.

  According to the image forming apparatus of the present invention, the intensity of light received by the light receiving element is changed as a result in accordance with the initial capacity of the cartridge, so that the developer can be used up to an appropriate deterioration state. Can do.

1 is a cross-sectional view of a laser printer as an example of an image forming apparatus according to a first embodiment. FIG. 3 is an enlarged cross-sectional view of a developing cartridge. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 showing the configuration around the developing cartridge. It is a time chart which shows the output voltage value of a light receiving element. (A)-(d) is sectional drawing for demonstrating the operation | movement of an agitator and the motion of a toner. It is a flowchart of exchange time determination by a control device. It is a time chart which shows the output voltage value of a light receiving element when the emitted light intensity of a light emitting element is made small. It is sectional drawing which shows schematic structure of the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a time chart of the output voltage value of a light receiving element for explaining change of a light reception standard value.

<Schematic configuration of laser printer>
Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the direction will be described with reference to the user who uses the laser printer. That is, the left side in FIG. 1 is “front”, the right side is “rear”, the front side is “right”, and the back side is “left”. Also, the vertical direction in FIG.

  As shown in FIG. 1, a laser printer 1 includes a paper feed unit 3 that supplies paper P, an exposure device 4, a process unit 5 that transfers a toner image onto the paper P, and a paper in a main body housing 2. It mainly includes a fixing device 6 that thermally fixes the toner image transferred onto P.

  The paper feed unit 3 is provided in the lower part of the main body housing 2, and includes a paper feed tray 31 that accommodates the paper P, a paper pressing plate 32 that lifts the front side of the paper P, a lift lever 33, a pickup roller 34, A paper roller 35, a paper feed pad 36, and a registration roller 37 are mainly provided. The paper P in the paper feed tray 31 is brought to the pickup roller 34 by the lift lever 33 and the paper pressing plate 32 and is sent out by the pickup roller 34. The fed paper P is separated one by one by the paper feed roller 35 and the paper feed pad 36, passes through the registration roller 37, and is conveyed toward the photosensitive drum 51 and the transfer roller 53.

  The exposure apparatus 4 is provided at an upper portion in the main body housing 2 and mainly includes a laser light emitting unit (not shown), a polygon mirror 41 that is rotationally driven, lenses 42 and 43, and reflecting mirrors 44 and 45. The laser light (refer to the chain line) based on the image data emitted from the laser emission unit is reflected or passed through the polygon mirror 41, the lens 42, the reflecting mirror 44, the lens 43, and the reflecting mirror 45 in this order, and the surface of the photosensitive drum 51. Irradiated at high speed.

  The process unit 5 is disposed below the exposure apparatus 4 and is configured to be detachably attached to the main body housing 2 through an opening formed when the front cover 21 provided on the main body housing 2 is opened. Yes. The process unit 5 includes a photoconductor unit 5A and a developing cartridge 5B as an example of a cartridge.

  The photoreceptor unit 5A mainly includes a photoreceptor drum 51, a charger 52, and a transfer roller 53 in the photoreceptor frame 50A. The developing cartridge 5B is configured to be detachably attached to the photoreceptor unit 5A, and a developing roller 54, a supply roller 55, and a layer thickness regulating blade 56 are mainly provided in the developing frame 50B. And a toner storage chamber 58 for storing toner as an example of a developer.

  In the process unit 5, the surface of the photosensitive drum 51 is uniformly charged by the charger 52 and then exposed by high-speed scanning of the laser light from the exposure device 4, whereby image data is transferred onto the photosensitive drum 51. An electrostatic latent image based on is formed. The toner in the toner storage chamber 58 is supplied to the developing roller 54 via the supply roller 55 and enters between the developing roller 54 and the layer thickness regulating blade 56 so as to form a thin layer having a constant thickness. Supported on.

  The toner carried on the developing roller 54 is supplied from the developing roller 54 to the electrostatic latent image formed on the photosensitive drum 51. As a result, the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 51. Thereafter, the sheet P is conveyed between the photosensitive drum 51 and the transfer roller 53, whereby the toner image on the photosensitive drum 51 is transferred onto the sheet P.

  The fixing device 6 is provided behind the process unit 5, and mainly includes a heating roller 61 and a pressure roller 62 that sandwiches the paper P between the heating roller 61. The toner image transferred onto the paper P is thermally fixed by the paper P being conveyed between the heating roller 61 and the pressure roller 62. The sheet P on which the toner image is thermally fixed is conveyed from the fixing device 6 to the discharge path 23 and is discharged from the discharge path 23 onto the discharge tray 22 by the discharge roller 24.

<Determination of developer cartridge replacement time>
Next, determination of the replacement timing of the developing cartridge 5B will be described in detail with reference to the drawings as appropriate. In the following description, first, the configuration of the developing cartridge 5B and the main body housing 2 related to the determination of the replacement time will be described, and then the determination of the replacement time of the present embodiment will be described.

(Configuration of developer cartridge)
There are two types of developing cartridges 5B that can be attached to the laser printer 1 with different initial capacities of toner. Specifically, for example, a large-capacity type in which the number of printable sheets is set to 6000 and a small-capacity type in which the number of printable sheets is set to 3000 and the initial capacity of toner is smaller than that of the large-capacity type. Each type of developing cartridge 5B differs only in the initial capacity of the toner T accommodated in the toner accommodating chamber 58, and the configuration is substantially the same.

  As shown in FIG. 2, the developing cartridge 5B is partitioned by a developing frame 50B into a developing chamber 57 in which the supply roller 55 and the like are arranged and a toner containing chamber 58 in which the toner T is accommodated. The developing chamber 57 and the toner storage chamber 58 communicate with each other through a communication portion 59. The communication portion 59 is formed over substantially the entire width in the axial direction of the roller portion of the supply roller 55, and the toner T can go back and forth between the developing chamber 57 and the toner storage chamber 58 via the communication portion 59. It is like that.

  An agitator 70 that agitates the toner T by rotating is disposed in the toner storage chamber 58. As shown in FIG. 3, transparent light transmission windows 60 (light transmission portions) facing each other in the left-right direction are provided on the side walls 50L and 50R of the toner storage chamber 58 (development frame 50B).

As shown in FIG. 2, the agitator 70 mainly includes a rotation support shaft 71, a seat attachment portion 72, a sheet member 73, a wiper attachment portion 74, and a wiper 75.
The rotation support shaft 71 is an axis extending along the axial direction (left and right direction) of the developing roller 54 and the supply roller 55, and both ends thereof can rotate to the side walls 50L and 50R (only one is shown in FIG. 2) of the developing frame 50B. It is supported by.

The sheet attachment portion 72 is formed so as to extend radially outward from the rotation support shaft 71, and a sheet member 73 is fixed to the tip thereof by sticking or the like.
The sheet member 73 is a flexible sheet-like member that stirs the toner T while the front end is in sliding contact with the bottom wall of the toner storage chamber 58 by the rotation of the agitator 70 and further conveys the toner T toward the developing chamber 57.

  One wiper mounting portion 74 is provided in the vicinity of both ends in the axial direction of the rotation support shaft 71 (see FIG. 3). The wiper mounting portion 74 is formed to extend radially outward from the rotation support shaft 71 at a position substantially perpendicular to the seat mounting portion 72 at the rear of the seat mounting portion 72 in the rotational direction when viewed from the side. ing. A wiper 75 is fixed to the wiper mounting portion 74 on the outer surface in the axial direction of the rotary support shaft 71 by sticking or the like.

  As shown in FIG. 3, the wiper 75 is a member that is slidably contacted with the light transmission window 60 and wipes off the toner T adhering to the light transmission window 60, and is formed of a flexible material such as urethane rubber. FIG. 3 shows the position when the wiper 75 is in sliding contact with the light transmission window 60.

  The agitator 70 configured in this manner is provided with a rotational driving force from the motor M provided in the main body housing 2 with respect to the rotation support shaft 71, so that the inside of the toner storage chamber 58 is opposite to that shown in FIG. The toner rotates in the clockwise direction and the toner T is stirred and conveyed by the sheet member 73.

(Configuration of the main unit housing)
As shown in FIG. 3, the laser printer 1 includes a light emitting element 81, a light receiving element 82, a control device 100 as an example of a determination unit and a light emission intensity changing unit, and a developing cartridge mounted in the main body housing 2. A detection unit 200 that detects an initial capacity of 5B and a notification unit 300 that notifies a user of a message are provided.

  The light emitting element 81 and the light receiving element 82 are disposed so as to face each other with the pair of light transmission windows 60 of the developing cartridge 5B mounted on the main body housing 2 interposed therebetween. As such a light emitting element 81 and a light receiving element 82, a known optical sensor can be adopted.

  As indicated by a broken line in FIG. 3, the light emitted from the light emitting element 81 enters the developing cartridge 5 </ b> B (toner storage chamber 58) through one light transmission window 60 and passes through the other light transmission window 60. Light is received by the light receiving element 82. The light emitting element 81 is an element whose emission intensity can be changed by an input voltage from the control device 100. The light receiving element 82 is an element whose output voltage value changes according to the intensity of the received light, and outputs a light reception signal as shown in FIG. 4 to the control device 100 by receiving the light.

  Here, the light reception signal will be described with reference to FIGS. 4 and 5. FIG. In the present embodiment, a light receiving element 82 is employed in which the output voltage value is maximized when the intensity of received light is minimum, and the output voltage value is minimized when the intensity of received light is maximum. 4, the intensity of the received light decreases as the output voltage value increases, and the intensity of the received light increases as the output voltage value decreases. “V0” is an output voltage value when the light receiving element 82 is not receiving light (an output voltage value when the intensity of the received light is minimum).

  As shown in FIG. 5A, in the process in which the sheet member 73 scrapes and contacts the bottom wall of the toner storage chamber 58 by the rotation of the agitator 70 and collects the toner T and conveys the toner T to the developing chamber 57 side, When the light transmission window 60 is completely covered, the light receiving element 82 is in a state of not receiving light substantially, so that the output voltage value becomes maximum (in FIG. 4, it changes in the vicinity of V0) (area SA).

  As shown in FIG. 5B, when the sheet member 73 passes between the pair of light transmission windows 60 by the rotation of the agitator 70, the toner between the pair of light transmission windows 60 is conveyed to the sheet member 73. Since the amount of T decreases rapidly, the intensity of light received by the light receiving element 82 increases rapidly. As a result, the output voltage value decreases rapidly (region SB).

  At the time of the region SB, the toner T is attached to the light transmission window 60. However, as shown in FIG. 5C, the toner T attached to the light transmission window 60 is wiped off by the wiper 75. Since the intensity of light received by the element 82 is maximized, the output voltage value is minimized (region SC).

  In the process of FIGS. 5A to 5C, the toner T is accumulated in the developing chamber 57. However, as shown in FIG. 5D, the toner T passes through the communication portion 59 as a part of the toner T collapses. Then, it flows into the toner storage chamber 58. The toner T that has flowed in covers at least a part of the light transmission window 60, whereby the intensity of light received by the light receiving element 82 decreases, and the output voltage value increases (area SD).

  Thereafter, as shown in FIG. 2, while the sheet member 73 is in sliding contact with the upper wall and the front wall of the toner storage chamber 58, the amount of movement of the toner T in the vicinity of the light transmission window 60 is small, so that the output voltage value is approximately. It changes at a certain level (area SE). Then, the sheet member 73 enters the toner T accumulated on the bottom wall of the toner storage chamber 58, gradually scrapes the toner T while being in sliding contact with the bottom wall of the toner storage chamber 58, and conveys the toner T to the developing chamber 57 side. Since the light transmission window 60 is gradually covered by T, the output voltage value increases (area SF), and when the light transmission window 60 is completely covered, the output voltage value becomes maximum (area SA).

  Note that the time ratio of each region in the light reception signal changes according to the remaining amount of toner T in the developing cartridge 5B. That is, if the remaining amount of toner T is large, even if the toner T adhering to the light transmission window 60 is wiped off by the wiper 75, a large amount of toner T flows immediately after the wiper 75 and covers the light transmission window 60. Becomes shorter. In addition, since light does not easily pass through the developing cartridge 5B, the output voltage value of the region SE increases as a whole.

  Incidentally, when the amount of the toner T is sufficiently large, such as immediately after the development cartridge 5B is replaced, the toner T flows into the toner storage chamber 58 immediately after the sheet member 73 transports the toner T to the development chamber 57 and transmits light. Since the window 60 is covered, the output voltage value of the region SB increases as a whole and the region SC is almost eliminated.

  On the other hand, as the remaining amount of toner T decreases, the time for the area SC gradually increases and the time for the areas SD and SE decreases. In addition, since light can easily pass through the developing cartridge 5B, the output voltage values of the areas SA and SE are reduced as a whole.

  As illustrated in FIG. 3, the control device 100 includes a determination unit 110, a light emission intensity changing unit 170, and the like. The control device 100 includes a CPU, a RAM, a ROM, an input / output circuit, and the like (not shown). Information is input from the light receiving element 82 and the detection means 200, and the functions stored in the ROM are executed by the CPU. Is realized.

  The determination unit 110 determines the replacement timing of the developing cartridge 5B based on the light reception signal input from the light receiving element 82. The basic flow for determining the replacement time will be briefly described. As shown in FIG. 4, first, one or a plurality of periods (one period is a time for one rotation of the agitator 70, and in FIG. ) Is included, a time during which the output voltage value exceeds the preset light receiving reference value V1 (a time during which the output voltage value falls below V1 in FIG. 4) is calculated. Next, the ratio of the time during which the output voltage value exceeds the light reception reference value V1 in the fixed time TA is calculated. Then, it is compared with a predetermined determination threshold value, and when the calculated ratio exceeds the determination threshold value, it is determined that the developing cartridge 5B is at the replacement time.

  For example, when the ratio of the time during which the output voltage value exceeds the light reception reference value V1 in the fixed time TA is 13% and the determination threshold is set to 12%, the output voltage value is the light reception reference value V1. Since the ratio of the time exceeding the threshold exceeds the determination threshold, the determination unit 110 determines that it is time to replace the currently installed developing cartridge 5B.

  In addition, the determination method whether the output voltage value exceeded the light reception reference value V1 is not specifically limited. For example, the received light signal within a certain time may be divided into minute times to determine whether the output voltage value exceeds the received light reference value V1 every unit time, or the received light signal within a certain time may be continuously monitored. Then, it may be determined whether or not the output voltage value exceeds the light reception reference value V1. In addition, the output voltage value is acquired (sampling) from the received light signal within a predetermined time TA as a point every predetermined time, and whether or not the output voltage value (each sampling point) per predetermined time exceeds the received light reference value. You may judge. In this case, the ratio of the number of sampling points exceeding the determination reference value in the total number of sampling points is calculated, and the replacement time can be determined based on whether this ratio exceeds the determination threshold.

  The light emission intensity changing unit 170 changes the light emission intensity of the light emitting element 81 according to the initial capacity (whether it is a large capacity type or a small capacity type) of the developing cartridge 5B detected by the detection means 200 described later. Specifically, the light emission intensity of the light emitting element 81 is changed so that the light emission intensity of the small capacity type is smaller.

Specifically, the emission intensity changing portion 170 when a large-capacity type are mounted to emit the light emitting element 81 in the light-emitting intensity I _HIGH, if the small-capacity type are mounted from the luminous intensity I _HIGH The light emitting element 81 is caused to emit light with a low emission intensity I _LOW . Note that the emission intensities I _HIGH and I _LOW can be set based on a correlation between the initial capacity of the developing cartridge 5B and the deterioration time of the toner T by performing a test or the like in advance. it can. The effect of reducing the light emission intensity of the light emitting element 81 will be described later.

  The detecting means 200 detects whether the developing cartridge 5B mounted on the main body housing 2 is a large capacity type or a small capacity type, and outputs the result to the light emission intensity changing section 170. Such a detection means 200 can widely employ a known configuration for detecting the specification of the developing cartridge 5B mounted on the main body housing 2. For example, a device that reads information on the initial capacity from an IC chip or the like provided in the developing cartridge 5B, a sensor that detects the initial capacity of the developing cartridge 5B that is mounted according to a change in the detection state, and the like can be employed.

  The notification unit 300 notifies the user who uses the laser printer 1 of a message. In the present embodiment, when the determination unit 110 determines that it is “the time to replace the developing cartridge 5B”, the notification unit 300 notifies the user of a message to that effect. As such notification means 300, for example, a liquid crystal display that notifies a message with characters or pictures, a speaker that notifies a message with sound, a lamp that notifies a message with blinking light, or the like can be adopted. Moreover, you may employ | adopt the alerting | reporting means which combined two or more liquid crystal displays, speakers, lamps, etc.

(Determination of developer cartridge replacement time)
Next, the determination of the replacement timing of the developing cartridge 5B in this embodiment and the operation when the light emission intensity of the light emitting element 81 is reduced will be described with reference to the drawings as appropriate.
As shown in FIG. 6, the control device 100 (light emission intensity changing unit 170) is first attached to the main body housing 2 based on information on the type (initial capacity) of the developing cartridge 5 </ b> B detected by the detection unit 200. It is determined whether the developing cartridge 5B is a small capacity type or a large capacity type (step S110).

When it is a large capacity type (step S110, No), the control device 100 (light emission intensity changing unit 170) causes the light emitting element 81 to emit light with the light emission intensity I _HIGH (step S121). On the other hand, when it is a small capacity type (step S110, Yes), the control device 100 (light emission intensity changing unit 170) causes the light emitting element 81 to emit light with a light emission intensity I _LOW smaller than the light emission intensity I _HIGH (step S122). ).

  Thereafter, the control device 100 (determination unit 110) determines whether it is time to replace the developing cartridge 5B (step S130). When it is determined that it is the replacement time (step S130, Yes), the notification means 300 is notified of the message (step S140), and when it is not determined that the replacement time is determined (step S130, No). Ends the determination of the replacement time.

  As shown in FIG. 7, when the light emission intensity of the light emitting element 81 is reduced, the intensity of light received by the light receiving element 82 is reduced, so that the output voltage value can be increased as a whole (close to V0). Then, the ratio of the time during which the output voltage value exceeds the light reception reference value V1 within the predetermined time TA is smaller than that in the case where the light emission intensity shown in FIG. 4 is large, so that the ratio exceeds the determination threshold. The time required can be lengthened. As a result, it is possible to lengthen the time required until it is determined that the developing cartridge 5B is to be replaced.

  As described above, when the small-capacity type is mounted, the light emission intensity of the light-emitting element 81 is changed so as to be smaller than that of the large-capacity type, so that the small-capacity type developing cartridge 5B is in the replacement period. It is possible to lengthen the time required until it is determined. As a result, the use period of the small-capacity type developing cartridge 5B can be extended.

  As described above, even if the remaining amount of the toner T determined to be the replacement time in the large-capacity type is the same as the remaining amount of the toner T, the small-capacity type residual toner T is not deteriorated so as to lower the image quality. . Therefore, by reducing the light emission intensity of the light emitting element 81 and extending the use period of the small capacity type, it is possible to use the toner T in the small capacity type developing cartridge 5B to an appropriate deterioration state.

  According to this, since the small-capacity type toner T can be used effectively, the number of printable sheets of the small-capacity type can be increased. Further, it is possible to reduce the amount of toner T accommodated in the small-capacity type (the initial capacity of the toner T) by keeping the number of printable sheets, for example, 3000 sheets.

  In the present embodiment, an example in which the light emitting element 81 whose light emission intensity can be changed by an input voltage from the control device 100 (light emission intensity changing unit 170) is used to change the light emission intensity is shown. It is not limited. For example, a light emitting unit composed of a plurality of light emitting elements may be configured, and the light emission intensity may be changed by changing the number of light emitting elements that emit light according to an input (instruction) from the light emission intensity changing unit 170. In addition, a shutter (aperture), a movable filter, and a movable light shielding that can cover a part of the light transmission window as another example of the light emission intensity changing means between the light emitting element and the cartridge in the apparatus main body. A light emission intensity may be changed by providing a plate or the like.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the present embodiment, instead of changing the light emission intensity of the light emitting element 81, the light receiving reference value is changed. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 8, the laser printer 1 according to this embodiment includes a light emitting element 81, a light receiving element 82, a determination unit 180 that determines the replacement timing of the developing cartridge 5 </ b> B, and a detection unit in the main body housing 2. 200 and notification means 300.

  The determination unit 180 includes a CPU, a RAM, a ROM, an input / output circuit (not shown), and the like. Based on a program and data stored in the ROM, an output from the light receiving element 82 and the detection unit 200, and the like, Determine the replacement time. As will be described later, since the determination unit 180 determines the replacement time in the same manner as the determination unit 110 except for changing the light reception reference value, the description thereof will be omitted.

  When determining the replacement time, the determination unit 180 changes the light reception reference value according to the initial capacity of the developing cartridge 5B detected by the detection unit 200. Specifically, as shown in FIG. 9, the light reception reference value V1 is used to determine the replacement time of the large capacity type, and the light reception reference value V2 is used to determine the replacement time of the small capacity type. In the light receiving reference value V2, the difference D2 from the output value V0 when the light receiving element 82 is not receiving light is larger than the difference D1 from the output value V0 to the light receiving reference value V1. In FIG. 9, the light reception reference value V2 is smaller than the light reception reference value V1.

  By using such a light reception reference value V2 for the determination of the replacement time of the small capacity type, the ratio of the time when the output voltage value exceeds the light reception reference value V2 is calculated to be small. The time required to exceed the threshold can be lengthened. As a result, as in the first embodiment, the small-capacity type use period can be extended, so that the toner T in the small-capacity type developing cartridge 5B can be used to an appropriate deterioration state. it can.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

In the embodiment, the example in which the type of the developing cartridge 5B that can be attached to the laser printer 1 is two types has been described, but the present invention is not limited to this, and may be set to three or more types, for example. When three or more types are used, for example, the light emission intensity of the light emitting element may be set individually for each type of cartridge, or may be set for each initial capacity range of the cartridge. As a specific example of the latter, when the number of printable sheets is 6000 or more, the light emitting element emits light with an emission intensity I _HIGH , and when the cartridge is between 6000 and 3000 sheets, the light emitting element is emitted with an emission intensity I _MEDIUM. In the case of 3000 cartridges or less, the light emitting element emits light with a light emission intensity I _LOW (I _LOW <I _MEDIUM <I _HIGH ).

  In the above-described embodiment, the light receiving element 82 has the maximum output voltage value when the received light intensity is minimum and the output voltage value is minimum when the received light intensity is maximum. It is not limited to this. For example, a light receiving element may be employed in which the output voltage value is minimized when the intensity of received light is minimum and the output voltage value is maximized when the intensity of received light is maximum.

  In the embodiment, the developing cartridge 5B (cartridge) is configured to be detachable from the main body housing 2 in a state where the developing cartridge 5B (cartridge) is attached to the photosensitive unit 5A (state of the process unit 5), but the present invention is not limited thereto. It is not something. For example, the developing cartridge 5B may be configured to be directly detachable from the main body housing 2 (specifically, a configuration that is detachable from the photoconductor unit 5A fixed to the main body housing 2).

  In the above-described embodiment, the developing cartridge 5B including the developing roller 54, the supply roller 55, and the toner storage chamber 58 is employed as an example of the cartridge, but the present invention is not limited to this. For example, a toner cartridge mainly having a toner storage chamber may be employed, or a process unit (process cartridge) in which the photosensitive unit 5A and the developing cartridge 5B of the above-described embodiment are integrated (not removable) is employed. May be.

  In the above-described embodiment, the laser printer 1 is employed as an example of the image forming apparatus. However, the present invention is not limited to this, and for example, a copying machine or a multifunction machine may be employed.

DESCRIPTION OF SYMBOLS 1 Laser printer 5B Developing cartridge 81 Light emitting element 82 Light receiving element 110 Determination part 170 Light emission intensity change part 180 Determination means 200 Detection means D1 Difference D2 Difference V0 Output value V1 Light reception reference value V2 Light reception reference value T Toner

Claims (2)

An image forming apparatus configured to detachably attach a plurality of types of cartridges having different initial capacities of the developer and to optically detect the amount of the developer in the cartridge,
A light emitting element that emits light into the cartridge;
A light receiving element that receives light emitted from the light emitting element and passed through the cartridge;
Determination means for determining the replacement time of the cartridge based on the light reception signal of the light receiving element;
Detecting means for detecting an initial capacity of the mounted cartridge;
A light emission intensity changing means for changing the light emission intensity of the light emitting element according to the initial capacity of the cartridge detected by the detection means;
The image forming apparatus, wherein the light emission intensity changing unit changes the light emission intensity of the light emitting element so that the light emission intensity of a cartridge having a small initial capacity is relatively small. An image forming apparatus configured to detachably attach a plurality of types of cartridges having different initial capacities of the developer and to optically detect the amount of the developer in the cartridge,
A light emitting element that emits light into the cartridge;
A light receiving element that receives light emitted from the light emitting element and passed through the cartridge;
Determination means for determining that it is time to replace the cartridge when the ratio of the time when the output value of the light receiving element exceeds the light reception reference value exceeds a determination threshold;
Detecting means for detecting the initial capacity of the mounted cartridge,
The determination means changes the light reception reference value according to the initial capacity of the cartridge detected by the detection means,
An image forming apparatus characterized in that the light receiving reference value is larger in difference from an output value in a state where the light receiving element is not receiving light when used for determining the replacement time of a cartridge having a small initial capacity. .

Images