Patent Publication Number: US-10331076-B2

Title: Method of manufacturing a molded article having a conductive sheet adhered thereto

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Divisional of U.S. application Ser. No. 14/325,825, filed Jul. 8, 2014, which claims the benefit of Japanese Patent Application No. 2013-146303, filed Jul. 12, 2013, all of which are hereby incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a developing apparatus, a developing cartridge, a process cartridge, and a method of manufacturing molded articles. 
     The developing apparatus is apparatus including a developing roller, and configured to visualize an electrostatic latent image formed on an electrophotographic photosensitive drum by using developer (hereinafter, referred to as toner) with the developing roller. 
     The developing cartridge is formed by integrating the developing apparatus into a cartridge, and is demountably mounted on a main body of an electrophotographic image forming apparatus. The process cartridge includes the electrophotographic photosensitive drum and the developing apparatus configured to act on the electrophotographic photosensitive drum integrated into the cartridge and is configured to be demountably mounted on the main body of the electrophotographic image forming apparatus. 
     Description of the Related Art 
     An electrophotographic image forming apparatus using an electrophotography forming process of the related art employs a process cartridge system including an electrophotographic photoreceptor and a process device acting thereon integrated into a cartridge so as to allow the cartridge to be demountably mountable on a main body of the electrophotographic image forming apparatus. 
     According to the process cartridge system, maintenance of the apparatus can be performed by users themselves without resort to a serviceman, and hence operability is significantly improved. Therefore, the process cartridge system is widely used in the electrophotographic image forming apparatus. 
     In the case of the electrophotographic image forming apparatus employing the process cartridge system, the process cartridge is replaced by the users as described above. Therefore, an amount-of-remaining-toner sensing device configured to sense consumption of toner, and notify time for replacement to the users is often provided. 
     Examples of the amount-of-remaining-toner sensing device include a system that senses a change in electrostatic capacitance between a plurality of electrodes arranged in the process cartridge and senses an amount of remaining toner. As an example of the system as described above, Japanese Patent Laid-Open No. 2003-248371 proposes a configuration in which a developer bearing member is used as an input-side electrode by applying an AC bias thereto, and an electrostatic capacitance sensing member serving as an output-side electrode is provided at a position opposing the developer bearing member in the developing apparatus. In this configuration, a contact member configured to electrically connect the electrostatic capacitance sensing member and a conductive member having a spring property provided in the main body of the image forming apparatus (hereinafter, referred to as a main body-side amount-of-remaining-toner contact) is provided on the process cartridge. When the AC bias is applied to the developer bearing member, an electric current depending on the electrostatic capacitance (the amount of remaining toner) is induced between the developer bearing member and the electrostatic capacitance sensing member. The amount of remaining toner can be sensed successively by measuring a current value of an induced current with an amount-of-remaining-toner sensing unit in the main body of the image forming apparatus via the contact member provided on the process cartridge side and the main body-side amount-of-remaining-toner contact. 
     In the method of the related art, highly precise arrangement of many components such as keeping a distance between a member for sensing the electrostatic capacitance and the developer bearing member constant is required for sensing the amount of developer accurately in high degree of precision. 
     SUMMARY OF THE INVENTION 
     This disclosure realizes space saving and high reliability of sensing of an amount of remaining toner by achieving an electrical connection between a member configured to sense an electrostatic capacitance provided on a process cartridge and a main body-side amount-of-remaining-toner contact in a simple configuration. 
     This disclosure provides a developing apparatus including: a first frame member molded by pouring a resin from a gate; a conductive sheet adhered integrally to a sheet adhering portion of the first frame member by molding of the resin; and a second frame member configured to define a toner storage portion by being coupled with the first frame member, wherein the first frame member includes: a bent portion at the sheet adhering portion, and a portion having a different thickness provided at an adjacent portion to the adhering portion. 
     This disclosure also provides a process cartridge including: a first frame member molded by pouring a resin from a gate; a conductive sheet adhered integrally to a sheet adhering portion of the first frame member by molding of the resin; and a second frame member configured to define a toner storage portion by being coupled with the first frame member, wherein the first frame member includes: a bent portion at the sheet adhering portion, and a portion having a different thickness provided at an adjacent portion to the adhering portion. 
     This disclosure also provides a method of manufacturing a molded article including: inserting a conductive sheet between a first molding and a second molding; forming a cavity by mating the first molding and the second molding; and pouring a resin from a gate and molding with the conductive sheet integrally adhered thereto, wherein the first molding or the second molding includes a shape configured to differentiate a distance of the cavity formed at an adjacent portion to a portion where the conductive sheet is inserted, and the shape changes a flow of the resin to restrain extension of the conductive sheet. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a developing apparatus according to an embodiment. 
         FIG. 2  is a partly enlarged view of a first frame member according to the embodiment. 
         FIG. 3  is a cross-sectional view of a main body of an image forming apparatus and a process cartridge of an electrophotographic image forming apparatus according to the embodiment. 
         FIG. 4  is a cross-sectional view of the process cartridge according to the embodiment. 
         FIG. 5  is a perspective view of the main body of the image forming apparatus and the process cartridge according to the embodiment in a state in which an opening and closing door is opened. 
         FIG. 6  is an explanatory perspective view illustrating a configuration of the process cartridge according to the embodiment. 
         FIG. 7  is a partial perspective view of the first frame member molded with a conductive sheet of the embodiment adhered thereto. 
         FIG. 8  is a cross-sectional view of  FIG. 7 . 
         FIG. 9  is an explanatory partial perspective view for explaining coupling between the first frame member molded with the conductive sheet adhered thereto and a toner storage frame member according to the embodiment. 
         FIG. 10  is a perspective view of the developing apparatus to which this disclosure is applicable. 
         FIGS. 11A and 11B  are cross-sectional views of an entire molding for molding the first frame member according to the embodiment. 
         FIG. 12  is a conceptual drawing illustrating a flow of a resin in the interior of the molding in a state in which a portion having a shape for differentiating a distance of a cavity (thickness) is not formed. 
         FIGS. 13A to 13D  are partial cross-sectional views of  FIG. 12 . 
         FIG. 14  is a drawing illustrating a surface resistance value of the conductive sheet. 
         FIG. 15  is a conceptual drawing illustrating a flow of a resin in the interior of the molding in which the portion having a shape for differentiating a distance of the cavity (thickness) is provided. 
         FIGS. 16A to 16D  are conceptual drawings of the portions having a shape for differentiating the distance of the cavity (thickness) according to the embodiment. 
         FIGS. 17A and 17B  are conceptual drawings of the portions having a shape for differentiating the distance of the cavity (thickness) according to the embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     An embodiment of this disclosure will be described below with reference to the drawings in detail. 
     A direction of an axis of rotation of an electrophotographic photosensitive drum is defined as a longitudinal direction. 
     In the longitudinal direction, a side where the electrophotographic photosensitive drum receives a driving force from the main body of the image forming apparatus is defined as a driven side, and a side opposite thereto is defined as a non-driven side. 
     A general configuration and an image forming process will be described with reference to  FIG. 3  and  FIG. 4 . 
       FIG. 3  of the embodiment of this disclosure is a cross-sectional view of the main body of the image forming apparatus (hereinafter, referred to as an apparatus main body A) of the electrophotographic image forming apparatus and a process cartridge (hereinafter referred to as a cartridge B). 
       FIG. 4  is a cross-sectional view of the cartridge B. 
     Here, the apparatus main body A of the electrophotographic image forming apparatus is a portion of the electrophotographic image forming apparatus from which the cartridge B is removed. 
     General Configuration of Electrophotographic Image Forming Apparatus 
     In  FIG. 3 , the electrophotographic image forming apparatus is a laser beam printer using an electrophotographic technology in which the cartridge B is demountably mounted on the apparatus main body A. When the cartridge B is mounted on the apparatus main body A, an exposure unit  3  (laser scanner unit) is arranged in an upper side of the cartridge B. 
     Also, a sheet tray  4  in which a recording medium (hereinafter, referred to as a sheet material P) which is a target of image formation is stored is arranged on a lower side of the cartridge B. 
     In addition, the apparatus main body A includes a pickup roller  5   a , a feed roller pair  5   b , a conveyance roller pair  5   c , a transfer guide  6 , a transfer roller  7 , a transfer guide  8 , a fixing unit  9 , a discharge roller pair  10 , and a discharge tray  11  arranged in sequence along a direction of conveyance D of the sheet material P. The fixing unit  9  includes a heat roller  9   a  and a pressurizing roller  9   b.    
     Image Formation Process 
     Subsequently, the image forming process is described schematically. On the basis of a print start signal, the electrophotographic photosensitive drum (hereinafter, referred to as a drum  62 ) is driven to rotate at a predetermined circumferential velocity (process speed) in a direction indicated by an arrow R. 
     A charging roller  66  to which a bias voltage is applied, comes into contact with an outer peripheral surface of the drum  62 , and charges an outer peripheral surface of the drum  62  uniformly and evenly. 
     The exposure unit  3  outputs a laser beam L in accordance with image information. The laser beam L passes through an exposure window portion  74  on an upper surface of the cartridge B, and scans and exposes the outer peripheral surface of the drum  62 . 
     Accordingly, an electrostatic latent image corresponding to the image information is formed on the outer peripheral surface of the drum  62 . 
     In contrast, as illustrated in  FIG. 3  in a developing device unit  20  as the developing apparatus, toner T in a toner storage portion  29  is stirred and conveyed by a rotation of a conveyance member  43 . 
     The toner T is born on a surface of a developing roller  32  by a magnetic force of a magnet roller  34  (fixed magnet). 
     The toner T is controlled in layer thickness on the peripheral surface of the developing roller  32  while being charged by friction by a developing blade  42 . 
     The toner T is transferred to the drum  62  in accordance with the electrostatic latent image, and is visualized as a toner image. 
     As illustrated in  FIG. 3 , the sheet material P stored in a lower portion of the apparatus main body A is fed from the sheet tray  4  by the pickup roller  5   a , the feed roller pair  5   b , and the conveyance roller pair  5   c  at the same timing as outputting of the laser beam L. 
     Then, the sheet material P passes through the transfer guide  6 , and is fed to a transfer position between the drum  62  and the transfer roller  7 . At this transfer position, toner images are transferred in sequence from the drum  62  to the sheet material P. 
     The sheet material P to which the toner image is transferred is separated from the drum  62  and conveyed to the fixing unit  9  along the transfer guide  8 . The sheet material P then passes through a nip portion between the heat roller  9   a  and the pressurizing roller  9   b  which constitute the fixing unit  9 . 
     At the nip portion, pressurization and heat-fixation is performed, so that the toner image is fixed to the sheet material P. The sheet material P subjected to the fixation of the toner image is conveyed to the discharge roller pair  10 , and is discharged to the discharge tray  11 . 
     In contrast, as illustrated in  FIG. 4 , residual toner on the outer peripheral surface of the drum  62  after the transfer is removed by a cleaning blade  77 , and the drum  62  is used for the image forming process again. The toner removed from the drum  62  is stored in a waste toner chamber  71   b  of a cleaning unit  60 . 
     In the above-described description, the charging roller  66 , the developing roller  32 , and the cleaning blade  77  are process devices acting on the drum  62 . 
     Configuration of Mounting and Demounting of Cartridge 
     Subsequently, mounting and demounting of the cartridge B with respect to the apparatus main body A will be described with reference to  FIG. 5 . 
       FIG. 5  is a perspective view of the apparatus main body A in a state in which an opening and closing door  13  is opened for mounting and demounting the cartridge B and the cartridge B. 
     The opening and closing door  13  is rotatably mounted on the apparatus main body A. When the opening and closing door  13  is opened, a guide rail  12  is provided, and the cartridge B is mounted in the apparatus main body A along the guide rail  12 . 
     Subsequently, a drive shaft  14  driven by a motor (not illustrated) of the apparatus main body A engages a driving force receiving portion provided on the cartridge B. 
     Accordingly, the drum  62  coupled to the driving force receiving portion receives a driving force from the apparatus main body A and rotates. 
     General Configuration of Cartridge 
     Subsequently, a general configuration of the cartridge B will be described with reference to  FIG. 4  and  FIG. 6 . 
       FIG. 6  is an explanatory perspective view illustrating a configuration of the cartridge B. 
     The cartridge B includes the cleaning unit  60  and the developing device unit  20  combined with each other. 
     The cleaning unit  60  includes a cleaning frame member  71 , the drum  62 , the charging roller  66 , and the cleaning blade  77 . 
     In contrast, the developing device unit  20  includes a lid member  122 , a toner storage container  23 , a first side member  26 L, a second side member  26 R, the developing blade  42 , the developing roller  32 , the magnet roller  34 , the conveyance member  43 , the toner T and biasing members  46 . 
     The cartridge B is formed by coupling the cleaning unit  60  and the developing device unit  20  with a coupling member  75  so as to be rotatable with each other. 
     Specifically, rotation holes  26   b L and  26   b R, extending in parallel with the developing roller  32 , are formed at distal ends of arm portions  26   a L and  26   a R formed on the first side member  26 L and the second side member  26 R provided on the developing device unit  20  at both ends thereof in the longitudinal direction. 
     Fitting holes  71   a  for fitting coupling members  75  are formed at both ends of the cleaning frame member  71  in the longitudinal direction. 
     The cleaning unit  60  and the developing device unit  20  are coupled so as to be capable of rotating about the coupling members  75  by aligning the arm portions  26   a L and  26   a R to predetermined positions of the cleaning frame member  71  and inserting the coupling members  75  into the rotation holes  26   b L and  26   b R and the fitting holes  71   a.    
     At this time, the biasing members  46  mounted at roots of the arm portions  26   a L and  26   a R abut against the cleaning frame member  71 , thereby biasing the developing device unit  20  toward the cleaning unit  60  about the coupling members  75  as a center of rotation. 
     Accordingly, the developing roller  32  is reliably pressed in the direction of the drum  62 . 
     Developing Device Unit 
     Subsequently, a configuration of the developing device unit  20  of this disclosure will be described with reference to  FIG. 2 ,  FIG. 7 , and  FIG. 8 .  FIG. 7  illustrates a partial perspective view of a member formed by adhering a conductive sheet  24 , which corresponds to an amount-of-remaining-toner sensing member, to a sheet adhering portion  446  of the lid member  122 , which corresponds to a first frame member illustrated in  FIG. 2 . 
     When molding the first frame member, the conductive sheet  24  is preferably molded by inserting the conductive sheet  24  into the mold in advance so that the conductive sheet is molded in a state of being adhered to (being molded integrally with) a molded article at the time of molding of the first frame member. 
     As illustrated in  FIG. 7 , the conductive sheet  24  is functionally divided into two parts, namely, a toner remaining amount sensing unit  24   a  and a contact portion  24   b , and the entire part of the conductive sheet  24  is adhered to the first frame member (lid member)  122 . 
     The conductive sheet  24  may be a conductive sheet having a three-layer structure including a PS resin sandwiched between conductive layers of PS resin mixed with carbon black, or may be a conductive sheet having a single-layer structure formed of an EVA resin mixed with carbon black. The conductive sheet  24  may also be a conductive sheet having a two-layer structure formed of PS resin printed with carbon black. The entire thickness of the conductive sheet  24  preferably falls within a range from 0.05 mm to 0.3 mm. The conductive sheet  24  is not limited to those described above, and any conductive sheet may be used as long as it follows the molding by the application of resin pressure, and is fixed to the first frame member (lid member)  122  at least with a certain level of strength after molding. 
       FIG. 8  is a cross-sectional view taken along the line VIII-VIII in  FIG. 7 . As illustrated in the drawing, the contact portion  24   b  of the conductive sheet  24  is molded so that the conductive sheet  24  is exposed to a surface b, which is a surface opposite to a surface a on the side where the conductive sheet  24  comes into contact with the toner of the first frame member (lid member)  122 . 
     A portion where the conductive sheet  24  is adhered to includes a bent portion  44  at an arcuate angle between a R-shape  441  for allowing the rotation of a toner stirring conveyance member  43  (see  FIG. 4 ) and an upright wall  442 . 
     Most part of the first frame member (lid member)  122  is formed at a uniform thickness (M). The uniform thickness (M) is referred to as a basic thickness here. The basic thickness preferably falls within a range from 1.0 mm to 3.0 mm. 
     Subsequently, an amount-of-remaining-toner sensing system will be described with reference to  FIGS. 1, 8, 9, and 10 . 
     As described above, the first frame member (lid member)  122  adhered to the conductive sheet  24  is fixed by means such as welding to the toner storage container  23 , which corresponds to a second frame member, as illustrated in  FIG. 9 . In this embodiment, a welding rib  122   b  is provided on the first frame member (lid member)  122 , and ultrasonic vibrations are applied to the second frame member (toner storage container)  23 , so that the first frame member (lid member)  122  and the second frame member (toner storage container)  23  are coupled. 
     The developing roller  32  having a conductivity arranged so as to oppose the conductive sheet  24  is supported by bearing members  37  and  38  as illustrated in  FIG. 10 , and is rotatably mounted on the toner storage container  23  via side members  26 L and  26 R. 
     In this embodiment, hollow aluminum is used for the developing roller  32  and conductive resin is used for a bearing member  38  on the non-driven side as materials, and an outer periphery  38   a  of the bearing member  38  supports an inner periphery of the non-driven side of the developing roller  32 . 
     When the cartridge B is inserted into the apparatus main body A, a development contact spring, which is not illustrated, electrically connected to the circuit in the apparatus main body A comes into abutment with a lower surface c of the bearing member  38  ( FIG. 10 ), whereby bias is applied to the developing roller  32 . 
     The contact portion b of the conductive sheet  24  (see  FIG. 8 ) is configured to come into abutment with the main body-side amount-of-remaining-toner contact (not illustrated) which is electrically connected to the amount-of-remaining-toner sensing unit of the apparatus main body A when the cartridge B is inserted into the apparatus main body A. 
       FIG. 1  illustrates a cross-sectional view of the developing apparatus in a state in which the cartridge is inserted into the apparatus main body. 
     The cartridge includes a first chamber  9001  configured to store the toner therein, a second chamber  9002  in which the developing roller  32  is mounted, and an opening portion  9003  formed between the first chamber and the second chamber, and is configured in such a manner that the toner T is supplied from the first chamber  9001  through the opening portion  9003  to the second chamber  9002  to cause the toner T adhered to the developing roller  32 . 
     The first chamber  9001  is defined by a frame member formed with the conductive sheet  24  adhered to a portion adjacent to the opening portion  9003 . 
     The portion adjacent to the opening portion  9003  needs to be provided with the upright wall  442  so as to extend along a wall between the R-shape  441  for allowing the toner stirring conveyance member  43  to rotate and the second chamber  9002 , and hence the bent portion  44  at an acute angle is included between the curved shape (R-shape)  441  and the upright wall  442 . 
     Since the shape is abruptly varied from a highest portion of the acute angled bent portion, the amount of remaining toner may be measured effectively by adhering the conductive sheet  24  to the bent portion  44  between the curved surface shape (R-shape)  441  and the upright wall  442 . 
     When molding the first frame member (lid member)  122 , a thickness varied portion  45  is formed between a gate (or a trace of the gate (gate trace))  102  for allowing the resin to flow into a space (cavity) having the shape of the first frame member and a portion to which the conductive sheet  24  is adhered. The gate trace for allowing the resin into the cavity for molding the first frame member (molded article) may remain on the first frame member (molded article). In this specification, the gate and the gate trace remaining on the molded article are collectively referred to as “gate”. 
     When an AC voltage is applied to the developing roller  32 , a current corresponding to the electrostatic capacitance between the developing roller  32  and the conductive sheet  24  is induced therebetween. The electrostatic capacitance changes in accordance with the amount of the toner T between the developing roller  32  and the conductive sheet  24 . Therefore, by measuring the current value with the amount-of-remaining-toner sensing unit (not illustrated), the toner remaining amount T between the developing roller  32  and the conductive sheet  24  may be sensed successively. 
     Description about Thickness Varied Portion (Portion where the Thickness is Different 
       FIG. 2  is a schematic drawing illustrating part of the first frame member (lid member)  122  in an enlarged scale. Reference numeral  446  denotes a sheet adhering portion to which the conductive sheet  24  is adhered. The thickness varied portion  45  is provided at an adjacent portion to the sheet adhering portion  446  (between the conductive sheet and gates  102  and  103 ). The thickness varied portion  45  corresponds to a portion where the thickness M of the first frame member (lid member) is different. The portion where the thickness M of the first frame member (lid member) is different is preferably a depression formed by reducing the thickness of the first frame member (lid member)  122 . However, it may be a projecting portion projected by increasing the thickness of the first frame member (lid member)  122 . The thickness varied portion  45  may be formed on the surface on a side coming into contact with the toner, or may be formed on a surface b on the back. However, the thickness varied portion  45  is preferably formed on the surface b on the back. 
     The adjacent portion to the sheet adhering portion  446  corresponds to an area Z ranging from the gates  102  and  103  for allowing the resin to flow into the space (cavity) having the shape of the first frame member when molding the first frame member (lid member)  122  to the sheet adhering portion. 
     The thickness varied portion preferably includes a portion  45   a  reduced in thickness from the thickness of the first frame member on a line N connecting the gate  102  and a bent portion closest to the gate  102 . A depressed amount (amount of thickness variation) t 1  of a portion having a reduced thickness preferably falls within a range from 0.2 mm to 0.5 mm. A width w 1  is preferably at least 20 mm. A portion  45   b  having a larger thickness may be provided adjacently to the portion having a reduced thickness. The portion having a larger thickness is preferably on a line F connecting the bent portion at an end of the conductive sheet  24  and the gate  102  closest to the bent portion at the end of the conductive sheet  24 . A width w 2  of the portion  45   b  is preferably at least 30 mm. 
     Method of Manufacturing Molded Article (First Frame Member (Lid Member)) 
     Subsequently, a method of manufacturing the molded article (first frame member (lid member))  122  will be described. The first frame member (lid member)  122  is molded by inserting the conductive sheet in a cavity in the molding in advance, then pouring resin into the cavity. Accordingly, the first frame member (lid member)  122  provided with the conductive sheet adhered thereto (adhered integrally thereto) is manufactured. 
       FIGS. 11A and 11B  illustrate an example of a cross-sectional view of a molding for molding the first frame member (lid member)  122  as a whole.  FIG. 11A  is a drawing illustrating a state in which the molding is opened, and  FIG. 11B  is a drawing illustrating a state in which the molding is closed. 
     Reference numeral  35  denotes a first molding, reference numeral  36  denotes a second molding, and reference numeral  1002  denotes a gate. The first molding  35  and the second molding  36  have a shape which forms a surface shape of the first frame member (lid member)  122  when being transferred. The conductive sheet  24  is inserted into the molding in advance when the molding is in an opened state. The conductive sheet  24  may be fixed to the first molding  35  by forming a fine air hole at a portion S and coupling the fine air hole to a suction unit, which is not illustrated. Here, the conductive sheet  24  is fixed to the first molding  35  for shortening a molding cycle by enabling the conductive sheet  24  to be set to the first molding  35  after infusion of the resin has been completed and while the second molding  36  is opened. Therefore, it is not necessarily required to fix the conductive sheet  24  to the first molding  35 , and may be fixed to the second molding  36 . A known method may also be used instead of the methods described above. 
     Subsequently, the first molding  35  and the second molding  36  are mated (the moldings is closed). Fused resin is poured into a cavity  1001  defined by mating the moldings is filled with the fused resin from a gate  1002  to mold the first frame member (lid member)  122 . When the first molding  35  and the second molding  36  are mated, the first molding  35  and the second molding  36  oppose each other at a distance M. Accordingly, the first frame member (lid member)  122  having a thickness M can be molded. 
     In the embodiment disclosed here, the second molding  36  includes a shape  110  for forming a portion which changes the interval of the distance M (the portion where the thickness is varied (thickness varied portion) formed in the adjacent portion to a portion in which the conductive sheet  24  is inserted, which corresponds to a part between the portion and the gate  1002 . 
     Subsequently, an effect achieved by providing the shape for differentiating the distance of the cavity (thickness) (the shape for differentiating the thickness) will be described. 
     When the conductive sheet without having the shape for differentiating the thickness is integrally molded, the difference in resistance value within the conductive sheet is significant, whereby sensed values of the amount of the residual toner may vary accordingly. As a result of research, the following causes are found. 
       FIG. 12  is a schematic drawing illustrating a flow of a resin in the interior of the molding in a state in which a shape for differentiating the thickness is not formed, and illustrates a state in which the cavity of the molding is filled with resin to a middle portion. Reference numeral  2010  denotes a distal end (flow front) of the resin. Reference numerals  2002  and  2003  denote gates, reference numeral  2004  denotes a resin, and reference numeral  224  denotes a conductive sheet. Reference numeral  2441  denotes a portion having a shape for transferring the bent portion  44  of the first frame member (lid member)  122  of the first molding. Here, a case where the resin is poured from the gates  2002  and  2003  at two positions will be described. 
     Reference numeral  244   g  denotes a portion having a shape for transferring the bent portion  44  of the first frame member (lid member)  122  in the first molding at a shortest distance from the gate  2002 , which is at the closest position from a sheet end. Reference numeral  237   g  denotes a portion having a shape for transferring the bent portion  44  of the first frame member (lid member)  122  in the second molding.  FIGS. 13A and 13B  are cross-sectional view taken along the line g-g including the portions  244   g  and  237   g.    
     Reference numeral  244   e  denotes a portion having a shape for transferring the bent portion  44  of the first frame member (lid member)  122  in the first molding at the end of the conductive sheet, and reference numeral  237   e  denotes a portion having a shape for transferring the bent portion  44  of the first frame member (lid member)  122  in the second molding.  FIGS. 13C and 13D  are cross-sectional views taken along the line e-e including the end  244   e  and the portion  237   e.    
     In a case where the thickness from the gate  2002  to a portion having a shape for transferring a bent portion is uniform, the fused resin flows concentrically. Subsequently, the resin first reaches the portions  244   g  and  237   g  having a shape for transferring the bent portion closest to the gate  2002 . At this time, a conductive sheet  224  is located on the second molding side  237   g  ( FIG. 13A ). Subsequently, the conductive sheet  224  is lifted upward by the resin  2004  filling the cavity, and is pressed against the first molding side  244   g  ( FIG. 13B ). Thereafter, a cavity is filled with resin from the portion  244   g  to the end  244   e  in sequence. In the conductive sheet end  244   e  apart from the gate  2002 , the resin reaches thereto in a state in which the sheet is almost fixed ( FIG. 13C ). Therefore, when a portion  2005 , which is not filled with resin, on the first molding side with respect to the conductive sheet is filled with resin, the conductive sheet  224  is expanded locally in the direction indicated by an arrow E, and hence the conductive sheet is thinned. It took about 0.6 seconds from a moment when the resin has reached the portion  244   g  until a moment when the resin has reached the end  244   e.    
     The surface resistance value of the conductive sheet  224  at a bent portion  244  of the first frame member (lid member) taken out from the molding was measured. The result is shown by a dot line  136  in  FIG. 14 . It will be understood that a resistance value  137  at the bent portion (portion molded by  244   g ) closest to the gate  2002  was the lowest, and the value increases as it goes away from the gate  2002 , and a ratio of a surface resistance value  138  at an end (portion molded by  244   e ) of the bent portion is the highest. The surface resistance value  138  at the end (portion molded by  244   e ) of the bent portion was approximately 2.2 times the surface resistance value  137  at the bent portion (portion molded by  244   e ) closest to the gate  2002 . It seems that the difference in time of reaching the portion having a shape for transferring a bent portion causes the fused resin to be solidified and the conductive sheet to be fixed and, in this state, the bent portion was filled with resin, whereby the conductive sheet was expanded. Accordingly, differences occurred in thickness of the conductive sheet, which results in variations in resistance value. 
     Therefore, in the embodiment, a shape for varying (differentiating) the thickness is provided between the gate and the portion having a shape for transferring a bent portion so as to reduce the difference in times of resin reaching the portion having a shape for transferring a bent portion. 
     The shape for varying (differentiating) the thickness for forming the thickness varied portion will be described in detail below. 
       FIG. 15  is a schematic drawing illustrating a flow of a resin in the interior of the molding having the shape  110  for differentiating the thickness and illustrates a state in which the cavity of the molding is filled with resin to a middle portion. Reference numeral  2010  denotes a distal end of the resin. Reference numerals  1002  and  1003  denote gates, reference numeral  1004  denotes a resin, and reference numeral  24  denotes a conductive sheet. Reference numeral  441  denotes a portion having a shape for transferring the bent portion  44  of the first frame member (lid member)  122  of the first molding. In this embodiment, a case where the cavity is filled with resin from the gates  1002  and  1003  at two positions will be described. However, this disclosure is not limited thereto, and the cavity may be filled with resin from only one gate or three or more gates. 
     Reference numeral  110  denotes a shape for differentiating the thickness formed in the molding, which is provided adjacent to the portion where the conductive sheet  24  is integrally adhered by the resin. The term “adjacent” means an area MW from an end of the portion where the conductive sheet is adhered to the gate. 
     In the embodiment disclosed here, an example in which a shape  110   a  for differentiating the thickness by a projecting shape having a projecting shape is formed in the second molding will be described. The shape  110   a  is formed on a line MN connecting a portion  44   g  having a shape for transferring the bent portion  44  of the first frame member (lid member)  122  in the second molding at the shortest distance from the gate  1002 , which is located at the closest position from the sheet end, and the gate  1002 . A projecting amount of the shape for differentiating the thickness by the projecting shape is preferably set to fall within a range from 0.2 mm to 0.5 mm. A width mw 1  of the shape for differentiating the thickness by the projecting shape is preferably set to 20 mm or more. 
     In addition, a shape  110   b  for differentiating the thickness by a depressed shape, which is formed by depressing the second molding, may be formed at the end of the conductive sheet and the gate  1002  on a line MF connecting a portion  44   e  having a shape for transferring the bent portion  44  of the first frame member (lid member)  122  in the second molding. A width mw 2  of a shape for differentiating the thickness by the depressed shape is preferably set to 30 mm or more. 
     The flow of the resin is differentiated by the shape for differentiating the thickness. Specifically by forming the shape for differentiating the thickness by the projecting shape in the second molding, the flow of the resin may be restrained. Specifically by forming the shape for differentiating the thickness by the depressed shape in the second molding, the flow of the resin may be accelerated. The shape for differentiating the thickness may be formed in the first molding. By forming the shape for differentiating the thickness by the projecting shape in the first molding, the flow of the resin may be restrained. By forming the shape for differentiating the thickness by the depressed shape in the first molding, the flow of the resin may be accelerated. 
     By forming the shape  110  for differentiating the thickness in the molding as described above in the mold, the difference at a distal end  2010  of the resin toward a portion  441  having a shape for transferring the bent portion is reduced in comparison with  FIG. 12 . The time required from a moment when the resin has reaches 44 g until a moment when the resin reaches 44 e may be controlled to be not more than approximately 0.4 seconds. 
     The first frame member (lid member) was molded with the molding in which the shape  110  for differentiating the thickness illustrated in  FIG. 15  was formed, and the surface resistance value of the conductive sheet  24  at the bent portion  44  was measured. The result is shown by a solid line  132  in  FIG. 14 . A resistance value  134  at the bent portion (portion molded by  44   g ) closest to the gate  1002  was the lowest, and the value increases as it goes away from the gate  1002 , and a surface resistance value ratio  135  at an end (portion molded by  244   e ) of the bent portion was the highest. It is understood that the difference in resistance value is significantly reduced by forming the shape  110  for differentiating the thickness. By reducing the difference in time from a moment when the resin reaches 44 g until the resin reaches 44 e as much as possible, the local extension of the sheet by being fixed can be successfully restrained, so that variations in thickness of the conductive sheet may be restrained and the difference in surface resistance value may be reduced. Accordingly, reliability of sensing of the amount of remaining toner is further improved. The different between the time required from a moment when the resin has reaches 44 g and a moment when the resin reaches 44 e is preferably controlled to be not more than 0.4 seconds. 
     Subsequently, a method of molding the contact portion  24   b  of the conductive sheet  24  will be described. A holding pin is arranged in the first molding in order to press the contact portion  24   b  of the conductive sheet reliably against the second molding. The holding pin is configured to be fixed at the contact portion  24   b  to the second molding by a spring force in a step in which the molding is closed. With a configuration in which a cavity is filled with resin so as to cause the holding pin to be retracted by a resin pressure in the step in which the molding is closed, the contact portion  24   b  is exposed to the surface b on the back when molding. 
     Although the first frame member (lid member) is molded and manufactured by the method of manufacturing the molded article of the embodiment disclosed here, the method is not limited thereto. 
     EXAMPLE 
     Subsequently, Examples will be described. A simulation was performed by varying the shape of the shape  110  for differentiating the thickness illustrated in  FIG. 15 .  FIGS. 16A to 16D  illustrate cross-sectional views taken along the line XVI-XVI in  FIG. 15  and top views of the shapes for differentiating the thickness. 
     Example 1 to Example 5, Comparative Example 
     A simulation using a molding shape having the shape  110   a  for differentiating the thickness by the projecting shape illustrated in  FIG. 16A  was performed. In this example, the shape  110   b  for differentiating the thickness is not provided. Specifically, a standard thickness (the thickness of the molded article of a portion where the thickness is not varied) was set to 1.5 mm. The shape of the shape  110   a  for differentiating the thickness by the projecting shape was set to a width mw 1  of 30 mm, a length ml 1  of 12 mm, and a projecting amount (amount of thickness variation) mt 1  was varied to 0.1 mm to 0.5 mm. The term “standard thickness” in this specification indicates the thickness of a portion of the molded article where the thickness is not varied, or a thickness which takes up a half or more of the thickness of the molded article. Subsequently, the time from a moment when the resin started to fill a cavity from the gate to a moment when the distal end of the resin (flow front) reaches the portion  44   g  having a shape for transferring the bent portion closest from the gate was obtained by the simulation. Also, the time from a moment when the resin started to fill a cavity from the gate to a moment when the resin reaches the portion  44   e  having a shape for transferring the bent portion at the sheet end was obtained by the simulation. Subsequently, the different in reaching time was obtained. The difference in reaching time was obtained in the same manner with Comparative Example in which the shape for differentiating the thickness was not provided. The result is shown in Table 1 
     
       
         
           
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                   
                 44g  
                 44e  
                 difference  
               
               
                   
                   
                 mt1  
                 reaching 
                 reaching 
                 in reaching  
               
               
                   
                   
                 (mm) 
                 time (s) 
                 time (s) 
                 time (s) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Example 1 
                 0.1 
                 1.196 
                 1.679 
                 0.483 
               
               
                   
                 Example 2 
                 0.2 
                 1.26 
                 1.659 
                 0.399 
               
               
                   
                 Example 3 
                 0.3 
                 1.323 
                 1.659 
                 0.336 
               
               
                   
                 Example 4 
                 0.4 
                 1.365 
                 1.66 
                 0.295 
               
               
                   
                 Example 5 
                 0.5 
                 1.367 
                 1.661 
                 0.294 
               
               
                   
                 Comparative 
                 0 
                 1.154 
                 1.7 
                 0.546 
               
               
                   
                 Example 
                   
                   
                   
                   
               
               
                   
                   
               
            
           
         
       
     
     From Table 1, in comparison with a case where the shape for differentiating the thickness is not provided, it was found that the difference in reaching time to  44   g  and the reaching time to  44   e  was reduced when the shape for differentiating the thickness is provided. Accordingly, the change in thickness of the sheet by solidification of the resin is restrained. Also, in order to achieve a better effect, it was found that the projecting amount (amount of thickness variation) mt 1  of the shape for differentiating the thickness is preferably set to fall within a range from 0.2 mm to 0.5 mm. 
     Example 6 to Example 10 
     A simulation using a molding shape having the shape  110   a  for differentiating the thickness by the projecting shape illustrated in  FIG. 16A  was performed. In this example, the shape  110   b  for differentiating the thickness is not provided. Specifically, a standard thickness (the thickness of the molded article of a portion where the thickness is not varied) was set to 1.5 mm. The shape of the shape  110   a  for differentiating the thickness was varied to have a length ml 1  of 12 mm, a projecting amount (amount of thickness variation) mt 1  of 0.3 mm, and a width mw 1  of 10 mm to 50 mm. Subsequently, the time from a moment when the resin started to fill a cavity from the gate to a moment when the distal end of the resin (flow front) reaches the portion  44   g  having a shape for transferring the bent portion closest from the gate was obtained by the simulation. Also, the time from a moment when the resin started to fill a cavity from the gate to a moment when the resin reaches the portion  44   e  having a shape for transferring the bent portion at the sheet end was obtained by the simulation. Subsequently, the difference in reaching time was obtained. The result is shown in Table 2 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                 44g  
                 44e  
                 difference  
               
               
                   
                 mt1 
                 reaching 
                 reaching 
                 in reaching  
               
               
                   
                 (mm) 
                 time (s) 
                 time (s) 
                 time (s) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Example 
                 10 
                 1.183 
                 1.7 
                 0.517 
               
               
                 6 
                   
                   
                   
                   
               
               
                 Example 
                 20 
                 1.28 
                 1.679 
                 0.399 
               
               
                 7 
                   
                   
                   
                   
               
               
                 Example 
                 30 
                 1.323 
                 1.659 
                 0.336 
               
               
                 8 
                   
                   
                   
                   
               
               
                 Example 
                 40 
                 1.386 
                 1.658 
                 0.272 
               
               
                 9 
                   
                   
                   
                   
               
               
                 Example 
                 50 
                 1.364 
                 1.658 
                 0.294 
               
               
                 10  
                   
                   
                   
                   
               
               
                   
               
            
           
         
       
     
     From Table 2, in comparison with a case where the shape for differentiating the thickness was not provided (see Comparative Example in Table 1), it was found that the difference in reaching time to  44   g  and the reaching time to  44   e  was reduced when the shape for differentiating the thickness was provided. Accordingly, the change in thickness of the sheet by solidification of the resin is restrained. Also, in order to achieve a better effect, it was found that the width mw 1  of the shape for differentiating the thickness was preferably set to be not smaller than 20 mm. 
     Example 11 to Example 13 
     A simulation using a molding shape having the shape  110   a  for differentiating the thickness by the projecting shape illustrated in  FIG. 16A  was performed. In this example, the shape  110   b  for differentiating the thickness is not provided. Specifically, a standard thickness (the thickness of the molded article of a portion where the thickness is not varied) was set to 1.5 mm. The shape of the shape  110   a  for differentiating the thickness was varied to have a projecting amount (amount of thickness variation) mt 1  of 0.3 mm, a width mw 1  of 30 mm, and a length ml 1  of 6 mm to 15 mm. Subsequently, the time from a moment when the resin started to fill a cavity from the gate to a moment when the distal end of the resin (flow front) reaches the portion  44   g  having a shape for transferring the bent portion closest from the gate was obtained by the simulation. Also, the time from a moment when the resin started to fill a cavity from the gate to a moment when the resin reaches the portion  44   e  having a shape for transferring the bent portion at the sheet end was obtained by the simulation. Subsequently, the difference in reaching time was obtained. The result is shown in Table 3 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                 44g  
                 44e  
                 difference  
               
               
                   
                 mt1 
                 reaching 
                 reaching 
                 in reaching  
               
               
                   
                 (mm) 
                 time (s) 
                 time (s) 
                 time (s) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Example 
                 6 
                 1.218 
                 1.68 
                 0.462 
               
               
                 11 
                   
                   
                   
                   
               
               
                 Example 
                 12 
                 1.323 
                 1.659 
                 0.336 
               
               
                 12 
                   
                   
                   
                   
               
               
                 Example 
                 15 
                 1.346 
                 1.661 
                 0.315 
               
               
                 13 
                   
                   
                   
                   
               
               
                   
               
            
           
         
       
     
     From Table 3, in comparison with a case where the shape for differentiating the thickness was not provided (see Comparative Example in Table 1), it was found that the difference in reaching time to  44   g  and the reaching time to  44   e  was reduced. Accordingly, the change in thickness of the sheet by solidification of the resin is restrained. 
     Example 14 to Example 16 
     A simulation using a molding shape having the shape  110   a  for differentiating the thickness by the projecting shape illustrated in  FIG. 16B  to  FIG. 16D  was performed. In this example, the shape  110   b  for differentiating the thickness is not provided. 
     The time from a moment when the resin started to fill a cavity from the gate to a moment when the distal end of the resin (flow front) reaches the portion  44   g  having a shape for transferring the bent portion closest from the gate was obtained by the simulation. Also, the time from a moment when the resin started to fill a cavity from the gate to a moment when the resin reaches the portion  44   e  having a shape for transferring the bent portion at the sheet end was obtained by the simulation. Subsequently, the difference in reaching time was obtained. The result is shown in Table 4 
     
       
         
           
               
               
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                   
                 Mt1(mm) 
                 44g  
                 44e  
                 difference  
               
               
                   
                   
                 *Number  
                 reaching 
                 reaching 
                 in reaching  
               
               
                   
                   
                 of Pieces 
                 time (s) 
                 time (s) 
                 time (s) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 Example 
                 □6*30*2 
                 1.324 
                 1.66 
                 0.336 
               
               
                   
                 14 
                   
                   
                   
                   
               
               
                   
                 Example 
                 □20*7*3 
                 1.238 
                 1.679 
                 0.441 
               
               
                   
                 15 
                   
                   
                   
                   
               
               
                   
                 Example 
                 ○7*3 
                 1.239 
                 1.68 
                 0.441 
               
               
                   
                 16 
                   
                   
                   
                   
               
               
                   
                   
               
            
           
         
       
     
     From Table 4, in comparison with a case where the shape for differentiating the thickness was not provided (see Comparative Example in Table 1), it was found that the difference in reaching time to  44   g  and the reaching time to  44   e  was reduced. Accordingly, the change in thickness of the sheet by solidification of the resin is restrained. 
     Example 17 to Example 20 
     A simulation with a molding shape having a shape for differentiating the thickness provided with the shape  110   b  for differentiating the thickness by the depressed shape adjacently to the shape  110   a  for differentiating the thickness by the projecting shape illustrated in  FIG. 17A  was performed. Specifically, a standard thickness (the thickness of the molded article of a portion where the thickness is not varied) was set to 1.5 mm. The shape of the shape  110   a  for differentiating the thickness was varied to have a projecting amount (amount of thickness variation) mt 1  of 0.3 mm, a width mw 1  of 30 mm, and a length ml 1  of 12 mm. The shape of the shape  110   b  for differentiating the thickness provided adjacent to the shape  110   a  for differentiating the thickness by the projecting shape was varied to have a depressed amount (amount of thickness variation) mt 2  of 0.3 mm, and a length ml 2  of 12 mm, and a width mw 2  of 10 mm to 40 mm. Subsequently, the time from a moment when the resin started to fill a cavity from the gate to a moment when the distal end of the resin (flow front) reaches the portion  44   g  having a shape for transferring the bent portion closest from the gate was obtained by the simulation. Also, the time from a moment when the resin started to fill a cavity from the gate to a moment when the resin reaches the portion  44   e  having a shape for transferring the bent portion at the sheet end was obtained by the simulation. Subsequently, the difference in reaching time was obtained. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 5 
               
               
                   
               
               
                   
                   
                 44g  
                 44e  
                 difference  
               
               
                   
                   
                 reaching 
                 reaching 
                 in reaching  
               
               
                   
                 mw2 
                 time (s) 
                 time (s) 
                 time (s) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Example 
                 10 
                 1.24 
                 1.661 
                 0.421 
               
               
                 17 
                   
                   
                   
                   
               
               
                 Example 
                 20 
                 1.261 
                 1.619 
                 0.358 
               
               
                 18 
                   
                   
                   
                   
               
               
                 Example 
                 30 
                 1.284 
                 1.578 
                 0.294 
               
               
                 19 
                   
                   
                   
                   
               
               
                 Example 
                 40 
                 1.284 
                 1.558 
                 0.274 
               
               
                 20 
                   
                   
                   
                   
               
               
                   
               
            
           
         
       
     
     From Table 5, in comparison with a case where the shape for differentiating the thickness was not provided (see Comparative Example in Table 1), it was found that the difference in reaching time to  44   g  and the reaching time to  44   e  was reduced. In Embodiment 19 and Embodiment 20, it was found that the difference in reaching time is reduced in comparison with a case where the shape  110   b  for differentiating the thickness is not provided (see Example 12). From these reasons, a width of a shape for differentiating the thickness by the depressed shape is preferably 30 mm or more. 
     Example 21 to Example 23 
     A simulation with a molding shape having a shape for differentiating the thickness provided with the shape  110   b  for differentiating the thickness by the depressed shape adjacently to the shape  110   a  for differentiating the thickness by the projecting shape illustrated in  FIG. 17A  was performed. Specifically, a standard thickness (the thickness of the molded article of a portion where the thickness was not varied) was set to 1.5 mm. The shape of the shape  110   a  for differentiating the thickness was varied to have a projecting amount (amount of thickness variation) mt 1  of 0.3 mm, a width mw 1  of 30 mm, and a length ml 1  of 12 mm. The shape of the shape  110   b  for differentiating the thickness provided adjacently to the shape  110   a  for differentiating the thickness by the projecting shape was varied to have a length ml 2  of 12 mm, a width mw 2  of 20 mm, and a depressed amount (amount of thickness variation) mt 2  to be 0.2 mm to 0.5 mm. Subsequently, the time from a moment when the resin started to fill a cavity from the gate to a moment when the distal end of the resin (flow front) reaches the portion  44   g  having a shape for transferring the bent portion closest from the gate was obtained by the simulation. Also, the time from a moment when the resin started to fill a cavity from the gate to a moment when the resin reaches the portion  44   e  having a shape for transferring the bent portion at the sheet end was obtained by the simulation. Subsequently, the difference in reaching time was obtained. The result is shown in Table 6 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
               
                   
                   
                 44g  
                 44e  
                 difference  
               
               
                   
                   
                 reaching 
                 reaching 
                 in reaching  
               
               
                   
                 mt2 
                 time (s) 
                 time (s) 
                 time (s) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Example 
                 0.2 
                 1.282 
                 1.64 
                 0.358 
               
               
                 21 
                   
                   
                   
                   
               
               
                 Example 
                 0.3 
                 1.261 
                 1.619 
                 0.358 
               
               
                 22 
                   
                   
                   
                   
               
               
                 Example 
                 0.5 
                 1.242 
                 1.599 
                 0.357 
               
               
                 23 
                   
                   
                   
                   
               
               
                   
               
            
           
         
       
     
     From Table 6, in comparison with a case where the shape for differentiating the thickness was not provided (see Comparative Example in Table 1), it was found that the difference in reaching time to  44   g  and the reaching time to  44   e  was reduced when the shape for differentiating the thickness is provided. Variations on the basis of the projecting amount were not much observed. 
     Example 24 
     A simulation with a molding shape having a shape for differentiating the thickness provided with the shape  110   b  for differentiating the thickness by the depressed shape adjacently to the shape  110   a  for differentiating the thickness by the projecting shape illustrated in  FIG. 17A  was performed. Specifically, a standard thickness (the thickness of the molded article of a portion where the thickness is not varied) was set to 1.5 mm. The shape of the shape  110   a  for differentiating the thickness was varied to have a projecting amount (amount of thickness variation) mt 1  of 0.3 mm, a width mw 1  of 30 mm, and a length ml 1  of 12 mm. The shape of the shape  110   b  for differentiating the thickness provided adjacently to the shape  110   a  for differentiating the thickness by the projecting shape was varied to have a width mw 2  of 20 mm, and a depressed amount (amount of thickness variation) mt 2  to be 0.3 mm, and a length ml 2  of 20 mm. Subsequently, the time from a moment when the resin started to fill a cavity from the gate to a moment when the distal end of the resin (flow front) reaches the portion  44   g  having a shape for transferring the bent portion closest from the gate was obtained by the simulation. Also, the time from a moment when the resin started to fill a cavity from the gate to a moment when the resin reaches the portion  44   e  having a shape for transferring the bent portion at the sheet end was obtained by the simulation. Subsequently, the difference in reaching time was obtained. The result is shown in Table 7 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 7 
               
               
                   
               
               
                   
                   
                 44g  
                 44e  
                 difference  
               
               
                   
                   
                 reaching 
                 reaching 
                 in reaching  
               
               
                   
                 ml2 
                 time (s) 
                 time (s) 
                 time (s) 
               
               
                   
               
             
            
               
                 Example 
                 20 
                 1.22 
                 1.578 
                 0.358 
               
               
                 24 
               
               
                   
               
            
           
         
       
     
     From Table 7, in comparison with a case where the shape for differentiating the thickness was not provided (see Comparative Example in Table 1), it was found that the difference in reaching time to  44   g  and the reaching time to  44   e  was reduced when the shape for differentiating the thickness was provided. Variations on the basis of the length were not much observed. 
     Example 25 
     A simulation with a molding shape having a shape for differentiating the thickness only by the shape  110   b  for differentiating the thickness by the depressed shape was performed without providing the shape  110   a  for differentiating the thickness illustrated in  FIG. 17B . Specifically, a standard thickness (the thickness of the molded article of a portion where the thickness is not varied) was set to 1.5 mm. The shapes  110   b  for differentiating the thickness by the depressed shape are provided at two positions 30 mm away from each other. The shape  110   b  for differentiating the thickness by the depressed shape was set to have a width mw 2  of 20 mm, and a depressed amount (amount of thickness variation) mt 2  of 0.3 mm, and a length ml 2  of 12 mm. Subsequently, the time from a moment when the resin started to fill a cavity from the gate to a moment when the distal end of the resin (flow front) reaches the portion  44   g  having a shape for transferring the bent portion closest from the gate was obtained by the simulation. Also, the time from a moment when the resin started to fill a cavity from the gate to a moment when the resin reaches the portion  44   e  having a shape for transferring the bent portion at the sheet end was obtained by the simulation. Subsequently, the difference in reaching time was obtained. The result is shown in Table 8 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 8 
               
               
                   
               
               
                   
                   
                 44g  
                 44e  
                 difference  
               
               
                   
                   
                 reaching 
                 reaching 
                 in reaching  
               
               
                   
                 mt2 
                 time (s) 
                 time (s) 
                 time (s) 
               
               
                   
               
             
            
               
                 Example 
                 0.3 
                 1.155 
                 1.639 
                 0.484 
               
               
                 25 
               
               
                   
               
            
           
         
       
     
     From Table 8, in comparison with a case where the shape for differentiating the thickness was not provided (see Comparative Example in Table 1), it was found that the difference in reaching time to  44   g  and the reaching time to  44   e  was reduced when the shape for differentiating the thickness was provided. Accordingly, the change in thickness of the sheet by solidification of the resin is restrained. 
     Advantageous Effects of the Invention 
     According to this disclosure, the conductive sheet may be molded integrally with the first frame member (lid member), and hence space saving of the image forming apparatus and improvement of reliability of sensing of the amount of remaining toner are realized in a simple configuration. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.