Sheet storage device and image forming apparatus

Abstract

Compared to a case where the guide groove of the retraction mechanism does not have a resistance mechanism, the retraction force of the sheet housing can be adjusted. [Solution] The device comprises a sheet housing that accommodates a sheet and is mounted on the main body of the device so as to be able to be pulled out and retracted, an engaging means provided on either the main body of the device or the sheet housing, and a retraction means provided on the other of the main body of the device or the sheet housing, which engages with the engaging means to guide the sheet housing while a retraction force is applied to it, and the guide groove is provided with a resistance force acting part that applies resistance to the retraction movement of the sheet housing and a thrust acting part that applies thrust to propel the retraction movement.

Description

Technical Field

[0007] ,

[0001] This invention relates to a sheet storage device and an image forming apparatus.

Background Art

[0002] Conventionally, as technologies related to sheet storage devices, for example, those disclosed in Patent Documents 1 and 2 have already been proposed.

[0003] Patent Document 1 is configured such that the groove of the guide means is composed of a straight portion parallel to the mounting direction of the sheet storage means and a curved portion provided on the downstream side in the mounting direction of the straight portion and curved in the direction of the swing fulcrum of the drawing means.

[0004] Patent Document 2 is configured such that the formation range in the direction orthogonal to the mounting direction of the sheet storage portion of the introduction opening is the same as or less than the formation range in the direction orthogonal to the mounting direction of the sheet storage portion of the guide groove.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of this invention is to make it possible to adjust the drawing force of the sheet storage body as compared with the case where the guide groove of the drawing means does not have a resistance acting portion.

Means for Solving the Problems

[0007] The invention according to claim 1 includes a sheet storage body that is mounted so as to be able to store sheets and be drawn out and drawn into the apparatus main body, An engaging means provided in either the main body of the device or the seat housing, A retraction means is provided on the other of the device body or the sheet housing, and has a guide groove that engages with the engaging means to guide the retraction operation of the sheet housing, and the guide groove is provided with a resistance force acting part that acts resistance against the retraction operation of the sheet housing, This is a seat storage device equipped with [a specific feature].

[0008] Furthermore, resistance force refers to the force exerted by one object in response to the force exerted by another object when one object contacts and exerts a force on it. In this case, when the engaging means contacts and exerts a force on the resistance-acting part of the guide groove of the retracting means, resistance force is the force exerted by the resistance-acting part of the guide groove on the engaging means in response to that force.

[0009] The invention described in claim 2 is a sheet storage device according to claim 1, wherein the resistance force acting part is arranged on the starting end side of the guide groove relative to the sheet storage body.

[0010] The invention described in claim 3 is a sheet storage device according to claim 2, wherein the resistance acting portion comprises a region in which the guide groove is bent and / or curved with respect to the retraction direction of the sheet storage body.

[0011] The invention described in claim 4 is a sheet storage device according to claim 3, wherein the resistance acting portion comprises multiple regions bent in the direction of retraction of the sheet storage body.

[0012] The invention described in claim 5 is a sheet storage device according to claim 1, wherein the guide groove is provided with an accelerating part for promoting the retraction operation of the sheet storage body.

[0013] The invention described in claim 6 is a sheet storage device according to claim 5, wherein the facilitating part is arranged on the end end side of the retraction operation of the guide groove relative to the sheet storage body.

[0014] The invention described in claim 7 is a sheet storage device according to claim 6, wherein the acceleration portion comprises a region in which the guide groove is formed in a straight line.

[0015] The invention described in claim 8 is a sheet storage device according to claim 5, wherein the guide groove has a curved portion between the resistance portion and the acceleration portion that curves in a direction intersecting the retraction direction of the sheet storage body.

[0016] The invention described in claim 9 is a sheet storage device according to claim 8, wherein the curved portion is formed in an arc shape having a constant radius of curvature.

[0017] The invention described in claim 10 is a sheet storage means for storing a sheet, Image forming means for forming an image on the aforementioned sheet, Equipped with, The image forming apparatus uses the sheet storage device described in any one of claims 1 to 9 as the sheet storage means. [Effects of the Invention]

[0018] According to the invention described in claim 1, compared to the case in which the guide groove of the retraction means is not provided with a resistance force, the retraction force of the sheet housing that is mounted on the device body so as to be pullable and retractable can be adjusted.

[0019] According to the invention described in claim 2, the resistance force acting part can counteract excessive pushing force on the sheet housing earlier compared to the case where it is positioned behind the starting end of the retraction operation of the guide groove relative to the sheet housing.

[0020] According to the invention described in claim 3, the resistance portion can effectively apply resistance to the sheet housing compared to the case where the guide groove is formed linearly with respect to the retraction direction of the sheet housing.

[0021] According to the invention described in claim 4, the drag force acting portion can act a drag force more effectively on the seat housing body as compared with the case where it is formed from a single bent region with respect to the pulling-in direction of the seat housing body.

[0022] According to the invention described in claim 5, the guide groove can surely perform the pulling-in operation of the seat housing body as compared with the case where it does not include the promoting portion.

[0023] According to the invention described in claim 6, the promoting portion can surely pull in the seat housing body to a predetermined position as compared with the case where it is provided on the upstream side from the middle of the pulling-in operation.

[0024] According to the invention described in claim 7, the promoting portion can effectively exert the pulling-in action as compared with the case where the guide groove is formed in a curved shape.

[0025] According to the invention described in claim 8, the guide groove can smoothly shift from the action of the drag force on the seat housing body to the action of the promoting force as compared with the case where the promoting portion is provided continuously to the drag force acting portion.

[0026] According to the invention described in claim 9, the curved portion can act a substantially constant pulling-in force on the seat housing body as compared with the case where it is formed in an arc shape in which the radius of curvature changes.

[0027] According to the invention described in claim 10, as compared with the case where the seat housing device according to any one of claims 1 to 9 is not used as the seat housing means, the pulling-in force of the seat housing body that is detachably attached to and pulled in and out of the apparatus main body can be adjusted, and the operability is improved.

Brief Description of the Drawings

[0029] Embodiments of this invention will be described below with reference to the drawings.

[0030] [Embodiment 1] Figures 1 and 2 show an image forming apparatus to which the sheet storage device according to Embodiment 1 is applied. Figure 1 shows an overview of the entire image forming apparatus, and Figure 2 shows a magnified view of the main parts (such as the image forming device) of the image forming apparatus. In Figure 1, the symbol X indicates the horizontal direction (width direction) of the image forming apparatus, the symbol Y indicates the depth direction of the image forming apparatus, and the symbol Z indicates the vertical direction of the image forming apparatus.

[0031] <Overall configuration of the image forming apparatus> The image forming apparatus 1 according to Embodiment 1 is configured, for example, as a color copier. This image forming apparatus 1 is equipped with an image reading device 2 (not shown) at the upper end of the apparatus body 1a for reading an image of a document. In addition to the function of copying the image of the document read by the image reading device 2, the image forming apparatus 1 also functions as a color printer, etc., for recording image information sent from a host computer, etc. (not shown).

[0032] The image forming apparatus 1 comprises, inside the apparatus body 1a, a plurality of image forming devices 10, an intermediate transfer device 20, a sheet storage device 50 according to this embodiment 1, a fixing device 40, etc. The plurality of image forming devices 10 form toner images developed with toner constituting the developer. The intermediate transfer device 20 holds the toner images formed by each image forming device 10 and transports them to a secondary transfer position where they are ultimately transferred to a recording sheet 5, which is an example of a sheet. The sheet storage device 50 stores and feeds the recording sheet 5 to be supplied to the secondary transfer position of the intermediate transfer device 20. The fixing device 40 fixes the toner image on the recording sheet 5 that has been transferred by the intermediate transfer device 20. The plurality of image forming devices 10 and the intermediate transfer device 20 constitute an image forming means for forming an image on the recording sheet 5. The apparatus body 1a of the image forming apparatus 1 is formed of support structural members, an exterior cover, etc.

[0033] The imaging device 10 consists of four imaging devices 10Y, 10M, 10C, and 10K, each dedicated to forming toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K). These four imaging devices 10 (Y, M, C, K) are arranged in a single row at an inclination within the internal space of the device body 1a.

[0034] Each image-forming apparatus 10 (Y, M, C, K) for yellow (Y), magenta (M), cyan (C), and black (K) is equipped with a rotating photoreceptor drum 11 as an example of an image holder that holds an electrostatic latent image, as shown in Figures 1 and 2. Around this photoreceptor drum 11 are a charging device 12, an exposure device 13, a developing device 14, a primary transfer device 15, a drum cleaning device 16, etc. The charging device 12 charges the image-forming surface (image-holding surface) of the photoreceptor drum 11 to the required potential. The exposure device 13 irradiates the charged surface of the photoreceptor drum 11 with light based on image information (signals) to form electrostatic latent images for each color with potential differences. The developing device 14 develops the electrostatic latent image with toner from the corresponding color (Y, M, C, K) developer to form a toner image. The primary transfer device 15 transfers each toner image to an intermediate transfer device 20. The drum cleaning device 16 cleans the image-holding surface of the photoreceptor drum 11 by removing any toner or other deposits that remain after the primary transfer.

[0035] The photoreceptor drum 11 has an image-holding surface formed on the circumferential surface of a cylindrical or columnar substrate that is grounded, with a photoconductive layer (photosensitive layer) made of a photosensitive material. This photoreceptor drum 11 is supported so as to rotate in the direction indicated by arrow A by power transmitted from a drive device (not shown).

[0036] As shown in Figure 2, the charging device 12 consists of a contact-type charging roll 121 positioned in contact with the photoreceptor drum 11. A cleaning roll 122 is positioned on the back of the charging roll 121 to clean its surface. A charging voltage is supplied to the charging roll 121 of the charging device 12. If the developing device 14 performs reverse development, the charging voltage supplied is a voltage or current with the same polarity as the charging polarity of the toner supplied from the developing device 14.

[0037] The exposure device 13 irradiates the surface of the charged photoreceptor drum 11 with light configured according to the image information of the original document read by the image reading device 2 and the image information input to the image forming device 1, thereby forming an electrostatic latent image. When latent image formation is in progress, the exposure device 13 receives the image information of the original document read by the image reading device 2 and the image information input to the image forming device 1 by any means.

[0038] The exposure apparatus 13 consists of an LED print head that forms an electrostatic latent image by irradiating the photoreceptor drum 11 with light corresponding to image information using a plurality of LEDs (Light Emitting Diodes) arranged along the axial direction of the photoreceptor drum 11.

[0039] Each developing device 14 is constructed by arranging a developing roll 141, an agitation and supply member 142, an agitation and conveying member 143, and a layer thickness regulating member 144 inside a housing 140. The housing 140 has an opening facing the photoreceptor drum 11 and a developer storage chamber. The developing roll 141 holds the developer 4 and conveys it to the developing area facing the photoreceptor drum 11. The agitation and supply member 142 consists of a screw auger or the like that supplies the developer 4 so that it passes through the developing roll 141 while being agitated. The agitation and conveying member 143 consists of a screw auger or the like that conveys the developer 4 to the agitation and supply member 142 while being agitated. The layer thickness regulating member 144 regulates the amount (layer thickness) of the developer 4 held by the developing roll 141. In this developing device 14, a developing voltage is supplied between the developing roll 141 and the photoreceptor drum 11 from a power supply unit (not shown). As the developer for the four colors, for example, a two-component developer containing a non-magnetic toner and a magnetic carrier is used.

[0040] The primary transfer device 15 is a contact-type transfer device equipped with a primary transfer roll that rotates in contact with the photoreceptor drum 11 via an intermediate transfer belt 21 and to which a primary transfer voltage is supplied. The primary transfer voltage is a DC voltage with polarity opposite to that of the toner charge, supplied from a power supply device (not shown).

[0041] As shown in Figure 2, the drum cleaning device 16 consists of a main body 160, a cleaning plate 161, a delivery member 162, etc. The main body 160 is formed in the shape of a container with a part of it open. The cleaning plate 161 is positioned to contact the circumferential surface of the photoreceptor drum 11 after primary transfer with the required pressure to remove and clean any attached substances such as residual toner. The delivery member 162 consists of a screw auger or the like that collects the attached substances such as toner removed by the cleaning plate 161 and transports them to a collection system (not shown).

[0042] As shown in Figure 1, the intermediate transfer device 20 is positioned above each imaging device 10 (Y, M, C, K) along the vertical Z direction. This intermediate transfer device 20 mainly consists of an intermediate transfer belt 21, a plurality of belt support rolls 22-25, a secondary transfer device 30, and a belt cleaning device 26. As shown in Figure 2, the intermediate transfer belt 21 rotates in the direction indicated by arrow B while passing through the primary transfer position which is between the photoreceptor drum 11 and the primary transfer device 15. The plurality of belt support rolls 22-25 support the intermediate transfer belt 21 from its inner surface, holding it in a desired state and allowing it to rotate freely. The secondary transfer device 30 is positioned on the outer circumferential surface (image holding surface) side of the intermediate transfer belt 21 supported by the belt support rolls 25, and performs secondary transfer of the toner image on the intermediate transfer belt 21 to the recording paper 5. The belt cleaning device 26 cleans the outer circumferential surface of the intermediate transfer belt 21 by removing any toner, paper dust, and other deposits that remain and adhere to it after passing through the secondary transfer device 30.

[0043] The belt support roll 22 is configured as a drive roll that is rotationally driven by a drive device (not shown). The belt support roll 23 is configured as a surface-setting roll that holds the running position of the intermediate transfer belt 21. The belt support roll 24 is configured as a counter roll that faces a sensor (not shown). The belt support roll 25 is configured as a backup roll for secondary transfer.

[0044] The secondary transfer device 30 is a contact-type transfer device equipped with a secondary transfer roll 31. The secondary transfer roll 31 rotates in contact with the circumferential surface of the intermediate transfer belt 21, which is supported by the belt support roll 25 in the intermediate transfer device 20, at the secondary transfer position, which is the outer circumferential surface portion of the intermediate transfer belt 21, and is supplied with a secondary transfer voltage. In addition, a DC voltage with opposite or same polarity as the charge polarity of the toner is supplied as the secondary transfer voltage to the secondary transfer roll 31 or the belt support roll 25 of the intermediate transfer device 20.

[0045] As shown in Figure 2, the belt cleaning device 26 consists of a main body 260, a cleaning plate 261, a delivery member 262, etc. The main body 260 is formed in the shape of a container with a part of it open. The cleaning plate 261 is positioned to contact the circumferential surface of the intermediate transfer belt 21 after secondary transfer with the required pressure to remove and clean any attached substances such as residual toner. The delivery member 262 consists of a screw auger, etc., which collects the attached substances such as toner removed by the cleaning plate 261 and transports them to a collection system (not shown).

[0046] The fixing device 40 is composed of a heating rotating body 41 and a pressurizing rotating body 42, among other components. The heating rotating body 41 is formed in the form of a roll or belt that is heated by a heating means so that its surface temperature is maintained at a required temperature. The pressurizing rotating body 42 is formed in the form of a roll or belt that rotates in contact with the heating rotating body 41 at a predetermined pressure, substantially aligned with the axial direction of the heating rotating body 41. An outlet roll 43 is provided at the outlet of the fixing device 40 to transport the fixing processd recording paper 5. In this fixing device 40, the contact area where the heating rotating body 41 and the pressurizing rotating body 42 come into contact becomes the fixing processing area where the required fixing process is performed.

[0047] The sheet storage device 50 is positioned below the yellow (Y), magenta (M), cyan (C), and black (K) imaging devices 10 (Y, M, C, K) along the vertical Z direction. This sheet storage device 50 mainly consists of a plurality (or one) paper feed tray 51, a nurser roll 52, a feed roll 53a, and a retard roll 53b, as an example of a sheet storage unit. The paper feed tray 51 stores recording paper 5 of the desired size and type. The nurser roll 52 feeds the recording paper 5 from the paper feed tray 51. The feed roll 53a and retard roll 53b separate and feed the recording paper 5 fed by the nurser roll 52 one sheet at a time. The paper feed tray 51 is, for example, mounted so as to be retractable on the front side (the side the user faces when operating) of the device body 1a, on the front side of the paper surface in the illustrated example. The sheet storage device 50 will be described in detail later.

[0048] A paper feed transport path 56 is provided between the sheet storage device 50 and the secondary transfer device 30. The paper feed transport path 56 consists of multiple (or single) pairs of paper transport rolls 54, 55 and transport guides (not shown) that transport the recording paper 5 fed from the sheet storage device 50 to the secondary transfer position. The pairs of paper transport rolls 55 are configured, for example, as register rolls that adjust the transport timing of the recording paper 5. In addition, a paper discharge transport section 58 is provided at the top of the fixing device 40 along the vertical Z direction for discharging the fixed recording paper 5 fed from the outlet roll 43 of the fixing device 40 to the sheet discharge device 60. The sheet discharge device 60 is located at the top of the device body 1a. The paper discharge transport section 58 includes first to fourth paper discharge transport paths 57a to 57d.

[0049] The sheet discharge device 60 includes first and second discharge trays 61 and 62, and a third discharge tray 63. The first and second discharge trays 61 and 62 are of the so-called internal discharge type, located on the upper part of the device body 1a. The third discharge tray 63 is located on the side (left side in the figure) of the paper discharge transport unit 58, facing outwards. Inside the paper discharge transport unit 58, there is a first paper discharge transport path 57a, a third paper discharge transport path 57c, and a fourth paper discharge transport path 57d. The first paper discharge transport path 57a is equipped with a first paper discharge roll pair 64 that branches off from the second paper discharge transport path 57b and discharges the recording paper 5 into the first discharge tray 61. The third paper discharge transport path 57c is equipped with a second paper discharge roll pair 66 that branches off from the second paper discharge transport path 57b and discharges the recording paper 5 into the second discharge tray 62. The fourth paper discharge transport path 57d branches off from the third paper discharge transport path 57c and includes a third pair of paper discharge rolls 67 for discharging the recording paper 5 into the third discharge tray 63.

[0050] In Figure 1, reference numeral 68 indicates a pair of paper transport rolls installed in the middle of the second paper discharge transport path 57b. Reference numeral G1 indicates a first switching gate that branches off the first paper discharge transport path 57a and the second paper discharge transport path 57b. Reference numeral G2 indicates a second switching gate that branches off the third paper discharge transport path 57c and the fourth paper discharge transport path 57d.

[0051] Furthermore, a double-sided transport path 70 is provided inside the main body 1a of the device, as shown in Figure 1. The double-sided transport path 70 switches the rotation direction of the first paper discharge roll pair 64 from the forward direction to the reverse direction while the recording paper 5, on which an image has been formed on one side, is held by the first paper discharge roll pair 64. The double-sided transport path 70 includes a paper transport roll pair 69 that transports the recording paper 5, which has been reversed, back to the paper transport roll pair 55.

[0052] In Figure 1, reference numerals 145(Y, M, C, K) each indicate a toner cartridge containing a developer, at least toner, which is supplied to the corresponding developing device 14. Multiple toner cartridges 145(Y, M, C, K) are arranged in a direction perpendicular to the paper surface.

[0053] Furthermore, in Figure 1, reference numeral 200 indicates a control device that comprehensively controls the operation of the image forming apparatus 1. The control device 200 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), or a bus and communication interface connecting these CPU, ROM, etc. (not shown).

[0054] <Operation of the image forming apparatus> The following describes the basic image forming operation of the image forming apparatus 1.

[0055] This section describes the operation of forming a full-color image by combining four toner images (Y, M, C, K) using the four imaging devices 10 (Y, M, C, K).

[0056] When the control device 200 receives command information requesting an image forming operation (printing), the image forming apparatus 1 starts up the four image forming devices 10 (Y, M, C, K), the intermediate transfer device 20, the secondary transfer device 30, the fixing device 40, etc.

[0057] Then, in each imaging apparatus 10 (Y, M, C, K), first, each photoreceptor drum 11 rotates in the direction indicated by arrow A, and each charging apparatus 12 charges the surface of each photoreceptor drum 11 to the required polarity and potential. Subsequently, the exposure apparatus 13 irradiates the surface of the charged photoreceptor drum 11 with light emitted based on the image signal obtained by converting the image information input to the image forming apparatus 1 into each color component (Y, M, C, K). Then, electrostatic latent images of each color component, composed of the required potential difference, are formed on the surface of the charged photoreceptor drum 11.

[0058] Next, each developing device 14 supplies toner of the corresponding color (Y, M, C, K), charged to the required polarity, from the developing roll 141 to electrostatically adhere to the electrostatic latent images of each color component formed on the photoreceptor drum 11, thereby performing development. Through this development, the electrostatic latent images of each color component formed on each photoreceptor drum 11 are revealed as four toner images of the corresponding colors (Y, M, C, K), which have been developed with the toner of their respective colors.

[0059] Next, the toner images of each color formed on the photoreceptor drum 11 of each imaging device 10 (Y, M, C, K) are transported to the primary transfer position. Then, the primary transfer device 15 performs a primary transfer, sequentially overlapping the toner images of each color onto the intermediate transfer belt 21 of the intermediate transfer device 20, which rotates in the direction indicated by arrow B.

[0060] Furthermore, in each imaging apparatus 10 (Y, M, C, K) where the primary transfer has been completed, the drum cleaning device 16 cleans the surface of the photoreceptor drum 11 by scraping off any attached material. This prepares each imaging apparatus 10 (Y, M, C, K) for the next imaging operation.

[0061] Next, the intermediate transfer device 20 holds the toner image transferred in the first stage by the rotation of the intermediate transfer belt 21 and transports it to the secondary transfer position. Meanwhile, the sheet storage device 50 feeds the required recording paper 5 into the paper feed transport path 56 in accordance with the image formation operation. In the paper feed transport path 56, a pair of paper transport rolls 55 acting as registration rolls feed and supply the recording paper 5 to the secondary transfer position in accordance with the transfer timing.

[0062] At the secondary transfer position, the secondary transfer roll 31 of the secondary transfer device 30 transfers the toner image on the intermediate transfer belt 21 onto the recording paper 5 in one go. After the secondary transfer is completed, the belt cleaning device 26 of the intermediate transfer device 20 cleans the surface of the intermediate transfer belt 21 by removing any toner or other deposits remaining after the secondary transfer.

[0063] Next, the recording paper 5 on which the toner image has been secondarily transferred is peeled off from the intermediate transfer belt 21 and the secondary transfer roll 31 and then transported to the fuser 40. In the fuser 40, the recording paper 5 after the secondary transfer is introduced and passed through the contact area between the rotating heating body 41 and the pressurizing body 42. In this way, the necessary fixing process is performed to fix the unfixed toner image onto the recording paper 5. Finally, after fixing is complete, if the image formation operation only involves forming an image on one side of the recording paper 5, it is discharged via the first to fourth paper discharge transport paths 57a to 57d to one of the first to third discharge trays 61 to 63 installed on the top of the main body 1a.

[0064] Furthermore, when forming an image on both sides of the recording paper 5, the recording paper 5 with the image formed on one side is transported in the discharge direction to the first discharge tray 61 by the first paper discharge roll pair 64. Then, while the first paper discharge roll pair 64 is holding the rear end of the recording paper 5, the rotation direction of the first paper discharge roll pair 64 is switched to the reverse direction. The recording paper 5 transported in the reverse direction by the first paper discharge roll pair 64 is transported to a double-sided transport path 70 equipped with a paper transport roll pair 69, etc., and is transported again to the paper transport roll pair 55 with its front and back sides reversed. The paper transport roll pair 55 feeds and supplies the recording paper 5 to the secondary transfer position in accordance with the transfer timing. The image is formed and fixed on the back side of the recording paper 5. The recording paper 5 with the image fixed on the back side is discharged to one of the first to third discharge trays 61 to 63 installed on the top of the device body 1a via one of the first to fourth paper discharge transport paths 57a to 57d.

[0065] Through the above operations, a recording sheet 5 is output, on which a full-color image, composed of four toner images combined, is formed on one or both sides.

[0066] <Configuration of the sheet storage device> The image forming apparatus 1 includes a sheet storage device 50, as shown in Figure 1. The sheet storage device 50 is located inside the apparatus body 1a, below the yellow (Y), magenta (M), cyan (C), and black (K) imaging devices 10 (Y, M, C, K) along the vertical Z direction. The apparatus body 1a of the image forming apparatus 1 also serves as the apparatus body for the sheet storage device 50. This sheet storage device 50 mainly consists of a plurality (four in the illustrated example) of paper feed trays 51, a nurser roll 52, a feed roll 53a, and a retard roll 53b. The paper feed trays 51 hold recording paper 5 of the desired size and type. The nurser roll 52, feed roll 53a, and retard roll 53b feed out one sheet of recording paper 5 at a time from each paper feed tray 51.

[0067] As described above, the paper feed tray 51 is mounted so that it can be pulled out, for example, on the front side (the side the user faces when operating) of the device body 1a, and in the illustrated example, on the side in front of the paper.

[0068] As shown in Figure 3, the paper feed tray 51 is configured as a roughly rectangular box-shaped body with a fully open top surface and a height corresponding to the number of sheets of recording paper 5 to be stored inside. The paper feed tray 51 comprises a bottom wall 511, left and right side walls 512, 513, and front and rear walls 514, 515. The bottom wall 511 is formed in a roughly rectangular shape in plan. The left and right side walls 512, 513 are arranged to the left and right along the horizontal direction X of the bottom wall 511. The front and rear walls 514, 515 are arranged to the front and rear along the depth direction Y of the bottom wall 511. The front of the paper feed tray 51 is formed as an operation panel 516. The operation panel 516, together with the front panel (not shown) of the device body 1a, constitutes the front external appearance of the device body 1a. The control panel 516 of the paper feed tray 51 is provided with a gripping section 517 for the user to hold when pulling the paper feed tray 51 out of the device body 1a or pushing (pulling) it into the device body 1a.

[0069] The main body of the device 1a is provided with a detection means (not shown) that detects when the user pulls out the paper feed tray 51 from the main body of the device 1a by placing their hand on the grip portion 517 of the operation panel 516. This detection means may also be combined with a size detection means 520b that detects the size of the recording paper 5, which will be described later.

[0070] A bottom plate 518 is positioned on the bottom wall 511 of the paper feed tray 51, on which multiple sheets of recording paper 5 are stacked. The bottom plate 518 is attached to the front and rear walls 514 and 515 of the paper feed tray 51 so as to be rotatable around a pivot point 518a. The pivot point 518a is provided on arm members 518b, which are provided at both the front and rear ends of the bottom plate 518 along the depth direction Y. As a result, the downstream end 518c of the bottom plate 518 along the paper feed direction is rotatable upward. A drive member 519 is rotatably positioned on the back surface of the downstream end 518c of the bottom plate 518 along the paper feed direction. The intermediate part 519a of the drive member 519 is formed in a crank shape, as shown by a dashed line in part in Figure 3. The tip of the drive member 519 is rotatably attached to the bottom wall 511 of the paper feed tray 51 via a pivot point 519b. A coupling member 519c is provided on the rear wall 515 of the paper feed tray 51 to receive driving force from the main body of the device 1a. As shown in Figure 5, when the paper feed tray 51 is mounted in the paper feed position of the main body of the device 1a, the driving member 519 receives driving force from the driving means 520a provided on the main body of the device 1a via the coupling member 519c and is rotated in the required direction and over the required angle.

[0071] Furthermore, when the paper feed tray 51 is pulled out from the main body 1a, the bottom plate 518 is disconnected from the drive means 520a on the main body 1a side and descends to the bottom wall portion 511 by its own weight. Figure 3 shows the state in which the bottom plate 518 has descended to the bottom wall portion 511.

[0072] Meanwhile, when a detection means (not shown) detects that the paper feed tray 51 has been mounted in the paper feed position of the device body 1a, the bottom plate 518 is moved upward by the drive member 519 via the coupling member 519c, driven by the drive means 520a on the device body 1a side. The bottom plate 518 then stops at the paper feed position where the uppermost sheet of recording paper 5 in the paper feed tray 51 is in contact with the nurser roll 52.

[0073] As shown in Figure 3, an end guide 521 and side guides 522 and 523 are positioned on the bottom wall 511 of the paper feed tray 51. The end guide 521 abuts against and positions the upstream end of the recording paper 5 contained inside the paper feed tray 51 along the paper feeding direction. The side guides 522 and 523 abut against and position both ends of the recording paper 5 along the width direction intersecting the paper feeding direction. The end guide 521 is attached to the bottom wall 511 of the paper feed tray 51 so as to be movable along the paper feeding direction of the recording paper 5 and so as to be able to hold a stopped position. The side guides 522 and 523 are attached to the bottom wall 511 of the paper feed tray 51 so as to be able to move in conjunction along the width direction intersecting the paper feeding direction by an equal distance, with reference to the center of the width direction intersecting the paper feeding direction of the recording paper 5, and so as to be able to hold a stopped position. The paper feed tray 51 feeds the recording paper 5 with its center along the depth direction Y, which intersects the paper feeding direction, as the reference point (so-called center register). On the rear wall 515 of the paper feed tray 51, a size identification means (not shown) is positioned facing the rear to identify the size of the recording paper 5 according to the positions of the end guide 521 and the side guides 522, 523. This size identification means is detected by a size detection means 520b consisting of multiple switches, etc., on the device body 1a side, as shown in Figure 5.

[0074] The bottom plate 518 is provided with a plurality of planar rectangular openings 524 that allow the movement of the end guide 521 and the side guides 522, 523.

[0075] As shown in Figure 4, the sheet storage device 50 has a nurser roll 52 positioned to rotate at the required timing, corresponding to the downstream end of each paper feed tray 51 along the paper feeding direction. The nurser roll 52 contacts the surface of the topmost sheet of recording paper 5 among those stacked on the bottom plate 518 and feeds that topmost sheet of recording paper 5.

[0076] Furthermore, the sheet storage device 50 has a feed roll 53a and a retard roll 53b positioned downstream of the nurser roll 52 in the paper feeding direction. The feed roll 53a and retard roll 53b are rotated at the required timing. The feed roll 53a presses against the retard roll 53b and transports only the top sheet of recording paper 5 fed by the nurser roll 52 downstream in the paper feeding direction. On the other hand, the retard roll 53b is biased to rotate in the opposite direction to the feed roll 53a. The retard roll 53b transports the second and subsequent sheets of recording paper 5, which are fed together with the top sheet of recording paper 5, in the opposite direction to the paper feeding direction. The retard roll 53b also functions to separate multiple sheets of recording paper 5 so that they are not fed simultaneously.

[0077] The nurser roll 52, feed roll 53a, and retard roll 53b are positioned towards the rear of each paper feed tray 51, along the width direction intersecting the paper feeding direction of the recording paper 5.

[0078] As shown in Figure 4, the left side wall portion 512, located at the downstream end of the paper feed tray 51 along the paper feeding direction, is provided with an introduction plate 525 on the front side along the width direction intersecting the paper feeding direction of the recording paper 5. This introduction plate guides the leading edge of the recording paper 5 fed by the nurse roll 52 to the nip portion of the feed roll 53a and retard roll 53b.

[0079] The main body of the device 1a is equipped with a guide member 526, which is an example of a guide member. The guide member 526 guides the recording paper 5, which is fed from the paper feed tray 51 by the nurser roll 52, feed roll 53a and retard roll 53b, upward along the vertical direction Z.

[0080] As shown in Figure 6, the sheet storage device 50 is attached to a plurality of support frames 71, 72, etc., which constitute the main body 1a of the image forming apparatus 1. Horizontal frames 73, a front plate 74, a partition plate 75, a section plate 76, etc., are attached to the support frames 71, 72 by means of fastening with bolts (not shown). The horizontal frames 73 are arranged on the left and right sides along the horizontal direction X of the main body 1a. The left and right side walls 512, 513 of the paper feed tray 51 are attached to the left and right horizontal frames 73 via guide rails and guide rollers (not shown) so that they can be pulled out and pushed in. The image forming apparatus 10 (Y, M, C, K) for yellow (Y), magenta (M), cyan (C), and black (K) is attached to the front plate 74. The partition plate 75 separates the image forming apparatus 10 (Y, M, C, K) from the sheet storage device 50. The partition plate 76 partitions the multiple paper feed trays 51 of the sheet storage device 50. The left horizontal frame 73 is used to mount the nurser roll 52, feed roll 53a, retard roll 53b, etc., of the sheet storage device 50.

[0081] The recording paper 5, fed from the sheet storage device 50 and guided upward along the vertical direction Z by the guide member 526, is transported to the secondary transfer position via a paper feed transport path 56, which consists of multiple (or single) pairs of paper transport rolls 54, 55 and transport guides (not shown), as shown in Figure 1.

[0082] <Configuration of the seat storage device's retraction mechanism> The sheet storage device comprises an engaging means provided on either the device body or the sheet storage body, and a retracting means provided on the other of the device body or the sheet storage body, which has a guide groove that engages with the engaging means to guide the retraction operation of drawing the sheet storage body into the interior of the device body.

[0083] In the seat storage device 50 according to this embodiment 1, as shown in Figure 6, an engagement pin 77, as an example of an engagement means, is provided on the device body 1a. The engagement pin 77 is formed in a cylindrical shape from a metal such as stainless steel. The engagement pin 77 is attached to the tip of the swing arm 78 in an upright position facing upward along the vertical direction Z. As shown in Figure 7, the swing arm 78 is positioned to swing around a pivot point 78a at the front end of the horizontal frame 73 located at the left end of the device body 1a along the horizontal direction X. The swing angle of the swing arm 78 is restricted by a regulating plate 78b provided at the end opposite the engagement pin 77 relative to the pivot point 78a, which engages with a fan-shaped groove 79 opened in the horizontal frame 73.

[0084] As shown in Figure 6, the sheet storage device 50 is equipped with a retraction device 80 on the paper feed tray 51 side as an example of a retraction means. The retraction device 80 performs a retraction operation to pull the paper feed tray 51 into the interior of the device body 1a by engaging with an engagement pin 77 on the device body 1a side. As shown in Figure 3, the retraction device 80 is fixed to the back side of the operation panel 516 at the front end of the paper feed tray 51 along the depth direction Y and the downstream end along the paper feeding direction. The engagement pin 77 may be located on the paper feed tray 51, and the retraction device 80 may be located on the device body 1a side, such as at the rear end of the device body 1a. However, if the retraction device 80 is located on the paper feed tray 51, the installation space on the rear side of the device body 1a can be reduced compared to if it is located on the rear side of the device body 1a, making it possible to miniaturize the device body 1a.

[0085] As shown in Figure 8, the retraction device 80 is configured as a relatively low-height, flat box-shaped structure with a roughly rectangular plan, where one end (the upper end in the figure) protrudes trapezoidally toward the rear along the depth direction Y. As shown in Figures 9 and 10, the retraction device 80 broadly comprises a housing case 81, a bracket 82, a coil spring 83, a plurality of gears 94-98, a low-torque damper 99, and the like.

[0086] As shown in Figure 8, the housing case 81 consists of a case body 810 and a lid 811 that closes the upper end surface of the case body 810. As shown in Figure 9, the case body 810 includes a bottom wall 812 and an outer peripheral wall 813 that covers the entire outer circumference of the bottom wall 812. The bottom wall 812 of the case body 810 has different heights in parts, i.e., different positions along the vertical direction Z of the bottom wall 812. The area of ​​the bottom wall 812 where the guide groove 91 (described later) is provided is relatively high, while the area where the multiple gears 94-98 and the low torque damper 99 are provided is relatively low.

[0087] The outer periphery wall 813 of the case body 810 has left and right side walls 814 and 815 located on the left and right sides along the horizontal direction X, and front and rear side walls 816 and 817 located at the front and rear along the depth direction Y. The rear side wall 817 of the case body 810 is composed of a first rear side wall 817a, an inclined wall 817b, and a second rear side wall 817c, as shown in Figure 9. The first rear side wall 817a is located at the rearmost end along the depth direction Y and is formed to be short along the horizontal direction X. The inclined wall 817b is provided at an angle from the right end of the first rear side wall 817a in the figure toward the front along the depth direction Y. The second rear side wall 817c is located at the frontmost end along the depth direction Y and is formed to be relatively long along the horizontal direction X. An inlet 90 for introducing the engagement pin 77 on the device body 1a side is opened in the first rear side wall 817a of the case body 810. As shown in Figure 9, the inlet 90 is formed in a roughly V-shape with two sides 90a and 90b that are inclined to the left and right at approximately 45 degrees each with respect to the depth direction Y, which is the retraction direction. In addition, the front wall 816 of the case body 810 is provided with a notch 816a that allows the bracket 82 to rotate.

[0088] The case body 810, which houses the bracket 82, coil spring 83, multiple gears 94-98, low torque damper 99, etc., is closed by a lid 811 whose upper end surface is snap-engaged, as shown in Figure 8. In the figure, reference numerals 818a and 818b indicate snap-engagement parts, respectively. Reference numeral 818c indicates a fixing piece that is positioned and fixed by engaging with a groove (not shown) provided on the inner surface of the lid 811. The case body 810 is attached to the paper feed tray 51 by screws 86 through mounting holes 819 (see Figure 9) provided at three corners of the bottom wall 812, as shown in Figure 10.

[0089] As shown in Figures 9 and 10, a guide groove 91 is provided in the bottom wall 812 of the case body 810, communicating with the inlet 90 of the first rear wall 817a. An upright wall 92 is formed around the entire circumference of the outer periphery of the guide groove 91, with the bottom wall 812 of the case body 810 raised inward. The inner circumferential surface 92a of this upright wall 92 functions as a guide surface for guiding the engagement pin 77.

[0090] Inside the case body 810, a bracket 82 that rotates in engagement with an engagement pin 77 is rotatably mounted. As shown in Figure 11, the bracket 82 is constructed as a hollow frame with a roughly rectangular cross-section by bending sheet metal. The bracket 82 has an upper end 820 and a lower end 821 that are arranged roughly parallel to each other. The upper end 820 and the lower end 821 of the bracket 82 are connected to each other by a side wall portion 822 located at the end on the guide groove 91 side. The bracket 82 is constructed in a hollow manner with the upper end 820 and the lower end 821 spaced apart vertically from each other, except for the side wall portion 822. The bracket 82 is provided with a regulating plate 823 at the end facing the side wall portion 822, which is bent downward from the end of the upper end 820 to regulate the position of the coil spring 83. Furthermore, a stopper piece 824 is provided at the lower end 821 of the bracket 82, on the end facing the inlet 90 and opposite the side wall 822, in a bent upward position. The stopper piece 824 contacts the inner surface of the inclined wall 817b of the case body 810, thereby stopping the rotation of the bracket 82 in a clockwise direction.

[0091] The bracket 82 is rotatably supported by pivot shafts 825 and 826 on the case body 810 and the lid 811. The pivot shafts 825 and 826 are positioned to protrude vertically from the upper end 820 and lower end 821 of the bracket 82, respectively.

[0092] An engaging member 84 is integrally provided at the lower end 821 of the bracket 82, on the end facing the inlet 90. The engaging member 84 has an engaging groove 841 that engages with the engaging pin 77. The engaging member 84 is made of synthetic resin or the like. The engaging member 84 is fitted to the tip of the lower end 821 of the bracket 82 by clamping it from both the front and back sides, or it is fixed to the bracket 82 by means of adhesive or other means. The engaging groove 841 has a straight section 841a arranged linearly along one side wall 90a of the inlet 90, and a short bent section 841b at the far end of the straight section 841a that is bent in the direction of retraction. The open ends 842 and 843 of the engaging groove 841 are formed in a curved shape so that the engaging pin 77 can be introduced. The engaging groove 841 may also be formed directly on the sheet metal constituting the bracket 82.

[0093] As shown in Figure 9, one end 831 of a coil spring 83, which constitutes a tension spring as an example of a biasing means for applying a rotational moment to the bracket 82, is locked to the bracket 82. As shown in Figure 11, one end 831 of the coil spring 83 is locked to a locking portion 827a of a locking pin 827, which is provided near the side wall portion 822 of the bracket 82 and has a small outer diameter. The other end 832 of the coil spring 83 is locked to a locking portion 85a of a locking pin 85, which is installed below the right side wall 815 of the case body 810, as shown in Figure 10. The coil spring 83 is always in an extended state, and acts a tensile force on the bracket 82 according to the spring constant of the coil spring 83.

[0094] Before engaging with the engagement pin 77, the bracket 82 is positioned as shown in Figure 9, with the engagement groove 841 slightly rotated clockwise from the position facing the paper feed opening 90. At this time, the coil spring 83 is positioned slightly above the rear of the paper feed tray 51 in the figure, relative to the pivot axes 825 and 826 of the bracket 82. As a result, a clockwise moment acts on the bracket 82 due to the contraction force of the coil spring 83. The bracket 82 is stopped by the stopper piece 824 contacting the inner surface of the case body 810.

[0095] As shown in Figure 6, when the paper feed tray 51 is pushed into the main body 1a of the image forming apparatus 1, the engagement pin 77 on the main body 1a side of the bracket 82 moves from the inlet 90 into the guide groove 91. Then, as shown in Figure 9, the engagement pin 77 of the bracket 82 engages with the engagement groove 841, and the bracket 82 rotates counterclockwise as the engagement pin 77 moves. As a result, the coil spring 83 moves downward in Figure 9, which is on the front side of the paper feed tray 51, relative to the pivot axes 825 and 826 of the bracket 82. Consequently, a counterclockwise moment acts on the bracket 82 due to the contraction force of the coil spring 83.

[0096] Then, as the engaging pin 77 moves along the guide groove 91 inside the case body 810, the bracket 82 rotates counterclockwise under the influence of a rotational moment due to the contraction force of the coil spring 83.

[0097] As shown in Figures 9 and 10, a plurality of gears 94 to 98 are arranged inside the case body 810 to transmit the rotation of the bracket 82 to the low torque damper 99. The first gear 94 is fixed to the bracket 82. The first gear 94 rotates together with the bracket 82. The bracket 82 rotates within the case body 810 over a required angle (approximately 180 degrees). The teeth 941 constituting the first gear 94 are provided only in the region in which the bracket 82 rotates. Specifically, the teeth 941 are formed on the first gear 94 over an angle of approximately 180 degrees, which is the angular range in which the bracket 82 can rotate.

[0098] As shown in Figure 10, an insertion opening 942 is provided at the center of the first gear 94, into which the pivot shaft 826 of the bracket 82 is inserted in a rotation-preventing manner. The first gear 94 is also provided with a roughly triangular-shaped abutment portion 943 that extends radially outward at a position opposite to the area where the teeth 941 are provided. When the first gear 94 rotates clockwise together with the bracket 82, the abutment portion 943 contacts the inner surface of the inclined wall 817b of the case body 810, thereby stopping the rotation of the bracket 82 together with the stopper piece 824.

[0099] The first gear 94 meshes with the second gear 95, which forms a multi-speed-increasing gear train. The number of teeth n2 of the second gear 95 is less than the number of teeth n1 calculated over the entire circumference of the first gear 94. The outer diameter R1 of the first gear 94 is greater than the outer diameter R2 of the second gear 95. Note that the symbols R1, R2, etc., indicating the outer diameters of the first gear 94 and the second gear 95 are not shown in the illustration. Therefore, the rotation of the first gear 94 is transmitted to the second gear 95 at an increased speed according to the ratio of the number of teeth. Below the second gear 95, a third gear 96 is positioned coaxially and rotatably with respect to the rotation axis 99b. The outer diameter R3 of the third gear 96 is greater than the outer diameter R2 of the second gear 95. The number of teeth n3 of the third gear 96 is greater than the number of teeth n2 of the second gear 95. The second gear 95 and the third gear 96 form a mechanical one-way clutch 100. As shown in Figure 12, the lower surface 95a of the second gear 95 has multiple protrusions 95b with a right-angled triangular cross-section, which are provided at equal intervals along the circumferential direction around the rotation axis 99b. On the other hand, the upper surface 96a of the third gear 96 has multiple protrusions 96b with a right-angled triangular cross-section, which mesh with the protrusions 95b of the second gear 95, and are provided at equal intervals along the circumferential direction around the rotation axis 99b. The second gear 95 is pressed against the third gear 96 by a coil spring 101. The coil spring 101 is pressed against the inner surface of the cover 811 when the cover 811 is attached to the case body 810.

[0100] The mechanical one-way clutch 100 transmits rotational force to the third gear 96 when the second gear 95 rotates clockwise, as the protrusion 95b of the second gear 95 engages with the protrusion 96b of the third gear 96. On the other hand, when the second gear 95 rotates counterclockwise, the inclined surface of the protrusion 95b of the second gear 95 rides up onto the inclined surface of the protrusion 96b of the third gear 96 and slips, so the rotational force of the second gear 95 is not transmitted to the third gear 96. Therefore, when the paper feed tray 51 is pulled out from the main body 1a, if the bracket 82 rotates clockwise, the second gear 95 rotates counterclockwise, and the rotation of the bracket 82 is not transmitted to the third gear 96 by the mechanical one-way clutch 100.

[0101] Furthermore, the third gear 96 is meshed with the fourth gear 97. The outer diameter R4 of the fourth gear 97 is smaller than the outer diameter R3 of the third gear 96. The number of teeth n4 of the fourth gear 97 is less than the number of teeth n3 of the third gear 96. The fifth gear 98 is coaxially and integrally mounted on the fourth gear 97. The outer diameter R5 of the fifth gear 98 is larger than the outer diameter R4 of the fourth gear 97. The number of teeth n5 of the fifth gear 98 is more than the number of teeth n4 of the fourth gear 97.

[0102] The fifth gear 98 meshes with the sixth gear 99a, which is provided on the low-torque damper 99. The outer diameter R6 of the sixth gear 99a is smaller than the outer diameter R5 of the fifth gear 98. The number of teeth n6 of the sixth gear 99a is less than the number of teeth n5 of the fifth gear 98. The low-torque damper 99 is fixed to the lower bottom wall 812 of the case body 810. When a rotational force (torque) acts on the sixth gear 99a, the low-torque damper 99 limits the torque to a relatively low, approximately constant value. A torque damper is a damping device that, for example, uses the viscous resistance of oil to limit the torque acting on the rotating shaft of the sixth gear 99a to a constant value. The low-torque damper 99 has a relatively low limitable torque value. The low-torque damper 99 is smaller and less expensive compared to a high-torque damper.

[0103] In this embodiment 1, the rotation of the bracket 82 is transmitted to the low-torque damper 99 by a multi-stage (3-stage) speed-increasing gear train consisting of multiple gears 94 to 98. Conversely, the limiting torque of the low-torque damper 99 is amplified via the multiple gears 94 to 98 and transmitted to the bracket 82. Therefore, in the pull-in device 80 according to this embodiment 1, even when using a small and inexpensive low-torque damper 99, it is possible to apply a sufficiently large limiting torque to the bracket 82.

[0104] By the way, in the conventional sheet storage device 50, as shown in Figure 13, the shape of the guide groove 91 of the retraction device 80 is formed in an arc shape with a substantially constant radius of curvature.

[0105] Therefore, in the conventional sheet storage device 50, if the paper feed tray 51 is forcefully pushed into the device body 1a by the user, the rotational moment acting on the bracket 82 via the engagement pin 77 of the device body 1a becomes excessive. As a result, there is a risk that the low-torque damper 99, which limits the rotation of the bracket 82 to a nearly constant torque, will not function adequately. Consequently, the retraction speed of the paper feed tray 51 becomes unintentionally fast, resulting in a technical problem where the paper feed tray 51 cannot be sufficiently decelerated.

[0106] On the other hand, in the conventional sheet storage device 50, the shape of the guide groove 91 is formed as an arc with a substantially constant radius of curvature. As a result, the retraction force acting on the paper feed tray 51 is substantially constant. Consequently, when the paper feed tray 51 is pushed into the inside of the device body 1a, the retraction force acting on the paper feed tray 51 may be insufficient, potentially causing a failure to retract the paper feed tray 51.

[0107] In particular, in conventional sheet storage devices 50, in order to reduce costs, a low-torque damper 99 may be used as a component of the retraction device 80, or parts such as the one-way clutch 100 may be omitted and replaced with mechanical ones. As a result, in conventional sheet storage devices 50, the following technical problems arise due to variations in internal reaction force that occur when the paper feed tray 51 is attached to the device body 1a. In other words, in conventional sheet storage devices 50, there is a risk that the retraction speed of the paper feed tray 51 may be too fast or the retraction force may be insufficient due to insufficient limiting torque caused by the low-torque damper 99 or operational delay due to the omission of the one-way clutch 100.

[0108] Therefore, in order to adjust the retraction force of the sheet housing, the sheet housing device according to this embodiment 1 is configured to have a resistance force acting part in the guide groove of the retraction means that acts a resistance force against the retraction operation of the sheet housing.

[0109] Furthermore, in the sheet storage device according to this embodiment 1, the resistance force acting part is positioned on the starting end side of the guide groove's retraction operation relative to the sheet storage body.

[0110] Furthermore, in the sheet storage device according to this embodiment 1, the resistance portion is composed of a region in which the guide groove is bent and / or curved with respect to the retraction direction of the sheet storage body. In addition, the resistance portion is composed of multiple regions that are bent with respect to the retraction direction of the sheet storage body.

[0111] In other words, as shown in Figures 10 and 14, the sheet storage device 50 according to this embodiment 1 is equipped with a guide groove 91 in the storage case 81 of the paper feed device 80, and a resistance force acting portion 910 which is a region in which the guide groove 91 is bent and / or curved with respect to the paper feed tray 51's retraction direction.

[0112] As shown in Figure 14, the resistance section 910 is positioned at the end of the guide groove 91 on the inlet 90 side, which is the starting end of the retraction movement of the guide groove 91. The resistance section 910 consists of a bent section 911, which is formed by bending the guide groove 91 located at the inlet 90 side end at approximately 90 degrees, and a curved section 912, which is formed by curving the guide groove 91 at an angle greater than 90 degrees, located at the tip of the bent section 911. The bending or curving directions of the bent section 911 and the curved section 912 are set to be opposite to each other. The starting end of the retraction movement of the guide groove 91 is positioned linearly along one side wall 90a of the inlet 90. The bent section 911 of the resistance section 910 is formed by bending a short section of approximately 90 degrees from a short straight section following the starting end of the retraction movement of the guide groove 91.

[0113] The bent portion 911 of the resistance portion 910 has an outer surface 911a that is formed in an arc shape. Therefore, the engagement pin 77, which has a circular cross-section, makes smooth contact with the outer surface 911a of the bent portion 911. In addition, both the inner and outer surfaces 912a and 912b of the curved portion 912 of the resistance portion 910 are formed in a curved shape.

[0114] The guide groove 91 has an intermediate section 913 following the resistance section 910 that is formed in the shape of a long arc with a constant radius of curvature. The intermediate section 913 has its arc center O at a required distance along a direction intersecting the retraction direction. When the engaging pin 77 moves through the intermediate section 913 of the guide groove 91, it receives a retraction force along the retraction direction from the coil spring 83.

[0115] Furthermore, the sheet storage device 50 according to this embodiment 1 is equipped with a facilitating section 914 that facilitates the retraction of the paper feed tray 51 by the guide groove 91. The facilitating section 914 is located at the end end of the retraction movement of the guide groove 91 relative to the paper feed tray 51. The facilitating section 914 is formed in a straight line that is slightly inclined with respect to the depth direction Y, which is the retraction direction, from the end end of the intermediate section 913. As a result, the engaging pin 77 that moves along the facilitating section 914 moves in a direction away from the pivot axes 825 and 826 of the bracket 82, that is, the retraction force acting by the bracket 82 increases, and the retraction movement is facilitated.

[0116] <Operation of the sheet storage device> In the sheet storage device according to this embodiment 1, the retraction force of the sheet storage body can be adjusted in the following manner, compared to the case in which the guide groove of the retraction means is not provided with a resistance force acting part.

[0117] In other words, in the sheet storage device 50 according to this embodiment 1, as shown in Figure 6, when replenishing recording paper 5 inside the paper feed tray 51, the user pulls the paper feed tray 51 out to the front side of the device body 1a. Then, the recording paper 5 is replenished inside the paper feed tray 51. After that, the paper feed tray 51 is installed in the paper feed position inside the device body 1a by the user pushing it into the device body 1a via the gripping portion 517 of the operation panel 516.

[0118] At that time, when the paper feed tray 51 is pushed into the main body 1a to a certain extent, the engagement pin 77 of the main body 1a is introduced into the paper feed tray 51 through the inlet 90 of the paper pull-in device 80 provided on the paper feed tray 51. At this time, the engagement pin 77 is located somewhere within the movable range of the swing arm 78, as shown in Figure 7. The inlet 90 of the paper pull-in device 80 is opened in a roughly V-shape in plan view, as shown in Figure 14. Therefore, the engagement pin 77 is introduced into the interior of the inlet 90 of the paper pull-in device 80 along both sides 90a and 90b, which are opened in a roughly V-shape in plan view.

[0119] The paper feed tray 51 is connected to the device body 1a via the engaging pin 77 and the retraction device 80, when the engaging pin 77 of the device body 1a is introduced into the retraction device 80. As shown in Figure 15, when the engaging pin 77 is introduced into the retraction device 80 from the inlet 90, it moves to the guide groove 91 which is provided continuously with the inlet 90. A resistance force acting part 910 is provided at the starting end of the retraction operation of the guide groove 91, that is, at the entrance of the guide groove 91. Therefore, when the engaging pin 77 moves from the inlet 90 to the guide groove 91, it receives resistance from the resistance force acting part 910 provided at the starting end of the retraction operation of the guide groove 91.

[0120] As shown in Figure 15, the drag-acting portion 910 of the guide groove 91 includes a bent portion 911 that is bent at approximately 90 degrees with respect to the introduction direction from the inlet 90, and a curved portion 912 that is curved at an angle greater than 90 degrees from the bending direction of the bent portion 911. Therefore, when the engaging pin 77 comes into contact with the outer circumferential surface 911a of the bent portion 911 that constitutes the drag-acting portion 910 of the guide groove 91, the direction of travel is changed by approximately 90 degrees. At this time, assume that a retraction force F1 is acting on the engaging pin 77 along the retraction direction. Then, by coming into contact with the outer circumferential surface 911a of the bent portion 911, the engaging pin 77 receives a drag force -F2 that is approximately equal in value to the contact force F2, which is a component of the retraction force F1 against the outer circumferential surface 911a, and is directed in the opposite direction. Simultaneously, a thrust force F3 acts on the engaging pin 77 in a direction parallel to the outer circumferential surface 911a of the retraction force F1, with the retraction force F1 reduced.

[0121] Similarly, as the engaging pin 77 passes through the curved portion 912 of the resistance portion 910, it receives resistance from the inner and outer surfaces 912a and 912b of the curved portion 912, and the initial pulling force F1 is significantly reduced.

[0122] Furthermore, in the retraction device 80 according to this embodiment 1, as shown in Figure 16, when the engagement pin 77 moves along the resistance force acting portion 910 of the guide groove 91, the bracket 82 engaged with the engagement pin 77 rotates counterclockwise. As a result, the rotation of the bracket 82 is transmitted to the low torque damper 99 via the first to fifth gears 94 to 98. Therefore, the limiting torque from the low torque damper 99 is amplified and acts on the rotation of the bracket 82 via the first to fifth gears 94 to 98.

[0123] As a result, when the engagement pin 77 moves through the resistance mechanism 910, in addition to the resistance force from the resistance mechanism 910, a limiting torque is applied by the low-torque damper 99 amplified by the first to fifth gears 94-98. Therefore, even when the paper feed tray 51 is forcefully pushed into the main body 1a by the user, the pulling force of the engagement pin 77 is significantly reduced by the resistance mechanism 910, and the rotational torque of the bracket 82 is limited, effectively braking the pushing motion of the paper feed tray 51.

[0124] Subsequently, the engaging pin 77 moves to the facilitating portion 914 via the intermediate portion 913 of the guide groove 91, as shown in Figure 17. The facilitating portion 914 of the guide groove 91 is linear and positioned away from the rotation axes 825 and 826 of the bracket 82. Therefore, a sufficient counterclockwise rotational moment acts on the engaging pin 77 as it passes through the facilitating portion 914 of the guide groove 91 due to the slightly stretched coil spring 83. Thus, it is possible to reliably pull the engaging pin 77 toward the end of the facilitating portion 914 of the guide groove 91.

[0125] Therefore, according to this embodiment 1, the sheet storage device 50 can apply sufficient braking force to the paper feed tray 51 even when the paper feed tray 51 is forcefully pushed into the device body 1a, compared to the case where the guide groove 910 of the retraction device 80 is not provided with a resistance force acting part 910.

[0126] Furthermore, according to the sheet storage device 50 of this embodiment 1, compared to the case in which the guide groove 911 of the retraction device 80 is not equipped with a promotion section 914, it is possible to reliably retract the paper feed tray 51 into the device body 1a without insufficient retraction force acting on the paper feed tray 51.

[0127] Comparative Example Figure 18 is a diagram showing a comparative example. In this comparative example, the end of the guide groove 91 on the inlet side is formed in a straight line along the retraction direction. Therefore, when the paper feed tray 51 is pushed in forcefully, it cannot be decelerated, resulting in a technical problem where the low torque damper becomes ineffective.

[0128] [Embodiment 2] Figure 19 is a configuration diagram showing a sheet storage device according to Embodiment 2.

[0129] In this second embodiment of the sheet storage device, the shape of the guide groove differs from that of the first embodiment.

[0130] In other words, in the sheet storage device 50 according to this second embodiment, as shown in Figure 19, the resistance portion 910 of the guide groove 91 is configured to consist of multiple (twice in the illustrated example) bent portions 911a and 911b with respect to the retraction direction of the paper feed tray 51, and a single curved portion 912.

[0131] Thus, in the sheet storage device 50 according to this second embodiment, by configuring the resistance force acting portion 910 of the guide groove 91 to consist of a plurality of bent portions 911c, 911d and a single curved portion 912, the resistance force acting on the engagement pin 77 can be increased, and the retraction speed of the paper feed tray 51 can be sufficiently reduced.

[0132] The other configurations and operations are the same as in Embodiment 1, so their description will be omitted.

[0133] In the above embodiment, the case in which an image is formed by an electrophotographic method as the image forming apparatus was described, but the invention is not limited to this, and images may be formed by other methods such as an inkjet method.

[0134] Furthermore, although the above embodiment described the case in which the sheet storage device is applied to an image forming apparatus, it is not limited to this, and of course, the sheet storage device may also be applied to other devices such as a paper feeder dedicated to paper feeding.

[0135] Furthermore, although the above embodiment described a case in which the engagement pin is provided on the main body of the device and the paper retraction device is located on the paper feed tray, the invention is not limited to this, and the device may be configured in such a way that the engagement pin is provided on the paper feed tray and the paper retraction device is located on the main body of the device.

[0136] (Note) (((1))) A seat housing that houses the seat and is mounted on the main body of the device so as to be able to be pulled out and retracted, An engaging means provided in either the main body of the device or the seat housing, A retraction means is provided on the other of the device body or the sheet housing, and has a guide groove that engages with the engaging means to guide the retraction operation of the sheet housing, and the guide groove is provided with a resistance force acting part that acts resistance against the retraction operation of the sheet housing, A seat storage device equipped with the following features. (((2))) The sheet housing device according to (((1))), wherein the resistance acting part is arranged on the starting end side of the retraction operation of the guide groove relative to the sheet housing. (((3))) The sheet storage device according to (((2))), wherein the resistance acting portion comprises a region in which the guide groove is bent and / or curved with respect to the retraction direction of the sheet storage body. (((4))) The sheet storage device according to (((3))), wherein the resistance acting portion comprises a plurality of regions bent in the direction of retraction of the sheet storage body. (((5))) The sheet storage device according to (((1))), wherein the guide groove is provided with an accelerating part to facilitate the retraction operation of the sheet storage body. (((6))) The sheet housing device according to (((5))), wherein the acceleration portion is positioned on the end end side of the retraction operation of the guide groove relative to the sheet housing. (((7))) The sheet storage device according to (((6))), wherein the acceleration portion comprises a region in which the guide groove is formed in a straight line. (((8))) The sheet storage device according to (((5))), wherein the guide groove has a curved portion between the resistance portion and the acceleration portion that curves in a direction intersecting the retraction direction of the sheet storage body. (((9))) The sheet storage device according to (((8))), wherein the curved portion is formed in the shape of an arc having a constant radius of curvature. (((10))) A seat storage means for storing a seat, Image forming means for forming an image on the aforementioned sheet, Equipped with, An image forming apparatus using a sheet storage device as described in any of (((1))) to (((9))) as the sheet storage means.

[0137] According to the sheet storage device described in (((1))), compared to the case in which the guide groove of the retraction means is not provided with a resistance force, the retraction force of the sheet storage body, which is mounted on the device body so as to be pullable and retractable, can be adjusted. According to the sheet housing device of (((2))), the resistance force acting part can counteract excessive pushing force on the sheet housing earlier, compared to the case where the resistance force acting part is positioned behind the starting end of the retraction operation of the guide groove toward the sheet housing. According to the sheet storage device described in (((3))), the resistance force application part can effectively apply resistance force to the sheet storage body compared to the case in which the guide groove is formed linearly with respect to the direction in which the sheet storage body is pulled in. According to the sheet housing device of (((4))), the resistance force acting portion can apply resistance to the sheet housing more effectively than when it is formed from a single bent region with respect to the retraction direction of the sheet housing. According to the sheet storage device described in (((5))), the guide groove ensures that the sheet storage body is retracted more reliably than in the case where the facilitating part is not provided. According to the sheet storage device described in (((6))), the acceleration unit can reliably pull the sheet storage body to a predetermined position compared to the case where it is provided upstream of the middle of the retraction operation. According to the sheet storage device of (((7))), the promotion section can exert a pulling action more effectively compared to the case in which the guide groove is formed in a curved shape. According to the sheet storage device of (((8))), the guide groove can smoothly transition from the action of resistance on the sheet storage body to the action of acceleration, compared to the case in which an acceleration section is provided continuously with the action of resistance. According to the sheet storage device described in (((9))), the curved portion can apply a substantially constant pulling force to the sheet storage body, compared to the case where it is formed in the shape of an arc with a changing radius of curvature. According to the image forming apparatus described in (((10))), compared to the case in which no sheet storage device described in any of (((1))) to (((9))) is used as the sheet storage means, the retraction force of the sheet storage body, which is mounted on the main body of the apparatus so as to be pullable and retractable, can be adjusted, thereby improving operability. [Explanation of symbols]

[0138] 1…Image forming apparatus 5…Record sheet 50...Seat storage device 51... Paper feed tray 77…Engaging pin 80...Inlet device 81…Storage case 82...Bracket 94~99a... Gears 91... Guide groove 910... Part of action

Claims

1. A seat housing that houses the seat and is mounted on the main body of the device so as to be able to be pulled out and retracted, An engaging means provided in either the main body of the device or the seat housing, A retraction means is provided on the other of the device body or the sheet housing, and has a guide groove that engages with the engaging means to guide the retraction operation of the sheet housing, and the guide groove is provided with a resistance force acting part that acts resistance against the retraction operation of the sheet housing, A seat storage device equipped with the following features.

2. The sheet storage device according to claim 1, wherein the resistance acting portion is arranged on the starting end side of the retraction operation of the guide groove relative to the sheet storage body.

3. The sheet storage device according to claim 2, wherein the resistance acting portion comprises a region in which the guide groove is bent and / or curved with respect to the retraction direction of the sheet storage body.

4. The sheet storage device according to claim 3, wherein the resistance acting portion comprises multiple regions bent in the direction of retraction of the sheet storage body.

5. The sheet storage device according to claim 1, wherein the guide groove is provided with an accelerating part for promoting the retraction operation of the sheet storage body.

6. The sheet storage device according to claim 5, wherein the acceleration portion is arranged on the end end side of the retraction operation of the guide groove relative to the sheet storage body.

7. The sheet storage device according to claim 6, wherein the acceleration portion comprises a region in which the guide groove is formed in a straight line.

8. The sheet storage device according to claim 5, wherein the guide groove has a curved portion between the resistance portion and the acceleration portion that curves in a direction intersecting the retraction direction of the sheet storage body.

9. The sheet storage device according to claim 8, wherein the curved portion is formed in the shape of an arc having a constant radius of curvature.

10. A seat storage means for storing a seat, Image forming means for forming an image on the aforementioned sheet, Equipped with, An image forming apparatus using a sheet storage device according to any one of claims 1 to 9 as the sheet storage means.

Images