JP2024026996A - Transfer device and image forming apparatus - Google Patents

Abstract

To speed up the attachment and detachment of a unit, and prevent the wrong operation of a contact and separation mechanism.SOLUTION: A transfer device has: a transfer unit 20 that has a belt member (intermediate transfer belt 2) and first holding members (belt holding members 1-1 to 1-4) for holding warped ends in a width direction of the belt member, and is detachably arranged with respect to an apparatus body in the width direction of the belt member; functional members 2-1 to 2-5 that are detachably arranged with respect to the apparatus body in the width direction of the belt member while being adjacent to the belt member of the transfer unit 20, and are prevented from separating from the apparatus body by second holding members (PCDU holdings 4-1, 4-2); and a contact and separation mechanism that brings the transfer unit and the functional members into contact with each other and separated from each other. At least one of the first holding members, the second holding members, and the contact and separation mechanism can be actuated by an operation to rotate an operation member. The operation member is urged by urging means to rotate in a predetermined direction. The operation member is operated to rotate by a predetermined angle against the urging means to hold the operation member at the predetermined angle.SELECTED DRAWING: Figure 3A

Description

The present invention relates to a transfer device equipped with a belt member for conveying a sheet member, and an image forming apparatus equipped with the same.

An image forming apparatus includes a plurality of units provided with various functions related to image formation within the apparatus main body. These multiple units include a process cartridge unit and a transfer unit. The process cartridge unit is also abbreviated as PCDU (Photo Conductor Development Unit).

The transfer unit includes a belt member that conveys the sheet member. A PCDU forms an image on a sheet member, and is usually composed of multiple units. These multiple units include four units that use yellow (Y), magenta (M), cyan (C), and black (K) toners, and one unit that uses toners other than these (hereinafter referred to as "special color toners"). It can be composed of a total of 5 units.

Special color toners include transparent toner, white toner, gold toner, and the like. A plurality of PCDUs using different spot color toners can be prepared, and one desired spot color toner can be selected and installed in the apparatus main body.

Each unit is removably arranged in the width direction of the belt member with respect to the main body of the apparatus for maintenance, cleaning, parts replacement, unit replacement, etc. On the other hand, since the belt member of the transfer unit has a multilayer structure including a base layer, an elastic layer, etc., warping is likely to occur at the widthwise ends of the belt due to thermal deformation or deterioration over time.

Since the transfer unit and the PCDU are arranged adjacent to each other with a narrow gap in between, a portion of the unit may get caught in the warp of the belt end during attachment and detachment of the unit. If this happens, crease marks will remain on the belt, and these crease marks will cause transfer defects and image defects.

Therefore, it has been proposed to provide a belt presser to suppress warpage of the belt end (see, for example, Patent Document 1). This belt presser is supported by a contact/separation mechanism, and the belt presser is moved vertically by the contact/separation mechanism when the unit is attached/detached, thereby preventing a part of the unit from being caught by the warp of the belt end.

A device having such a contact/separation mechanism is provided with a foolproof structure in which the unit cannot be removed unless the contact/separation mechanism is operated when the PCDU is removed. This foolproof structure has a PCDU retainer that prevents the PCDU from detaching. Then, by operating the contact/separation mechanism, the PCDU presser can be released.

However, when attaching and detaching the unit, it is necessary to operate the contact/separation mechanism and the PCDU holder in sequence twice, and it takes time to attach and detach the unit. In addition, there was a possibility of an erroneous operation in which the operator misunderstood that the belt holder had been moved completely downward and released the PCDU holder even though the separating operation of the approaching/separating mechanism was incomplete.

The present invention is intended to solve the above-mentioned problems, and aims to speed up the attachment and detachment of the unit and prevent erroneous operation of the contact/separation mechanism.

In order to solve the above problems, a transfer device according to the present invention includes a belt member that conveys a sheet member, and a first pressing member that suppresses warping of the widthwise end portion of the belt member, and has a first pressing member that presses against the main body of the device. a transfer unit that is removably disposed in the width direction of the belt member; and a transfer unit that is removably disposed in the width direction of the belt member with respect to the apparatus main body in a state adjacent to the belt member of the transfer unit; In the transfer device, the transfer device includes a functional member that cannot be separated from the device main body by a second holding member, and a contact/separation mechanism that brings the transfer unit and the functional member into contact with and separates from each other. At least one of the presser member and the approaching/separating mechanism can be actuated by a rotational operation of an operating member, and the operating member is rotationally biased in a predetermined direction by a biasing means, and the operating member is rotated in a predetermined direction by a biasing means. It is characterized in that the operating member can be held at the predetermined angle by rotating the operating member by a predetermined angle.

According to the present invention, it is possible to speed up the attachment and detachment of the unit and to prevent erroneous operation of the contact/separation mechanism.

1 is a schematic configuration diagram of an image forming apparatus. FIG. 3 is a perspective view of the transfer unit. FIG. 2 is a side view of a transfer device in which a PCDU is mounted on a transfer unit. (a) A perspective view of a transfer unit having a two-part front cover, (b) a perspective view of the two-part front cover, and (c) a perspective view of an integrated front cover. FIG. 3 is a perspective view of the transfer unit with the PCDU holder in an upright position. FIG. 3 is a front view of the operating lever in the first switching position. FIG. 3 is a front view of the operating link of the PCDU holder. FIG. 3 is a perspective view of the operating link of the PCDU holder. FIG. 3 is a perspective view of the transfer unit with the PCDU presser laid down. FIG. 7 is a front view of the operating lever in the second switching position. FIG. 6 is a front view of the operating link of the PCDU holder. FIG. 3 is a perspective view of the operating link of the PCDU holder. FIG. 3 is a perspective view of the rotation shaft of the operating lever and the operating link. FIG. 3 is a side view of the rotation shaft and operating link of the operating lever. They are (a) a side view of the belt presser in an upright state, and (b) a side view of the belt presser in a collapsed state. FIG. 3 is a perspective view of the operating link of the belt holder. FIG. 3 is a side view of a state in which the primary transfer roller is in contact with the PCDU and the PCDU presser is erected. FIG. 3 is a side view of a state in which the primary transfer roller is separated from the PCDU and the PCDU presser is laid down. FIG. 3 is a perspective view of the operating lever. FIG. 3 is a front view of the operating lever. It is a perspective view of a cam member. FIG. 3 is a perspective view of the cam member and its peripheral structure as seen from the back side. FIG. 3 is a front view showing the configuration around the first arm and the second arm. FIG. 3 is a perspective view showing a second arm and its peripheral configuration. FIG. 3 is a perspective view of the second arm and its peripheral configuration as seen from the back side. FIG. 3 is a front view showing a configuration in which a detection sensor and a sensor bracket come into contact with each other. FIG. 3 is a perspective view of the first sensor bracket and the second sensor bracket as seen from the front side of the image forming apparatus. FIG. 7 is a plan view showing how the second sensor bracket is positioned in a “separated” state.

Embodiments according to the present invention will be described below with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and repeated explanations thereof will be simplified or omitted as appropriate.

(Image forming device)
FIG. 1 is a diagram showing the configuration of an image forming apparatus 1 according to an embodiment of the present invention. An image forming apparatus 1 shown in FIG. 1 is a color printer having a tandem configuration in which a plurality of photoreceptors serving as latent image carriers are arranged side by side. Each photoreceptor can form a toner image of a color corresponding to color separation using toner as a developer supplied from a developing device. After the toner images formed on each photoreceptor are superimposed and transferred to an intermediate transfer member, the superimposed images are transferred all at once to a sheet member such as recording paper, thereby forming a multicolor image on the sheet member. In the present invention, it goes without saying that the image forming apparatus 1 is not limited to a color printer, but also includes a color copying machine, a facsimile machine, a printing machine, and the like.

In FIG. 1, the image forming apparatus 1 includes an image forming section 1A disposed near the center in the vertical direction, a paper feed section 1B below the image forming section 1A, and an original document mounting table 1C1 above the image forming section 1A. Scanning units 1C are arranged respectively. The image forming section 1A includes a transfer unit 20. In this transfer unit 20, an intermediate transfer belt 2 serving as a belt member serving as an intermediate transfer body is arranged.

The intermediate transfer belt 2 has a horizontally extending surface. A configuration is provided above the intermediate transfer belt 2 for forming an image of colors complementary to the color separation colors.

The image forming section 1A includes image forming sections 10K, 10C, 10M, 10Y, and 10T that can form images using complementary color toners (yellow, magenta, cyan, and black) and glossy images using transparent toner. ing. In each of the image forming units 10K, 10C, 10M, 10Y, and 10T, photoreceptors 3K, 3C, 3M, 3Y, and 3T (transparent toner) capable of carrying images are arranged side by side along the stretched surface of the intermediate transfer belt 2. . In the following description, if the content is common to all photoconductors, the photoconductor is indicated by the reference numeral 3.

Each of the photoreceptors 3K, 3C, 3M, 3Y, and 3T is composed of a drum that can rotate in the same direction (counterclockwise in FIG. 1). A charging device, a writing device 5, a developing device 6, a primary transfer roller 7 as a primary transfer member, and a cleaning device are arranged. (shown).

The transfer unit 20 includes an intermediate transfer belt 2, a plurality of primary transfer rollers 7 as transfer members (for convenience, only the primary transfer roller 7T is shown with a reference numeral), and a plurality of rollers 2A to 2C.

Toner images from an image forming section including each photoreceptor 3 are sequentially transferred to the intermediate transfer belt 2 . The intermediate transfer belt 2 is wound around a plurality of rollers 2A to 2C and a plurality of rollers not numbered in FIG. 1, and can travel in the direction of the arrow in FIG. The rollers 2A and 2B stretch the intermediate transfer belt 2 on both sides of the outer side in the running direction of the intermediate transfer belt 2 at opposing positions facing each photoreceptor 3 of the intermediate transfer belt 2. The secondary transfer opposing roller 2C faces the secondary transfer device 9 with the intermediate transfer belt 2 in between.

The secondary transfer device 9 has a secondary transfer roller 9A. The secondary transfer roller 9A forms a secondary transfer nip with the secondary transfer opposing roller 2C with the intermediate transfer belt 2 in between. A secondary transfer bias having the same polarity as the toner is applied to the secondary transfer opposing roller 2C, while the secondary transfer roller 9A is grounded. As a result, a secondary transfer electric field is formed in the secondary transfer nip that electrostatically moves the multicolor toner image on the intermediate transfer belt 2 from the belt side toward the secondary transfer roller 9A side. This secondary transfer nip transfers the multicolor toner image onto the sheet member that has been conveyed to the secondary transfer nip.

A sheet member is fed to the secondary transfer position from the paper feeding section 1B. The paper feed section 1B includes a plurality of paper feed cassettes 1B1 and a plurality of transport rollers 1B2. The plurality of conveyance rollers 1B2 are arranged on a conveyance path for sheet members fed out from the paper feed cassette 1B1.

The writing device 5 irradiates the photoreceptors 3K, 3C, 3M, 3Y, and 3T with writing light to form electrostatic latent images on the photoreceptors 3K, 3C, 3M, 3Y, and 3T according to image information. This image information is obtained by scanning the original on the original mounting table 1C1 included in the original scanning unit 1C, or from image information output from a computer.

The document scanning section 1C is equipped with a scanner 1C2 and an automatic document feeder 1C3. The scanner 1C2 exposes and scans the original on the original placing table 1C1. The automatic document feeder 1C3 is arranged on the upper surface of the document placement table 1C1. The automatic document feeder 1C3 has a configuration capable of reversing the document fed onto the document placement table 1C1, and is capable of scanning both the front and back sides of the document.

The electrostatic latent image formed on the photoreceptor 3 by the writing device 5 is processed into a visible image by a developing device 6 (indicated by reference numeral 6T for convenience in FIG. 1), and is primarily transferred to the intermediate transfer belt 2. Ru. When the toner images of each color are superimposed and transferred to the intermediate transfer belt 2, the toner images of the respective colors are secondarily transferred all at once to the sheet member by the secondary transfer device 9.

The unfixed image carried on the surface of the second-transferred sheet member is fixed by the fixing device 11 . The fixing device 11 includes a belt fixing structure including a fixing belt heated by a heating roller and a pressure roller opposing and abutting the fixing belt. By providing a contact region, that is, a nip region, between the fixing belt and the pressure roller, the heating region for the sheet member can be expanded compared to the structure of the heat roller fixing method.

The conveyance direction of the sheet member that has passed through the fixing device 11 is switched by a conveyance path switching claw arranged at the rear of the fixing device 11. Specifically, the conveyance path switching claw selects the conveyance direction between the conveyance path toward the paper discharge section 13 and the reverse conveyance path RP.

In the image forming apparatus 1 having the above configuration, the uniformly charged photoreceptor 3 is exposed to light by scanning the original placed on the original placing table 1C1 or by using image information from a computer. After the electrostatic latent image is processed into a visible image by the developing device 6, the toner image is primarily transferred onto the intermediate transfer belt 2.

In the case of a single color image, the toner image transferred to the intermediate transfer belt 2 is transferred as it is to the sheet member fed out from the paper feed section 1B, and in the case of a multicolor image, the primary transfer is repeated. After being superimposed, the images are secondarily transferred to the sheet member all at once. After the unfixed image is fixed on the sheet member after the secondary transfer by the fixing device 11, the sheet member is fed to the paper discharge section 13 or reversed and fed again to the secondary transfer position.

In FIG. 1, the intermediate transfer belt 2 is composed of a single layer or multiple layers of PVDF (vinyldene fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), PI (polyimide), PC (polycarbonate), etc. Constructed by dispersing conductive material such as carbon black. The volume resistivity of the intermediate transfer belt 2 is adjusted to be in the range of 10 ⁸ to 10 ¹² Ωcm, and the surface resistivity is adjusted to be in the range of 10 ⁹ to 10 ¹³ Ωcm.

Note that a release layer may be coated on the surface of the intermediate transfer belt 2 if necessary. Materials used for the coating include ETFE (ethylene-tetrafluoroethylene copolymer), PTFE (polytetrafluoroethylene), PVDF (vinyldene fluoride), PEA (perfluoroalkoxy fluororesin), and FEP (tetrafluoroethylene). Fluororesins such as ethylene fluoride-propylene hexafluoride copolymer) and PVF (vinyl fluoride) can be used, but are not limited thereto.

The intermediate transfer belt 2 can be manufactured by a casting method, a centrifugal molding method, etc., and its surface may be polished if necessary. If the volume resistivity of the intermediate transfer belt 2 exceeds the above-mentioned range, the bias required for transfer will increase, which is undesirable because it will lead to an increase in power supply cost.

Further, the charging potential of the intermediate transfer belt 2 becomes high during the transfer process, the transfer paper peeling process, etc., and self-discharge becomes difficult, so it becomes necessary to provide a neutralizing means. Furthermore, if the volume resistivity and surface resistivity are below the above range, the charge potential decays quickly, which is advantageous for eliminating static electricity by self-discharge, but since the current flows in the surface direction during transfer, toner scattering may occur. It ends up.

Therefore, the volume resistivity and surface resistivity of the intermediate transfer belt 2 in this embodiment are preferably within the above ranges. The volume resistivity and surface resistivity were measured by connecting an HRS probe (inner electrode diameter 5.9 mm, ring electrode inner diameter 11 mm) to a high resistance resistivity meter (manufactured by Mitsubishi Chemical Corporation: Hiresta IP), and using the intermediary transfer belt 2. A voltage of 100 V (surface resistivity is 500 V) was applied to the front and back surfaces of the substrate, and the measured value 10 seconds later was used.

The intermediate transfer belt 2 is wound around at least a pair of rollers 2A and 2B, and a secondary transfer opposing roller 2C provided at a secondary transfer position, so that the drive roller 2A is set to rotate clockwise. The intermediate transfer belt 2 can be moved in the direction of the arrow shown inside the intermediate transfer belt 2 in FIG. The transfer surface of the belt moving between rollers 2A and 2B faces photoreceptors 3K, 3Y, 3C, 3M, and 3T of each image forming unit.

At a position facing each photoconductor with the intermediate transfer belt 2 in between, there is a primary transfer roller 7 (in FIG. 1, a primary transfer roller 7 is used for special toner), which corresponds to a transfer member for electrostatically transferring the visible image on the photoconductor. 7T) are arranged respectively. The primary transfer roller 7 used in this embodiment is one in which a foamed resin agent is applied to a metal core (iron, SUS, AI, etc.).

The wall thickness of the foamed resin agent is 2 mm to 10 mm. Note that a known blade-like or brush-like member can also be used as the transfer member.

In this embodiment, in addition to the toner used for full-color image formation, white toner is used for the purpose of forming a white base on the image. In addition, a transparent toner may be used to improve the glossiness and transferability of the image, and a light cyan toner, light magenta toner, etc. may be selected to increase the color gamut. In order to create a colored metallic color such as red copper or bronze, metallic toner such as gold toner or silver toner may be used as a base.

(●Transfer unit and transfer device)
FIG. 2A is a perspective view of the transfer unit 20 described above. Belt pressers 1-1, 1-2, 1-3, and 1-4, which serve as first press members, are provided at two positions on the left and right sides of the front side of the transfer unit 20 and at two positions on the left and right sides of the rear side. These belt pressers 1-1 to 1-4 make it possible to suppress upward warping of both ends of the intermediate transfer belt 2 in the width direction.

Further, PCDU pressers 4-1 and 4-2 as second press members are provided at two positions on the left and right sides of the front side of the transfer unit 20. These PCDU retainers 4-1 and 4-2 prevent the two PCDUs 2-1 and 2-2 on the right side (downstream side) in FIG. 2B from coming off toward the front side in FIG. 2B. Note that a similar PCDU holder may be provided on the front side of the three PCDUs 2-3 to 2-5 on the left side (upstream side) in FIG. 2B.

At the front right end of the transfer unit 20, an operating lever 16 as an operating member is provided. By rotating this operating lever 16, the belt pressers 1-1 to 1-4 and the PCDU presses 4-1 and 4-2 can be moved to an operating position and a non-operating position. . By disposing the operation lever 16, the belt pressers 1-1 to 1-4, and the PCDU presses 4-1 and 4-2 in the transfer unit 20, the link mechanism described below can be easily constructed at low cost.

FIG. 2B shows the transfer device of this embodiment. In this transfer device, five PCDUs 2-1 to 2-5 are arranged above the transfer unit 20. The five PCDUs 2-1 to 2-5 correspond to the image forming units 10T, 10C, 10M, 10Y, and 10K in FIG.

PCDUs 2-1 to 2-5 are arranged in order from the downstream side to the upstream side in the running direction of the intermediate transfer belt 2. PCDU2-1 is connected to the image forming section 10T (transparent toner), PCDU2-2 is connected to the image forming section 10C (cyan), PCDU2-3 is connected to the image forming section 10M (magenta), and PCDU2-4 is connected to the image forming section 10Y (yellow). ), the PCDU 2-5 corresponds to the image forming section 10K (black), respectively.

(●Arrangement of operation lever and front cover)
In the transfer device shown in FIG. 2B, a front cover 20-1 of the transfer unit 20 is disposed on the near side of the operation lever 16. In the conventional transfer device, as shown in FIGS. 2C(a) and 2C, the shaft portion 16d of the operation lever 16 of the transfer unit 20 is sandwiched between the first front cover 20-1-1 and the second front cover from both upper and lower sides. It was common to install 20-1-2. This is to reduce the clearance around the shaft portion 16d so that the inner mechanism of the front cover 20-1 cannot be seen from the outside.

However, when such a two-part front cover is used, when replacing the transfer unit 20, the first front cover 20-1-1 and the second front cover 20-1-2 can be moved up and down as shown in FIG. 2C(b). Since the transfer unit 20 must be removed separately in each direction, it takes time and effort to attach and detach the transfer unit 20. Furthermore, even if the integrated front cover 20-1-3 is used as shown in FIG. 2C(c), the front cover 20-1-3 cannot be removed unless the operation lever 16 is removed in the axial direction. Therefore, the effort required to attach and detach the transfer unit 20 remains the same.

Therefore, in this embodiment, an integrated front cover 20-1 is provided on the front side of the operating lever 16 as shown in FIG. 2B. The front cover 20-1 has a notch 20-2 through which the operating lever 16 is partially exposed, as detailed in FIGS. 8A and 8B. The operating lever 16 has a knob portion 16a and a disk-shaped main body portion 16b, and has a structure in which a portion of the knob portion 16a and the disk-shaped main body portion 16b are exposed from the cutout portion 20-2.

Since the front cover 20-1 is disposed so as to overlap the front side of the outer peripheral edge of the main body portion 16b, the inner mechanism of the front cover 20-1 is not visible from the outside. Furthermore, since the integrated front cover 20-1 can be removed without removing the operating lever 16 as shown in FIG. 2C(c), the transfer unit 20 can be quickly attached and detached.

(●Second link mechanism for holding PCDU)
3A to 3D and 4A to 4D show the second link mechanism between the operating lever 16 and the PCDU presses 4-1 and 4-2. Via this second link mechanism, the movement of the operating lever 16 is transmitted to the PCDU pressers 4-1 and 4-2.

3A to 3D show a state in which the operating lever 16 is in the first switching position and the PCDU presses 4-1 and 4-2 are moved to the operating position. In this operating position, the PCDU holders 4-1 and 4-2 stand up, preventing the PCDUs 2-1 and 2-2 from coming off toward the front in FIG. 2B.

4A to 4D show a state in which the operating lever 16 is in the second switching position and the PCDU presses 4-1 and 4-2 are moved to the non-operating position. In this non-operating position, the PCDU holders 4-1 and 4-2 are laid down, allowing the PCDUs 2-1 and 2-2 in FIG. 2B to be removed to the front side.

The operating lever 16 is attached to the rotating shaft 14 in FIG. 3C. A first link 9 is fixed to the rotating shaft 14. The first link 9 is biased clockwise by a tension spring 50 as biasing means, that is, from the second switching position to the first switching position. Instead of the tension spring 50, it is also possible to use a compression spring as a biasing means to bias the first link 9 in the clockwise direction.

In the first switching position shown in FIG. 3C, the tension spring 50 has the shortest length, and the rotation shaft 14 is located on the longitudinal extension of the tension spring 50. In this state, the biasing force of the tension spring 50 becomes zero. The rotation shaft 14 or the operating lever 16 cannot be rotated further to the right than in FIGS. 3C and 3D due to the stopper.

The first link 9 is connected to the fourth link 6 via a second link 12 and a third link 11, as shown in FIGS. 5A and 5B. That is, one ends of the second link 12 and the third link 11 are connected to the pin 9a of the first link 9.

Further, the other ends of the second link 12 and the third link 11 are connected to the right end of the fourth link 6. That is, the pin 12a at the other end of the second link 12 is engaged with the long hole 15 formed near the right end of the fourth link 6. Further, a pin 11a at the other end of the third link 11 is connected to the right end of the fourth link 6.

As shown in FIGS. 3A and 4A, the fourth link 6 is disposed horizontally between the PCDU pressers 4-1 and 4-2 on the near side of the transfer unit 20. By sliding the fourth link 6 in the left and right longitudinal directions, the PCDU retainers 4-1 and 4-2 rise and fall.

By rotating the rotating shaft 14 left and right, the fourth link 6 of the second link mechanism slides left and right. By this sliding movement, the PCDU retainers 4-1 and 4-2 are raised up as shown in FIGS. 3A to 3D, or laid down as shown in FIGS. 4A to 4D.

Elongated holes 4-1-1 and 4-2-1 are formed in the longitudinal middle of the PCDU retainers 4-1 and 4-2, and fixing pins 8-1 and 8-2 are slidably engaged with these elongated holes. are doing. One longitudinal end of the PCDU retainers 4-1 and 4-2 is connected to the fourth link 6 with pins 4-1-2 and 4-2-2.

Therefore, by sliding the fourth link 6 left and right, the PCDU retainers 4-1 and 4-2 can be raised and lowered as described above. A retaining pin 4-1-3 is attached to the tips of the pins 4-1-2 and 4-2-2 to prevent the PCDU retainers 4-1 and 4-2 from coming off, as shown in FIG. 5A.

The left end of the fourth link 6 is connected to the connecting shaft 8 via the fifth link 7. The connecting shaft 8 is supported by the machine frame, and connects the front cam 7-1 and the rear cam 7-2, as shown in FIGS. 3A and 4A. The belt pressers 1-1 to 1-4 can be moved up and down by the cams 7-1 and 7-2.

(●First link mechanism of belt holder)
The operating lever 16 as an operating member is connected to four belt pressers 1-1, 1-2, 1-3, and 1-4 via a first link mechanism shown in FIGS. 6A and 6B. 6A and 6B show a connection structure that connects the rear cam 7-2 and the rear belt pressers 1-3 and 1-4. The cam 7-1 on the near side and the belt pressers 1-1 and 1-2 on the near side are also connected by a similar connection structure.

At the first switching position of the operating lever 16 in FIGS. 3A to 3D, the belt pressers 1-1 to 1-4 move to the non-operating position (separated from the intermediate transfer belt 2). Further, at the second switching position of the operating lever 16 in FIGS. 4A to 4D, the belt pressers 1-1 to 1-4 move to the operating position (pressing the widthwise ends of the intermediate transfer belt 2).

A cam follower 5-2-2 is engaged with the cam 7-2 at the right end in FIG. 6A. The cam follower 5-2-2 has an F-shape in side view and is integrated with the slider 5-2. The slider 5-2 is biased to the right in FIG. 6A by a tension spring 5-2-3.

Pins 5-2-1 are fixed to both ends of the slider 5-2. This pin 5-2-1 engages with the belt press rotating portions (cam grooves) 1-3-3 and 1-4-3 of the belt presses 1-3 and 1-4.

The belt holders 1-3 and 1-4 are supported so as to be rotatable in the left-right direction in FIG. 6A. When the pin 5-2-1 slides in the left and right direction together with the slider 5-2, the belt pressers 1-3 and 1-4 rise (erect) as shown in FIG. 6A(a) or as shown in FIG. 6A(b). It descends (lodges) as in .

To suppress upward warping of both ends of the intermediate transfer belt 2 in the width direction, the slider 5-2 is moved to the left by the cam 7-2 as shown in FIG. 6A(b), and the belt pressers 1-3 and 1-4 are To descend (lodge). In this state, the belt pressers 1-3 and 1-4 press the ends of the intermediate transfer belt 2 in the width direction by their own weight.

Therefore, the force acting on the cam 7-2 is small, and when rotating the operating lever 16 from the first switching position to the second switching position and when rotating the operating lever 16 from the second switching position to the first switching position. The operating force is very small. Therefore, the cam 7-2 and the belt holding rotating parts 1-3-3 and 1-4-3 can be constructed from resin molded products at low cost. Furthermore, the durability of these cams 7-2 and the like can be improved.

Each belt presser 1-3, 1-4 has a two-layer structure including an upper hard plate portion and a lower soft felt portion. That is, to explain one belt holder 1-3 with reference to FIG. 6B, the belt holder 1-3 has a two-layer structure of an upper hard plate part 1-3-1 and a lower soft felt part 1-3-2. have The soft felt portion 1-3-2 is for preventing damage to the intermediate transfer belt 2, and in the lowered state shown in FIGS. contact with the part.

(●Transfer unit approach/separation mechanism)

Next, with reference to FIGS. 7A and 7B, a mechanism (third link mechanism) for moving the driven roller 33A at the left end of the transfer unit 20 toward and away from (up and down) the PCDU 2-1 at the downstream end will be described. do. The first transfer roller 19-1, the driven roller 21A, and the second transfer roller 19-2 at the right end are brought into contact with and separated from (raised and lowered) relative to the PCDU 2-1 and PCDU 2-2 by another contact and separation mechanism.

7A and 7B are cross-sectional views of the image forming apparatus 1 viewed from the back side, which is the opposite side from FIGS. 1 to 4C. A rotating shaft 14 connected to the aforementioned operating lever 16 protrudes toward the back side of the device. A cam 14-1 is attached to this rotating shaft 14.

The front slider 17 is arranged so as not to interfere with the rotating shaft 14. The front slider 17 is arranged so as to be movable in the left-right direction in FIGS. 7A and 7B.

A cam follower 23 is formed on the front slider 17 and can be brought into contact with the cam 14-1. When the operating lever 16 is rotated as shown in FIG. 4B against the tension spring 50, the cam 14-1 comes into contact with the cam follower 23 as shown in FIG. 7B, and the front slider 17 is moved to the right.

The cam 14-1 and the cam follower 23 constitute a locking mechanism that holds the operating lever 16 at the second switching position shown in FIG. 4B in the state shown in FIG. 7B, as will be described later. By providing the cam 14-1 as a locking mechanism on the highly rigid rotating shaft 14, it is possible to avoid applying a large force to the weak parts of the link mechanism after the cam follower 23 to hold the operating lever 16 in the second switching position. It's done.

On the other hand, a driven roller 33A, which is one of the rollers that tensions the intermediate transfer belt 2, is provided at one end of the rotating member 33. The rotating member 33 is rotatably provided around a rotational fulcrum 33a. The rotating member 33 has a hole 33b at the end opposite to the side where the driven roller 33A is provided.

An insertion portion 17a provided on the front slider 17 is inserted into the hole 33b. The insertion portion 17a is constructed by press-fitting a ball bearing into a shaft portion fixed to the front slider 17. By providing the ball bearing in the insertion part 17a, the sliding resistance between the insertion part 17a and the rotating member 33 can be reduced.

When the front slider 17 moves to the right as shown in FIG. 7B, the rotating member 33 rotates counterclockwise around the rotation fulcrum 33a, separating the driven roller 33A from the PCDU 2-1 at the downstream end. In this state, the cam 14-1 is in contact with the cam follower 23, and the frictional force between the two exceeds the tension spring 50. Therefore, even if the user releases the operating lever 16 in the state shown in FIG. 4B, the operating lever 16 remains stopped in the state shown in FIG. 4B. That is, the cam 14-1 and the cam follower 23 constitute a locking mechanism that holds the operating lever 16 at the second switching position shown in FIG. 4B.

Therefore, with one release operation of the operating lever 16 from the first switching position to the second switching position,
1) The driven roller 33A can be kept separated from the PCDU 2-1.
2) It is possible to hold the PCDU holders 4-1 and 4-2 in a laid down state.
3) By lowering (lowering down) the belt pressers 1-1 to 1-4, it is possible to hold the intermediate transfer belt 2 in a state in which upward warping of both ends in the width direction is suppressed. Therefore, the work of attaching and detaching the PCDUs 2-1 to 2-2 in the front-rear direction in FIG. 2B can be easily and quickly performed without damaging the intermediate transfer belt 2.

As described above, the operating lever 16 is biased clockwise by the tension spring 50, that is, from the second switching position to the first switching position. If the operating lever 16 is not biased clockwise by the tension spring 50, there is a possibility that the operating lever 16 will stop at a halfway position between the first switching position and the second switching position.

In this case, the user may mistakenly believe that the operating lever 16 has been completely switched to the second switching position, and may mistakenly believe that the belt pressers 1-1 to 1-4 are in the operating state (belt press state). Then, there is a risk that the intermediate transfer belt 2 may be unexpectedly damaged by continuing to perform the work of attaching and detaching the PCDUs 2-1 and 2-2.

By providing the tension spring 50 on the operating lever 16, it is possible to prevent the operating lever 16 from unexpectedly stopping at a halfway position between the first switching position and the second switching position. Therefore, it is possible to prevent the user from erroneously attaching or detaching the PCDU based on the user's erroneous belief in the position of the operating lever 16 described above.

Furthermore, if the operating lever 16 is moved even slightly clockwise from the second switching position after the PCDUs 2-1 to 2-2 are attached, the cam 14-1 will be removed from the cam follower 23. Immediately, the operating lever 16 is instantly returned to the first switching position by the biasing force of the tension spring 50. Accordingly, the PCDU pressers 4-1 and 4-2 instantly return to the upright position, and the belt pressers 1-1 to 1-4 also instantaneously rise (stand up). In this way, the work of attaching and detaching the PCDU can be completed quickly and reliably.

In the first switching position shown in FIG. 3C, the tension spring 50 has the shortest length, and the rotation shaft 14 is located on the longitudinal extension of the tension spring 50. In this state, the biasing force of the tension spring 50 becomes zero. The rotation shaft 14 or the operating lever 16 cannot be rotated further to the right than in FIGS. 3C and 3D due to the stopper.

(●Other contact/separation mechanisms)
The driving force of the motor is transmitted to other contact/separation mechanisms that bring the first transfer roller 19-1, the driven roller 21A, and the right-most second transfer roller 19-2 into contact with and away from the PCDU 2-1 and PCDU 2-2. It has a cam member 31. The cam member 31 has a first cam 31A and a second cam 31B as shown in FIG. 9, and is rotatably provided around a rotating shaft 31a.

The second cam 31B is a ball bearing having an outer ring, and is an eccentric cam with respect to the rotating shaft 31a. The first cam 31A contacts the front slider 17 as a sliding member.

The front slider 17 is urged leftward by a spring 18. The driving force of the motor causes the first cam 31A to rotate and change the surface that contacts the front slider 17, thereby moving the front slider 17 to the right in FIGS. 7A and 7B against the biasing force of the spring 18. be able to.

A primary transfer roller 19-1 (corresponding to the primary transfer roller 7T in FIG. 1) is provided at one end of the rotating member 34. The rotating member 34 is rotatably provided around a rotational fulcrum 34a. The rotating member 34 has a hole 34b at the end opposite to the side where the primary transfer roller 19-1 is provided.

A pin 17b provided on the front slider 17 is inserted into the hole 34b. The spring 35 is fixed to the casing of the image forming apparatus 1, and urges the rotating member 34 to rotate clockwise in FIGS. 7A and 7B around the rotation fulcrum 34a.

The driven roller 33A is a first tension roller provided downstream of the primary transfer roller 19-1 in the most downstream primary transfer section. As the front slider 17 moves in the left-right direction in FIGS. 7A and 7B, the insertion portion 17a pushes the rotating member 33, and the rotating member 33 rotates around the rotational fulcrum 33a.

This causes the driven roller 33A to change its position. Further, as the front slider 17 moves to the right in FIGS. 7A and 7B, the rotating member 34 is pushed by the pin 17b and rotates counterclockwise about the rotational fulcrum 34a against the biasing force of the spring 35. .

Alternatively, when the front slider 17 moves to the left in the figure, the rotating member 34 rotates clockwise around the rotational fulcrum 34a due to the biasing force of the spring 35. As a result, the primary transfer roller 19-1 provided on the rotating member 34 moves toward and away from the photoreceptor 3.

Further, as shown in FIGS. 7A and 7B, on the upstream side of the primary transfer roller 19-1 in the traveling direction of the intermediate transfer belt 2, on the downstream side of the primary transfer roller 7C upstream from the primary transfer roller 19-1, , a driven roller 21A that stretches the intermediate transfer belt 2 and is driven by the rotation of the intermediate transfer belt 2 is provided. The driven roller 21A is provided at one end of the rotating member 21.

The rotating member 21 is rotatably provided around a rotational fulcrum 21a. The rotating member 21 receives a force from the spring 39 that causes it to rotate clockwise around the rotational fulcrum 21a.

For example, as shown in FIG. 7A⇒FIG. 7B, when the front slider 17 moves to the right in FIG. 7A, the rotating member 34 rotates counterclockwise around the rotation fulcrum 34a against the biasing force of the spring 35. , the primary transfer roller 19-1 moves in a direction away from the photoreceptor 3.

Further, as the front slider 17 moves to the right in FIG. 7A, the pin 17c (see FIG. 12) provided on the front slider 17 presses the side of the rotating member 21 opposite to the side where the driven roller 21A is provided.

As a result, the rotating member 21 rotates counterclockwise about the rotation fulcrum 21a against the biasing force of the spring 39. As a result, the driven roller 21A separates from the intermediate transfer belt 2 in FIG. 7B.

In this way, by changing the arrangement of the driven roller 33A in each of the "contact" and "separation" states, the position at which the intermediate transfer belt 2 is stretched can be changed in each state. Therefore, the intermediate transfer belt 2 can be stretched at an appropriate position, and the traveling speed of the intermediate transfer belt 2 can be detected with high accuracy by the detection sensor 22.

The detection sensor 22 optically detects the scale mark of the scale tape attached to the inner surface of the end of the intermediate transfer belt 2, and is sometimes called a "scale mark sensor" or simply a "scale sensor". . The detection sensor 22 is a reflective sensor, and the light emitting side is disposed below the end of the intermediate transfer belt 2, and the scale tape, which is the reflective side, is disposed above. If the intermediate transfer belt 2 is wavy, the detection sensor 22 will not be able to read it properly, so a pressing portion 22a that presses the intermediate transfer belt 2 from above is provided integrally with the detection sensor 22, as shown in FIG. 3D.

By pressing the end portion of the intermediate transfer belt 2 from above, the pressing portion 22a maintains a constant distance between the detection sensor 22 and the belt, thereby ensuring detection accuracy. Therefore, the holding portion 22a of the detection sensor 22 additionally provides a belt holding function.

In particular, in this embodiment, by changing the tensioning position of the driven roller 33A, which is disposed downstream of the primary transfer roller 19-1 of the most downstream primary transfer section and tensions the intermediate transfer belt 2, the intermediate transfer belt The tensioning posture of the intermediate transfer belt 2 can be changed appropriately, and the detection sensor 22 can accurately detect the running speed of the intermediate transfer belt 2. By shifting the tensioned position of the intermediate transfer belt 2 downward as shown in FIG. 7B, interference between the photoreceptor 3T (see FIG. 1) and the intermediate transfer belt 2 can be avoided when the PCDU or transfer unit 20 is attached or detached. Damage to the photoreceptor 3T and intermediate transfer belt 2 can be prevented.

(●Detection sensor contact/separation mechanism)
Next, the approach and separation mechanism for raising and lowering the detection sensor 22 will be described. As shown in FIG. 7A, the first arm 37 grips the outer peripheral surface of the second cam 31B provided on the cam member 31. As shown in FIG. The first arm 37 is rotatably provided around a rotation fulcrum 37a.

The rotational fulcrum 37a is fixed to the front slider 17 via a ball bearing. The rotation of the second cam 31B causes the first arm 37 to rotate about the rotation fulcrum 37a, as shown in FIG. 7A. Furthermore, as the front slider 17 moves due to the rotation of the first cam 31A (see FIG. 12) provided on the cam member 31, the first arm 37 moves in the left-right direction in FIG. 7A.

FIG. 9 is a perspective view showing the cam member 31. As shown in FIG. 9, the cam member 31 includes a first cam 31A and a second cam 31B. The cam member 31 is rotatably provided around a rotating shaft 31a.

The first cam 31A has a small diameter portion, a medium diameter portion, and a large diameter portion each having a different diameter by 120 degrees. As shown in FIG. 10, the first cam 31A contacts a cam follower 36 made of a ball bearing.

The cam follower 36 is a first transmission member provided on the first arm 37. By rotating the first cam 31A and changing the surface that contacts the cam follower 36, the front slider 17 can be moved in the left-right direction in FIG. 7A. Further, as the front slider 17 moves, the first arm 37 whose rotational fulcrum 37a is fixed to the front slider 17 moves in the left-right direction in FIG. 7A in conjunction with the front slider 17.

As shown in FIGS. 10 and 11, the first arm 37 grips the second cam 31B at two locations: grip portions 37c1 and 37c2. The rotation of the second cam 31B causes the first arm 37 to rotate about the rotation fulcrum 37a.

As shown in FIG. 10, a thrust stopper member 60 is attached to the first arm 37 as a regulating member and a stopper member. The thrust stopper member 60 has an abutting part 60a and a regulating part 60b as a stopper part.

By bringing the contact portion 60a into contact with the rotational fulcrum 37a of the first arm 37 from above in FIG. 10, it functions as a prevention for the rotational fulcrum 37a to come off against the front slider 17. Note that FIG. 11 is a diagram with the thrust stopper member 60 removed.

The thrust stopper member 60 also contacts the rotation fulcrum 37a from below in FIG. 10, and also prevents the thrust stopper from coming off in the downward direction in FIG. The regulating portion 60b of the thrust stopper member 60 is a surface provided along the outer peripheral surface of an outer ring provided on the second cam 31B, which is a bearing.

By regulating the position of the outer circumferential surface of the second cam 31B by the regulating portion 60b, it is possible to regulate the direction of relative movement of the first arm 37 with respect to the second cam 31B. In other words, it is possible to prevent the first arm 37 from moving in a direction other than the direction along the outer peripheral surface of the second cam 31B, for example, in a sliding direction with respect to the second cam 31B. Therefore, it is possible to prevent positional deviation such as inclination of the first arm 37 with respect to the second cam 31B, and it is possible to prevent wear of the gripping portions 37c1 and 37c2.

In this embodiment, the contact portion 60a that functions as a stopper for the first arm 37 against the front slider 17 and the restriction portion 60b that restricts the direction of relative movement of the first arm 37 with respect to the second cam 31B are formed by a common thrust stopper member. 60, the number of parts of the transfer device can be reduced. However, these may be provided on separate members.

FIG. 12 is a front perspective view of the periphery of the first arm 37 and the second arm 38. FIG. 13 is a perspective view of the back side of the first arm 37 and the second arm 38.

As shown in FIG. 12, the second arm 38 serving as the second link member has another elongated hole 38a and another elongated hole 38b at both ends thereof. One end 37b of the first arm 37 is inserted into another long hole 38a.

As shown in FIG. 13, one end 37b of the first arm 37 has a bearing 40. As shown in FIG. The bearing 40 is provided so as to be relatively movable within the other elongated hole 38a. The bearing 40 is another insertion part for the other elongated hole 38a.

The bearing 40 is provided with a parallel pin 40a as a retaining portion on the back side thereof. The length of the parallel pin 40a is set shorter than the length of the other elongated hole 38a in the longitudinal direction.

By arranging the parallel pin 40a substantially parallel to the longitudinal direction of the other elongated hole 38a, the bearing 40 can be inserted into the other elongated hole 38a. In the state shown in FIG. 13, the parallel pin 40a functions as a retainer for the other long hole 38a of the bearing 40.

As shown in FIG. 12, a bearing 41 is inserted into the long hole 38b. The bearing 41 is fixed to a first sensor bracket 43 as a holding member by a step screw 42.

The bearing 41 is provided so as to be movable within the elongated hole 38b. The bearing 41 is an insertion portion into the elongated hole 38b.

The rotation of the cam member 31 moves the front slider 17 to the right from the state shown in FIG. 7A, and the rotation of the second cam 31B causes the first arm 37 to rotate counterclockwise about the rotation fulcrum 37a. As a result, the tip of the first arm 37 moves upward as shown in FIG. 7A⇒FIG. 7B.

This moves the second arm 38 to the upper right as shown in FIG. 7B. As a result, the bearing 41 moves relatively to one end of the elongated hole 38b and comes into contact with a wall portion forming the elongated hole 38b. Then, the second arm 38 pulls the first sensor bracket 43 toward the lower left as shown in FIG. 7B.

FIG. 14 is a diagram showing the configuration around the first sensor bracket 43 and the detection sensor 22, and is a diagram with the rotating member 21 removed from FIG. 7A and the like. In FIG. 14, the detection sensor 22 and the second sensor bracket 44 are illustrated in a simplified manner for convenience.

As shown in FIG. 14, the first sensor bracket 43 is rotatably provided around a rotation fulcrum 43a. The first sensor bracket 43 receives a force from a spring 45 fixed to the casing of the image forming apparatus 1 in a direction that causes it to rotate counterclockwise in FIG. 14 about the rotation fulcrum 43a.

Further, a regulating member 63 is fixed to the first sensor bracket 43. The pin 17d of the front slider 17 is inserted into the hole 63a of the regulating member 63. In the "contact" state in FIG. 7A and the "separated" state in FIG. A force is applied to rotate clockwise in FIG. 14 about the fulcrum 43a.

A second sensor bracket 44 is fixed to the first sensor bracket 43 via a stud 43b provided on the first sensor bracket 43. The second sensor bracket 44 holds the detection sensor 22. As shown in FIG. 14, the second sensor bracket 44 includes a hook 44a to which one end of the spring 62 (see FIGS. 7A and 7B) is attached, a first contact portion 44b, and a second contact portion 44c.

In the "contact" state of FIG. 7A, the second sensor bracket 44 is biased by the spring 62 and moves in a clockwise direction around the rotation fulcrum 43a, and the first contact portion 44b It is positioned at a position where it comes into contact with a stud 64 provided on the casing of the image forming apparatus 1 .

On the other hand, in the "separated" state of FIG. 7B, the pin 17d provided on the front slider 17 moves to the right side compared to FIG. 7A, so that the first sensor bracket 43, the second sensor bracket 44, and the detection sensor 22 Due to its own weight and the urging force of the spring 45, it receives a force to rotate counterclockwise around the rotation fulcrum 43a. Further, the pin 43c provided on the first sensor bracket 43 shown in FIG. 15 presses the bent portion 44d of the second sensor bracket 44, and the second sensor bracket 44 rotates counterclockwise in FIG. 7B around the rotational fulcrum 43a. receive the power to

As a result, the first sensor bracket 43, the second sensor bracket 44, and the detection sensor 22 rotate counterclockwise in FIG. 7B and move downward in FIG. 7B, which is a direction farther away from the photoreceptor 3 than in FIG. 7A. Note that FIG. 15 is a perspective view showing the first sensor bracket 43 and the second sensor bracket 44 on the back side of the page in FIG. 7B.

In addition, in the "separated" state of FIG. 7B, the pin 17d further moves to the right, and as shown in FIG. 14, the force with which the pin 17d presses the regulating member 63 to the left in FIG. 14 is released. At the same time, as described above, the second arm 38 pulls the first sensor bracket 43 toward the lower left in FIG. 14, so that the first sensor bracket 43 rotates clockwise in FIG. 14 about the rotational fulcrum 43a. As a result, the second sensor bracket 44 fixed to the first sensor bracket 43 via the stud 43b moves upward in FIG. 14, and the detection sensor 22 also moves upward in FIG. 14.

At this time, as shown in FIG. 16, the second sensor bracket 44 is positioned at a position where the second contact part 44c of the second sensor bracket 44 contacts the positioning part 21b of the rotating member 21. That is, upward movement of the second sensor bracket 44 and the detection sensor 22 in FIG. 14 is restricted, and the detection sensor 22 is positioned.

In this way, by transmitting the driving force of the cam member 31 to the first sensor bracket 43 via the link members such as the first arm 37 and the second arm 38, and rotating the first sensor bracket 43, The first sensor bracket 43 can be rotated in a desired direction.

The number of link members connected to the first sensor bracket 43 holding the detection sensor 22 is not limited to two as in this embodiment. There may be three or more or one.

Further, the combination of the elongated hole and the member for providing the insertion member such as the pin inserted therein may be reversed. Furthermore, it is not necessary to operate all of the detection sensor 22, primary transfer roller 19-1, and driven rollers 21A and 33A by the driving force of the motor.

As described above, in this embodiment, the front slider 17 can be moved in the left-right direction in FIG. 7A by the rotation of the first cam 31A shown in FIG. 9, and each primary transfer roller 7 and the driven roller can be moved. Further, the detection sensor 22 can be moved by rotating the first cam 31A and the second cam 31B.

Specifically, in the "contact" state in FIG. 7A and the "separated" state in FIG. The position of the detection sensor 22 can be changed by applying a force in the direction of rotation. In the "separated" state, the first sensor bracket 43 is drawn into the second arm 38 by the rotation of the second cam 31B, so that the position of the detection sensor 22 can be changed.

(●Operation lever)
The operating lever 16 has a disc-shaped main body portion 16b as shown in FIGS. 8A and 8B. The center of the disc-shaped main body portion 16b is connected to the rotating shaft 14. A knob portion 16a is formed on the front side of the main body portion 16b so as to overlap with an extension line of the rotating shaft 14.

The knob portion 16a extends linearly from near the center of the main body portion 16b to the outer periphery in the radial direction. That is, the knob portion 16a extends linearly from near the center of the main body portion 16b (near the rotating shaft 14) to the outer periphery in the radial direction in one direction (the direction marked with △ in FIGS. 8A and 8B), and in the opposite direction. It extends shorter in a straight line with different lengths (about half the length of the longer one).

In this way, since the grip portion 16a extends linearly across the extension line of the rotating shaft 14, the force F can be applied to both ends of the grip portion 16a in opposite directions. Therefore, the force F can be dispersed and the knob portion 16a can be easily rotated.

Concave portions 16e are formed on both side surfaces of the knob portion 16a on one side (the side marked with △) and on the opposite side. On one side, three (six on both sides) recesses 16e are formed at equal intervals in the longitudinal direction, and on the opposite side, one (two on both sides) recesses 16e are formed. These recesses 16e prevent the fingers holding the knob 16a from slipping, and allow the force F to be efficiently applied to the knob 16a.

The main body portion 16b is formed lower than the height of the knob portion 16a. A stepped portion 16c is formed on the outer periphery of the main body portion 16b, and the entire periphery of this stepped portion 16c is covered with the front cover 20-1 of the transfer unit 20. Thereby, the internal mechanism inside the front cover 20-1 cannot be seen at all from the front side or even from an oblique direction to the front. Further, since the entire circumference of the stepped portion 16c is covered with the front cover 20-1, even if the screw between the operating lever 16 and the rotating shaft 14 becomes loose, the operating lever 16 will not fall off.

Furthermore, a notch 20-2 is formed in the front cover 20-1. The operating lever 16 is exposed on the left side of this notch 20-2. The notch 20-2 has an obtuse V-shape, and when the knob 16a is rotated to the first switching position indicated by the solid line and the second switching position indicated by the chain line in FIG. 8B, the finger holding the knob 16a will touch the front cover. It is made so as not to interfere with the notch 20-2 of 20-1.

That is, at the first switching position and the second switching position, the two sides of the V-shape of the notch 20-2 are substantially parallel to the knob 16a. The knob portion 16a cannot be rotated further to the right than the first switching position, and cannot be rotated further to the left than the second switching position. By thus limiting the rotation range of the knob 16a, it is possible to prevent fingers from being caught in the notch 20-2 when rotating the knob 16a.

The operating force of the operating lever 16 is lighter than that of the operating lever of the transfer device of Patent Document 1 (manual lever 549 in FIG. 14). In the transfer device disclosed in Patent Document 1, a single operating lever is used to raise and lower a plurality of transfer rollers and a plurality of belt pressing members. Therefore, large force is required to operate the operating lever. Further, it is necessary to take measures such as making the material of the cam, etc. used in the contact/separation mechanism a strong metal.

In contrast, in this embodiment, the driven roller 33A that stretches the downstream end of the intermediate transfer belt 2 is raised and lowered by the operation lever 16, but the other rollers (the first transfer roller 19-1, the driven roller 21A, the second transfer roller 19-2 at the right end is moved up and down by a motor-driven cam member 31. Therefore, the operating lever 16 can be operated with a light force, and costs can be reduced by using a material other than metal, such as resin, for the cam, etc. used in the contact/separation mechanism.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention. For example, in the embodiment described above, all of the belt pressers 1-1 to 1-4, the PCDU presses 4-1 and 4-2, and the approaching/separating mechanism can be operated by rotating the operation lever 16. One may be made actuable by rotating the operating lever 16. Further, the present invention relates to a device other than a transfer device, which has two units adjacent to each other and at least one of the two units is removably disposed, with a presser that prevents the unit from being detached. It is applicable to prevent erroneous operation of the operating member that operates the member.

In addition to paper (plain paper), sheet materials include cardboard, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheets, plastic films, prepregs, copper foil, etc. included. Further, the functional member on the transfer unit is not limited to the PCDU, and various functional members capable of performing arbitrary treatments on the sheet member can be applied.

<Additional notes>
Hereinafter, preferred embodiments of the present invention will be additionally described.
<First aspect>
A transfer unit that includes a belt member that conveys a sheet member, and a first pressing member that suppresses warping of a widthwise end portion of the belt member, and is removably disposed in the width direction of the belt member with respect to the apparatus main body. and is arranged to be removably attached to the apparatus main body in the width direction of the belt member in a state adjacent to the belt member of the transfer unit, and configured to be non-removable from the apparatus main body by a second pressing member. In the transfer device including a functional member and a contact/separation mechanism for bringing the transfer unit and the functional member into contact with each other, at least one of the first pressing member, the second pressing member, and the contact/separation mechanism is configured to control the operation member. The operating member is actuated by a rotational operation, and the operating member is rotationally biased in a predetermined direction by a biasing means, and the operating member is rotated by a predetermined angle against the biasing means. A transfer device characterized in that it can be held at the predetermined angle.
<Second aspect>
The transfer device according to the first aspect, wherein the functional member is configured to be detachable while the operating member is held at the predetermined angle.
<Third aspect>
The first pressing member, the second pressing member, and the approaching/separating mechanism are actuated by rotating the operating member, and the first pressing member suppresses warping of the widthwise end portion of the belt member. The second pressing member is configured to be movable between an operating position and a non-operating position spaced apart from a widthwise end of the belt member, and the second pressing member is in an operating position where the functional member cannot be removed and a non-operating position where the functional member is detachable. The first presser member is configured to be movable, and when the operating member is held at the predetermined angle, the first presser member is held at the operating position to suppress warping of the widthwise end portion of the belt member, and the second presser member is The transfer device according to the first or second aspect, wherein the member is held in the non-operating position so that the functional member can be removed.
<Fourth aspect>
The transfer according to any one of the first to third aspects, wherein the operating member has a disc-shaped main body, and the entire circumference of the main body is covered with a front cover of the transfer unit. Device.
<Fifth aspect>
The operating member is held at the predetermined angle by a frictional force between a cam connected to the center of the disc-shaped main body of the operating member via a rotating shaft and a cam follower in contact with the cam. A transfer device according to a fourth aspect.
<Sixth aspect>
The disc-shaped main body of the operating member has a knob extending in the radial direction of the main body, and the knob extends in one direction and the opposite direction from the center of the disc-shaped main body. The transfer device according to the fourth aspect, characterized in that the transfer device extends at different lengths.
<Seventh aspect>
The transfer device according to the sixth aspect, wherein a recess is formed in the knob.
<Eighth aspect>
The transfer device according to any one of the fourth to sixth aspects, wherein the front cover has a V-shaped notch, and the operating member is partially exposed in the notch. .
<9th aspect>
The rotational operation range of the knob part is restricted between a first switching position and a second switching position, and the knob part is parallel to the V-shaped notch part in the first switching position and the second switching position. The transfer device according to the eighth aspect.
<10th aspect>
In a device having two units adjacent to each other, at least one of the two units being removably disposed, a holding member is disposed that makes the at least one unit unremovable from the device, The pressing member is actuated by the rotation of the operating member that is rotationally biased in a predetermined direction by the biasing means, and by rotating the operating member by a predetermined angle against the biasing means, A device characterized in that the operating member can be held at the predetermined angle.
<Eleventh aspect>
The apparatus according to the tenth aspect, wherein the at least one unit is configured to be detachable while the operating member is held at the predetermined angle.
<Twelfth aspect>
The device according to the tenth or eleventh aspect, wherein the operating member has a disc-shaped main body, and the entire circumference of the main body is covered with a front cover of the device.
<13th aspect>
The operating member is held at the predetermined angle by a frictional force between a cam connected to the center of the disc-shaped main body of the operating member via a rotating shaft and a cam follower in contact with the cam. The device according to the twelfth aspect.
<Fourteenth aspect>
The disc-shaped main body of the operating member has a knob extending in the radial direction of the main body, and the knob extends in one direction and the opposite direction from the center of the disc-shaped main body. The device of the twelfth aspect, characterized in that it extends at different lengths.
<15th aspect>
The device according to the fourteenth aspect, characterized in that a recess is formed in the knob.
<16th aspect>
The device according to any one of the twelfth to fifteenth aspects, wherein the front cover has a V-shaped notch, and the operating member is partially exposed in the notch.
<17th aspect>
The rotational operation range of the knob part is restricted between a first switching position and a second switching position, and the knob part is parallel to the V-shaped notch part in the first switching position and the second switching position. The apparatus according to the sixteenth aspect, characterized in that:

1: Image forming device 1-1 to 1-4: Belt presser (first presser member)
1-3-1: Hard plate-shaped part 1-3-2: Soft felt part 1-3-3: Rotating part (cam groove) 1A: Image forming part 1B: Paper feeding part 1B1: Paper feeding cassette 1B2: Conveying roller 1C: Document scanning unit 1C1: Document mounting table 1C2: Scanner 1C3: Automatic document feeder 2: Intermediate transfer belt 2: Intermediate transfer belt (belt member) 2-1 to 2-5: PCDU (functional member)
2A to 2C: Roller 3K, 3Y, 3M, 3C, 3T: Photoreceptor
4-1, 4-2: PCDU holding member (second holding member) 4-1-1, 4-2-1: Long hole
4-1-2, 4-2-2: Pin 4-1-3: Retaining pin 5: Writing device 5-2: Slider 5-2-1: Pin 5-2-2: Cam follower 5-2-3 : Tension spring 6: Developing device 7: Primary transfer roller 7-1, 7-2: Cam 8: Connection shaft 8-1, 8-2: Fixed pin 9: Secondary transfer device 9A: Secondary transfer roller 9a: Pin 10K, 10Y, 10M, 10C, 10T: Image forming section 11: Fixing device 11a, 12a: Pin 13: Paper ejection section 14: Rotating shaft 14-1: Cam 15: Long hole 16: Operation lever (operation member) 16a: Knob section 16b: Main body section 16c: Step section 16d: Shaft section 16e: Recessed section 17: Front slider 17a: Insertion section 17b to 17d: Pin 18: Spring 19-1: Primary transfer roller 20: Transfer unit 20-1: Front cover 20-1-1: First front cover 20-1-2: Second front cover 20-1-3: Front cover 20-2: Notch portion 21: Rotating member 21A, 33A: Followed roller 21a: Rotation fulcrum 21b : Positioning part 22: Detection sensor 22a: Holding part 23: Cam follower 31: Cam member 31a: Rotating shaft 33: Rotating member 33A: Followed roller 33a: Rotating fulcrum 33b: Hole 34: Rotating member 34a: Rotating fulcrum 34b: Hole 35: Spring 36: Cam follower 37: First arm 37a: Rotation fulcrum 37b: One end 37c1, 37c2: Grip portion 38: Second arm 38a, 38b: Long hole 39: Spring 40: Bearing 40a: Parallel pin 41: Bearing 42: Step screw 43a: Rotation fulcrum 43b: Stud 43c: Pin 44a: Hook 44d: Bending portion 45: Spring 50: Tension spring (biasing means) 60: Thrust stop member 60a: Contact portion 60b: Regulation portion 62: Spring 63: Regulating member 63a: Hole 64: Stud RP: Reversing conveyance path

Patent No. 6394151

Claims (17)

A transfer unit that includes a belt member that conveys a sheet member, and a first pressing member that suppresses warping of a widthwise end portion of the belt member, and is removably disposed in the width direction of the belt member with respect to the apparatus main body. and,
a functional member that is arranged adjacent to the belt member of the transfer unit so as to be removable from the apparatus main body in the width direction of the belt member, and configured to be non-removable from the apparatus main body by a second pressing member; and,
A transfer device including a contact/separation mechanism that brings the transfer unit and the functional member into contact with and separate from each other,
At least one of the first pressing member, the second pressing member, and the approaching/separating mechanism is actuated by a rotational operation of an operating member, and the operating member is rotationally biased in a predetermined direction by a biasing means, A transfer device characterized in that the operating member can be held at the predetermined angle by rotating the operating member at a predetermined angle against the urging means. 2. The transfer device according to claim 1, wherein the functional member is configured to be detachable while the operating member is held at the predetermined angle. The first pressing member, the second pressing member, and the approaching/separating mechanism are actuable by a rotational operation of the operating member,
The first pressing member is configured to be movable between an operating position for suppressing warping of the widthwise end portion of the belt member and a non-operating position spaced apart from the widthwise end portion of the belt member,
The second pressing member is configured to be movable between an activated position where the functional member cannot be removed and a non-activated position where the functional member is made separable;
With the operating member held at the predetermined angle, the first pressing member is held at the operating position to suppress warping of the widthwise end portion of the belt member, and the second pressing member is held at the non-operating position. 2. The transfer device according to claim 1, wherein the functional member is held in place so that the functional member can be removed. 2. The transfer device according to claim 1, wherein the operating member has a disc-shaped main body, and the entire circumference of the main body is covered with a front cover of the transfer unit. The operating member is held at the predetermined angle by a frictional force between a cam connected to the center of the disc-shaped main body of the operating member via a rotating shaft and a cam follower in contact with the cam. 5. The transfer device according to claim 4, characterized in that: The disc-shaped main body of the operating member has a knob extending in the radial direction of the main body, and the knob extends in one direction and the opposite direction from the center of the disc-shaped main body. 5. Transfer device according to claim 4, characterized in that the transfer device extends in different lengths. 7. The transfer device according to claim 6, wherein a recess is formed in the knob. 7. The transfer device according to claim 6, wherein the front cover has a V-shaped notch, and the operating member is partially exposed in the notch. The rotational operation range of the knob part is restricted between a first switching position and a second switching position, and the knob part is parallel to the V-shaped notch part in the first switching position and the second switching position. 9. The transfer device according to claim 8, characterized in that: In a device having two units adjacent to each other, at least one of the two units being removably installed,
A holding member is provided that makes it impossible to remove the at least one unit from the device,
The pressing member is actuable by rotation of an operating member that is rotationally biased in a predetermined direction by a biasing means,
An apparatus characterized in that the operating member can be held at the predetermined angle by rotating the operating member by a predetermined angle against the biasing means. 11. The apparatus of claim 10, wherein the at least one unit is configured to be removable while the operating member is held at the predetermined angle. 11. The apparatus according to claim 10, wherein the operating member has a disc-shaped main body, and the entire circumference of the main body is covered with a front cover of the apparatus. The operating member is held at the predetermined angle by a frictional force between a cam connected to the center of the disc-shaped main body of the operating member via a rotating shaft and a cam follower in contact with the cam. 13. The apparatus of claim 12. The disc-shaped main body of the operating member has a knob extending in the radial direction of the main body, and the knob extends in one direction and the opposite direction from the center of the disc-shaped main body. 13. Device according to claim 12, characterized in that it extends in different lengths. 15. The device according to claim 14, wherein said knob portion has a recess formed therein. 13. The apparatus according to claim 12, wherein the front cover has a V-shaped notch, and the operating member is partially exposed in the notch. The rotational operation range of the knob part is restricted between a first switching position and a second switching position, and the knob part is parallel to the V-shaped notch part in the first switching position and the second switching position. 17. The device of claim 16.

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