JP2012171766A - Image forming apparatus - Google Patents

Abstract

In an image forming apparatus of an ink jet system that requires a conveyance stop operation of a conveyance belt at the time of image printing, a drive coupling configuration that allows the conveyance belt unit to be attached / detached / replaced more easily and driving generated at the time of attachment / detachment / replacement are provided. Prevents the paper stop position accuracy from being lowered due to backlash.
A gear 101 provided on a conveyor belt unit 115 that can be attached to and detached from the apparatus main body 1 and an apparatus drive that meshes with the gear 101 when the conveyor belt unit 115 is attached to the apparatus main body 1 and constitutes a gear connecting portion. An idler gear 102 provided in the system, a motor 113 connected to the idler gear 102 and capable of rotating forward and backward, and the idler gear 102 mesh with the gear 101 when the conveyor belt unit 115 is mounted on the apparatus main body 1. A swinging mechanism 110 that pressurizes and displaces by pressing with a constant force in the direction, and a control unit 121 that controls the motor 113 to remove backlash generated in the gear connecting portion are provided.
[Selection] Figure 5

Description

  The present invention relates to an image forming apparatus. More specifically, the present invention relates to a conveyance belt that conveys a sheet, and is disposed so as to face the conveyance belt, and is scanned in a main scanning direction orthogonal to the sheet conveyance direction to eject ink onto the sheet. The present invention relates to an ink jet image forming apparatus that includes a recording head that prints an image, requires a transport stop operation of the transport belt during image printing, and intermittently performs the transport operation of the transport belt.

The recording head that forms an image by ejecting ink onto the sheet is scanned in the main scanning direction orthogonal to the sheet conveying direction, and the conveyance stop operation of the sheet (hereinafter represented by the “paper” example) is required during image printing. In order to improve maintenance and assemblability, at least two rollers in an ink jet type image forming apparatus called a serial type in which conveyance of a conveyance belt that holds and conveys a sheet is intermittently performed. In some cases, a conveyor belt that is hung between (rotating members) is integrated with a roller so as to be configured as a conveyor belt unit that can be attached to and detached from the apparatus main body.
In the ink jet type image forming apparatus provided with such a conveyor belt unit, when a gear-to-gear connection structure is used as a drive connection structure with a main body drive system on the apparatus main body side, an intermittent drive operation is performed. The backlash of the drive system such as backlash that occurs sometimes greatly affects the paper stop position accuracy, leading to a decrease in image quality. For this reason, a drive transmission configuration using a timing belt that does not generate backlash and is suitable for precision driving of the transport belt is generally widely used (see, for example, Patent Documents 1 and 2).

  As a general drive transmission configuration using a timing belt, there is a configuration in which drive from a motor as a drive source is transmitted to a transport roller (drive roller) on the upstream side of the transport belt unit by a timing belt. Can be mentioned. Further, the drive transmission on the downstream side (paper discharge side) is supported by an elastic body on the downstream side of the conveyor belt unit via the conveyor belt, and the conveyor belt tension roller (driven) is responsible for keeping the tension of the conveyor belt constant. Roller) and connected to a paper discharge roller disposed further downstream by a timing belt to transmit driving.

However, in the drive transmission configuration provided with the timing belt described above, when the transport belt unit is attached / detached / replaced, it is essential to attach / detach the timing belt of the drive connecting unit, and tension management of the timing belt before and after the attachment / detachment is a problem. It is done. Further, the variation in the tension of the timing belt has a great influence on the sheet stop control.
Further, the drive connection configuration has a problem that the number of replacement work accompanying the replacement of the conveyor belt unit is increased, and the serviceability may be deteriorated due to an increase in downtime at the customer site.

In order to eliminate the problems in the case of using the timing belt and to make it possible to easily attach and detach (replace) the conveyor belt unit, the drive between the conveyor belt unit and the main body drive train (main body drive system) It is preferable to use a gear for the connecting portion. In that case, in addition to problems such as backlash between the gears, which is a concern in drive connection between gears, and drive play due to positional shift of the gear connection part, the gear connection part of the gear connection part that occurs when the conveyor belt unit is attached / detached / replaced The variation in the distance between the shafts of the gears is cited as a problem, and if both bite too much, there is a risk of causing mutual wear and damage of the gears. Conversely, if the two are too far apart, there is a risk of driving force transmission being insufficient.
In addition, the backlash between the gears at the gear connecting portion described above, and the drive play due to the positional shift of the gear connecting portion, the paper stopping control of returning to the target paper stopping position by repeating a minute forward / reverse operation when the paper stops. There is a possibility that the target value is not determined and the paper stop position accuracy is lowered.

  Note that in the field of electrophotographic image forming apparatuses, driving is performed for the purpose of providing an image forming apparatus capable of releasing the driving connection of the sheet conveying means with a simple operation and capable of performing a processing operation such as jamming very easily. A sheet conveying unit having a driving roller body to which driving is transmitted via a transmission gear, interlocking with opening / closing of an opening / closing member provided in the main body of the image forming apparatus, releasing drive connection, and the opening / closing member A technique having a drive contact / separation mechanism for returning drive connection when closed is disclosed (for example, see Patent Document 3).

  However, the technique described in Patent Document 3 is a drive configuration on the premise that it is continuously driven in one direction, and an image of an ink jet system that requires intermittent drive of a conveyance belt with paper stop at the time of image printing. Even if the technique described in Patent Document 3 is applied to the forming apparatus, the problem that the stop position varies due to backlash between drive gears in the vicinity of the paper stop position cannot be solved.

The present invention has been made in view of the above-described problems and circumstances, and requires an operation for stopping conveyance of the conveyance belt during image printing, and an inkjet image in which conveyance of the conveyance belt holding a sheet is intermittently performed. In the forming device, in order to improve maintenance and assembling, it is possible to make it easy to attach and detach / replace the conveyor belt unit. The main purpose is to prevent decline.
Specifically, firstly, the transport belt unit and the drive system of the main body are driven by gears, and a mechanism for keeping the distance between the shafts of both gears constant is provided, so that the transport belt unit can be connected at the time of attachment / detachment / replacement. It is to prevent the backlash of the part.
Secondly, by using the paper stop control in consideration of the influence of the backlash and backlash between the gears generated by the gear drive, the target value of the paper stop position is not determined by the backlash and backlash between the gear connecting portions. This is to prevent the sheet stop position accuracy from being lowered.

In order to solve the above-described problems and achieve the above-mentioned object, the invention according to each claim employs the following characteristic means / invention-specific matters (hereinafter referred to as “configuration”).
According to the first aspect of the present invention, a main belt scanning direction that is wound around at least two rotating members and is circulated and conveys a sheet, and is disposed to face the conveying belt and is orthogonal to the sheet conveying direction. And a recording head that prints an image by ejecting ink onto a sheet, and requires an operation of stopping the conveyance of the conveyance belt during image printing, and the conveyance operation of the conveyance belt is intermittently performed. In the image forming apparatus of the type, the at least two rotating members and the conveying belt are integrated, and the conveying belt unit is configured to be detachable from the apparatus main body, and the rotating member of the conveying belt unit is provided on the rotating member. The first gear and the device that meshes with the first gear and constitutes a gear connecting portion when the conveyor belt unit is mounted on the apparatus main body. A second gear provided in a main body drive system on the main body side, a drive means capable of rotating in the forward and reverse directions, and the second gear when the transport belt unit is mounted; Displacement means that pressurizes and displaces with a certain force in a direction to mesh with one gear, transport amount detection means that detects the transport amount of the transport belt, and when the transport belt unit is mounted, the transport amount Based on a signal from the detection means, a deviation between the rotation amount of the drive means and the conveyance amount of the conveyance belt is detected, and a calculation means for calculating the deviation as a correction constant, and during a sheet stop operation during the image printing In order to remove the backlash generated in the gear connecting portion when the sheet is conveyed more than the target sheet stop position, the driving means is used to reverse the rotation amount taking the correction constant into account, and then again. It and a control means for causing the sheet stop control for driving the rolling direction is an image forming apparatus according to claim.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, each of the first gear and the second gear has a constant distance between the centers of the gear shafts and is formed of a conical gear. The at least one gear is configured to be slidable in the gear axis direction, and is pressurized with a constant force in the gear axis direction by the pressurizing means.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the image forming apparatus further includes a rotation amount detection unit that detects a rotation amount of the drive unit, and the calculation unit includes the conveyance amount detection unit and the rotation. Based on each signal from the amount detection means, a deviation between the rotation amount of the driving means and the conveyance amount of the conveyance belt is detected, and a correction constant is calculated.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, when the correction constant is calculated, the control unit operates not only in one direction of forward / reverse rotation but also in two directions of forward / reverse rotation. An image forming apparatus characterized by performing the accompanying control.
According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect, the deviation is repeatedly detected by the computing unit and the correction constant is repeatedly calculated during the sheet feed conveyance operation by the conveyance belt. Is fed back to the line feed amount of the next line feed.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the transport amount detection means includes a linear encoder provided on the surface of the transport belt, and the linear encoder. A linear encoder sensor that detects a conveyance amount, and based on a signal from the linear encoder sensor, the calculation unit detects a deviation between the rotation amount of the driving unit and the conveyance amount of the conveyance belt, and calculates the deviation. The correction means feeds back to the driving means.

According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, as the linear encoder, fine black and white stripes or slit holes at equal intervals corresponding to image resolution are provided on the surface of the conveying belt. Features.
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the operation of detecting the deviation is periodically performed, and the correction constant is rewritten automatically or by a user operation. It is characterized by implementing by.

  According to the present invention, the above configuration can realize and provide a novel image forming apparatus that solves the above problems. That is, according to the present invention, the conveyor belt unit and the main body drive system are driven and connected by a gear, and the displacement means for keeping the distance between the shafts of both gears constant is provided, so that the conveyor belt unit can be attached and detached more easily. The ease of maintenance improves the ease of maintenance and assembly, as well as the ability to prevent backlash at the gear connection when attaching / detaching or replacing the conveyor belt unit. By having a seat stop control configuration that takes into account the effects of drive play and backlash in advance, the target value of the seat stop position cannot be determined due to drive play or backlash between the gear connecting parts, so that the seat stop position accuracy is reduced. It can be prevented in advance.

1 is an external perspective view of an inkjet recording apparatus as an inkjet image forming apparatus to which the present invention is applied, as viewed from the front. It is a typical side view of the main mechanism part of the ink jet recording apparatus. It is a top view of the principal part of the inkjet recording device. It is a top view around the drive transmission mechanism of the conveyance belt in 1st Embodiment. It is a figure explaining the attachment / detachment mechanism of a conveyance belt unit, (a) is the state in which the conveyance belt unit was attached to the apparatus main body, (b) is the state in which the conveyance belt unit was removed from the apparatus main body, It is a left view showing each. It is a top view explaining the rocking | fluctuation mechanism of 1st Embodiment. It is a side view of the rocking | fluctuation mechanism of FIG. (A) is a block diagram illustrating a control configuration of the first embodiment, and (b) is an explanatory diagram illustrating an example of input and output values of a motor and a conveyor belt. It is a top view explaining the rocking | fluctuation mechanism of 2nd Embodiment. (A) is a block diagram showing a control configuration of the third embodiment, and (b) is a diagram showing an example of input / output values of a motor and a conveyor belt. (A) is a block diagram which shows the control structure of 4th Embodiment, (b) is a figure which shows an example of the input-output value etc. of a motor and a conveyance belt. (A) is a block diagram which shows the control structure of 5th Embodiment, (b) is a figure which shows an example of the input-output value etc. of a motor and a conveyance belt. (A) is a top view around the drive transmission mechanism of the conveyance belt in 6th Embodiment, (b) is an enlarged view of the principal part of (a) explaining the arrangement | positioning location of a linear encoder and a sensor.

  Hereinafter, embodiments of the present invention including examples will be described in detail with reference to the drawings. In each embodiment and each modification, etc., components (members, components, etc.) having the same function, shape, etc. will be described by giving the same reference numerals after having been described once unless there is a possibility of confusion. Is omitted. In order to simplify the drawings and the description, even if the components are to be represented in the drawings, the components that do not need to be specifically described in the drawings may be omitted as appropriate. When quoting and explaining constituent elements such as published patent gazettes, the reference numerals are shown in parentheses to distinguish them from those of the embodiments.

  First, an overall configuration and operation of an ink jet recording apparatus as an example of an ink jet image forming apparatus to which an embodiment described later of the present invention is applied will be described with reference to FIGS. FIG. 1 is an external perspective view of an ink jet recording apparatus to which the present invention is applied, as viewed from the front, FIG. 2 is a schematic side view of main mechanisms of the ink jet recording apparatus, and FIG. It is a top view of the principal part.

The ink jet recording apparatus shown in FIGS. 1 to 3 is a so-called serial type ink jet recording apparatus. The ink jet recording apparatus shown in FIG. 1 has an apparatus main body 1, a paper feed tray 2 for loading paper sheets mounted on the apparatus main body 1, and a detachable attachment to the apparatus main body 1 to record images. A paper discharge tray 3 for stocking the formed paper is provided.
A cartridge loading unit 4 for loading an ink cartridge that protrudes from the front side to the front side of the apparatus main body 1 and is lower than the upper surface, on one end side of the front side of the apparatus main body 1 (side of the paper supply / discharge tray section). The upper surface of the cartridge loading unit 4 is an operation / display unit 5 provided with operation buttons and a display.

The front side of the cartridge loading unit 4 contains recording liquids (inks) that are different color materials, such as black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink, respectively. Ink cartridges 10k, 10c, 10m, and 10y (hereinafter referred to as “ink cartridge 10” when the colors are not distinguished) as recording liquid cartridges as a plurality of recording liquid storage units are moved from the front side of the apparatus main body 1 to the rear side. A front cover (cartridge cover) 6 that is opened when the ink cartridge 10 is attached or detached is provided so as to be openable and closable.
The ink cartridges 10k, 10c, 10m, and 10y are configured to be loaded side by side in the vertical direction.

  In the operation / display unit 5, the remaining amounts of the ink cartridges 10k, 10c, 10m, and 10y for each color are near-end at the placement positions corresponding to the placement positions (placement positions) of the ink cartridges 10k, 10c, 10m, and 10y for each color. A remaining amount display section for each color for displaying the end of the color is arranged. The operation / display unit 5 is also provided with a power button, a paper feed / print resume button, a cancel button, and the like.

  The left and right side plates 21A and 21B shown in FIG. 3 that constitute the frame 21 that forms the framework of the apparatus main body 1 of FIG. 1 are provided with guide rods 31 that are horizontal guide members and stays 32 shown in FIG. Has been. The guide rod 31 and the stay 32 hold the carriage 33 slidably in the main scanning direction, and are moved in the direction indicated by the arrow (carriage main scanning direction) in FIG. 3 via a timing belt by a main scanning motor (not shown). Scan. The left and right side plates 21A and 21B and a later-described rear plate 21C constitute a frame 21.

As described above, the carriage 33 includes a plurality of recording heads 34 including four droplet ejection heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.
As an inkjet head constituting the recording head 34, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a metal phase change caused by a temperature change. A shape memory alloy actuator used, an electrostatic actuator using an electrostatic force, or the like provided as pressure generating means for generating a pressure for discharging a droplet can be used. A driver IC is mounted on the recording head 34 and is connected to a control unit (not shown) via a harness (flexible print cable) 22.

The carriage 33 is mounted with head tanks 35 (shown in FIG. 3 for the head tanks 35a and 35b) for supplying inks of the respective colors to the print head 34 (shown in the print heads 34a and 34b in FIG. 3). is doing. As described above, each color head tank 35 is supplementarily supplied with ink of each color from the ink cartridge 10 of each color mounted in the cartridge loading unit 4 via the ink supply tube 36 of each color.
The cartridge loading unit 4 is provided with a supply pump unit 24 for feeding the ink in the ink cartridge 10, and the ink supply tube 36 is attached to the rear plate 21 </ b> C constituting the frame 21 in the middle of turning. It is held by the locking member 25.

On the other hand, as shown in FIG. 2, the sheets 42 are separated one by one from the sheet stacking section 41 as a sheet feeding section for feeding the sheets 42 stacked on the sheet stacking section (pressure plate) 41 of the sheet feeding tray 2. A half-moon roller (sheet feeding roller) 43 for feeding and a separation pad 44 facing the sheet feeding roller 43 and made of a material having a large friction coefficient are provided. The separation pad 44 is urged toward the paper feed roller 43 side.
In order to feed the paper 42 fed from the paper feeding unit to the lower side of the recording head 34, the paper has a guide member 45 for guiding the paper 42, a counter roller 46, a transport guide member 47, and a tip pressure roller 49. In addition to a pressing member 48, a feeding belt 51, which is a conveying unit for electrostatically attracting the fed paper 42 and conveying it to a position facing the recording head 34, is provided.

The transport belt 51 is an endless belt, and is configured to be looped between a transport roller 52 and a tension roller 53 as at least two rotating members, and to circulate in the belt transport direction (sub-scanning direction). ing.
Further, a charging roller 56 that is a charging unit for charging the surface of the transport belt 51 is provided. The charging roller 56 is disposed so as to come into contact with the surface layer of the transport belt 51 and to rotate following the rotation of the transport belt 51. On the back side of the conveying belt 51, a guide member 57 is arranged corresponding to the printing area by the recording head. The transport belt 51 rotates in the belt transport direction of FIG. 3 when the transport roller 52 is rotationally driven via a timing belt by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 42 recorded by the recording head 34, a separation claw 61 for separating the paper 42 from the conveying belt 51, a paper discharge roller 62 and a paper discharge roller 63, and a discharge A paper discharge tray 3 disposed below the paper roller 62.

  As shown in FIG. 2, a double-sided unit 71 is detachably attached to the apparatus main body 1 of FIG. The duplex unit 71 has a function of taking in the paper 42 returned by the reverse rotation of the conveyance belt 51, reversing it, and feeding it again between the counter roller 46 and the conveyance belt 51. The upper surface of the duplex unit 71 is a manual feed tray 72.

As shown in FIG. 3, a maintenance / recovery mechanism 81 including a recovery means for maintaining and recovering the state of the nozzles of the recording head 34 is disposed in a non-printing area on one side of the carriage 33 in the main scanning direction. .
The maintenance / recovery mechanism 81 includes cap members (hereinafter referred to as “caps”) 82 (hereinafter referred to as “caps”) 82 for capping the nozzle surfaces of the recording head 34. "Cap 82"), a wiper blade 83 which is a blade member for wiping the nozzle surface, and a liquid for performing idle ejection for ejecting liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid An empty discharge receptacle 84 for receiving drops is provided. Here, the cap 82a is a suction and moisture retention cap, and the other caps 82b and the like are moisture retention caps.

The waste liquid of the recording liquid generated by the maintenance and recovery operation by the maintenance and recovery mechanism 81 described above, the ink discharged to the cap 82, the ink attached to the wiper blade 83 and removed by the wiper cleaner (not shown), and the idle ejection receiver 84 The ink ejected empty is discharged and stored in a waste liquid tank (not shown).
Further, as shown in FIG. 3, in the non-printing area on the other side in the main scanning direction of the carriage 33, idle ejection for ejecting liquid droplets that do not contribute to recording is performed in order to discharge the recording liquid thickened during recording. An empty discharge receiver 88 for receiving droplets when performing the operation is disposed, and the empty discharge receiver 88 is provided with an opening 89 along the nozzle row direction of the recording head 34.

Next, the overall operation of the ink jet recording apparatus will be described with reference to FIG.
First, the sheets 42 are separated and fed one by one from the sheet feeding tray 2 by the cooperative action of the sheet feeding roller 43 and the separation pad 44. The sheet 42 fed substantially vertically upward is guided by the guide member 45, is transported while being sandwiched between the transport belt 51 and the counter roller 46, and is further guided at the front end by the transport guide member 47 to press the front end. The roller 49 is pressed against the conveyor belt 51 to change the conveyance direction by approximately 90 °.
At this time, the conveyance belt 52 is rotated in the sub-scanning direction (belt conveyance direction) by rotating the conveyance roller 52 by a sub-scanning motor (not shown). At this time, a charging voltage pattern in which a positive output and a negative output are alternately repeated from the AC bias supply unit of the control unit (not shown) to the charging roller 56, that is, an alternating voltage is applied and the conveying belt 51 alternates. That is, plus and minus are alternately charged in a band shape with a predetermined width in the sub-scanning direction which is the circumferential direction.

When the paper 42 is fed onto the positively and negatively charged conveying belt 51, the paper 42 is attracted to the conveying belt 51, and the paper 42 is moved in the belt conveying direction (sub-scanning direction) by the circular movement of the conveying belt 51. It is conveyed to.
Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are ejected onto the stopped paper 42 to record one line, and after the paper 42 is conveyed by a predetermined amount, Record the next line.
Then, the paper 42 is transported by the transport belt 51 through the rotational drive of the transport roller 52 again. At this time, the separation claw 61 disposed so as to be swingable between the tension roller 53 and the transport roller 52 is provided. Thus, the printed paper 42 separated from the transport belt 51 is transported by a paper discharge roller (spur) 63 driven by a paper discharge roller 62. Upon receiving a recording end signal or a signal that the trailing edge of the paper 42 has reached the recording area, the recording operation is finished and the paper 42 is discharged onto the paper discharge tray 3.

During printing (recording) standby, as shown in FIG. 3, the carriage 33 is moved to the maintenance / recovery mechanism 81 side, the recording head 34 is capped by the cap 82, and the ink is dried by keeping the nozzle in a wet state. Prevents ejection failure due to In addition, the recording head 34 is capped with the cap 82, and the recording liquid is sucked from the nozzles by a suction pump (not shown) (referred to as “nozzle suction” or “head suction”) to recover the thickened recording liquid or bubbles. Perform the action. In addition, an idle ejection operation for ejecting ink not related to recording is performed before the start of recording or during recording. As a result, the stable ejection performance of the recording head 34 is maintained.
It should be noted that the operation during duplex printing performed using the duplex unit 71 is omitted because there is no need for explanation in the present embodiment.

(First embodiment)
The first embodiment of the present invention applied to the ink jet recording apparatus which is the ink jet type image forming apparatus shown in FIGS. 1 to 3 will be described with reference to FIGS.
FIG. 4 is a plan view around the drive transmission mechanism of the conveyance belt in the first embodiment, FIG. 5 is a left side view for explaining the attachment / detachment mechanism of the conveyance belt unit, and FIG. A state where the apparatus is mounted on the apparatus main body, and FIG. 7B shows a state where the conveyor belt unit is detached from the apparatus main body. FIG. 6 is a plan view illustrating the swing mechanism of the first embodiment, FIG. 7 is a side view of the swing mechanism, and FIG. 8 is an example of the control configuration and input / output values of the first embodiment. FIG. In the figure showing the state where the gears are engaged with each other, for simplification of the figure, the tooth tip circle to be shown by a solid line is omitted and the pitch circle diameter to be shown by a one-dot chain line is simply shown by a solid line. It is noted that it is shown in the figure.

As shown in FIG. 5, the transport belt 51, the transport roller 52, and the tension roller 53 are integrated via a unit side plate (not shown), and can be attached to and detached from the apparatus main body 1 in FIG. (Shown by a two-dot chain line). The shaft 52a of the conveying roller 52 and the shaft 53a of the tension roller 53 are rotatably supported on the unit side plate (not shown) via bearings (not shown).
As shown in FIGS. 4 to 6, a gear 101 as a first gear is fixed to the shaft 52 a of the conveyance roller 52 on the conveyance belt unit 115 side. Similarly, a shaft 104a of the tension roller 53 on the conveying belt unit 115 side is fixed with a gear 104 as a first gear.
As shown in FIG. 4, a gear 106 is fixed to the shaft 62 a of the paper discharge roller 62.

On the other hand, the main body drive system on the apparatus main body 1 side includes an idler gear 102 as a second gear that meshes with the gear 101 of the conveying roller 52 and constitutes a gear connecting portion when the conveying belt unit 115 is attached to the apparatus main body 1. A gear 103 meshing with the idler gear 102 and a motor 113 connected to the shaft 103a of the gear 103 are provided.
The motor 113 functions as a drive means capable of rotating in the forward / reverse direction to rotate the idler gear 102 via the gear 103, and is fixed to a non-illustrated immovable member of the apparatus main body 1. For example, a DC motor or a stepping motor driven by pulse input is used as the motor 113. In the present embodiment, a relatively inexpensive DC motor will be described below.

Similarly, the main body drive system on the apparatus main body 1 side includes an idler gear 105 as a second gear that meshes with the gear 104 of the tension roller 53 and constitutes a gear connecting portion when the transport belt unit 115 is attached to the apparatus main body 1. And a gear 106 that meshes with the idler gear 105 is provided.
The shaft 103a of the gear 103 of the main body drive system and the shaft 106a of the gear 106 are connected by a timing belt (not shown) via a toothed pulley (not shown) and have a driving force transmission relationship.

  As described above, the driving force of the motor 113 is transmitted from the motor 113 to the gear 103 (or a configuration in which the gear 103 is on the output shaft of the motor 113 may be used), and on the shaft 52a of the conveying roller 52 via the idler gear 102. , The conveying belt 51 is driven and travels in the belt conveying direction or in the opposite direction. By driving and running the transport belt 51, the driving force of the motor 113 is transmitted to the tension roller 53 on the downstream side in the belt transport direction, and the paper discharge roller 62 passes from the gear 104 on the shaft 53 a of the tension roller 53 through the idler gear 105. Is transmitted to the gear 106 on the shaft 62 a and to the paper discharge roller 62.

As shown in FIG. 4, a rotary encoder 108 is fixed to the shaft 52 a of the transport roller 52. On the other hand, when the conveyor belt unit 115 is mounted on the apparatus main body 1 and occupies the mounting position, an encoder sensor (hereinafter also simply referred to as “sensor”) 107 is fixed to the stationary member of the apparatus main body 1 so as to sandwich the rotary encoder 108. It is installed. The sensor 107 is a light transmission type photosensor. The sensor 107 and the rotary encoder 108 constitute conveyance amount detection means for detecting the conveyance amount of the conveyance belt 51 and are also called pulse encoders.
Since the conveyance amount of the paper 42 that is sucked and held by the conveyance belt 51 and is conveyed is known from the rotation amount of the conveyance roller 52 detected by the rotary encoder 108 and the sensor 107, the conveyance roller detected by the rotary encoder 108 and the sensor 107. By controlling the amount of rotation 52, the conveyance amount of the paper 42 can be determined.

FIG. 5A shows a state in which the transport belt unit 115 is mounted on the apparatus main body 1 from the upper direction to the lower direction and occupies the mounting position. FIG. 5B shows a state in which the conveyor belt unit 115 is detached from the apparatus main body 1 in the upward direction and occupies the separation position. In this embodiment, the attaching / detaching direction of the conveyor belt unit 115 with respect to the apparatus main body 1 is the vertical direction.
When the transport belt unit 115 occupies the mounting position, the gear 101 and the idler gear 102 mesh with each other as described above, and at the same time the gear 104 and the idler gear 105 mesh with each other, and the unit side plate (not shown) of the transport belt unit 115 is clamped or screwed. It is held at the mounting position by a holding means or a fastening means.
As described above, according to the present embodiment, since the conveyor belt unit 115 is configured to be detachable from the apparatus main body 1, it is possible to improve the maintainability with the replacement of the conveyor belt unit 115.

6 and 7 show that when the conveyor belt unit 115 is attached to the apparatus main body 1, the idler gear 102 on the main body drive system side is pressed and displaced with a certain force in a direction to engage with the gear 101 on the conveyor belt unit 115 side. The swing mechanism 110 as a displacement means to be moved is shown. The swing mechanism 110 includes a mechanism that relatively reduces backlash of the gear connecting portion.
As shown in FIGS. 6 and 7, in the swing mechanism 110, the idler gear 102 and the gear 103 on the main body drive system side are integrated with each other by a bracket 109 as a connecting member that connects these two gears. The idler gear 102 is configured to be swingable about the shaft 103 a of the gear 103. That is, when the conveyor belt unit 115 is detached from the apparatus main body 1, the idler gear 102 is configured such that the bracket 109 comes into contact with the stopper member 116 a that is implanted in the main body frame 116 provided on the apparatus main body 1 side, and thereby the conveyor belt unit 115. It is configured to be swingable between a separation position that is separated from the gear 101 on the unit 115 side and a meshing position that meshes with the gear 101 on the conveyance belt unit 115 side when the conveyance belt unit 115 is attached to the apparatus main body 1. ing.

  In FIG. 6, one end of the shaft 102a of the idler gear 102 on the left side and the shaft 103a of the gear 103 are rotatably supported by the bracket 109, and the other end of the shaft 103a on the right side in FIG. The frame 116 is supported so as to be rotatable and not to be moved. Further, the other end portion of the shaft 102a on the right side in FIG. 6 is formed on the main body frame 116 along an arc-shaped movement locus 117 shown by a broken line in the drawing with the shaft 103a as the center of oscillation as shown in FIG. It is guided and supported by a partially arcuate groove (not shown).

  Further, the idler gear 102 is pressed with a certain force in a direction to engage with the gear 101 by an elastic body 114 such as a spring (compression spring) or an urging means. One end of a spring as the elastic body 114 is locked to a stationary member of the apparatus main body 1 and the other end is locked to a bearing (not shown) interposed at both ends of the shaft 102a of the idler gear 102.

  As described above, according to the present embodiment, since the swing mechanism 110 is provided, the variation in the center-to-center distance between the meshing gear 101 and the idler gear 102 when the transport belt unit 115 is attached to the apparatus main body 1 is achieved. Can be reduced. Such a swing mechanism 110 is not limited to the upstream side of the conveyor belt 51, and the same effect can be expected by applying the same to the downstream drive system as described above. The gears of the swing mechanism 110 at that time are shown in parentheses in FIG.

Here, the attaching / detaching operation of the conveyor belt unit 115 and the operation of the swing mechanism 110 will be described. As shown in FIG. 5A, when the conveyor belt unit 115 is attached to the apparatus main body 1 mainly from the upper side to the lower side due to the weight of the conveyor belt unit 115 being lowered, the conveyor belt unit 115 in FIG. The side gear 101 (104) resists the pressing force (biasing force) of the elastic body 114 after contacting the idler gear 102 (105) which has occupied the separated position by the contact between the stopper member 116a and the bracket 109. When the conveyor belt unit 115 is lowered by its own weight, the idler gear 102 (105) swings counterclockwise and the gear 101 (104) and the idler gear 102 (105) mesh with each other under an appropriate pressure. Occupying the meshing position, the driving force of the motor 113 is the gear 101 (104) and the idler gear 102 ( 05) through the engagement between, it is transmitted to the conveying roller 52.
The operation in which the conveyor belt unit 115 is detached upward from the apparatus main body 1 and occupies the separation position is performed in reverse to the above-described operation. However, since it can be easily understood by those skilled in the art, further explanation is omitted.

  As described above, since the driving force of the motor 113 is transmitted to the tension roller 53 side through the driving / running of the conveyor belt 51, the gear 104 of the tension roller 53 and the gear trains 105, 106 of the main body driving system. Is not necessarily a required driving force transmission configuration, and may be removed including a swinging mechanism 110 (to be described later) disposed corresponding to the tension roller 53. In this case, as a method of supporting the apparatus main body 1 on the conveyor belt unit 115 side corresponding to the tension roller 53 when the conveyor belt unit 115 is mounted on the apparatus main body 1, for example, the lower end of the unit side plate (not shown) is used as the apparatus. It is desirable to adopt a configuration in which it is supported by an elastic member such as a compression spring disposed on the main body 1 side.

With reference to FIG. 8, control of the sheet conveyance amount when the sheet is stopped will be described. In the present embodiment, immediately after the transport belt unit attaching / detaching (or replacement) work is performed, the following operation is performed, and the driving play at the time of the attaching / detaching (or replacement) work is detected in advance and reflected as a correction value. I do.
That is, as a control configuration of the present embodiment, in FIG. 5A and FIG. 7, the conveyor belt unit 115 is mounted on the apparatus main body 1, and the gear 101 (104) and the idler gear 102 (105) occupy the meshing position. 8A, the deviation between the rotation amount of the motor 113 and the conveyance amount of the conveyance belt 51 is detected based on the signals from the rotary encoder 108 and the sensor 107, and the deviation is corrected by a correction constant. When the paper is transported more than the target paper stop position during the paper (sheet) stop operation at the time of image printing and the calculation means 120 that calculates as follows, it is generated at the gear connecting portion (meshing portion between the gear 101 and the idler gear 102). In order to remove backlash, the motor 113 is rotated to reverse the rotation amount taking the correction constant into account, and then the paper is stopped again to be driven in the forward direction. And control means 121 for causing the control.

The control unit 121 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Storage Device), a PROM, a RAM (Read / Write Storage Device), a timer, etc., which are connected by a signal bus (not shown). (The same applies to the following embodiments).
The CPU drives and controls the drive circuit of the motor 113 based on the signal relating to the calculated correction constant transmitted from the calculation means 120 and the operation program called from the ROM. The ROM stores relational data related to the input / output values shown in FIG. 8B, relational data for driving and controlling the drive circuit of the motor 113, and their operation programs. Called as appropriate. The RAM has a function of temporarily storing calculation results of the CPU, a function of storing data signals output from the sensor 107, and the like as needed. The calculation means 120 may be assigned to the calculation / control function of the CPU of the control means 121 as in this embodiment, or may be provided outside the control means 121 (the same applies to the following embodiments). ).

  In FIG. 8A, a preset sheet conveyance amount (corresponding conveyance amount of the conveyance belt 51) is instructed from the control means 121 to the motor 113, and the drive from the motor 113 is transmitted to the conveyance belt 51, thereby conveying the conveyance belt. The driving amount of the conveying roller 52, that is, the conveying amount of the conveying belt 51 is detected by a rotary encoder 108 on the axis of the conveying roller 52, which is a driving roller 51, and a sensor 107 disposed in the vicinity thereof. At this time, the calculation means 120 detects the rotation amount (for example, between A and B) by rotating the transport roller 52 once by the motor 113 shown in FIG. A deviation of the input / output value from the transport amount of the transport belt 51 (output between S and T is used as an output value) is detected, and this deviation (or difference) is calculated as a correction constant.

  The control means 121 takes into account the correction constant transmitted from the computing means 120 and feeds it back to a drive circuit (not shown) of the motor 113, that is, the target paper stop position in the paper (sheet) stop operation during image printing. When more paper is transported, after removing the backlash generated in the gear connecting portion (meshing portion between the gear 101 and the idler gear 102), the motor 113 is rotated and the rotation amount including the correction constant is reversed. The paper stop control for driving in the forward direction again is performed.

As described above, according to the present embodiment, by having the conveyor belt unit 115 and the swing mechanism 110, maintenance and assembly are improved, and the conveyor belt unit 115 and the drive system of the main body are driven and connected by a gear. In addition, by providing the swing mechanism 110 that keeps the distance between the shafts of both gears constant, variation in the center-to-center distance between the gear 101 on the conveyor belt unit 115 side and the idler gear 102 on the main body drive system side can be reduced.
In addition, by using paper stop control that takes into account the effects of backlash and backlash between the gears caused by the gear coupling, variations in the paper stop position caused by backlash and backlash between the gears can be reduced and the paper can be stopped. It is possible to prevent the positional accuracy from being lowered.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a plan view illustrating the swing mechanism of the second embodiment.
Compared with the second embodiment shown in FIGS. 4 to 8, the second embodiment replaces the gear 101 that is the first gear on the conveying belt unit 115 side, and has a cone as the first gear. A point using a tapered gear 101A having a shape, a point using a tapered gear 102A having a conical shape as the second gear of the main body drive system, instead of the idler gear 102 as the second gear of the main body drive system, and the swing mechanism 110 Instead, the main difference is that the swing mechanism 110A is used. This difference and the configuration of the second embodiment other than those described below are the same as those of the first embodiment.
Although not shown in the second embodiment, the second embodiment includes the conveyor belt unit 115, the sensor 107, the rotary encoder 108, the control configuration shown in FIG. 8, and the like, similar to the first embodiment.

  As shown in FIG. 9, the taper gear 101A is fixed to the shaft 52a of the conveying roller 52 on the conveying belt unit 115 side. The taper gear 102A is fixed to a shaft 102a that is rotatably provided in the main body drive system. In the taper gear 101A and the taper gear 102A, the center distance between the shafts 52a and 102a is set to be constant.

The main body drive system on the apparatus main body 1 side includes a taper gear 102A as the second gear described above, which meshes with the taper gear 101A of the conveying roller 52 and constitutes a gear connecting portion when the conveying belt unit 115 is mounted on the apparatus main body 1. A gear 118 fixed coaxially with the taper gear 102A, a gear 103 meshing with the gear 118, and a motor 113 connected to the shaft 103a of the gear 103 are provided.
The motor 113 functions as a drive means capable of rotating forward and backward through the taper gear 102 </ b> A via the gears 103 and 118, and is fixed to a non-illustrated non-illustrated member of the apparatus main body 1.

  As described above, the driving force of the motor 113 is transmitted from the motor 113 to the gear 103, and is transmitted to the tapered gear 101 </ b> A on the shaft 52 a of the conveying roller 52 via the tapered gear 102 </ b> A coaxial with the gear 118. Is driven and travels in the belt conveying direction or in the opposite direction. By the driving / running of the conveying belt 51, it is finally transmitted to the paper discharge roller 62 as in the first embodiment.

  As shown in FIG. 9, the swing mechanism 110 </ b> A includes a gear 103 and a gear 118 on the main body drive system side that are integrated with each other by a bracket 109, and a taper gear 102 </ b> A that is fixed to the same shaft 102 a as the gear 118. The taper gear 102 </ b> A is configured to be swingable about the shaft 103 a of the gear 103. That is, referring to FIG. 7, when the conveying belt unit 115 is detached from the apparatus main body 1, the taper gear 102A is bracketed to the stopper member 116a implanted in the main body frame 116 provided on the apparatus main body 1 side. 109 is in contact with the taper gear 101A on the conveyor belt unit 115 side and the meshing position where the conveyor belt unit 115 meshes with the taper gear 101A on the conveyor belt unit 115 side when the conveyor belt unit 115 is mounted on the apparatus main body 1. It is configured to be able to swing between. As described above, the swing mechanism 110A includes a mechanism that relatively reduces the backlash of the gear connecting portion.

  In FIG. 9, both end portions of the shaft 102a of the tapered gear 102A and the shaft 103a of the gear 103 are supported by the brackets 109 provided on both sides of the taper gear 102A so as to be rotatable and immovable. The shaft 103a between the bracket 109 and the bracket 109 is supported by the main body frame 116 so as to be rotatable and non-movable. Further, the shaft 102a between the gear 118 and the taper gear 102A will be described on the basis of FIG. 7. The shaft 102a is formed on the main body frame 116 along an arc-shaped movement locus 117 indicated by a broken line in the drawing with the shaft 103a as the center of oscillation. Guided and supported by a partially arcuate groove (not shown).

The taper gear 102A has a key groove 119 formed in the shaft 102a, and a convex portion (not shown) protruding from the insertion portion of the shaft 102a of the taper gear 102A is loosely fitted in the direction of the shaft 102a in FIG. It is slidable within a predetermined range.
The taper gear 102A is pressurized with a constant force in the direction of the right shaft 102a (thrust) in FIG. 9 by an elastic body 112 as pressurizing means interposed between one end of the taper gear 102A and the frame 116. Yes.

As described above, according to the present embodiment, by having the transport belt unit 115 and the swing mechanism 110A, the maintainability and assemblability are improved, and the taper gears 101A and 102A are provided between the transport belt unit 115 and the main body drive system. Is provided with a swing mechanism 110A that keeps the distance between the shafts of both the gears 101A, 102A constant, and the elastic body 112 applies a constant force in the direction of the shaft 102a (thrust) where the taper gear 102A further meshes with the taper gear 101A. By being pressed, variation in the center-to-center distance between the taper gear 101A on the conveyor belt unit 115 side and the taper gear 102A on the main body drive system side can be reduced.
Similarly to the first embodiment, the paper stop position caused by the drive play between the gears and the backlash is obtained by using the paper stop control in consideration of the influence of the drive play between the gears and the backlash generated by the gear connecting portion in advance. Can be reduced, and the paper stop position accuracy can be prevented from being lowered.

(Third embodiment)
With reference to FIG. 10, control of the sheet conveyance amount when the sheet is stopped in the third embodiment of the present invention will be described. FIG. 10 is a diagram illustrating an example of the control configuration of the third embodiment and input / output values of a motor and a conveyor belt.
Compared with the first embodiment, the third embodiment uses the control configuration shown in FIG. 10A instead of the control configuration shown in FIG. Instead of the input / output value examples of the motor 113 and the conveyor belt 51 shown in FIG. 10, only the input / output value examples of the motor 113 and the conveyor belt 51 shown in FIG. The configuration of the third embodiment other than this difference is the same as that of the first embodiment.
Although not shown in the third embodiment, hardware configurations such as the conveyor belt unit 115 and the swing mechanism 110 of the first embodiment shown in FIGS. 4 to 7 are provided. It is a precondition.

Compared with that of the first embodiment, the control configuration of the third embodiment has a rotary encoder 122 fixed on the shaft (not shown) of the motor 113 as shown in FIG. The sensor 123 is fixed to the stationary member of the apparatus main body 1 in such a manner that the rotary encoder 122 is sandwiched when the conveying belt unit 115 is attached to the apparatus main body 1 and occupies the attachment position, and the calculation means 120. Is mainly different in that a deviation between the rotation amount of the motor 113 and the conveyance amount of the conveyance belt 51 is detected based on the signals from the two sensors 107 and 123 and a correction constant is calculated.
The rotary encoder 122 and the sensor 123 function as a rotation amount detection unit that detects the rotation amount of the motor 113.

  That is, the control configuration of the present embodiment will be described with reference to FIG. 5A and FIG. 7. The transport belt unit 115 is attached to the apparatus main body 1, and the gear 101 (104) and the idler gear 102 (105) are connected. When the meshing position is occupied, a deviation between the rotation amount of the motor 113 and the conveyance amount of the conveyance belt 51 is detected based on the signals from the two sensors 107 and 123 as shown in FIG. When the paper is transported more than the target paper stop position at the time of the paper (sheet) stop operation at the time of image printing, the calculating means 120 for calculating the correction constant, and the gear connecting portion (the meshing portion between the gear 101 and the idler gear 102). In order to remove the backlash that occurs in (), the paper 113 is controlled so that the motor 113 is rotated in the reverse direction with the correction constant taken into account, and then driven in the forward direction again. And a control unit 121 for.

In FIG. 10B, during the correction constant calculation operation by the calculation means 120, for example, the rotation amount for rotating the transport roller 52 once by the motor 113 as the driving source (between A ′ and B is the input value of the correction value calculation range). And deviations T to B of the input / output values between the conveyance amount of the conveyance belt 51 (the output value of the correction value calculation range is between S ′ and T). Since the deviations T to B are driving play mainly generated when the conveyor belt unit 115 is mounted, the deviation (or difference) is calculated as a correction constant.
Here, the reason why the correction value calculation range is set to A ′ to B instead of A to B is to cancel the influence of backlash between the gear connecting portions during the correction constant calculation operation.

As described above, according to the present embodiment, in addition to the advantages and effects of the hardware configuration of the first embodiment, the rotation amount of the motor 113 that is a drive source is also detected, so The transmission error due to the backlash can be canceled and only the drive play can be detected, and the correction accuracy of the paper stop position is improved as compared with the paper stop control by the control configuration of the first embodiment.
Of course, the third embodiment can be applied to the hardware configuration of the conveyor belt unit 115, the swinging mechanism 110A, and the like of the second embodiment shown in FIG.

(Fourth embodiment)
With reference to FIG. 11, a description will be given of the control of the sheet conveyance amount when the sheet is stopped in the fourth embodiment of the present invention. FIG. 11 is a diagram illustrating an example of a control configuration according to the fourth embodiment and input / output values of a motor and a conveyor belt.
Compared with the third embodiment, the fourth embodiment uses the control configuration shown in FIG. 11A instead of the control configuration shown in FIG. Instead of the input / output value examples of the motor 113 and the conveyor belt 51 shown in FIG. 11, only the input / output value examples of the motor 113 and the conveyor belt 51 shown in FIG. The configuration of the fourth embodiment other than this difference is the same as that of the third embodiment.
Although not shown in the fourth embodiment, hardware configurations such as the conveyor belt unit 115 and the swing mechanism 110 of the first embodiment shown in FIGS. 4 to 7 are provided. It is a precondition.

  Compared to that of the third embodiment, the control configuration of the fourth embodiment is not limited to one direction of forward / reverse rotation of the motor 113 but the forward / reverse rotation of the motor 113 when calculating the correction constant by the calculation unit 120. The only difference is that the control involving the operation in two directions is performed.

  That is, the control configuration of the present embodiment will be described with reference to FIG. 5A and FIG. 7. The transport belt unit 115 is attached to the apparatus main body 1, and the gear 101 (104) and the idler gear 102 (105) are connected. When the meshing position is occupied, the deviation between the rotation amount of the motor 113 and the conveyance amount of the conveyance belt 51 is detected based on the signals from the two sensors 107 and 123 as shown in FIG. When the paper is transported more than the target paper stop position at the time of the paper (sheet) stop operation at the time of image printing, the calculating means 120 for calculating the correction constant, and the gear connecting portion (the meshing portion between the gear 101 and the idler gear 102). In order to remove the backlash that occurs in (), the motor 113 controls the amount of rotation taking into account the correction constant to perform sheet stop control with two forward and reverse movements. ; And a stage 121.

  In FIG. 11B, after the input value 1 (reverse rotation) due to the rotation amount (A to B) due to the reverse rotation of the motor 113 that is the drive source, the rotation amount for rotating the transport roller 52, for example, once by the normal rotation of the motor 113. A deviation 1 (T to U) from the conveyance amount of the conveyor belt 51 generated by normal rotation as an input value 2 (forward rotation) (between B and C) is detected as the maximum value of backlash, and the control unit 121 This is reflected in the line feed amount during paper stop control.

As described above, according to the present embodiment, in addition to the advantages and effects of the hardware configuration of the first embodiment, the rotation amount of the motor 113 that is a drive source is also detected. In addition to the advantages and effects, the maximum backlash value is detected, and the deviation 1 is clarified and reflected in the line feed amount during seat stop control, thereby minimizing the amount of reverse rotation near the stop position. Also, the productivity is improved.
Naturally, the fourth embodiment can be applied to the hardware configuration of the conveyor belt unit 115, the swinging mechanism 110A and the like of the second embodiment shown in FIG.

(Fifth embodiment)
With reference to FIG. 12, the control of the sheet conveyance amount when the sheet is stopped in the fifth embodiment of the present invention will be described. FIG. 12 is a diagram illustrating an example of the control configuration of the fifth embodiment and input / output values of the motor and the conveyor belt.
Compared with the third embodiment, the fifth embodiment uses the control configuration shown in FIG. 12A instead of the control configuration shown in FIG. Instead of the input / output value examples of the motor 113 and the conveyor belt 51 shown in FIG. 12, only the input / output value examples of the motor 113 and the conveyor belt 51 shown in FIG. The configuration of the fifth embodiment other than this difference is the same as that of the third embodiment.

  Compared with that of the third embodiment, the control configuration of the fifth embodiment repeatedly detects a deviation by the calculation means 120 and repeatedly calculates the correction constant during the sheet feed conveyance operation by the conveyance belt 51. The only difference is that it feeds back to the line feed amount of the next line feed.

  As shown in FIG. 12 (b), the deviation 1 between the input value 1 (A to B) of the first line feed due to the rotation amount of the motor 113 and the output value 1 (S to T) due to the conveyance amount of the conveyance belt 51. TT ′) is added to the input value (B ′ to C) of the second line feed according to the rotation amount of the motor 113. Thereafter, the same control is repeated, that is, the control unit 120 repeatedly detects the deviation, and performs a control to feed back the result of repeatedly calculating the correction constant to the line feed amount of the next line feed.

As described above, according to the present embodiment, in addition to the advantages and effects of the hardware configuration of the first embodiment, the rotation amount of the motor 113 that is a drive source is also detected. In addition to the advantages and effects, the input / output deviation is repeatedly detected during the line feed operation and reflected in the next line feed, thereby improving the stop position accuracy.
The fifth embodiment can be applied to the control of the fourth embodiment, and of course, the hardware configuration of the conveyor belt unit 115, the swing mechanism 110A, etc. of the second embodiment shown in FIG. Of course, it can be applied.

(Sixth embodiment)
With reference to FIG. 13, control of the sheet conveyance amount when the sheet is stopped in the sixth embodiment of the present invention will be described. FIG. 13 is an enlarged view of the area around the drive belt drive transmission mechanism and the arrangement of linear encoders and linear encoder sensors (hereinafter also simply referred to as “sensors”) in the sixth embodiment.
Compared with the first embodiment shown in FIG. 4, the sixth embodiment removes the rotary encoder 108 and the sensor 107 fixed to the shaft 52a of the conveying roller 52 and replaces this combination with the conveying belt. As the conveyance amount detecting means for directly detecting the conveyance amount 51, a linear encoder 126 shown by hatching is provided on the surface of the left side edge in the drawing of the conveyance belt 51 and close to the linear encoder 126. The only difference is that the sensor 125 is provided. The configuration of the sixth embodiment other than this difference is the same as that of the first embodiment.

That is, the control configuration of the sheet conveyance amount when the sheet is stopped in the sixth embodiment is omitted, but instead of the combination of the rotary encoder 108 and the sensor 107 in the block diagram of FIG. The only difference is the combination of the linear encoder 126 and the sensor 125. The sensor 125 is composed of, for example, a reflective photosensor, and is fixed to the apparatus main body 1 side.
As a linear encoder function on the surface of the conveyor belt 51, the linear encoder 126 is provided with black and white stripes or slit holes at equal intervals corresponding to image resolution on the surface of the conveyor belt 51.

  The control of the sheet conveyance amount when the sheet is stopped in the sixth embodiment will be described with reference to FIGS. 5A, 7 and 8B. That is, when the conveyor belt unit 115 is mounted on the apparatus main body 1 and the gear 101 (104) and the idler gear 102 (105) occupy the meshing position, the motor 113 is controlled based on signals from the linear encoder 126 and the sensor 125. A calculation unit 120 that detects a deviation between the rotation amount and the conveyance amount of the conveyance belt 51 and calculates the deviation as a correction constant, and a sheet more than the target sheet stop position at the time of sheet (sheet) stop operation at the time of image printing. In order to remove the backlash generated in the gear connecting portion (meshing portion between the gear 101 and the idler gear 102), the motor 113 is rotated to reverse the rotation amount in consideration of the correction constant, and then the forward rotation direction again. And a control unit 121 that performs sheet stop control to be driven.

According to the present embodiment, the conveyance amount of the conveyance belt 51 directly detected by the linear encoder 126 and the sensor 125 is controlled by the above-described control, so that the conveyance is performed for each apparatus due to variations in the conveyance roller 52 and the like. There is an effect that the belt is not affected by the difference in the conveyance speed of the belt or the fluctuation of the conveyance speed depending on the position of the conveyance belt.
In addition, by mounting the linear encoder 126 formed of slit holes, there is also an effect that it is less susceptible to the influence of encoder reading skipping due to dirt such as ink mist, other dust, and dust.

  The linear encoder 126 and the sensor 125 of the present embodiment are not limited to the first embodiment, but instead of the combination of the rotary encoder 108 and the sensor 107 in the second to fifth embodiments, the second to fifth embodiments. Of course, it can be applied to forms.

(Seventh embodiment)
The seventh embodiment of the present invention will be described below. In the seventh embodiment, in the ink jet recording apparatuses according to the first to sixth embodiments, input / output between the rotation amount (input value) of a motor that is a driving source and the conveyance amount (output value) of a conveyor belt. The operation of detecting the value deviation is performed not only when the conveyor belt unit is mounted, but also periodically, and the correction constant is rewritten automatically or by a user operation.

When the above operation is periodically performed and the correction constant is automatically rewritten, for example, a program including the execution time and the like is stored in advance in the ROM of the control unit 121 in the first to sixth embodiments. You can let it go. Further, when the operation is performed by a user operation, for example, a PROM (EPROM, EEPROM / flash memory, etc.) that can rewrite data and programs including an execution time, a correction constant, and the like is provided in the control unit 121 and an operation / display unit. An example of using a so-called service program or service man program that makes it possible to set rewrite data from 5 etc. is given.
According to the present embodiment, with the above configuration, it is possible to reduce variations in the sheet stop position due to drive play caused by changes in usage environment, changes with time, and the like.

  As described above, the present invention has been described with respect to specific embodiments and the like. However, the technology disclosed by the present invention is not limited to those exemplified in the embodiments including the above-described examples. It will be apparent to those skilled in the art that various embodiments, modifications, and examples can be configured within the scope of the present invention in accordance with the necessity and application.

The image forming apparatus according to the present invention is not limited to the ink jet recording apparatus according to the above-described embodiment, and may be an ink jet recording apparatus in, for example, a printer, a plotter, a word processor, a facsimile, a copying machine, or a multifunction machine having two or more functions. It is also applicable to an image forming apparatus including
Further, the sheet is not limited to a sheet, and includes all sheets that can form an image by an inkjet method, from usable thin paper to thick paper.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Paper feed tray 3 Paper discharge tray 4 Cartridge loading part 5 Operation / display part 33 Carriage 34 Recording head (image recording means and image forming means)
42 Paper (Recording medium, sheet / sheet-like recording medium)
51 Conveying belt (conveying means)
52 Conveying roller (driving / rotating member)
53 Tension roller (driven / rotating member)
101 gear (first gear)
101A Taper gear (first gear, conical gear)
102 Idler gear (second gear)
102A Taper gear (second gear, conical gear)
107 Rotary encoder sensor (conveyance amount detection means)
108 Rotary encoder (conveyance amount detection means)
110, 110A Oscillation mechanism (displacement means)
112 Elastic body (pressurizing means)
113 Motor (drive means)
120 arithmetic means 121 control means 122 rotary encoder (rotation amount detection means)
123 Rotary encoder sensor (rotation amount detection means)
125 linear encoder sensor (conveyance amount detection means)
126 Linear encoder (conveyance amount detection means)

JP 2010-58431 A JP 2005-211983 A1 JP 11-119583 A

Claims (8)

A conveying belt that is wrapped around at least two rotating members and is circulated and conveys a sheet;
A recording head that is disposed to face the conveying belt, is scanned in a main scanning direction orthogonal to the sheet conveying direction, and discharges ink onto the sheet to print an image;
In an image forming apparatus of an ink jet system that requires a transport stop operation of the transport belt at the time of image printing, and the transport operation of the transport belt is intermittently performed,
A conveyor belt unit configured such that the at least two rotating members and the conveyor belt are integrated and detachable from the apparatus main body;
A first gear provided on the rotating member of the conveyor belt unit;
A second gear provided in a main body drive system on the apparatus main body side, which meshes with the first gear and constitutes a gear connecting portion when the transport belt unit is attached to the apparatus main body;
Drive means capable of rotating forward and backward to rotate the second gear;
Displacement means for pressing and displacing the second gear with a constant force in a direction to mesh with the first gear when the transport belt unit is mounted;
A transport amount detecting means for detecting a transport amount of the transport belt;
When the transport belt unit is mounted, a deviation between the rotation amount of the driving unit and the transport amount of the transport belt is detected based on a signal from the transport amount detection unit, and the deviation is calculated as a correction constant. Computing means for
In the sheet stop operation at the time of image printing, when more sheets are conveyed than the target sheet stop position, the driving means is used to remove the backlash generated in the gear connecting portion, and the rotation amount including the correction constant A control means for performing sheet stop control to drive again in the forward rotation direction after reversing
An image forming apparatus comprising: The image forming apparatus according to claim 1.
The first gear and the second gear each have a constant center-to-center distance between the gear shafts, each consisting of a conical gear,
At least one of the gears is configured to be slidable in the gear axial direction, and is pressurized with a certain force in the gear axial direction by a pressurizing unit. The image forming apparatus according to claim 1 or 2,
A rotation amount detecting means for detecting a rotation amount of the driving means;
The calculation means detects a deviation between the rotation amount of the driving means and the conveyance amount of the conveyance belt based on each signal from the conveyance amount detection means and the rotation amount detection means, and calculates a correction constant. An image forming apparatus. The image forming apparatus according to claim 1.
The image forming apparatus according to claim 1, wherein the control unit performs a control not only in one direction of forward / reverse rotation but also in two directions of forward / reverse rotation when calculating the correction constant. The image forming apparatus according to claim 3 or 4, wherein:
An image forming apparatus, wherein the deviation is repeatedly detected by the computing means during a sheet line feed operation by the transport belt, and the result of repeatedly calculating the correction constant is fed back to the line feed amount of the next line feed. The image forming apparatus according to claim 1,
The transport amount detection means comprises a linear encoder provided on the surface of the transport belt, and a linear encoder sensor that detects the transport amount of the linear encoder,
Based on a signal from the linear encoder sensor, a deviation between a rotation amount of the driving unit and a conveyance amount of the conveyance belt is detected by the calculation unit, and the deviation is fed back to the driving unit as a correction constant. An image forming apparatus. The image forming apparatus according to claim 6.
An image forming apparatus, wherein as the linear encoder, fine black and white stripes or slit holes at equal intervals corresponding to image resolution are provided on the surface of the conveyor belt. The image forming apparatus according to any one of claims 1 to 7,
An image forming apparatus, wherein the operation of detecting the deviation is periodically performed, and the correction constant is rewritten automatically or by a user operation.

Images