JP2008102324A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which is capable of reducing the force required when a user processes a jam. <P>SOLUTION: The image forming apparatus is provided with: a conveying means conveying a recording medium; a motor driving the conveying means; a rotation detecting means detecting the rotation of the motor; a jam detecting means 310 detecting the jam of the recording medium; and a control means 308 controlling the driving of the motor. In the image forming apparatus, the control means stops the driving of the motor, when the jam is detected by the jam detecting means and then, starts the driving of the motor, when the rotation of the motor is detected by the rotation detecting means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to assisting the jam processing.

Conventionally, an electrophotographic printer has a configuration as shown in FIG.
Here, 1 is a photosensitive drum for forming an electrostatic latent image, 2 is a charging roller for uniformly charging the photosensitive drum 1, and 5 is an optical for scanning the laser beam on the photosensitive drum 1. A unit 6 is a laser beam emitted from the optical unit 5. Reference numeral 3 denotes a developing unit for developing the electrostatic latent image formed on the photosensitive drum 1 by a laser beam with toner, and 4 a toner image on the photosensitive drum 1 is transferred to a predetermined sheet. A transfer roller charger 7 is a fixing device that melts the toner on the paper and fixes it on the paper. 8 is a standard cassette for stacking paper for printing, 9 is a standard cassette paper feed roller for picking up paper from the standard cassette 8, 10 is a manual feed tray, 11 is a manual paper feed roller, and 12 is a paper outside the machine. A first discharge roller for discharging. A reversing roller 12-1 is connected to a forward / reverse motor for forward rotation only during single-sided continuous printing, reverses during double-sided conveyance to feed the paper into a double-sided conveyance path, which will be described later, and 13 for printing the conveyed paper. It is a registration roller that takes the leading edge resist. 14 is a TOP sensor for detecting the leading edge of the paper, 15 is a paper discharge sensor for confirming whether the paper is normally discharged from the fixing device 7, 16 is a sensor for detecting the presence or absence of paper in the standard cassette 8, and 17 is manual paper. It is a sensor for detecting the presence or absence. Reference numerals 18 and 19 denote double-sided conveyance rollers for conveying the paper for double-sided printing sent from the reverse roller 12-1 at the time of the above-described double-side reversal. Reference numeral 20 denotes a double-side sensor that detects the leading edge of the paper in order to stop the paper that has been conveyed during double-sided printing and check the stop position for restarting the paper conveyance after receiving a request for printing on the second side of both sides. . An apparatus for forming an image on both sides of a sheet is described in, for example, Patent Document 1.

Conventionally, in such a configuration, when a user processes jammed paper from the face-up tray 32 or the face-down tray 31, the user has to pull out the paper from the nip portion of the fixing device 7 to the end. It was.
JP-A-8-82960

  In the above-described conventional example, when processing jammed paper, the user has to pull out from the nip portion of the fixing device to the end, and there is a problem that force is required when pulling out by the pressing force of the fixing device. It was.

  The present invention has been made under such circumstances, and an object of the present invention is to provide an image forming apparatus that can reduce the force required when a user processes jammed paper.

  In order to solve the above-described problems, in the present invention, an image forming apparatus is configured as described in (1) below.

(1) Conveying means for conveying a recording medium, a motor for driving the conveying means, a rotation detecting means for detecting rotation of the motor, a jam detecting means for detecting jam of the recording medium, and driving of the motor And an image forming apparatus comprising:
The control unit stops driving of the motor when a jam is detected by the jam detection unit, and then starts image driving when the rotation detection unit detects rotation of the motor. apparatus.

  According to the present invention, when the paper is pulled out for jam processing, the force applied by the user during jam processing can be reduced by driving the motor that drives the transport unit, and usability can be greatly improved.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples of electrophotographic printers.

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an “electrophotographic printer” according to a first embodiment.
In FIG. 1, 101 is a photosensitive drum for forming an electrostatic latent image, 102 is a charging roller for uniformly charging the photosensitive drum 101, and 105 is for scanning a laser beam on the photosensitive drum 101. The optical unit. Reference numeral 130 denotes a process cartridge for holding the photosensitive drum 101 and the like, and 131 denotes a cartridge cover for taking in and out the process cartridge 130. Reference numeral 106 denotes a laser beam emitted from the optical unit 105, and reference numeral 103 denotes a developing device for developing the electrostatic latent image formed on the photosensitive drum 101 by the laser beam 106 with toner. Reference numeral 104 denotes a transfer roller charger that transfers the toner image on the photosensitive drum 101 to a predetermined sheet, 107 a fixing unit that melts and fixes the toner on the sheet to the sheet, and 108 loads a sheet to be printed. It is a standard cassette for. 109 is a standard cassette paper feed roller for picking up paper from the standard cassette 108, 110 is a manual feed tray, 111 is a manual paper feed roller, and 112 is a first discharge roller for discharging paper out of the apparatus.

  The pressing roller 135 of the fixing device 107 is driven by a DC brushless motor (not shown). The DC brushless motor is provided with an FG pulse generator.

  112-1 rotates only in the discharge direction during single-sided continuous printing and discharges the paper, and during double-sided printing, the paper is discharged to a predetermined position to feed the paper to the double-sided conveyance unit, and then the rollers reverse and the double-sided conveyance unit This is a second discharge roller that rotates to the side of feeding the sheet to the sheet. Thus, the second discharge roller 112-1 also has a reversing function. The reverse roller 112-1 is driven by a stepping motor (not shown). 113 is a registration roller for registering the leading edge for printing the conveyed paper, 114 is a TOP sensor for detecting the leading edge of the paper and measuring the length of the paper being conveyed, and 115 is for normally fixing the fixing device 107 to the paper. This is a paper discharge sensor for confirming whether or not the discharge is completed. 116 is a sensor for detecting the presence or absence of paper in the standard cassette 108, 117 is a sensor for detecting the presence or absence of manual paper, 118 is a retard roller for canceling double feeding of the fed paper, and 119 is paper feeding / separating A transport roller for feeding the sheet to the registration unit. Reference numeral 120 denotes a first double-sided conveyance roller for feeding the sheet reversed by the reversing roller 112-1 to the double-sided conveyance unit, and 121 denotes a second double-sided conveyance roller for feeding from the double-sided conveyance unit to the registration unit. Reference numeral 122 denotes a double-side reversing sensor for detecting a position where the paper fed from the reversing roller 12-1 waits for a print request at a predetermined position before the first double-sided conveyance roller 120. Reference numeral 132 denotes a face-up tray, and 134 denotes a face-down tray.

  FIG. 2 is a block diagram showing the configuration of the printer control unit in this embodiment. In FIG. 2, reference numeral 301 denotes a printer controller. The printer controller 301 communicates with a host computer (not shown), receives image data, develops the received image data into information that can be printed by the printer, and sends a signal to a printer engine control unit described later. Exchange and serial communication. An engine control unit 302 performs signal exchange with the printer controller 301 and controls each unit of the printer engine via serial communication. A serial communication command / status line 303 between the printer controller 301 and the engine control unit 302 has a bidirectional function. Reference numeral 304 denotes a serial synchronization clock for transferring the command status, and reference numeral 305 denotes a / TOP signal which becomes a vertical synchronization signal indicating to the printer controller 301 that the sheet has been conveyed and has reached the TOP sensor. Reference numeral 306 denotes a horizontal synchronizing signal for outputting an image / BD signal, and reference numeral 307 denotes an image signal.

  Reference numeral 308 denotes a paper conveyance control unit that feeds and conveys a paper to be printed and performs paper conveyance until printing after printing based on an instruction from the engine control unit 302. A paper presence / absence sensor input unit 309 transmits the states of the TOP sensor 114, the paper discharge sensor 115, and the paper presence / absence sensor 116 to the engine control unit 302. A jam detection unit 310 detects a paper jam based on an instruction from the engine control unit 302. The jam detection unit detects a jam according to whether or not a sheet passes through the paper discharge sensor 115 within a predetermined time. Reference numeral 311 denotes an optical system control unit that executes scanner motor drive and laser ON / OFF control based on an instruction from the engine control unit 302. Reference numeral 312 denotes a high-voltage system control unit that executes a high-voltage output necessary for an electrophotographic process such as charging, development, and transfer based on an instruction from the engine control unit 302. A fixing temperature control unit 313 performs temperature control of the fixing device 107 based on an instruction from the engine control unit 302 and detects abnormality of the fixing device 107. Reference numeral 314 denotes a failure detection unit that detects a failure of a functional unit in the printer.

  Control of jam processing assistance by the configuration of the printer control unit as described above will be described with reference to the flowchart of FIG.

  First, when a print request is received from the print instruction waiting state (S1) from the printer controller 301, various drive systems, that is, a DC brushless motor and a stepping motor are sequentially activated (S2). After the motor is started, temperature control of the fixing heater is started and various voltages of the electrophotographic process around the drum, that is, primary charging, developing bias, and transfer bias are sequentially raised (S3). Thereafter, after waiting for the temperature of the fixing heater to reach a predetermined temperature (S4, S5), paper for printing is fed from the paper feed port (S6).

  If a jam occurs in the vicinity of the paper discharge unit after the start of paper feeding (S7), the driving of the DC brushless motor is stopped (S8). At that time, when the paper discharge sensor 115 detects that there is paper (S9) and the user pulls out the paper for processing jammed paper with the cartridge door closed (S10), the DC brushless motor rotates. Then, an FG pulse having a frequency proportional to the rotation speed is output by the FG pattern patterned on the substrate of the DC brushless motor and the magnet magnetized by the rotor magnet of the DC brushless motor (FG pulse generator). With this FG pulse, the engine control unit 302 detects that the DC brushless motor is rotating (S11), drives the DC brushless motor (S12), and discharges the jammed paper. After discharging (S13), the driving of the DC brushless motor is stopped (S14), and the jam processing is ended (S15).

  When the occurrence of a jam is not detected (S7), the paper discharge is completed (S16), the driving of the DC brushless motor is stopped (S17), and the printing is finished (S18).

  In the embodiment, the rotation of the DC brushless motor is detected by the signal of the FG pulse generator for controlling the rotational speed of the DC brushless motor. However, the present invention is not limited to this, and the DC brushless motor is not driven when the DC brushless motor is not driven. Any suitable device capable of detecting the rotation of the above can be used. For example, a rotary encoder can be used.

  As described above, according to this embodiment, when the paper is pulled out during the jam processing, the motor is rotated by the FG pulse generator that detects the rotational speed of the DC brushless motor that drives the pressing roller of the fixing device. Is detected. Then, by driving the DC brushless motor, it is possible to reduce the force applied by the user during the jam processing, and the usability can be greatly improved.

Sectional drawing which shows schematic structure of Example 1. FIG. FIG. 1 is a block diagram illustrating a configuration of a control system of the first embodiment Flowchart showing processing in the first embodiment. Sectional drawing which shows schematic structure of a prior art example

Explanation of symbols

302 Engine control unit 308 Paper conveyance control unit 310 Jam detection unit

Claims (5)

A conveyance unit that conveys the recording medium, a motor that drives the conveyance unit, a rotation detection unit that detects rotation of the motor, a jam detection unit that detects a jam of the recording medium, and a drive of the motor are controlled. An image forming apparatus comprising: a control unit;
The control means stops driving the motor when a jam is detected by the jam detecting means, and then starts driving the motor when the rotation detecting means detects the rotation of the motor. An image forming apparatus. The image forming apparatus according to claim 1.
The image forming apparatus according to claim 1, wherein the controller stops driving the motor when jamming is no longer detected after driving of the motor is started. The image forming apparatus according to claim 1, wherein
The image forming apparatus, wherein the rotation detecting means is an FG pulse generator attached to the motor. The image forming apparatus according to claim 1, wherein
The image forming apparatus according to claim 1, wherein the rotation detecting means is a rotary encoder attached to the motor. The image forming apparatus according to claim 1, wherein the jam detection unit includes a sensor that detects the recording medium, and detects a jam based on a detection result of the sensor.

Images