JPH0482767A - Image forming device - Google Patents

Abstract

PURPOSE:To remove damage of a data and information which are stored in a memory by a method wherein a mechanism in which a memory cartridge is inserted and drawn out only under a state wherein supply of line electric power is thoroughly off. CONSTITUTION:A resilient projection capable of retracting is attached to a contact part of a cartridge shielding cover 36 near a side edge of a memory cartridge slot 36. Then, a line voltage supply circuit is installed between a line power source 302 and a connector 16. Herein, when the cartridge shielding cover 36 is closed, the projection is pushed with the cartridge shielding cover 36 to close a mechanical switch 45, and line voltage is supplied from the power source 302. Besides, when the cartridge shielding cover 36 is opened, the projection is returns toward the front of the title image forming device body, and a connection circuit of the switch 45 is released. Supply of the line voltage to a font card 17 (17) is stopped, and the font card or the memory cartridge 17 becomes capable of being drawn out.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to improvements in image forming apparatuses such as laser printers and wire dot printers, and more specifically relates to the improvement of image forming apparatuses such as laser printers and wire dot printers. , relates to an image forming apparatus in which a memory cartridge containing an emulation card is removably connected to the entire apparatus as a function-added memory.

(Prior Art) For example, in a wire dot printer, the structure of image data processed by a printer control unit often differs depending on the type, control method, and performance of the printer. Therefore, by removably connecting a memory cartridge containing multiple memories with different emulation data and font data to the main body of the printer, and replacing the memory housed in the cartridge according to the control content, a new memory can be installed in the printer control unit. Adds functionality.

However, in the conventional image forming apparatus of this type, the memory cartridge attachment/detachment section of the apparatus main body is only provided with an opening for inserting the cartridge and does not have a shielding device.

Therefore, the memory cartridge could be freely removed and inserted while power was being supplied to the image forming apparatus.

(Problem to be Solved by the Invention) However, when the power supply is cut off while the image forming apparatus is on, noise is generated and the noise is downloaded to the RAM of the control unit in the image forming apparatus. -L
There was a problem in that the data and information in the font card and emulation card (o a d) were damaged.

In addition, even if the power supply is not cut off and the operating device is turned off by operating the operation panel, it is possible to insert or remove the installed font card or emulation card. When the image forming apparatus is removed, residual image data sent from an external device and stored in a buffer may cause the image forming apparatus to malfunction or cause printing errors.

Therefore, the present invention has been made to solve this problem, and when the memory cartridge is attached to and removed from the main body of the device, noise and residual data are generated. It is an object of the present invention to provide an image forming apparatus that does not cause malfunctions or printing errors due to damage to the image forming apparatus.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the image forming apparatus according to claim (1) of the present invention has a memory cartridge that stores a memory for storing image information that is detachable. an image forming apparatus having a detachable part connected to the detachable part, a shielding means attached to the detachable part so as to be openable and closable; a detection means for detecting opening and closing of the shielding means; and opening of the shielding means by the detection means. and power supply means for stopping and restarting the supply of power to the attachment/detachment section in conjunction with the detection of closure.

Further, the image forming apparatus according to claim (2) is provided with a connection detection signal line in the attachment/detachment section of the image forming apparatus according to claim (+), and only when a detection signal flows through this signal line,
A power supply means is provided for supplying electric power to the attachment/detachment section from the power supply means.

Further, the image forming apparatus according to claim (3) is provided with the image forming apparatus according to claim (1).
) and (2), the image forming apparatus is characterized in that a transparent shielding means is used as the shielding means.

(Function) With the above-described configuration, the image forming apparatus according to claim (1) includes a shielding means attached to the memory cartridge attachment/detachment portion so as to be openable and closable, and the shielding means can be opened and closed. A detection means for detecting closure is provided, and in conjunction with the detection of opening and closing of the shielding means by this detection means, the power supplied from the power source power supply means to the attachment/detachment section is cut off and then resumed. Memory cartridges are inserted and removed only when the supply is completely turned off.

Therefore, a situation in which power supply is stopped and noise is generated while power is being supplied to the image forming apparatus is eliminated, and data and information stored in the memory are not damaged.

Further, according to the image forming apparatus of claim (2), the shielding means is attached to the attachment/detachment portion so as to be openable and closable, and the detection signal line is provided in the memory connection portion, and the detection signal is passed through the signal line. Since power is supplied from the power source power supply means to the memory connection portion only when the power source power supply means is in use, the memory cartridge can be inserted or removed only after the power source power supply is completely turned off.

This prevents the situation where a worker (specifically, an operator) accidentally removes the memory cartridge while power is being applied to the image forming apparatus, causing noise and damaging the data and information stored in the memory. can do.

Furthermore, according to the image forming apparatus of claim (3), since the shielding means of the memory cartridge inserted into the image forming apparatus is made transparent, the memory cartridge can be visually recognized from the outside through the shielding means.

Therefore, it is possible to prevent the occurrence of a situation in which an operator or other worker cuts off the power supply to the image forming apparatus, or an operator operates the operation panel to turn off the apparatus. I can do it.

(Example) Based on the drawings, a laser printer will be described as an example of an image forming apparatus according to the present invention.

1 to 3 are a perspective view of an electrophotographic image forming apparatus (laser printer) using the laser beam scanning exposure device of this embodiment, a right side view, and main parts showing the internal configuration of the vcW main body. It is a schematic sectional view.

The image forming apparatus of this embodiment has a top cover 40 on the upper surface of the apparatus main body 1, as shown in FIG. 1, and an engine control circuit in the center of the apparatus main body 1, as shown in FIG. A mounted printer control board 2 is arranged. and,
An electrophotographic process unit 3 for forming images is arranged behind the printer control board 2 (toward the right side in FIG. 3), and further functions are added to the printer control board 2 at the lower front of the main body 1. In order to do this, a plurality of function-adding control boards 4 (three in the embodiment shown in FIG. 3) are accommodated, and a paper ejecting section 6 is further formed in the upper front part.

Insert the memory cartridge 17 storing the function addition memory into the memory card connector 16 disposed at the front edge of the function addition control board 4 located at the bottom of the function addition control board 4, By installing a memory card, functions can be added to the printer control board. Furthermore, two interfaces (not shown) are provided on the left end surface of the function addition control board 4 located at the bottom.

) are provided, and these interfaces are connected to the device main body 1.
It faces an opening 18 (see FIGS. 1 and 2) formed on the left side surface.

Furthermore, the lower part of the main body 1 is a cassette accommodating section 8 that accommodates a paper feed cassette 7.

As shown in FIG. 1, the paper discharge section 6 consists of a recess formed in the upper front surface of the apparatus main body 1, and the front edge thereof has a
A rotatable paper discharge tray 9 that can be folded up or unfolded as shown in the figure is provided in the paper discharge section 6.

In addition, the left frame portion 1a of the apparatus main body located on the left side of the paper ejection section 6
An operation panel 14 consisting of a light emitting diode 11 for operation instruction, a display section 12 for indicating the operating state of the device, and a switch 13 is arranged on the upper surface of the apparatus.

Furthermore, as shown in FIGS. 1 to 3, a memory cartridge is installed at the tip of the function addition control board 4 at the bottom of the center wall of the front (right side in FIG. 1) of the device main body 1 (left end in FIG. 3). An opening 36 is formed in the connector 16 for attaching and detaching a memory card (more specifically, a memory cartridge) 17, and a cartridge shielding cover 35 is attached to this opening 36 so that it can be opened and closed. .

Further, a manual feed tray 15 is attached to the back side of the main body 1 of the apparatus.

Inside the apparatus main body l, an electrophotographic process unit 3 is provided for performing electrophotographic processes such as charging, exposing, developing, transferring, peeling, cleaning, and fixing the photoreceptor, and an electrophotographic process unit 3 housing section is provided. A drum-shaped photoreceptor 20 serving as an image carrier is arranged approximately in the center of the image bearing member.
Around the photoreceptor 2o, along the direction of rotation, there is a charging means 21, a static charger, an exposure section 22a of a laser beam scanning exposure unit 22 for forming a latent image, and a device that simultaneously performs a developing process and a cleaning process. A magnetic brush type developing unit 23 and transfer means 24 are arranged in this order.

Also, inside the apparatus main body 1, paper P fed from the paper feed cassette 7 via the paper feed means 27 and a manual feed tray 15 are stored.
A paper conveyance path 29 is formed which guides the paper P manually fed from the photoconductor 20 and the transfer means 24 to the paper discharge section 6 provided on the upper surface side of the apparatus main body 1 via the image transfer section 28. There is.

Further, a pair of conveying rollers 30, a pair of aligning rollers 31, and a pair of conveying rollers 32 are arranged on the upstream side of the image transfer section 28 of the paper conveying path 29, and a fixing unit 33 and a paper ejecting roller unit 34 are arranged on the downstream side. is located.

When a printing start signal is received from an external device, the drum-shaped photoreceptor 20 rotates, and the photoreceptor 20 is charged by the charging means 21. In this state, the laser beam a modulated in response to dot image data from an external device is scanned and exposed on the photoreceptor 20 by the laser beam scanning exposure unit 22, and an electrostatic layer corresponding to the image signal is formed on the photoreceptor 20. form an image.

This electrostatic latent image is developed and visualized by the toner in the developer of the developing unit 23.

Meanwhile, in synchronization with this toner image forming operation, the paper feed cassette 7
The paper P taken out from the tray or manually fed from the manual feed tray 15 is fed through a pair of aligning rollers 31, and the toner image formed on the photoreceptor 20 is transferred to the paper P by the function of the transfer means 24. After that, the paper P passes through the paper transport path 29 and is sent to the fixing unit 33, where the toner image is melted and fixed on the paper P. Next, the paper is discharged to the paper discharge section 6 via the paper discharge roller unit 34.

Further, the paper discharge roller unit 34 includes a lower roller and an upper roller, and is provided with a static elimination brush that contacts the non-image forming side of the paper P in the conveying direction.

A top cover is provided in the open part 1a on the upper surface of the apparatus main body 1 so as to be openable and closable, and the transfer means 2 is provided on the inner surface of the top cover.
4. The upper roller of the paper ejection roller unit 34 is attached, including a conveyance guide and a static elimination brush. The top cover can rotate upward by up to about 120° using a pivot provided at the upper rear end of the apparatus main body 1 as a rotation fulcrum.

The laser beam scanning exposure unit 22 also includes a semiconductor laser oscillator (hereinafter referred to as "laser") 90 (see FIG. 4),
It consists of a polygon scanner consisting of a polygon mirror (not shown) and a mirror motor, a second lens for RE, a second lens for FE, a reflection mirror for scanning the scanned laser beam a to a predetermined position, etc. There is.

Further, the control board of this laser beam scanning exposure unit 22 is connected to the printer control board 2 via a connector (not shown).

As shown in FIG. 4, the image forming apparatus of the embodiment includes a printer control unit 300 for generating and developing a bit image based on image data received from the host device f409;
The engine control section 200 outputs the bit image generated and developed by the printer control section 300 to form an image on transfer paper.

First, the configuration of engine control section 200 will be explained. FIG. 4 shows a block diagram of the engine control section 200 and its surrounding parts, and FIG. 5 shows the relationship between the control circuit of the engine control section 200 and its surrounding parts.

In FIGS. 4 and 5, 302 is a power supply device of the image forming apparatus, and when the main switch 301 is turned on, +5V and +24V are output.

When the main switch 301 is turned on, +5v and +24
V is output. +5V is supplied to the engine control circuit and further to the printer control circuit connected to this engine control circuit, while +24V is sequentially connected to cover switches 303, 304, high voltage power supply 305, and are respectively supplied to the configuration circuits 306;
The laser beam scanning control circuit 101 and the high voltage power supply 30
5, and component drive circuit 306, respectively;
It is used as a driving device for a laser oscillator, mirror motor, high voltage power supply 305, early exposure device 21, main motor, cassette paper feed solenoid 309, manual paper feed solenoid 308, aligning solenoid 310, toner replenishment solenoid 311, etc. It has become.

Furthermore, the power supply device 302 drives the heater lamp. For example, the above +24V is used as a driving power source for the LED on the light-emitting side of a heater lamp of a zero-cross switch type consisting of a phototriac coupler and a triac. In the heater lamp drive circuit with this configuration, as is well known, when the LED on the light emitting side is turned on and off, the phototriac on the light receiving side is turned on and off at the zero cross point of the AC power supply, and serves as the next stage main switch element. Turn the triac on and off and supply AC to the heater lamp” +j /
&χ is designed to energize and cut off. And a heater control signal 3 for turning on and off the light emitting side LED.
18 is connected from the engine control circuit to the power supply device 302, and a thermistor 45 provided in the fixing device 33 is connected to the engine control circuit.

Further, the cover switch 303 is turned off when the top cover 40 is rotated upward, and the cover switch 303 is turned off when the top cover 40 is rotated upward.
04 is designed to turn off when the rear cover is opened. Therefore, when the top cover 40 or the rear cover is opened, +24V is cut off by the switches 303 and 304, so that the laser, mirror motor, voltage power supply 305, main motor 307, solenoids 308 to 311, heater lamp, etc. The operation is digital, so that even if the operator touches the inside of the device main body 1, there is no pressure.

In FIG. 5, the CPU 350 controls engine control 0200.
It performs overall control, and is stored in the ROM 351 and operates according to a control program.

The RAM 352 is used as a work buffer for the CPU 350. The E2PROM 353 stores the total number of prints, etc. The printer control circuit interface 354 mediates the exchange of the interface signal 317 with the printer control circuit. Laser modulation control circuit 355
controls the laser to be forced to turn on periodically in order to generate a laser light detection signal 315 to be described later, and also modulates the laser according to the image data sent from the printer control circuit 4 using the interface signal 317. In addition, a laser modulation signal 314 is output to the laser beam scanning control circuit 101. The output register 356 is connected to the mechanism drive circuit 306,
Control signals 313, 316, 318.degree. 319 are output for controlling the laser beam scanning control circuit 101, the high voltage power supply 305, and the heater lamp drive circuit, respectively. The voltage generated by the thermistor 37b and the toner sensor 324 is input to the A/D converter 357, and this voltage value is converted into a digital value.

The input register 358 receives state signals from the paper empty switch, manual feed switch 321, paper discharge switch 322, mounting switch 323, and aligning switch, as well as the +24V on/off state signal. Further, the internal bus 359 is connected to the CPU 35
0, ROM351, RAM352, E' FROM3
53, printer control circuit interface 354, laser modulation control circuit 355, output register 356, A/D converter 357, and input register 358.

The mechanical unit drive circuit 306 is provided with a drive circuit for driving a motor, a solenoid, etc., and the control signal 313 output from the output register 356 is
On and off are controlled by binary values of ``1'' and ``0''. That is, for example, each drive circuit is turned on when rl'J is "
0", it is turned off, and the pre-exposure device 21 and main motor 3
07, solenoids 308 to 311. ? = +24V all or cut off. The scanner control circuit 101 is provided with a semiconductor laser 90 and a drive circuit for the mirror motor 13. turned on, turned off,
Further, the mirror motor 13 is controlled to be turned on or off by control signals rlJ and rOJ outputted from the output register 356. Furthermore, a PIN diode is used for the laser light detection sensor 312,
When the laser beam a passes through the laser beam detection sensor 312, a current proportional to the energy flows therethrough. Therefore, within the laser beam scanning control circuit 101, this current is converted into a voltage, amplified, and sent as a laser beam detection signal 315 to the laser modulation control circuit 355.

Further, from the high-voltage power supply 305, only the developing bias power supply section (not shown), the charging device W18, and the wire hole pressure power supply section of the transfer device 20 are supplied with a developing bias 305a.

High voltages of a charging bias 305c and a transfer bias 305e are output. These on and off are output register 3
It is controlled by rlJ and rOJ of control signals 316 output from 56.

As described above, within the engine control unit 200, power is supplied to each electric circuit via the engine control circuit, and the electric circuits are controlled by binary signals of "0" and "1" output from the engine control circuit. .

This engine control section 200 and a printer system S section 300, which will be described later, are connected via an interface signal 317.

Next, the configuration of the printer control section 300 will be explained.

FIG. 6 shows the main part of the electric circuit of the printer control section 300. In the figure, a CPU 401 controls the entire printer control section 300. ROM402
Since the CPU 401 stores a control program, the CPU 401 operates according to this program.

Further, the upper LE ROM 402 stores data related to the paper P, such as a password, top margin, left margin, paper type, etc., which are verified when data is changed. Data and the like corresponding to inputs from the host device al1409 and the key switches 13 of the operation panel 14 are written in the RAM 403. The RAM 403 is used as a page buffer for temporarily storing image data sent from an external device 409, or as a buffer for the work of the CPU 401. Expanded memory 404
When the image data sent from the host device M409 is a large amount of data such as bitmap data, the above RA
The M403 is a large-capacity memory used when data for one page cannot be stored. Video RAM405
The image data expanded into a bit image is stored, and the output thereof is supplied to the serial-parallel conversion circuit 406. The serial-parallel conversion circuit 406 converts the image data, which is developed into a bit image in the video RAM 405 and sent as parallel data, into serial data and sends it to the engine control circuit.

The host interface 408 transfers data between the printer control unit 300 and the host device ff1409, which is composed of a computer or an image reading device, for example, and has two types: a serial transfer line 410a and a parallel transfer line 410b. We are prepared. and,
It can be used appropriately depending on the type of data transferred to and from the host device 409. Engine interface 411 is printer $-1111
1 circuit 300 and engine control circuit 200 to mediate the transfer of the interface signal 317. When the font card 17° is inserted into or removed from the connector 16, the connection circuit 413 cuts off the power supply and signal line supplied to the font card 17, and prevents noise generated during insertion and removal. This is to prevent the data stored in the font card 171 from being damaged by the font card 171.

The operation panel control circuit 407 displays a guidance message on the liquid crystal display 100a of the operation panel 14, controls lighting, extinguishing, and blinking of the LED display 100b, or controls switching.
It controls the sending of data input from the /chie 00c to the CPU 401, etc. In addition, the internal bus 412
The above CPU 401, ROM 402, RAM 403,
This bus is used to mutually exchange data with the expansion memory 404, video RAM 405, operation panel control circuit 407, host interface 408, engine interface 411, and connection circuit 413.

The font card 171 described above is attached to the printer control board 2.
It is used to add functions to a cartridge, and is composed of non-volatile memory, such as static RAM with battery backup, E-mask ROM, etc., and accommodates multiple font cards in the cartridge. Depending on the control content, required font cards can be replaced and inserted. The above-mentioned cartridge (more specifically, memory cartridge) is inserted into the mounting main body 1 from the memory cartridge insertion/removal port 36 as described above, and the font card containing the memory contents to be added in the cartridge is mounted to the connector 16. .

These font cards 17+ have, for example, written character fonts, emulation programs, etc.

The memory cartridge containing the above-mentioned font card 171 (and a memory in which control contents are written in the membrane) is inserted through the cartridge attachment/detachment port 36 (see FIG. 3) formed on the front of the device main body 1. Functions can be added to the control board 4 by inserting the memory cartridge into the memory cartridge attachment/detachment section and attaching the memory in the cartridge to the connector 16.

Furthermore, the memory cartridge attachment/detachment port 36 is provided with a cartridge shielding cover 36 (located at the bottom of the integration/detachment port) that is rotatable to the right (or left) of the device main body 1 about a vertical axis (not shown). 1 and 2), and a cartridge shielding cover 36 near the side end of the attachment/detachment port 36 is provided.
The contact portion is provided with an elastic projection (not shown) that can be pushed down and projected. and a power source 30
2 and the connector 16 (see FIG. 2), a power supply voltage supply circuit having a circuit configuration shown in FIG. 7 is provided.

In FIG. 7, 45 and 46 are a mechanical switch and a transistor switch, respectively, 43 is a transistor, 47 and 47 are a DC voltage source (+5V) and a voltage dividing resistor arranged on the switch side, and the connector 16 (second A signal detection line 53 is connected between the transistor 46 (see figure) and the base side of the transistor 46 via a resistor 51. connector 16
The font cards 17t, 172. connected to the font cards 17t, 172. A plurality of ... are accommodated in the cartridge 17 and can be connected to the cartridge attachment/detachment port 36.

Between the power supply 302 (see FIG. 4), the font card 171 (172), and the connector 16,
Seventh, a power supply voltage supply circuit having the circuit configuration shown in the figure is provided. Then, the above-mentioned cartridge shielding cover 36
When the cartridge is closed, the protrusion is pressed by the cartridge shielding cover 36, the mechanical switch 45 is closed, and electric voltage is supplied from the power source 302. On the other hand, when the cartridge shielding cover 36 is opened, the protrusion is elastically pushed outward from the main body of the apparatus, and the connection circuit of the switch 45 is disconnected and the power supply voltage to the font card 17° (172) is disconnected. The supply will be stopped and the font card or
The memory cartridge 17 can now be removed.

In the power supply voltage supply circuit shown in FIG.
VCC is used as VEC. In the power supply voltage supply circuit shown in FIG. 7, the output signal voltage flowing to the base side of the transistor 43, the mechanical switch 45, the transistor switch 46, and the transistor switch 46 is as follows.
For example, it is configured to enter the font card 17 + connected connector through the signal line 53. Further, a voltage dividing resistor 47 is arranged between the emitter side of the transistor 45 and the base side of the transistor switch 46, and when the switch 45 is turned on, a voltage is supplied to the emitter side of the transistor switch 46. The configuration is such that a signal current flows into the signal line 53.

If the timing at which the power supply voltage font card can be removed by turning on and off the mechanical switch 46 and the transistor switch 46 by the power supply voltage supply circuit shown in FIG. 7 is shown, a timing chart as shown in FIG. 8 can be obtained. That is, at time T1, the cartridge shielding cover 3
6, the switch 45 is released and the voltage supplied from the power source 30 is stopped, allowing the memory cartridge to be removed. On the other hand, the inflow voltage to the transistor switch 46 is stopped at time T2, which is delayed from the off operation of the mechanical switch 45, and the font card attached to the connector 16 can be removed.

In this way, if the power supply voltage supply circuit shown in FIG. 7 is provided between the cartridge shielding cover 36 and the protrusion, as well as between the power supply 302 and the connector 16, the memory cartridge cannot be removed unless the cartridge shielding cover 36 is opened. Therefore, even though the power to the image forming apparatus is not cut off, the data and information written in the memory are not damaged.

Furthermore, if the above-mentioned cartridge shielding cover 36 is made of a material such as transparent plastic, the presence or absence of a memory cartridge inserted can be visually confirmed from the outside of the device, allowing a worker such as an operator to turn off the device by operating the operation panel. In this case, there will be no malfunction due to residual image data stored in a buffer or the like.

As shown in FIG. 4, the image forming apparatus of this embodiment includes a printer control section 300 for generating and developing a bit image based on image data received from an external device, and a printer control section 300 for generating and developing a bit image based on image data received from an external device. The apparatus includes an engine control section 200 that outputs the expanded bit image to form an image on transfer paper.

First, the configuration of engine control section 200 will be explained. FIG. 4 shows a block diagram of the engine control section 200 and its surrounding parts, and FIG. 5 shows the relationship between the control circuit of the engine control section 200 and its surrounding parts.

5 and 6, 302 is a power supply device of the image forming apparatus, and when the main switch 301 is turned on, +
5V and +24V are output.

When the main switch 301 is turned on, +5v and +24
V is output. +5V is supplied to the engine control circuit and further to the printer control circuit connected to this engine control circuit, while +24V is sequentially connected to cover switches 303, 304, high voltage power supply 305, and component circuits. 306, and the laser beam scanning control circuit 1o1 and the high voltage power supply 305.
, and component drive circuit 306, respectively, and are supplied to the semiconductor laser oscillator 9o, mirror motor 92, and high voltage power supply 3.
05, early exposure device 21, main motor 307, cassette paper feed solenoid 309, manual paper feed solenoid, 30
g, aligning solenoid 310,) toner supply solenoid 311, etc.

Furthermore, the power supply device 302 drives the heater lamp. For example, the above +24V is used as a driving power source for the LED on the light-emitting side of a heater lamp of a zero-cross switch type consisting of a phototriac coupler and a triac. In the heater lamp drive circuit with this configuration, as is well known, when the LED on the light emitting side is turned on and off, the phototriac on the light receiving side is turned on and off at the zero cross point of the AC power supply, and serves as the next stage main switch element. By turning on and off the triac, AC power is supplied to and cut off from the heater lamp 37a.

Then, a heater control signal 318 for turning on and off the light emitting side LED is sent to the power supply device 30 from the engine control circuit.
2, and a thermistor 45 provided within the fixing device 33 is also connected to the engine control circuit.

The cover switch 303 is turned off when the top cover 40 is initially moved upward, and the cover switch 303 is turned off when the top cover 40 is initially moved upward.
04 is designed to turn off when the rear cover is opened. Therefore, when the top cover 60 or the rear cover is opened, +24V is cut off by the switches 303 and 304, so that the semiconductor laser 9o,
The operations of the mirror motor 92, voltage power source 305, main motor 3.7, solenoids 308 to 311, heater lamps, etc. are digital, so that even if the operator touches the inside of the apparatus main body 1, there will be no interference.

In FIG. 5, the CPU 350 is the engine control section 200.
It performs overall control, and is stored in the ROM 351 and operates according to a control program.

The RAM 352 is used as a work buffer for the CPU 350. The E2FROM 35B stores the total number of prints, etc. The printer control circuit interface 354 mediates the exchange of the interface signal 317 with the printer control circuit. Laser modulation control circuit 35
5 controls the semiconductor laser 90 to be forced to turn on periodically in order to generate a laser light detection signal 315 which will be described later, and also controls the semiconductor laser 90 according to the image data sent from the printer control circuit 4 using the interface signal 317. The device that modulates and controls the laser 90 transmits the laser modulation signal 314 to the laser beam scanning control circuit 101.
It is designed to output to . The output register 356 is
Mechanism drive circuit 306, laser beam scanning control circuit 101,
Control signals 313, 316, 318, 31 that control the high voltage power supply 305 and the heater lamp drive circuit, respectively.
9 is output. A/D converter 35
7 includes the thermistor 37b and the toner sensor 32.
4 is input, and this voltage value is converted into a digital value.

The input register 358 receives state signals from the paper empty switch, manual feed switch 321, paper ejection switch 322, mounting switch 323, and aligning switch, as well as the +24V on/off state signal. . Further, the internal bus 359 is connected to the CPU 3 mentioned above.
50, ROM351, RAM352, E2 FROM3
53, a printer control circuit interface 354, a laser modulation control circuit 355, an output register 356, an A/D converter 357, and a manual register 358.

The mechanical unit drive circuit 306 is provided with a drive circuit for driving a motor, a solenoid, etc., and the control signal 313 output from the output register 356 is
On and off are controlled by binary values of ``1'' and ``0''. That is, for example, each drive circuit is on when rlJ is "0".
”, the pre-exposure device 21 and main motor 30 are turned off.
7. +24V is energized or cut off to the solenoids 308 to 311. Scanner control circuit 1
01 is provided with a semiconductor laser 90 and a drive circuit for the mirror motor 13, and the semiconductor laser 90 is turned on and off by "1" and "0" of the laser light detection signal 314 output from the laser modulation control circuit 355. The mirror motor 13 is turned on and off by rlJ and rOJ of the control signal 319 output from the output register 356. Further, a PIN diode is used in the laser light detection sensor 312, and when the laser light a passes through the laser light detection sensor 312, a current proportional to the energy flows therethrough. Therefore, in the laser beam scanning control circuit 101, this current is converted into a voltage.
It is amplified and sent to the laser modulation control circuit 355 as a laser light detection signal 315. Further, from the high voltage voltage #305, the developing bias power supply section (
(not shown), the charging device 18, and the wire high-voltage power supply portion of the transfer device 20, respectively, output high voltages of the developing bias 305a, the charging bias 305C, and the transfer bias 305e. These on/off states are controlled by "1" and "0" of the control signal 316 output from the output register 356.

As described above, within the engine control unit 200, power is supplied to each electric circuit via the engine control circuit, and "0" and "1" are output from the engine control circuit.
It is controlled by a binary signal. This engine control section 300 and a printer control section 300, which will be described later, are connected via an interface signal 317.

Next, the configuration of the printer control section 300 will be explained.

FIG. 6 shows the main part of the electric circuit of the printer control section 300. In the figure, a CPU 401 controls the entire printer control section 400. ROM402
Since the CPU 401 stores a control program, the CPU 401 operates according to this program.

Further, the ROM 402 stores data related to the paper P, such as a password, top margin, left margin, paper type, etc., which are verified when data is changed. R
AM40B is written with data corresponding to the external device 409 and the manual operation of the keys/switches 13 of the operation panel 14. The RAM 403 is used as a page buffer for temporarily storing image data sent from an external device 409, or as a buffer for the work of the CPU 401. When the image data sent from the host half 2409 is a large amount of data such as bitmap data, the extended memory 404 is used to store the RAM 40.
3 is a large-capacity memory used when data for one page cannot be stored. Video RAM 405 stores image data expanded into bit images, and its output is supplied to serial-parallel conversion circuit 406. The serial-parallel conversion circuit 406 converts the image data developed into a bit image in the video RAM 405 and sent as parallel data into serial data, and sends the serial data to the engine control circuit.

The host interface 408 transfers data between the printer control unit 300 and an external device 409, such as an electronic computer or an image reading device, and connects a serial transfer line 410a and a parallel transfer line 410b. It has a lot of variety. Then, it can be used appropriately depending on the type of data transferred to and from the external device 409. The engine interface 411 mediates the exchange of the interface signal 317 between the printer control circuit and the engine control circuit. When the cartridge 17 containing a font card is inserted into or removed from the connector 16, the connection circuit 413 shuts off the power supply and signal line supplied to the font card, and prevents noise generated during insertion and removal. This prevents the data stored in the font card from being damaged by the font card.

The operation panel control circuit 407 performs controls such as sending data input by operating the operation panel 14 to the CPU 401. The internal bus 412 also exchanges data with the CPU 401, ROM 402, RAM 40.3, expansion memory 404, video RAM 405, operation panel control circuit 407, host interface 408, engine interface 411, and connection circuit 413. This is a bus that carries out

The cartridge 17 is for adding functions to the printer control board 2, and is a non-volatile memory, for example, a static RAM with battery backup.
It is composed of OM and the like. These cartridges 17 contain, for example, character fonts, emulation programs, and the like.

Next, the configuration of the interface signal 317 will be explained.

FIG. 9 shows each signal of the interface signal 317. In the figure, DO-D7 is the engine control circuit 2
The bidirectional data bus transmits status from the engine control circuit to the printer control circuit, and commands from the printer control circuit to the engine control circuit, so that the status and command can be switched at the timing shown in FIG. That is, the busy signal B output from the engine control circuit
When SYO is "1", if the bus direction signal is set to "0",
DO-D7 is switched in the direction of engine control circuit-printer control circuit, and the status is output on DO-D7, so that the printer control circuit can read the status. On the other hand, when the printer control circuit sends a command and the busy signal BSYO is 1, the bus direction signal D
When the IR is set to "1", the Do-D7 is switched in the direction from the printer control circuit to the engine control circuit, so it outputs a command and then sets the strobe signal 5TBO to 0. At this time, the engine control circuit reads the commands above D0-D7 and also outputs the busy signal BSYO.
is set to 0 and processing such as command analysis is performed. When the busy signal BSYO is set to "0", the printer control circuit returns the strobe signal 5TBO to "1" and ends the command transmission. Then, when the command processing in the engine control circuit is completed, the busy signal BSYO is returned to "1" again. In fact, commands sent while the busy signal BSYO is "0" are not received by the engine control circuit. Further, the status of the data bus DO-D7 does not change immediately when there is a change in the state in the engine control unit 300, but is updated only after the change in the state with respect to the received command.

The attention signal ATN1 is output when the basic status on the print sequence changes between the engine control circuit and the printer control circuit, and when the engine control circuit becomes able to receive a print command or VSYNC command, which will be described later. , and when one page of image data has been received, it is set to "1", and when an attention reset/sort command is received, it is reset to "0". Therefore, attention signal A
When TN1 changes to ``0''-, the printer control circuit sends an attention reset command to the data bus [)Q-D7, resets the attention signal ATNI to ``1'', and determines the next step. <I'm coming. In addition, the above basic status is also output on the data bus by the basic status request command that requests the basic status, so the content of the basic status can be known by the basic status request command prior to the above attention reset command. It is now possible to do so. The ready signal PRDYO indicates that the engine control unit 300 is in a ready state when it is “0”, and indicates that the engine control unit 300 is in a not-ready state when it is “1”. Operation is possible.

The system clear signal 5CLRI is a reset signal for the printer control circuit.
It becomes "1" during m5ec, and the printer control circuit is in a reset state during this period.

The prime signal PRIMEO is a reset signal to the engine control circuit, and while this signal is "0", the busy signal B
SYO becomes "0", ready signal PRDYO becomes "1", and the engine control circuit returns to a predetermined initial state.

The horizontal synchronization signal 'HS Y N CO corresponds to the effective print length in the transport direction of the paper P after receiving the VSYNC command, among the laser light detection signals 315 generated by the laser light scanning exposure unit 22 for each scan. The number of lines corresponding to the number of lines is output in synchronization with the laser light detection signal 315.

The video clock VCLKO is the horizontal synchronization signal I(S
This is a synchronization clock for inputting one line of video data (image data) VDO to the engine control circuit following YNCO, and is output in a number corresponding to the effective print width of paper P in the horizontal scanning direction. Then, the video data VDO is received by the engine control circuit 2 in synchronization with the falling edge of the video clock VCLK0, and is recorded as an electrostatic groove Q on the photoreceptor 20 by the laser beam scanning optical unit 22. There is. Note that when the video data VDO is "0", it is visualized on the paper P as a dot image.

〔Effect of the invention〕

As is clear from the above description, according to the image forming apparatus of the present invention (claims (+), (2), and (3)), the memory cartridge can be inserted and removed only when the power is turned off. Because of this structure, memory extraction will not damage stored data or stored information due to noise generation.

In addition, since the shielding means is made transparent, the inserted memory cartridge can be seen from the outside of the image forming apparatus, so an operator can accidentally cut off the power supply or turn off the apparatus by operating the operation panel. Therefore, it is possible to eliminate malfunctions and printing errors in the image forming apparatus.

[Brief explanation of the drawing]

1 is an external perspective view of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a right side view of the image forming apparatus shown in FIG. 1, and FIG. 3 is an image forming apparatus shown in FIG. FIG. 4 is a block diagram showing the relationship between the engine control section and printer control section of the image forming apparatus shown in FIG. 1, and FIG. 6 is a block diagram of the main part of the printer control section shown in FIG. 4, and FIG. 7 is a block diagram of the main part of the printer control section shown in FIG. An example power supply voltage supply circuit diagram, FIG. 8 is a timing chart showing the relationship between opening and closing of switches in the power supply voltage supply circuit shown in FIG. 7 and voltage supply timing, and FIG. 9 is an image shown in FIG. 1. FIG. 10 is a timing chart of the interface signals shown in FIG. 9, which is an interface signal diagram between the engine control HEz of the forming apparatus and the printer control section. U...Device body 2...Printer 1. Control board 4... Function addition control board 4... Operation panel 16... Memory card connector 17... Memory cartridge 7+, 172.173... Font card 35.
・Cartridge shielding cover 36 ・Memory cartridge insertion/removal port 40 ・Top cover

Claims (3)

[Claims] (1) In an image forming apparatus having a removable part for removably connecting a memory cartridge containing a memory for storing image information, a shielding means attached to the removable part so as to be openable and closable; The shielding device is characterized by being provided with a detection means for detecting closure, and a power supply means for stopping and restarting power supply to the attachment/detachment section in conjunction with detection of opening and closing of the shielding means by the detection means. Image forming device. (2) The attachment/detachment section is provided with a connection detection signal line, and only when a detection signal flows through this signal line, the power supply means supplies power to the attachment/detachment section. image forming device. (3) The image forming apparatus according to claims (1) and (2), characterized in that the shielding means is a transparent shielding means.