JPH04349767A - Image forming device - Google Patents

Abstract

PURPOSE:To receive a status data with main control of a scanner as a command transmission side by recognizing the success of the transmission of the command data immediately in the transmission and reception of a serial command data and status data between the scanner and a printer. CONSTITUTION:When a command data is transmitted scanner 1 to a printer 2 through an interface line S, the printer 2 sets a busy signal(PBSY signal) representing the operation corresponding to the command data immediately. The scanner 1 receiving the set PBSY signal confirms it that the command data is received by the printer 2. When the printer 2 is ready for a status reply responding to the operation corresponding to the command data, since the PBSY signal is reset, the scanner 1 recognizes the reception of the status data.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, such as a digital copying machine, in which a scanner and a printer are separated.

0002

[Prior Art] Conventionally, in digital image forming apparatuses such as copying machines that have separate scanners and printers, command data and status data signals are used to communicate (transfer) between the scanner and the printer. It is being Transfer of command data and status data is performed by serial communication, and it is confirmed whether the command data has been received by fixed length transfer. Furthermore, since the scanner cannot confirm whether or not the printer is running after receiving the command data, the printer supplies the clock signal for status data transfer. Therefore, it is necessary to transfer command data on the scanner side and status data on the printer side many times.

0003

[Problem to be Solved by the Invention] As mentioned above, the scanner cannot immediately confirm whether or not command data has been received from the scanner to the printer in serial communication, and if the transfer is not successful, Otherwise, there was a problem in that command data and status data had to be transferred (exchanged) many times between the scanner and the printer, which took a long time. Furthermore, as the amount of information transferred between scanners and printers increases, a problem has arisen in which fixed-length command data and status data cannot be transferred.

Accordingly, the present invention provides an apparatus in which serial command data and status data are transmitted and received between a reading means and an image forming means, in which the success or failure of command data transmission can be immediately known, and It is an object of the present invention to provide an image forming apparatus that can also receive status data under the initiative of a reading means serving as a command transmitting side.

[0005]

[Means for Solving the Problems] The image forming apparatus of the present invention includes: a reading means for reading an image; an image forming means for forming an image corresponding to the image read by the reading means on an image carrier; a first transmitting means for transmitting a reference clock from the reading means to the image forming means; and a first transmitting means for transmitting a reference clock from the reading means to the image forming means in synchronization with the reference clock transmitted by the first transmitting means. second transmitting means for transmitting command data specifying the operation of the image forming means to the image forming means, and transmitting status data indicating the operating state of the image forming means from the image forming means to the reading means; a third transmitting means for transmitting identification data identifying the type of data transmitted by the second transmitting means from the reading means to the image forming means; and a third transmitting means for transmitting identification data identifying the type of data transmitted by the second transmitting means; When the command data is transmitted to the image forming means, the image forming means transmits the command data to the reading means so that the reading means can determine that the image forming means has received the command data. and fourth transmitting means for transmitting processing information indicating that the content of the received command data is being determined.

[0006]

[Operation] This invention transmits command data that defines the operation of the image forming means in synchronization with a reference clock to the image forming means that forms an image corresponding to the image read by the reading means on the image carrier. and transmits status data indicating the operating state of the image forming means from the image forming means to the reading means, transmits identification data for identifying the type of data to be transmitted from the reading means to the image forming means, and sends a command to the image forming means. When the data is sent to the image forming means, the image forming means sends processing information indicating that the content of the received command data is being judged to the reading means. The system is designed to determine whether the command data has been received.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 4 show an image forming apparatus of the present invention,
A scanner 1 as a reading means that outputs image information of each color read from a color original, and a printer as an image forming means that forms a color image based on the image information of each color supplied from the scanner 1. 2 and
It consists of an interface line S interposed between a scanner 1 and a printer 2. FIG. 2 shows the configuration of the scanner 1.

That is, on the top surface of the scanner 1, there is a document mounting table (platen glass) made of transparent glass.
3 is fixed. For example, A3
It is possible to place originals G up to this size. Further, on the upper surface of the scanner 1, a document cover 4 that can cover the document G on the document table 3 is rotatably provided.

The scanner 1 includes a first carriage 5, an exposure lamp 6 in the first carriage 5, a first mirror 7, a second carriage 8, and a second carriage 5 as a document scanning section below the document table 3. 8, a second mirror 9, a third mirror 10, an optical system (light focusing lens) 11, and a line sensor 12 are provided.

The original G placed on the original placing table 3 by an operator or the like is moved between the first carriage 5 and the second carriage 8.
is exposed and scanned by moving along the lower surface of the document table 3. In this case, the second carriage 8 moves at half the speed of the first carriage 5 so as to keep the optical path length constant.

The light reflected from the original G by the scanning of the optical system, that is, the light reflected from the original G by the light irradiation of the exposure lamp 6 is reflected by the first mirror 7, the second mirror 9, and the third mirror 1.
After being reflected by 0, the optical system (light focusing lens) 1
1 and is received by the line sensor 12.

The line sensor 12 detects the original G by photoelectrically converting reflected light or transmitted light from the original G.
It outputs the image as an electrical signal, for example CC
It is mainly composed of a D-type line image sensor.

A shading correction plate 13 is also provided for shading correction. This is done at startup before the start of the reading operation. First, a black shading operation is performed, and then when the first carriage 5 comes under the shading correction plate 13, the exposure lamp 6 is turned on and the shading correction plate 13 is turned on. 13 is read and white shading is executed. After this shading correction is completed, the original G on the original placing table 3 is read. FIG. 3 shows the configuration of the printer 2. As shown in FIG.

That is, the printer 2 sequentially transmits image information of each color supplied from the scanner 1 to a laser beam 21.
The photoreceptor drum 23, which has been charged in advance, is irradiated with the light through the mirrors, lenses, etc. of the exposure optical system 22, thereby forming an electrostatic latent image. The photoreceptor drum 23 has an organic photoreceptor coated on its surface, and is rotated by a pulse motor 24 in the direction of arrow E. The photosensitive drum 23 is
By adsorbing the first color toner from the developing device 25A, the electrostatic latent image formed by the laser beam 21 is visualized to form a toner image.

A transfer drum 26 as a rotating body is provided below the photosensitive drum 23 and is connected to the photosensitive drum 23, and is configured to rotate in the direction of arrow F. This transfer drum 26 is provided with a flat portion 26a, and a gripper 28 as a support member is provided on this flat portion 26a. This gripper 28 is
The transfer paper (image forming medium) P stored in the paper feed cassette 29 is sandwiched, and the sandwiched transfer paper P is attached to the outer peripheral surface of the transfer drum 26. In addition, this transfer drum 2
A vertical synchronization signal generating section 26b that detects the position of the transfer drum 26 and generates a vertical synchronization signal is provided near the transfer drum 6.

The photosensitive drum 23 and the transfer drum 26 are located at a point 3 at a portion other than the flat portion 26a of the transfer drum 26.
Rotate facing each other while maintaining contact at the 0C position,
The first color toner image formed on the photosensitive drum 23 is transferred onto the transfer paper P. When the transfer of the first color to the transfer paper P is completed, the transfer drum 26 is rotated so that the flat part 26a of the transfer drum 26 faces the position 30C of the photoreceptor drum 23, and they are separated from the contact state and stopped. do.

As a result, the transfer paper P on the transfer drum 26
The initial position is opposite to the photoreceptor drum 23 at the point 30C. Further, while rotating the photosensitive drum 23 in the E direction, it is similarly set to a position where transfer can be resumed when the initial position reaches the point 30C. In this way, the second, third, and fourth color toner images are sequentially transferred onto the transfer paper P. When the transfer is completed, the transfer paper P is peeled off from the transfer drum 26 and sent to a fixing device 31, where it is fixed and discharged onto a collection tray 32.

The exposure optical system 22 is provided at the top of the printer 2, and includes a high-speed rotation motor 33, a polyhedral rotating mirror 34, and an fθ
Lens 35, reflective mirrors 36, 37, aspherical lens 38
, and a protective glass 39. A laser beam 21 according to image information oscillated from a semiconductor laser oscillator (not shown) is input to the exposure optical system 22 after being shaped by a beam shaping optical system (not shown) comprising, for example, a collimator lens. be done.

Further, the laser beam 21 is transmitted to a drive controller 41 adjacent to the exposure optical system 22 in the upper part of the printer 2.
The beam is deflected by a polyhedral rotating mirror 34 that is rotationally driven by a high-speed rotating motor 33 using an air bearing that is drive-controlled. Then, the deflected laser beam 21 passes through the fθ lens 35, is reflected by the mirror 36 and the mirror 37, passes through the aspherical lens 38 and the protective glass 39, and passes through the exposure position 30A on the photoreceptor drum 23.
A spot image is formed at the required resolution and scanned and exposed.

Around the photosensitive drum 23, a charger 43 is arranged along the rotational direction E to charge the drum surface.
, a developing device support 44 equipped with developing devices for each color, a transfer drum 26 that rotates with transfer paper P attached to the drum surface, a cleaner 45, and an erasing and discharging lamp 46 are provided. The photosensitive drum 23 is rotationally driven by a pulse motor 24, which will be described later, and the drum surface is charged by a charger 43 having a grid electrode 47 and provided facing the drum surface.

A spot image of the laser beam 21 is formed at the exposure position 30A on the drum surface of the charged photosensitive drum 23 via the aspherical lens 38 and the protective glass 39.
As a result, the electrostatic charge is removed in response to the laser beam 21, thereby forming an electrostatic latent image. When the photosensitive drum 23 on which the electrostatic latent image is formed is rotated at an outer circumferential speed V in the direction of arrow E to the developing position 30B, it comes into contact with the developing device 25A of the developing device support 44 and is released from the developing sleeve 49A. Yellow toner is supplied to the photoreceptor drum 23 and adsorbed.

A cylindrical developing device support 44 housing the developing device 25A includes a developing device 2 having a developing sleeve 49B storing magenta toner in addition to the developing device 25A.
5B, a developing device 25C having a developing sleeve 49C containing cyan toner, and a developing device 25D having a developing sleeve 49D containing black toner are provided adjacent to each other. This developing device support 44 is connected to the center shaft 5.
The developing units 25A to 25D are rotated in the direction of the arrow H by a mechanism (not shown) around the center of the photosensitive drum 23, and each time the transfer of each color to the transfer paper P attached to the transfer drum 26 is completed, the developing units 25A to 25D are rotated in the direction of the arrow H by a mechanism (not shown). It is moved to the development position 30B.

For example, the toner image formed with the first yellow toner is transferred to the transfer position 30 of the photosensitive drum 23.
The image is transferred to the transfer paper P attached to the transfer drum 26 at point C, but between the end of the transfer and the start of the second color transfer, the developer support 44 moves in the direction of arrow H. It rotates and moves the second color magenta developing device 30B to the developing position 30B of the photosensitive drum 23.

The photosensitive drum 23, on which a toner image is formed by adsorbing toner of one color in the developing device 25B, continues to rotate, and the photosensitive drum 23 is transferred to the transfer drum 2 at the transfer position 30C.
The toner image is transferred to the transfer paper P attached to the paper 6. After the transfer at the transfer position 30C, the photosensitive drum 23 moves in the direction of arrow E.
The photoreceptor drum 23 continues to rotate further in the direction, and the photoreceptor drum 23 is
The residual toner adhering to the surface of the photosensitive drum 23 is removed, and the residual potential on the surface of the photoreceptor drum 23 is further removed by the erasing and neutralizing lamp 46.

The rotating shaft of the photosensitive drum 23 is connected to the photosensitive drum 23 through a pulley 51 that is connected to the drive shaft of the pulse motor 24 and a timing belt 52. The signal is transmitted to the pulley 53 which is connected to the pulley 53.

The transfer drum 26 is configured such that the rotational force from the pulse motor 24 is transmitted to a pulley 56 to which a rotating shaft of the transfer drum 26 is connected via a timing belt or a gear (not shown). There is. Further, in addition to the photoreceptor drum 23, a paper feed roller 57, a corona charger 58 for removing electricity from the transfer paper, and a movable guide plate 59 are arranged around the transfer drum 26.

When the transfer paper P stored in the paper feed cassette 29 is fed one by one by the rotational drive of the paper feed roller 57, the gripper 28 provided on the flat part 26a of the transfer drum 26 grips the transfer paper P stored in the paper feed cassette 29 one by one. Hold the tip of P. Subsequently, by applying a bias voltage to the transfer drum 26, the transfer paper P is attached to the transfer drum 26. The transfer drum 26 to which the transfer paper P is attached rotates in the direction of arrow F at the same speed as the photosensitive drum 23.

Then, at the transfer position 30C, the leading edge position of the toner image on the photosensitive drum 23 and the leading edge position of the transfer paper P match, so that the toner image formed on the photosensitive drum 23 is transferred to the transfer drum. The image is transferred to the transfer paper P on 26. Then, the toner image formed on the photosensitive drum 23 for the next image information is also transferred to the transfer paper P on the transfer drum 26. Thereafter, it operates in the same manner as above. This series of operations is repeated until full-color transfer, in which four colors are superimposed and transferred, is completed.

When the transfer of toner images of all colors is completed, a movable guide plate 59 whose one end is rotatably supported and whose other end is movable toward and away from the surface of the transfer drum 26 moves toward the surface of the transfer drum 26. For example, from a position (59a) several cm away from 5
By being moved in the direction 9b, it comes into contact with the transfer drum 26.

As a result, the transfer paper P adhering to the transfer drum 26 is peeled off by the movable guide plate 59 and guided to the fixing device 31 provided near the movable guide plate 59.
The toner is conveyed between a heat roller 60 and a pressure roller 61 in the fixing device 31 . The conveyed transfer paper P has a toner image heated and fixed onto the transfer paper P by a heat roller 60 and a pressure roller 61, and then is further conveyed by paper discharge rollers 62 and 63 and discharged onto a collection tray 32.

FIG. 4 schematically shows the overall control system of the scanner 1 and printer 2. That is, the CPU 70 as a control unit that controls the entire scanner 1 has a program ROM 72 via an internal bus 71, a RAM 73 in which various data are stored, a lamp regulator 74 that adjusts the light amount of the exposure lamp 6, and the 1. A motor control circuit 76 that rotationally controls the carriage motor 75 that moves the second carriages 5 and 8, a read signal control circuit 77 that controls the read signal (image information) supplied from the line sensor 12, and a read signal control circuit. a color signal processing circuit 78 that performs image processing on the read signal (image information) supplied from 77; a printer I/F control circuit that outputs the image information processed by the color signal processing circuit 78 as a read result to the printer 2; 79, an operation panel 80 for inputting various instructions such as erasing binding margins and document size, or displaying various states; various sensors 81; and an interrupt signal for generating an interrupt signal in response to interface signals of the printer 2, etc. They are respectively connected to a generating section 82 and a horizontal synchronizing signal supply section 83 that supplies an internal or external horizontal synchronizing signal.

The CPU 90 as a control unit that controls the entire printer 2 also has a program ROM 92 via an internal bus 91, a RAM 93 in which various data are stored,
A paper feed motor 94 that rotationally drives the paper feed roller 57, a first motor control circuit 95 that rotationally controls the paper feed motor 94 and the pulse motors 24, 27, and a developer switching motor 9.
6, a second motor control circuit 99 that controls the rotation of the fuser motor 97 and the cleaner motor 98, a third motor control circuit 101 that controls the rotation of the high-speed rotation motor 33 and the wire cleaning motor 100, the developer 25A, ~25
A high-voltage power supply 102 that applies a developing bias to D, a charging charger 43, a transfer bias to the transfer drum 26, a scanner I/F control circuit 103 that inputs an image signal from the scanner 1, a laser diode 104, and a horizontal synchronization signal generator. a laser drive control circuit 106 that controls 105;
and are connected to various sensors 107, respectively. Next, the transfer state of the interface signal on the interface line S between the scanner 1 and the printer 2 will be explained using FIG.

In FIG. 1, a power-on signal (POWR signal) is a signal indicating that the printer 2 is powered on. The print ready signal (READY signal) is a signal indicating that the printer 2 is in a print ready state. The initialization signal (PRIM signal) is a signal used when the scanner 1 wants to initialize the printer 2. The image formation request signal (PREPR signal) is a signal for causing the printer 2 to perform a print standby operation and prepare to start a print operation at any time.

[0035] Print request signal (PREQ signal)
is a request signal for a print operation from the printer 2. This is a signal that the printer 2 notifies the scanner 1 that it can receive a print signal (PRINT signal). That is, the printer 2 receives P from the scanner 1.
This indicates that the printer is in a state where it can immediately start a printing operation upon receiving the RINT signal.

Command/Status Data Line (CSDT)
line; second transmission means) Sa is the scanner 1 and printer 2
This is a bidirectional data line used for communicating (transferring) command data or status data between serial data.

The clock signal (CSCK signal) is a signal used for transmitting and receiving the command data and status data, and is transmitted from the scanner 1 to the printer 2 via the clock signal line (first transmitting means) Sb.

The busy signal (PBSY signal; processing information) is a signal indicating that the printer 2 has received command data from the scanner 1 and is performing an operation corresponding to the command data. (transmission means) Sd from the printer 2 to the scanner 1. The printer 2 performs an operation corresponding to the command data from the scanner 1, and turns off the busy signal when it is ready to respond with the corresponding status data.

The discrimination signal (STAT signal; identification data) is a signal emitted from the scanner 1 to distinguish whether the CSDT line is transmitting command data or receiving status data. 3 transmission means)
Sc is sent from the scanner 1 to the printer 2.

The vertical synchronization signal (VSYN signal) is a signal for synchronizing the printing operations of the scanner 1 and the printer 2, and is emitted from the printer 2. Similarly, the horizontal synchronization signal (HS
YN signal) is also a signal for synchronizing the printing operations of the scanner 1 and the printer 2. Page printing operation end signal (PG
The END signal) is a signal for notifying the scanner 1 that the printing operation for one page has been completed.

The transmission start signal (VDEN signal) is a signal emitted from the scanner 1 when the signal for transmitting image information from the scanner 1 is started in response to the vertical synchronization signal from the printer 2. During transfer, it remains on, indicating that input is in progress. Then, it is reset to off by the PGEND signal from the printer 2.

The data lines (VDAT7-0) are data lines for transferring image information from the scanner 1 to the printer 2, and are transmitted from the scanner 1 to the printer 2 via the data line Se.

The synchronous clock signal (VCLK signal) is a synchronous signal for transferring image information, and is sent from the scanner 1 to the printer 2 via the synchronous clock signal line Sf.

Next, the operation of the above configuration will be described with reference to timing charts of the interface signal printing operation by the scanner 1 and printer 2 shown in FIGS. 5(a) to 5(m).

First, when power is turned on to the scanner 1 and the printer 2, a warming-up operation is started, and communication of command data and status data is started. What is communicated at this time is the size of the transfer paper P, the total number of copies used by the developer of each developing device (25A, 25B, 25C, 25D), the total number of copies used by the photoreceptor drum 23, and the total number of copies used by the fixing device 31. This is information about consumables such as the number of copies used, the total number of copies used in the main body of the machine, or information inside the machine of the printer 2. Based on this information, the printer 2 is also displayed on the operation panel 80 of the scanner 1.
Information about can be displayed.

When the warm-up of the printer 2 is completed and the printer 2 becomes ready for printing, the READY
The signal is turned on and the printer 2 notifies the scanner 1.

In this state, when the copy start button on the operation panel 80 of the scanner 1 is pressed and communication of command data and status data between the scanner 1 and the printer 2 is started, the process shown in FIG. 5(f) occurs. Like PREP
The R signal turns on. When the printer 2 determines that the PREPR signal is on, it rotates the developer holder 44 according to the pre-designated color designation, and prints Y (yellow), M
(magenta), C (cyan), K (black)
Three developing devices (25A, 25B, 25C, 25D) are set to contact the photosensitive drum 23, a step motor 27 that rotationally drives the transfer drum 26, a high-speed rotation motor 33 that rotationally drives the polyhedral rotating mirror 34, and a cleaner. 45
The cleaner motor 98 of the fuser 31, the fuser motor 97 of the fuser 31, and the charger 43 are turned on to standby the printing operation.

[0048] The printer 2 is on standby for printing operation,
When the high-speed rotation motor 33 of the polygonal rotating mirror 34 reaches a constant speed, the laser diode controlled by the laser drive control circuit 106 is turned on, and the light beam causes the horizontal synchronization signal generation optical beam sensor 105 to move as shown in FIG. ) generates the horizontal synchronization signal (HSYN signal) shown in
Start sending signals to scanner 1. This HSYN signal is used by both the printer 2 and the scanner 1, and is very important for commonizing horizontal synchronization. Also, this H
The SYN signal continues to be sent while the PREPR signal is on.

Unless this HSYN signal is supplied from the printer 2 to the scanner 1, the printer 2 and scanner 1 cannot be synchronized. Therefore, scanner 1 is P
After turning on the REPR signal, the H shown in FIG. 5(c)
The status of the printer 2 is checked to see if the SYN signal is being output.

After this standby operation is completed, the printer 2 sends a PREQ signal to the scanner 1 when the transfer drum 26 reaches a predetermined position (not shown). The transfer drum 26 rotates in conjunction with the photoreceptor drum 23, and is configured such that it cannot be stopped. Furthermore, the transfer drum 26 is provided with a gripper 28 that grips the transfer paper P, and the position at which the transfer paper P is gripped is determined in advance. Therefore, the transfer paper P
The transfer drum 26 determines not only the timing at which paper feeding starts but also all timings related to printing. Therefore, the position of the transfer drum 26 is constantly monitored by various sensors 107, and the paper feeding start timing, printing start timing, and peeling claw timing are determined based on the outputs thereof.

Now, when a PRINT signal is sent from the scanner 1 in response to this PREQ signal, the printer 2 rotates the paper feed roller 57 and grips the transfer paper P between the gripper 28 attached to the transfer drum 26. wear. continue,
When the transfer drum 26 comes to a predetermined synchronization position with the scanner 1, the printer 2 performs a process (see FIG. 5) with respect to the scanner 1.
Send the VSYN signal shown in d). Since this VSYN signal requires time for the carriage motor 75 of the scanner 1 to start up, it is output earlier than the start of actual image information transfer.

Upon receiving the VSYN signal, the scanner 1 moves the first carriage 5 to perform a black shading operation, and then, when the first carriage 5 comes under the shading correction plate 13, the exposure lamp 6 is turned on. , reads the shading correction plate 13 and executes white shading. Thereafter, the scanner 1 performs exposure scanning on the original G on the original platen 3 to read image information, processes the read image information, and outputs the data to the printer 2 together with the VDEN signal shown in FIG. 5(j).

The printer 2 checks the VDEN signal before and after the rise of the VSYN signal, and detects the VDE within a specified time.
Check whether the N signal has been sent. This is also confirmed by the scanner 1 at the same time, and is used to check whether synchronization has been achieved successfully. If synchronization cannot be achieved, after the printing operation is completed and the transfer paper P is discharged outside, the operator is informed of the malfunction of the machine without starting the next printing operation.

The printer 2 modulates the laser beam 21 according to the image information sent from the scanner 1, forms a latent image on the photosensitive drum 23, and uses a developing device (25A) of a specified color.
, 25B, 25C, and 25D), and the image is transferred to the transfer paper P on the transfer drum 26.

When the printing operation is completed with only a single color, the transfer paper P is peeled off by a peeling claw at the peeling position and sent to the fixing device 31. However, when printing is performed in the next color, such as in color, it is designed not to peel off. In this way, when the transfer of image information for one page is completed, the PGEND signal shown in FIG. 5(e) is sent from the printer 2 to the scanner 1.
The image transfer is completed and the VDE
The N signal is also reset. Further, the scanner 1 returns the first carriage 5 and the second carriage 8 to the reading start position to prepare for the next scan.

The printer 2 rotates the developer holder 44 upon completion of printing, and removes the developer (25) to be used for the next development.
A, 25B, 25C, 25D) is set on the photosensitive drum 23. Next, when the transfer drum 26 comes to a predetermined synchronization position with the scanner 1, the printer 2 transmits a VSYN signal to the scanner 1. In this way, the printing sequence is repeated between the scanner 1 and the printer 2. The transfer paper P that has been printed a specified number of times is peeled off by a peeling claw, fixed by a fixing device 31, and then discharged to a paper discharge tray 32.

[0057] During this peeling process, if printing is to be performed on a second sheet subsequently, the PREPR signal sent from the scanner 1 to the printer 2 is kept on. This PREPR signal is an image formation request signal as described above, and is a signal for causing the printer 2 to perform a print standby operation. In this case, the PREPR signal is a signal for maintaining a state (standby) in which the printing operation can be started at any time. When the position of the transfer drum 26 reaches the paper feeding timing, the printer 2 turns on the PREQ signal shown in FIG. 5(b) to the scanner 1, and starts the next printing sequence. In this way, the scanner 1 continues to turn on the PREPR signal to the printer 2 as long as there is a continuous printing operation.

Furthermore, even if the scanner 1 cannot output the PRINT signal shown in FIG. PRI for PREQ signal
If the NT signal can be output, PR to printer 2.
Keep the EPR signal on. This is because if the standby state is continuously requested, the printing operation can be performed quickly. In other words, once the termination sequence is entered, it takes a very long time to return to the standby state.

The operation of the timing chart in FIG. 5 describes the printing sequence for two sheets (two pages) of monochrome printing, but the same applies to multicolor printing as described above.

As shown in FIG. 7, the printer I/F control circuit 79 includes a command write register 110, a timing generation circuit 111, a parallel-to-serial converter 112,
Counter output selection circuit 113, transmission clock counter 1
14, NAND circuits 115a, 115b, 115c, inverter circuits 116a, 116b, resistors R1, R2, R3
, exclusive OR circuit (EOR circuit) 117, OR circuit 1
18 and D-type flip-flop circuit (FF circuit) 11
It is composed of 9.

In such a configuration, the transmission/reception sequence of command data and status data will be explained with reference to timing charts shown in FIGS. 6(a) to 6(o).

In this embodiment, overall control is performed by the scanner 1 having an interface with the operator, so the scanner 1 is also responsible for controlling the transmission and reception of command data. Printer 2's PBSY (
When the PBSY1) signal is off, the scanner 1 can send command data to the printer 2. At this time, the CPU 70 on the scanner 1 side instructs the command data write register 110 to write command data.

First, when the command write signal (CMWR0 signal) shown in FIG. 6(g) together with the transmission clock signal (CSCK0 signal) shown in FIG. 6(e). When a predetermined number of clock signals are sent, the printer 2
A busy signal (PBSY0 signal) is returned. The scanner 1 can reliably determine that the command data has been received by the printer 2 based on this PBSY0 signal.

At this time, if this busy signal is not returned to the scanner 1, the timing generation circuit 111
The PBSY0 signal at the next clock after the last clock is sampled with the transmission signal of the clock having the same frequency as the K0 signal, and the error signal (ERR1 signal) shown in (k) of Fig. 6 is generated.
This generates an interrupt to the CPU 70 for scanner control.

When the printer 2 receives the command data from the scanner 1, it immediately responds by turning on the PBSY0 signal and performs the operation corresponding to the command data.
After preparing the corresponding status data, the PBSY signal is turned off. The timing generation circuit 111 is a PBS
When the off state of the Y signal is detected, the CSDT shown in Fig. 6(g)
The timing generation circuit 11 shown in FIG.
Turn off the STAT0 signal output from 1.

The STAT0 signal, which is a signal for distinguishing between command data and status data, is sent to the NAND circuit 115c.
The STAT1 signal is also transmitted to the printer 2 via the distinction signal line Sc, and the status data can be transmitted via the command/status data line Sa. Thereafter, the status data is received by the scanner 1 in synchronization with the transmission clock signal (CSCK0 signal) from the timing generation circuit 111 and input to the parallel-serial converter 112. Then, when a predetermined number of clock signals are transmitted, the timing generation circuit 11
1, the CP indicates that the reception of status data has been completed.
An interrupt signal (ENDS1 signal) is set to notify U70. Thereby, the CPU 70 reads the status data in the parallel-serial converter 112 using the status read signal (STRD0 signal) shown in (n) of FIG. 6, and ends the transmission/reception sequence of command data and status data.

[0067] Normally, command data and status data are often transmitted and received using a fixed length, usually 8 bits. In this embodiment as well, the processing is normally performed using 8 bits, and the busy signal from the printer 2 is also set by eight clock transmissions and sent back to the scanner 1. In a normal print sequence, one set of 8-bit command data and status data is sufficient, but in order to form a higher quality image, condition feedback in the image forming process or life management of each part is required. As the amount of information exchanged between the scanner 1 and the printer 2 has increased due to the amount of data exchanged between the scanner 1 and the printer 2, some information cannot be handled using only 8 bits.

However, if communication in a normal print sequence is performed using 16 bits, which is twice the amount of data, problems such as time constraints will occur. For this reason, 8-bit communication is performed in a normal print sequence, etc.
If there is time available, the communication data length between the scanner 1 and the printer 2 is changed using a command/status bit length change command. This is, for example, C
8 bits or 16 bits are selected in advance by a dip switch (not shown) connected to the PU 70. As a result, the CPU 70 outputs a bit number selection signal (QSEL signal). When the QSEL signal is on, the counter output selection circuit 113 selects the output terminal Q3 of the transmission clock counter 114.
The output signal in 8-bit units from the count-up signal (
CNTUP signal), and when the QSEL signal is off, the counter output selection circuit 113 uses the output signal in units of 16 bits from the output terminal Q4 of the transmission clock counter 114 as a count up signal (CNTUP signal). There is.

In FIG. 7, the counter output selection circuit 11
3, the length is changed from 8 bits to 16 bits depending on the count of the transmission clock signal (CSCK0 signal) by the transmission clock counter 114. Returning from 16-bit length to 8-bit length may be performed after a predetermined number of 16-bit communications, or by providing command data for returning the command/status bit length to the 16-bit length command data and transmitting this command data. You can change it back later. Note that the counter output selection circuit 113 includes, for example,
It is composed of two AND circuits 113a, 113b and one OR circuit 113c. Next, synchronization between the printer 2 and scanner 1 will be explained.

As mentioned above, in the printer 2 of this embodiment, the transfer paper P stuck on the transfer drum 26 is
A color image can be obtained by accurately overlapping the developed images formed on the photosensitive drum 23 in each color. Therefore, the accuracy of this registration must be very precise.

Here, the photosensitive drum 23 and the transfer drum 2
6, for structural reasons, the printer 2 always rotates at the same circumferential speed while it is in motion. Therefore, synchronization between the printer 2 and the scanner 1 is performed using a synchronization signal from the printer 2, and the scanner 1 needs to be accurately aligned and send image information using the synchronization signal from the printer 2. As mentioned earlier, the synchronization signal includes a vertical synchronization signal (VSYN signal), which is generated by the vertical synchronization signal generator 26b that detects the position of the transfer drum 26 from the printer 2 when the synchronization is to be achieved, and a horizontal synchronization signal. There are two horizontal synchronization signals (HSYN signals) that are generated by the synchronization signal generator 105 in synchronization with laser scanning. Here, the VSYN signal will be explained with reference to FIGS. 8, 9, and 10. FIG. 8 shows the VSYN signal and the first
This shows the relationship between the speed of the carriage 5 and time.

FIG. 9 shows the scanner 1 to which the synchronization signal is input.
The operating circuit shown in FIG. 1 is composed of a CPU 70, an interrupt signal generation section 82, a motor control circuit 76, and a printer interface (I/F) control circuit 79. Further, the interrupt signal generating section 82 includes a register 82a for writing vertical synchronizing signals and horizontal synchronizing signals, a counter 82b consisting of three counting sections, and an interrupt controller 82c for controlling interrupts to the CPU 70.

The counter 82b is connected to the clock terminal CK.
1. The HSYN signal from the horizontal synchronization signal supply unit 83 supplied to CK2 is counted as a clock. It is composed of first and second counting sections and a third counting section that counts an internal basic clock from an oscillator (not shown) supplied to the clock terminal CK3, and the values of the first, second, and third counting sections are When the value set by the CPU 70 is reached, INT is output from output terminals 01, 02, and 03, respectively.
MST signal, INT VDE signal, INT MOT
A signal is now output.

FIGS. 10A to 10C show timing charts for checking whether or not the scanner 1 has been successfully synchronized with the VSYN signal of the printer 2.

In this configuration, the first carriage 5 of the scanner 1 always stops at the same position except in special cases. Therefore, the time from the start of acceleration until reaching the leading edge of the document G differs depending on each scaling ratio, but the moving distance is the same. %, the area surrounded by lines indicating the respective speeds of the first carriage 5 from its start until it reaches the leading edge of the document G is constant. first,
The movement of the scanner 1 at 50% will be explained.

[0076] In the scanner 1, from the printer 2 to the VS
When the YN signal is input, an interrupt is generated to the CPU 70. More precisely, this VSYN signal is HSYN
Transfer is performed in synchronization with the signal. This is because accurate image position can be achieved by performing this on a horizontal scanning line basis.

That is, the VSYN signal is first input to the register 82a of the interrupt signal generating section 82. The register 82a outputs the input VSYN signal to the interrupt controller 82c as a vertical synchronization interrupt signal (INT VSYN signal). The interrupt controller 82c outputs the input INT VSYN signal to the CPU 70. Based on the input INT VSYN signal, the CPU 70 uses a counter 82b to count the number of HSYN signals up to the position (up to the carriage start) calculated in advance based on the magnification.
is set in the first counting section of , and the counting operation is started. When the first counting section of the counter 82b starts counting, a motor start interrupt signal (INT MST signal) is input from the output terminal 01 of the counter 82b to the CPU 70 via the interrupt controller 82c.

When the first counting section of the counter 82b finishes counting the number of HSYN signals up to the position calculated in advance by the multiplication factor, the output terminal 01 of the counter 82b
The INT MST signal from is counted up. In response to this, the CPU 70 similarly sets the HSYN signal to the second counting section of the counter 82b to start counting the time until the image information is output. counter 8
When the second counting section of 2b starts counting operation,
The transmission start interrupt signal (INT VDE signal) is sent from the output terminal 02 of the counter 82b to the interrupt controller 82c.
is input to the CPU 70 via the printer I/
It is also input to the F control circuit 79.

[0079] At the same time, the CPU 70 also controls the counter 82.
The internal basic clock SCK1 signal is set in the third counting section of the controller b to start the counting operation. counter 82
When the third counting unit of counter 82b starts counting, a motor interrupt signal (I
NT MOT signal) is input to the CPU 70 via the interrupt controller 82c, and the motor control circuit 7
6 is input. The motor control circuit 76 is INT M
When the OT signal is input, the carriage motor 75 is operated to start scanning by the first carriage 5. At this time, the carriage motor 75 controlled by the motor control circuit 76 uses a pulse motor that can control accurate acceleration, speed, travel distance, etc., and therefore requires accurate synchronization as in this embodiment. This is particularly effective in cases where

When the second counting section of the counter 82b finishes counting the number of HSYN signals up to the position calculated in advance by the multiplication factor, the output terminal 02 of the counter 82b
The INT VDE signal from is counted up. In response to this, the CPU 70 controls the document G of the line sensor 12.
Start reading.

When the line sensor 12 starts reading the document G, the first carriage 5 is accelerated as shown in FIG. 8 and moves at a constant speed just before the leading edge of the document. The document G is scanned.

The image information of the document G read by the line sensor 12 is first input to the read signal control circuit 77, as shown in FIG. The read signal control circuit 77 is
The input image information is output to a color signal processing circuit 78 that performs color signal processing. The color signal processing circuit 78 outputs the image information after color signal processing to the printer I/F control circuit 79. The printer I/F control circuit 79 connects the interface line S
It is designed to output to the printer 2 via. The color signal processing circuit 78 includes, for example, a correction section 78a that performs filter processing and line shift correction, an arithmetic processing section 78b that performs color calculations and gradation processing, and an editing processing section 78c that performs editing processing. ing.

The image information read from the leading edge of the document G by the line sensor 12 is subjected to image processing by the color signal processing circuit 78 and output as described above, so the actual image information output is performed by the first carriage. This is carried out a little later than the passage of the leading edge of the document in step 5. Therefore, the INTVDE signal from the output terminal 02 of the second counting section of the counter 82b is incremented by taking this delay into account. In response to this, the CPU 70 starts outputting the image information.

Similarly, when the value is 100% and 200%, the first counting section of the counter 82b is changed by changing the time until the carriage motor 75 of the scanner 1 starts operating and the time from the start of the operation until image information transfer. , and set in the second counting section, and the printer 2 and scanner 1 are synchronized. As described above, even when the scaling ratio is 1%, by setting the pre-calculated time (the count number of the HSYN signal) in the first count section and the second count section of the counter 82b, the above-mentioned The same operation is possible.

However, as shown in FIG. 8, at a magnification of 400%, it takes too long to move at a constant speed, and synchronization takes a very long time, and in addition, such a magnification is rarely used. Therefore, in this embodiment, when the enlargement rate exceeds 200%, the start position of the carriage is changed to make the synchronization time the same. This is possible because the scanning range of the first carriage 5 is narrower than during normal operation and there is time margin.

As described above, the VSYN of printer 2
The scanner 1 is synchronized with the signal, but whether or not this synchronization has been successfully performed is checked in the printer I/F control circuit 79 of the scanner 1 using a circuit as shown in FIG.

That is, the vertical synchronization signal (VSYN signal)
The transmission start signal (VDEN signal) with respect to the trailing edge of the signal has a waveform with polarity inversion in this part. If the VDEN signal is sent at the same position not before or after this VSYN signal, Figure 7
FF circuit 119 is not set. This FF circuit 11
Since the clock 9 is an HSYN signal generated from the printer 2, synchronization of each scanning line can be confirmed.

[0088] If this synchronization is not successful,
A synchronization error signal (VSERR1 signal) is generated, and the CPU 70 of the scanner 1 performs processing accordingly. The set of the FF circuit 119 receives a signal (CARY
1 signal) is on. Next, the HSYN signal will be explained.

HS during normal copying operation in this embodiment
The YN signal is supplied from the printer 2 to the scanner 1. This is because the HSYN signal is generated by the scanning position of the laser beam scanned by the rotation of the polyhedral rotating mirror 34 of the printer 2, and the timing cannot be changed freely from the outside. Also, horizontal synchronization is necessary because a line buffer, which will be described later, is used to transfer image information between scanner 1 and printer 2, and the number of line buffers required is only two lines. and,
This is because if the same clock is used to read and write image information, no errors will occur.

However, if the scanner 1 is configured to use only the HSYN signal supplied from the outside (the printer 2 in this embodiment), even if the printer 2 does not need to perform an adjustment operation alone, It will not operate unless the HSYN signal is supplied. For this reason, the HSYN signal is normally generated inside the scanner 1 as well.

[0091] In scanner 1, internally created HSYN
The priority of signals and external HSYN signals is determined by printer 2.
However, it is very difficult to make the distinction. Therefore, in the past, the output of an internal HSYN signal generation counter and a means for switching between the external HSYN signal were used to distinguish between them. However, in this case, if the HSYN signal from the outside is not supplied by any chance, the supply to the line sensor 12 will be stopped and there is a risk that the line sensor 12 and other components of the scanner 1 will be adversely affected. .

In this embodiment, internal HSYN signal generation is performed using a counter that counts the period of the HSYN signal and a counter that counts the period of the HSYN signal.
It is composed of two counters that count the ON period of the N signal, and is configured to reset the counter that counts the period with the external HSYN signal, giving priority to the external HSYN signal, but when it is not supplied externally. , it is possible to immediately generate the HSYN signal internally.

[0093] This is shown in FIGS. 12(a) to (d) and FIG.
(a) to (e), the timing charts shown in FIGS. 14A and 14B, and the horizontal synchronization signal supply section 83 shown in FIG.
This will be explained with reference to the circuit. That is, the horizontal synchronization signal supply section 83 includes, for example, the counter 120 and the AND circuit 1.
21, 122, 123, inverter circuit 124, 125
, OR circuits 126, 127, and a D-type flip-flop circuit 128.

The counter 120 counts the period of the HSYN signal based on the internal basic clock signal (SCK1 signal) shown in FIG. 12(d) supplied from an oscillator (not shown), and also counts the width of the HSYN signal. It has become. The internal horizontal synchronization signal (MHS) shown in FIG. 12(a) is generated by the two signals of the counter 120, output CO1 shown in FIG. 12(b) and CO2 shown in FIG. 12(c).
YN signal) is created. Here, when an external horizontal synchronization signal (OUTRHSYN1 signal) is input from the outside, the count value of the counter 120 is reset.

OUTRHSYN1 shown in FIG. 13(d)
While the signal is off, the counter 120 continues counting, but when the OUTRHSYN1 signal is input at a constant cycle, the count value of the counter 120 becomes OUTRHSYN1.
It was reset when the YN1 signal was input, and the MHSY
The N signal will not be generated. This is OUTRHS
The period in which the OUTRHSYN1 signal is off in the input period of the YN1 signal is equal to the MHSYN signal in the period of the MHSYN signal.
This is because the counter 120 is reset by the OUTRHSYN1 signal before it finishes counting the fixed period for generating the MHSYN signal because it is shorter than the off period of the N signal.

In this way, while the OUTRHSYN1 signal is being input, the MHSYN signal is not generated internally. However, OUTRHSYN1
When the signal is no longer input, since the counter 120 is operating, the MHSYN signal with the same cycle is generated internally. Output signal C01 shown in FIG. 13(a),
Output signal C02 shown in (b) and MHSY shown in (c)
The N signal is the MHSYN signal and OUTRHSYN at this time.
1 shows the relationship between signals.

In this way, the internal basic clock signal (SCK
1 signal) is sufficiently shorter than the pulse width of the HSYN signal supplied from the outside, a counter 120 configured to count the period of the HSYN signal configured to be reset by the HSYN signal from the outside, and the counter 120 configured to count the period of the HSYN signal by the output thereof. The counter 120 that determines the width to be operated makes it possible to generate the MHSYN signal with priority given to the HSYN signal from the outside. HSYN shown in FIG. 13(e)
1 signal is MHS with priority given to OUTRHSYN1 signal.
This shows that a YN signal is also generated and output.

Next, image information is transferred in the image forming apparatus of this embodiment by two line buffers 130 and 131 provided in the printer 2, as shown in FIG. That is, for example, when the scanner 1 is writing data to the line buffer 130, the printer 2 reads data written one line before from the line buffer 131. line buffer 1
30 and 131 are switched each time by outputting a switching signal by a signal switching section (not shown) based on the HSYN signal (horizontal synchronization signal), and inputting this switching signal to the changeover switches 132 and 133. It is supposed to be done.

Conventionally, as shown in FIG. 17, a synchronous clock signal (VC
LK signal), the printer 2 receives image information (VDAT7
This would not have been necessary if it had been done by receiving a signal (~0 signal). However, this method
In response to the synchronized clock signal (VCLK signal) shown in FIG. 18(a), the scanner 1 reads the image information (shown in FIG. 18(b)).
VDAT signal), there is a limit to the transfer speed, and there is a problem that it is not suitable for high-speed data transfer.

On the other hand, as shown in FIG.
In the method of sending the synchronized clock signal (VCLK signal) for transfer with the VDAT7-0 signal from the same direction, the method shown in Figure 2
As shown in Figure 0, both the clock signal (VCLK signal) in (a) and the image information (VDAT) in (b) have almost the same delay, so even faster transfer is possible.However, in this case , line buffers 130, 131
The configuration must be such that the scanner 1 can write at any speed, which is necessary for high-speed data transfer.

As explained above, according to the above embodiment,
When the printer side receives command data sent from the scanner along with a predetermined number of command transfer clocks, the printer side returns a busy signal indicating that the command data has been received to the scanner side, so that the command data can be transferred immediately. , the scanner side can know the success of command transfer. Furthermore, when the printer side is ready to execute the operation corresponding to the command data and prepare the status data for reply, the busy signal output from the printer side is canceled, so the status data is also used as the command data sending side. It can be read under the initiative of the scanner side.

[0102] Furthermore, since reading can be performed on the initiative of the scanner side, it is now possible to easily change the data length for command/status data transfer (exchange) from the usual 8 bits to 16 bits. Ta. By changing the normal 8 bits to 16 bits, which is twice the amount of data, it is possible to cope with an increase in the amount of information exchanged between the scanner and the printer, such as feedback of conditions of the image creation process for higher quality copy execution. I can do it. Furthermore, since data length changes can be easily handled by changing the busy signal determination position each time the data length is changed, busy signal determination can also be easily performed.

Furthermore, by sampling this busy signal at the clock next to the last clock of the transfer clocks having the same timing as the transfer clock, the busy signal can be determined reliably using a simple algorithm.

[0104]

As described in detail above, according to the present invention, in an apparatus in which serial command data and status data are transmitted and received between the reading means and the image forming means, the success or failure of command data transmission can be immediately determined. In addition, it is possible to provide an image forming apparatus in which the status data can be received under the initiative of the reading means as the command transmitting side.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the state of transfer of interface signals between a scanner and a printer in an embodiment of the present invention.

FIG. 2 is a configuration diagram showing the configuration of a scanner.

FIG. 3 is a cross-sectional view schematically showing the internal structure of the printer.

FIG. 4 is a block diagram showing the overall schematic configuration of a scanner and a printer.

FIG. 5 is a timing chart showing the operation of each interface signal in an image transfer sequence.

FIG. 6 is a timing chart showing the operation of each signal in transmitting and receiving command data and status data.

FIG. 7 is an electrical circuit diagram showing the configuration of a printer I/F control circuit.

FIG. 8 is a timing chart showing the operation of signals related to vertical synchronization between a scanner and a printer.

FIG. 9 is a diagram showing a configuration related to vertical synchronization between a scanner and a printer.

FIG. 10 is a timing chart showing an operation for confirming vertical synchronization between a VSYN signal and a VDEN signal.

FIG. 11 is a block diagram showing signal processing of image information read by a scanner.

FIG. 12 is a timing chart for explaining the generation of an internal horizontal synchronization signal (MHSYN signal).

FIG. 13 is a timing chart for explaining the supply timing of a horizontal synchronization signal (HSYN1 signal).

FIG. 14 is a diagram for explaining internal and external horizontal synchronization signals.

FIG. 15 is a circuit diagram showing an electrical circuit that provides a horizontal synchronization signal.

FIG. 16 is a circuit diagram showing the configuration of a line buffer.

FIG. 17 is a diagram for explaining a conventional example regarding transfer of a VCLK signal and a VDATA signal.

FIG. 18 is a diagram for explaining a conventional example regarding transfer of a VCLK signal and a VDATA signal.

FIG. 19 is a diagram for explaining an embodiment regarding transfer of a VCLK signal and a VDATA signal.

FIG. 20 is a diagram for explaining an embodiment regarding transfer of a VCLK signal and a VDATA signal.

[Explanation of symbols]

1...Scanner, 2...Printer, 5...First carriage, 8
...Second carriage, 12...Sensor, 21...Laser light, 2
3... Photosensitive drum, 26... Transfer drum, 25A, 25B
, 25C, 25D...Developer, 31...Fixer, 70,90
...CPU, 76...Motor control circuit, 79...Printer I/
F control circuit, 82... interrupt signal generation section, 83... horizontal synchronization signal supply section.

Claims (3)

[Claims] 1. A reading means for reading an image; an image forming means for forming an image corresponding to the image read by the reading means on an image carrier; a first transmitting means for transmitting a reference clock; and a command for specifying an operation of the image forming means from the reading means to the image forming means in synchronization with the reference clock transmitted by the first transmitting means. send the data,
and a second transmitting means for transmitting status data indicating the operating state of the image forming means from the image forming means to the reading means, and an identification for identifying the type of data transmitted by the second transmitting means. third transmitting means for transmitting data from the reading means to the image forming means;
When the command data is transmitted to the image forming means by the second transmitting means, the reading means can determine that the image forming means has received the command data. An image forming apparatus comprising: fourth transmitting means for transmitting processing information indicating that the content of the command data transmitted to the image forming means is being judged to the reading means. 2. The image forming apparatus according to claim 1, wherein the second transmitting means selectively changes data lengths of status data and command data to be transmitted. 3. The fourth transmitting means determines that the content of the command data transmitted to the image forming means is determined at the timing of a first reference clock generated after outputting the command data. The image forming apparatus according to claim 1.