GB2203381A - Printer using a thermosensitive stencil for reproducing the same or different images of a plurality of documents side by side on a single sheet of greater size than the documents - Google Patents

Abstract

In a printer of the type comprising an automatic original document feeding section 12, a reading section 14, an image making section 18 cutting a thermosensitive stencil and a printing section 20 for supplying ink to the cut stencil, control 22 controls document feed 30 and roller 66 (which transports stencil 64 while pressing the stencil against thermal head 60) such that when the image making area of the stencil is great enough to accommodate the number of images set to be produced side by side the roller 66 is deactivated until a document is discharged and the same or a different document is ready to be fed again to reading station 14 so that its image can also be cut into the stencil, whilst when the image making area is not great enough the roller 66 is not deactivated. A particular region of each of the documents may be specified by a marking sheet in order to extract only those image fragments which lie in that region, the image fragments extracted from the different documents being produced side by side on the single stencil. <IMAGE>

Description

PRINTER USING A MIMEOGRAPH The present invention relates to an image recorder with a capability of reproducing the same or different images which are carried on a plurality of original documents of a relatively small size on a single paper sheet which is greater size than the original documents, and a capability of extracting only fragments of an image of each of a plurality of original documents of a relatively small size which is specified by a marking sheet so as to reproduce the extracted image fragments together on a single paper sheet which is greater size than the documents. More particularly, the present invention is concerned with a printer of the type using a mimeograph in the form of a thermosensitive stencil.

A printer of the type using a thermosensitive stencil as a mimeograph known in the art is generally made up of a device for reading an image which is carried on a document, a device for cutting a stencil to make a mimeograph which is representative of the image read, and a device for supplying ink to the mimeograph to print out the image on a paper sheet. The reading device includes a feeding member so arranged as to feed a document along a glass platen, reading member which forms a part of optics and reads the document while the latter is in transport, and a sensing member for sensing the document which is read by the reading member. On the other hand, the mimeograph making device includes a thermal head, and a platen roller for pressing a stencil paid out from a roll against a heating portion of the thermal head and rotatable to transport the stencil.The printing device includes a print drum for supplying ink to a stencil perforated so as to print out image data on a paper sheet.

The prior art printer of the type described is only capable of faithfully reproducing the image of a single document in that area of a stencil which corresponds to one mimeograph.

Specifically, it is not capable of providing two identical images of a single document of, for example, 35 size side by side on a single stencil whose mimeograph making area is of B4 size (double the B5 size), or providing images of two different documents of B5 size which may be the same or different from each other side by side on a single stencil whose mimeograph making area is of B4 size. Such a capability is unachievable unless, for example, a B4 document on which two identical images of a B5 document are carried side by side is prepared by using another printer and then used to make a mimeograph.

This results in a troublesome and time-consuming mimeograph making operation.

Further, with the prior art printer of the type using a stencil, it is impracticable to demarkate or select a particular region of each of two different documents of, for example, B5 size by using a marking sheet so that only those image fragments which lie in the demarkated regions may be extracted and printed out side by side on a single B4 stencil. In this case, too, a B4 document having the extracted regions of the B5 documents printed thereon side by side has to be prepared beforehand by, for example, a copier at the cost of time.

It is, therefore, an object of the present invention to provide a printer capable of forming the same or different images which are printed on a plurality of relatively small documents on a single thermosensitive stencil which is greater size than the documents.

It is another object of the present invention to provide a printer capable of extracting a desired region of each of a pluralty of relatively small documents which is selected by a marking sheet and forming the extracted regions together on a single stencil which is greater size than the documents.

It is another object of the present invention to provide a generally improved printer of the type using a mimeograph.

In accordance with the present invention, there is provided a printer capable of producing a mimeograph on which images of a plurality of documents smaller in size than a thermosensitive stencil are provided side by side in a predetermined mimeograph making area of the stencil and in an intended direction of transport of the stencil, comprising document feeding means for feeding the documents one at a time through an image reading station, reading means for reading an image printed on the document being fed, sensing means for producing an end-ofread signal by sensing a time when the image on the document has been fully read, a thermal head for perforating the stencil to form the image read, roller means rotatable to transport the stencil while pressing the stencil against the thermal head, setting means for setting a number of images to be produced side by side on the stencil while generating a set signal, and control means for controlling the document feeding means and roller means after determining whether the mimeograph making area of the stencil is great enough to accommodate the number of images set in response to the set signal from the setting means, such that when the mimeograph making area is great enough to accommodate the number of images, the roller means is deactivated until the document fed and discharged by the document feeding means becomes ready to be again fed to the reading station while, when the mimeograph making area is not great enough to do so, the roller means is not deactivated.

In accordance with the present invention, there is also provided a printer capable of producing a mimeograph on which images of a plurality of documents smaller in size than a thermosensitive stencil may be provided side by side in a predetermined mimeograph making area of the stencil and in an intended direction of transport of the stencil, and prior to reading the image of any of the documents reading a marking sheet which includes an indication for specifying a particular region of the image, storing data associated with the marking sheet in a memory, and processing in a preselected image processing mode the image of the document read after the marking sheet based on the particular region which is stored in the memory, the printer comprising document feeding means for feeding the document one at a time through an image reading station, reading means for reading the image printed on the document being fed, sensing means for producing an end-ofread signal by sensing a time when the image on the document has been fully read, a thermal head for perforating the stencil to form the image read, roller means rotatable to transport the stencil while pressing the stencil against the thermal head, setting means for setting a number of images which are to be produced side by side on the stencil while generating a set signal, image processing means for processing the image of the document in a preselected image processing mode by using the marking sheet, and control means for controlling the document feeding means and roller means after determining whether the mimeograph making area of the stencil is great enough to accommodate the number of images set in response to the set signal from the setting means, such that when the mimeograph making area is great enough to accommodate the number of images, the roller means is deactivated until the document fed and discharged by the document feeding means becomes ready to be again fed to the reading station while, when the mimeograph making area is not great enough to do so, the roller means is not deactivated.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is an external perspective view of a printer in accordance with the present invention; Fig. 2 is a vertical section showing the constrution of the printer of Fig. 1; Fig. 3 is a fragmentary view of an operation board associated with a first embodiment of the present invention; Fig. 4 is a schematic block diagram of a controlling section associated with the operation board of Fig. 3; Fig. 5 is a flowchart demonstrating the operation of the controlling section; Figs. 6A to 6C and 7A and 7B are each representative of how the same or different images are provided side by side on a single stencil;; Fig. 8 is a view associated with a second embodiment of the present invention, showing how a particular region of a document is selected and extracted by a marking sheet; Fig. 9 is a fragmentary view showing an operation board associated with the second embodiment of the present invention; Fig. 10 shows various configurations of boarder lines which may be written on the marking sheet; Fig. 11 is a view associated with the second embodiment of the present invention, showing how demarkated regions of different documents are formed together on a single stencil; Fig. 12 shows a group of documents and marking sheets which may be laid on a glass platen; Fig. 13 is a schematic block diagram showing a controlling section associated with the second embodiment of the present invention; Fig. 14 shows bilevel pixel data which are written in a memory;; Figs. 15 and 16 are views explanatory of decision processing which is applied to pixel data written in the memory; Fig. 17 is a schematic block diagram showing a specific constrution of a density conversion timing circuit and that of the memory; Fig. 18 is a timing chart representative of various signals which appear in the circuitry of Fig. 17; Fig. 19 is a schematic block diagram showing a specific constrution of an inside/outside decision circuit; Figs. 20A to 20C are flowcharts showing various timings for causing the inside/outside decision circuit to perform decision; Fig. 21 is a schematic block diagram showing an alternative arrangement for decision processing; and Fig. 22 is a schematic block diagram showing a specific construction of an image processing circuit.

Referring to Fig. 1 of the drawings, a first embodiment of the printer in accordance with the present invention is shown and generally designated by the reference numeral 10. The printer 10 is generally constituted by an automatic document feeding section 12, a reading section 14 for reading an original document, an operating section 16, and a body 15 in which a mimeograph making section 18 for cutting a stencil and a printing section 20 for supplying ink to the stencil cut by the section 18 are accommodated. Also accommodated in the body 15 is a control section 22.

Fig. 2 shows the printer 10 in detail. As shown, the reading section 14 has a document transport path 28 which is defined by a glass platen 24 and an upper guide plate 26. A feed roller pair 30 is located at the upstream side of the transport path 28 so as to feed into the transport path 28 documents 34 which are sequentially inserted via an inlet 36 and separated by separator means 38, the lowermost document being fed first Located at the downstream side of the transport path 28 is a discharge roller pair 40 which functions to driven the document 34 out of the transport path 28 onto a tray 44 via an outlet 42. The reading section 14 further includes a first document sensor 46 responsive to the entry of a document 34 into the transport path 28, a second document sensor 48 response to the leading edge of a document 34, and a stepping motor 50 for driving the feed roller pair 30.

Disposed below the glass platen 24 are a fluorescent lamp 52 adapted to illuminate a document 34 when the latter is transported to a predetermined exposure station, i. e., to substantially the center of the glass platen 24, a mirror 54, a lens unit 56, a CCD (charge coupled device) image sensor 58 serving as a reading member, and the controlling section 22.

The mimeograph making section 18 includes a thermal head 60 having a heating portion 60a on its surface, and a platen roller 66 rotatable to transport a thermosensitive stencil 64 which is paid out from a roll 62 while urging the stencil 64 against the heating portion 60a of the thermal head 60. Located in front of the stencil 64 with respect to an intended direction of stencil transport are a cutter 68 for cutting the stencil 54 at a predetermined length, and a transport roller 70 for driving the stencil 64 toward the printing section 20.

The printing section 20 includes a print drum 72 which wraps the stencil 64 fed from the mimeograph making section 18 therearound while clamping the stencil 64 by means of a clamp 74, a roller pair 75 for removing the stencil 64 from the drum 72 at the end of printing and driving it to a collecting box 76, a sheet feeding section 82 in which the uppermost one of paper sheets 73 which are stacked on a tray 71 is fed by a roller 77 while being separated from the others by a roller 78 and a separator blade 79 and driven toward the print drum 72 via a feed roller pair 80, a sheet discharge section 90 constituted by a belt 86 and a discharge tray 88 for discharging the paper sheet 72 on which data have been printed out by the print drum 72 and a press roller 84.The feed roller pair 80 is operative to feed the paper sheet 73 to between the print drum 72 and the press roller 84 in synchronism with the rotation of the drum 72.

The print drum 72 is provided with an ink supply section thereinside so as to press the paper sheet 73 in cooperation with the press roller 84, whereby ink is transferred to the paper sheet 73 via apertures which are formed through the stencil 64. The pirnt drum 72 is constructed into a drum unit together with an ink container, an ink supply pump, an ink supply unit and others, not shown. A plurality of drum units such as those individually containing black ink and red ink are selectively usable with the drum unit. For details of a drum unit mounting and dismounting structure, a reference may be made to Japanese Laid-Open Utility Model Publication (Kokai) No. 61-85462.

Referring to Fig. 3, an operation board 16a included in the operating section 16 is shown in a fragmentary view. There are arranged on the operation board 16a a start key 92, a stop key 94, a display 96, numeral keys 98, and a juxtapose mode key 100.

As shown in Fig. 4, the controlling section 22 includes a controller 102 for controlling the entire printer 10 and constituting a central processing unit (CPU). Connected to the controller 102 is a memory 104 which includes a read only memory (ROM) and a random access memory (RAM) for storing beforehand a length of a mimeograph making area which defines one mimeograph, or plate, and a program represented by a flowchart in Fig. 5. Also connected to the controller 102 are the juxtapose mode key 100 and start key 92 of the operation board 16a. With this construction, the controlling section 22 delivers various commands to the reading section 14 and mimeograph making section 18.

Hereinafter will be described the operation of the printer 10, particularly the reading and plate making operations, in detail.

First, assume a case wherein two identical images of a single B5 document 34 which is dimensioned X x Y as shown in Fig. 6A are to be produced side by side on a single stencil 64 having a mimeograph making area 64a which is dimensioned 2X x Y as shown in Fig. 6B, the resulting images on the stencil 64 being shown in Fig. 6C. After the juxtapose mode key 110 and then the start key 92 has been pressed, a document 34 is laid on the tray 32 and pushed into the inlet 36. The document 34 is stopped when its leading edge is moved past the separator means 38 to abut against the feed roller pair 30. When the document 34 is moved so, the first document sensor 46 senses it and, upon the lapse of several seconds, the feed roller pair 30 is rotated to drive the document 34 into the transport path 28.

When the second document sensor 48 senses the leading edge of the document 34, the rotation of the feed roller pair 30 is stopped after feeding the document 34 by a further length I as measured from the position of the sensor 48 to a predetermined exposure station. This length I is secured by controlling the angle of rotation of the stepping motor 50. As the document 34 reaches the exposure station, the lamp 52 is turned on to illuminate the document 34. Light reflected by the document 34 is redirected by the mirror 54 and then focused by the lens unit 56 onto the image sensor 58. The light incident to the image sensor 58 is photoelectrically converted by the image sensor 58 into an electrical signal which is fed to the controlling section 22.

While the document 34 is read so, the platen roller 66 pressing the stencil 64 against the heating portion 60a of the thermal bead 60 is rotated to transport the stencil 64. As a result, the stencil 64 is perforated by the heating section 60a which generates heat based on the electrical signal from the controlling section 22, i. e. image data.

As stated above, the stencil 64 is sequentially cut to form an image in synchronism with the feed of the document 34. When the second document sensor 48 senses the trailing edge of the document 34, the controlling section 22 to which the output of the document sensor 48 and that of the juxtapose mode key 100 are applied determines via the RAM 108 whether the remaining part of the area 64a of the stencil 64 is long enough to accommodate another document image, after the document 34 and stencil 64 have individually been fed by a length of I from the position of the sensor 48. If the result of decision is positive, the rotation of the platen roller 66 is stopped to interrupt the mimeograph making operation.While the platen roller 66 is held in a halt, the feed roller pair 30 and discharge roller pair 40 are further rotated to fully discharge the document 34 onto the tray 44 and then stopped.

Subsequently, the document 34 discharged onto the discharge tray 44 is again placed on the feed tray 32 and then fed via the inlet 36 into the document transport path 28. Then, the feed roller pair 30 is topped after feeding the document 34 by the length of I as measured from the position of the second document sensor 48 which is responsive to the leading edge of the document 34, as stated earlier. In this condition, the start key 92 is pressed so that the image sensor 58 reads the document 34 while, at the same time, the heating portion 60a of the thermal head 60 cuts the stencil 64. When the stencil 64 is cut over the predetermined mimeograph making length, the heating portion 60a is deactivated. However, the platen roller 66 is further rotated to feed the stencil 64 by a predetermined amount and then stopped.Upon the stop of the platen roller 66, the cutter 68 is actuated to cut the stencil 64 at a predetermined length. This cut length of stencil 64 is driven by the transport roller 70 toward the drum 72. On the other hand, the document 34 is driven out of the transport path 28 by the feed roller pair 30 and discharge roller pair 40 onto the discharge tray 44.

By the procedure described above, two identical images of the single B5 document 34 are produced side by side on the stencil 64 whose mimeograph making area 64a is of B4 size. In the case that the length of the remaining part of the area 64a is less than a predetermined length, i. e., the length of B5 size, the controlling section 22 decides that the juxtapose print mode is impossible and drives the platen roller 66 without interruption so as to fully feed the stencil 64 by the amount corresponding to one mimeograph. Therefore, when a B4 document 34 is inserted and then the juxtapose mode key 100 and start key 92 are sequentially pressed, the juxtapose print mode is not effected and rePlaced with an ordinary print mode.

Next, assume a case wherein two different documents 34a and 34b of size B5 and each carrying a different image thereon as shown in Fig. 7A are reproduced side by side on the single stencil 64 having the mimeograph making area 64a of B4 size, as shown in Fig. 73. When such a stencil 64 is used, the period of time necessary for printing out the image data on the B4 paper sheet 73 is halved compared to a case wherein mimeographs of B5 documents are prepared one by one to sequentially print out image data on B5 paper sheets. In additibn, only a single stencil suffices. Further, the juxtapose mode key 100 will prove effective when a person desires to produce numerous reproductions of B4 size by using some different B5 documents, fold the individual reproductions to page, and bind them. Another advantage attainable with the juxtapose mode key 100 is that, for example, two identical images of a B5 document can be printed out together on a B4 stencile without recording to a copier.

A printer representative of a second embodiment of the present invention has a capability of extracting a particular region of each of a plurality of relatively small documents, which is specified by using a marking sheet, and forming those regions together on a single stencil which is greater size than the documents. The construction of such a printer is substantially identical with that of the printer 10 of Figs. 1 and 2.

First, a reference will be made to Fig. 8 for describing a case wherein only those image fragments which lie in a demarkated region of a document are extracted with the others deleted. A person lays on the document 34 a transparent or semitransparent marking sheet 110 for specifying a region of the document 34 to extract image fragments. Then, he or she writes a solid border line 112 on the marking sheet 110 which demarkates a desired region, i. e., alphabets "A", "B" and "C" of the document 34 by using a felt pen or the like. Thereupon, the operator manipulates an operation board 16b of the operating section 16 which is shown in Fig. 9 to set up an extract mode.

Specifically, the operator presses an extract mode key 116 for extracting all the image fragments which are surrounded by the border line 12, the extract mode being indicated by the turn-on of a light emitting diode (LED) 116. Alternatively, a delete mode key 18 on the operation board 16b may be pressed to select a delete mode in which all the image fragments in the demarkated region will be deleted, the delete mode being indicated by the turn-on of a LED 118a. A key 120 for selecting a juxtapose mode which will be described is provided on the operation board 16b in addition to the start key 92, stop key 94, display 96, and numeral keys 98. After the extract mode has been set up, the marking sheet 110 and the document 34 are sequentialy read in this order by the reading device 14 of Fig. 2 resulting in an image 34c being produced.

It is to be noted that any desired curve may be written on the marking sheet 11D as the border line 112, as shown in Fig.

10 by way of example.

As shown in Fig. 11, in this particular embodiment, a mimeograph is produced by, for example, extracting only the alphabets "A", "B" and "C" out of the various image fragments carried on a B5 document 34a by using a marking sheet 110a while, at the same time, extracting only the alphabets "d" and "e" out of the various image fragments carried on another B5 document 34b by using another marking sheet 110b, and producing the resulting images 34d and 34e in, respectively, a first part 64b and a second part 64c of a single B5 stencil 64.

All these operations are performed automatically. Specifically, the documents and the marking sheets are laid one upon another as shown in Fig. 12, and then they are loaded on the automatic document feeding section 12 with the surfaces of the documents 34a and 34b facing downward. Next, the juxtapose mode key 120 and the extract mode key 116 on the operation board 16b are sequentially pressed in this order to select a juxtapose mode and an extract mode, respectively.The operation board 1 6b may be provided with a key for selecting a blank or trim mode, a key associated with a mode for shading image fragments which lie in a marked area, a key associated with a mode for applying a graphic mode to the inside of a marked area and a text mode to the outside of the same, a key associated with a mode for trimming and extracting image fragments which lie in a marked area, a key associated with a mode for shading and extracting image fragments in a marked area, and others, in addition to the extract mode key 116 and delete mode key 118. If desired, such various modes may be stored in a memory or the like to eliminate those mode keys on the operation board 16b, in which case a desired mode will be selected via the numeral keys 98 and indicated by the display 96.

When the LED 116a is turned on indicating that the extract mode has been selected, the start key 92 is pressed so that the marking sheet liOa at the bottom of the stack is fed by the automatic document feeding section 12 to the reading section 14.

As the image sensor 58 reads the border line 112 written on the marking sheet 11 ova, its output is delivered to the controlling section 22. Next, the document 34a is fed by the section 12 to the reading section 14 and read by the image sensor 58 the output of which is fed to the controlling section 22. In response, the section 22 produces a signal which is representative of the image 34d as shown in Fig. 11, such a signal being routed to the thermal head 60 of the mimeograph making section 18. The thermal head 60 cuts the first part 64b of the mimeograph making area 64a of the stencil 64 to produce the image 34d therein. After the first part 64b of the stencil 64 has been completed by the above procedure, all the drive systems are once deactivated to allow an image process mode for cutting the second part 64c to be set up.Then, the extract mode key 116 on the operation board 16b is pressed again to select the extract mode. As the start key 92 is depressed, the marking sheet 110b and the document 34b are sequentially read by the image sensor 58 in the same manner as the marking sheet 110a and document 34a while, at the same time, the output signals of the image sensor 58 are processed. Thereupon, the controller 22 delivers a signal representative of the image 34e as shown in Fig. 11 to the thermal head 60, causing the latter to cut the second part 64c of the stencil 64.

As described above, only a desired region of each of the two documents 34a and 34b may be extracted and produced side by side on the single stencil 64. The resulting stencil or mimeograph 64 is wrapped around the print drum 72 to print the images on a paper sheet, as stated earlier.

Fig. 13 shows shows a specific construction of the controlling section 22 of this particular embodiment. The marking sheet 110a and the document 34a are sequentially read in this order by the reading section 14, as previously stated.

The marking sheet 11 0a is illuminated by light which issues from the lamp 52 and, therefore, read together with the border line 112 by the image sensor 58 by way of the mirror 54 and lens unit 56. The output of the image sensor 58 is fed to a binarizer 122 to be thereby converted into bilevel pixel data having density of sixteen dots per millimeter in both the main and sub scanning directions, i. e. pixel data of sixteen dots per millimeter. The sixteen dots per millimeter, bilevel pixel data are applied to a memory 124 and an image processing circuit, or image processor, 126. A controller 48 is adapted to control the entire printer and constituted by a CPU 128, a ROM, a RAM, an input/output interface, and others. A density conversion timing circuit 130 delivers read/write commands and address signals to the memory 124 in response to instructions which are generated by the controller 128. The bilevel data sequentially fed from the binarizer 122 to the memory 124 are thinned at a rate of seven out of eight, resulting that they are transformed into pixel data the density of which is as low as two dots per millimeter.

In Fig. 14, there is shown how the bilevel image data are written in the memory 124. An area indicated by hatching in the figure is representative of a size in which the border line 112 which would be written if the sixteen dots per millimeter, bilevel pixel data from the binarizer 124 were not thinned. On the other hand, an area B is representative a size in which the border line 112 is produced when the sixteen dots per millimeter pixel data are thinned at the rate of seven out of eight into two dots per millimeter pixel data, as previously stated.

Specifically, the density conversion timing circuit 130 extracts only one pixel out of each eight pixels of the hatched area A in both the column and row address directions. The pixel data extracted so, ie., two dots per millimeter pixel data are represented by solid dots b in Fig. 14. These pixel data b only are written in the memory 124 in a small configuration, as indicated by the area B. This reduces the memory capacity required to 1/64, compared to the sixteen dots per millimeter pixel data without thinning. This is because the thinning processing is effected in both the main and sub scanning directions, i. e. 1/8 x 1/8 = 1/64.Since the pixel data undergone thinning are not coded at all, the shape of data written in the memory 124 as represented by B appears analogous to that of original sixteen dots per millimeter Pixel data as represented by A, meaning a reduction of the image to 1/8.

Referring again to Fig. 13, an inside/outside decision circuit 132 applies decision processing to the pixel data which are written in the memory 124 as stated above. The decision processing implies filling the entire region which is marked by the line 112 with the same data as that of the line 112, i. e. logical ONE. More specifically, as shown in Fig. 15, in the raster data constituted by the pixel data of line 112 as represented by ONEs and those of the region inside of the line 112 as represented by ZEROs, ZEROs are changed to ONEs by the decision processing.

For such decision processing, among those pixels of a surrounding pixel matrix shown in Fig. 16, pixels A, B, C, D, F, G, H and I which surround a particular pixel E to be processed are used. For example, the particular pixel represented by E is discriminated by using an equation E = E + (C + F) x (D + G), in which the symbols +" and çx" are representative of ORing and ANDing, respectively. Details of the decision processing will be described in detail later.

After the marking sheet 110a, the document 34a is read by the reading section 14. The output of the image sensor 58 is fed to the binarizer 122 to be thereby converted into sixteen dots per millimeter pixel data. Simultaneously, in response to a command from the density conversion timing signal circuit 130, the two dots per millimeter data previously written in the memory 124 and representative of the line 112 and the region inside of the line 112 are read out timed such that they coincide with the sixteen dots per millimeter pixel data which are representative of the document 34a. Specifically, the same data are repeatedly read out eight consecutive times in the main scanning direction and, likewise, the same data are read eight consecutive times in the subscanning direction.The data associated with the sheet 110a as read out of the memory 124 and the data associated with the document 34a as fed from the binarizer 122 are routed to the image processor 126. The image processor 126 extracts that region of the document 34a which is defined by the line 112 that is written on the sheet 110a. The resulting image data are delivered to the thermal head 60 of the mimeograph making section 18.

Hereinafter will be described specific constructions of the memory 124, density conversion timing circuit 130, inside/outside decision circuit 132, and image processor 126. It is to be noted that the other structural elements can be implemented with those which per se are known in the art and, therefore, will not be described for the sake of simplicity.

Fig. 17 shows a combined specific construction of the density conversion timing circuit 130 and memory 124 while Fig. 18 shows various signals in a timing chart. As shown, the memory 124 is implemented with a so-called bit map memory in which pixels are associated with addresses in one-to-one correspondence. To write data associated with the marking sheet at at least B4 size at the density of two dots per millimeter, the memory 124 is sized 256 (millimeters) x 2 (dots per millimeter) = 512 (dots) in the column direction and 350 x 2 = 700 ( 1024 (dots) in the row direction, i. e. 512 (columns) x 1024 (rows).The density conversion timing circuit 130 is made up of four D flip-flops 502, 504, 506 and 508 which in combination constitute a first 1/8 frequency division network. four D flip-flops 510, 512, 514 and 516 constituting a second 1/8 frequency division network, a 9-bit column address counter 518, a 10-bit row address counter 520, and gates 522, 524, 526 and 528. Bilevel data DATA from the binarizer 122 are fed to the memory 124 clocked by synchronizing signals CK and LCK which are generated by the image sensor 58. While the synchronizing signal CK is outputted by the image sensor 58 for each pixel in the main scanning direction, the synchronizing signal LCK is outputted by the same on a line-by-line basis with respect to the subscanning direction. A clear signal CL and a write signal WR are fed from the controller 128.

First, the operation for writing pixel data in the memory 124 will be described. The synchronizing signal CK is applied to the four D flip-flops 502, 504, 506 and 508 so as to cause the flip-flops 502 and 504 to produce signals Q, and Q2, respectively. These signals Q, and Q2 are fed to the gate 522 which then produces AND, i. e. Q1 x Q2. As shown in Fig. 18, the signal Qi x Q2 remains high level only for the duration of one pixel out of eight consecutive pixels in the main scanning direction. At each positive-going edge of the signal Q, x Q2, the 9-bit column address counter 518 which is generating a column address is incremented (see wave-forms of signals Ao to A8 shown in Fig. 18).The column address counter 518 and four D flip-flops 502, 504, 506 and 508 are cleared by the synchronizing signal LCK so as to set up synchronization in the main scanning direction, the column address in the main scanning direction being incremented once for each eight pixels.

The synchronizing signal LCK, like the signal CK, is fed to the four D flip-flops 510, 512, 514 and 516 to cause the flip-flops 510 and 512 to produce signals QS and Q,, respectively. The signals Q5 and Q6 are ANDded by the gate 524 to become a signal Q5 X Q6- This output Q5 X Q6 of the gate 524 remains high level only for the duration of one line out of eight consecutive lines in the subscanning direction. At each positive-going edge of the signal Qs X Q, the 10-bit row address counter 520 which is generating a row address is incremented. Cleared by the clear signal CL, the row-address counter 520 and four D flip-flops 510, 512, 514 and 516 set up synchronization in the sub scanning direction, the row address being incremented once for each eight lines. The output Q1 x Q2 of the gate 522 and that Qs X Q6 & of the gate 524 are ANDded by the gate 526, the resulting AND being fed to the gate 528. Also applied to the gate 528 is the write signal WR which is outputted by the controller 48. The output WR of the gate 528 is delivered to the memory 44. When the signal WR is low level, the memory 124 stores bilevel pixel data DATA applied to its terminal DATA IN in a particular memory cell which is being accessed. When the signal WR is high level, the memory 44 outputs data from a particular memory cell being accessed via its terminal DATA OUT.In this manner, since the signal WR fed to the memory 124 causes the sigal Ql x Q2 which appears once for each eight pixels and the signal Q5 x Q6 which appears once for each eight lines to be ANDded, data are produced at a rate of one pixel per sixty-four (= 8 x 8) pixels and stored in the memory 124. The other data are not stored in the memory 124. Stated another way, the other data are thinned. Needless to mention, it is only when the controller 128 generates the write signal WR that data are written in the memory 124.

Image data stored in the memory 124 are read thereoutof in the same order as the document 34a is read by the image sensor 58 and written in the memory 124. Specifically, since data can be always read so long as the output WR of the gate 528 is high level, all that is required is sequentially incrementing the address. The column address counter 518 generating a column address is not changed throughout eight pixels of image data which are read out of the document 34a, so that data are read out of the memory 124 with the address unchanged. This is true with the row address also, i. e., the row address is unchanged throughout eight consecutive rows.

Referring to Fig. 19, a specific construction of the inside/outside decision circuit 132 is shown. As shown, the decision circuit 132 is constituted by D flip-flops 542, 544, 546, 548, 550, 552, 554, 556 and 558 which are arranged in association with the surrounding pixel matrix of Fig. 16 in order to latch the surrounding pixels, FIFO (first-in-first-out) memories 560 and 562 adapted to lodge data of the immediately preceding line and those of the line occurred two lines before, and gates 564, 566, 568, and 570. The image data DATA are fed from the memory 124 to the flip-flop 558 and subjected to the processing which fills the line 112 and the whole region defined by the line 112, Fig. 15, with ONEs, the resulting data being delivered via the gate 570 to the memory 124.For details of the procedure for replacing ZEROs with ONEs in a particular area of an image memory as mentioned, a reference may be made to Japanese Laid-Open Patent Publication (Rokai) No.

62-58508.

The decision performed by the inside/outside decision circuit 132 as discussed above may be programed in any of three different flows which are shown in Figs. 20A to 20C. In Fig.

20A, the decision is effected at the same time as the image data associated with the marking sheet 110a are read out, i. e. , as the bilevel pixel data from the binarizer 122 are thinned by the density conversion timing circuit 130 to the density of two dots per millimeter, the result being written in the memory 124. In Fig. 20B, the thinned two dots per millimeter pixel data associated with the sheet 110a are directly written in the memory 124 and discriminated later when they are read out of the memory 124. In Fig. 20C, the thinned two dots per millimeter pixel data which are directly written in the memory are read out by raster-scanning the memory 124 when the data associated with the document 34a are read by the image sensor 58 and, then, discriminated, the result being written in the memory 124 again.

Alternatively, as shown in Fig. 21, the decision processing stated above may be executed by a CPU which is connected to the memory 124 for accessing it. In this case, the CPU will read a plurality of times those pixels which surround a pixel to be discriminated in the memory 124, store data of the surrounding pixels in a register which is built in the CPU, perform computation with those data, and write the result in a particular address of the memory 124. This corresponds to the flow of Fig. 20C.

Referring to Fig. 22, a specific construction of the image processor 126 is shown. As shown, the image processor 126 is comprised of two gates 462 and 464. The gate 462 is supplied with the data ONEs representative of the line 112 and the inside of the line 112, as shown in Fig. 15, from the memory 124 and an image data extract/erase signal from the controller 128, delivering an output thereof to the gate 464. The gate 464, on the other hand, is supplied with the bilevel pixel data from the binarizer 122 while feeding its output to the thermal head 60.

When the extract/erase signal from the controller 128 is low level, the output of the memory 124 is directly routed to the gate 464. Since the whole region delimited by the line 112 is a ONE, only those image data in the region of the document which is located outside of the region which is in register with the marked region are effective. Consequently, the region other than the marked region becomes all ZERO, i. e. blank. When the extract/erase signal from the controller 128 is high level, the region outside the marked region is all ONE so that only the image data outside of the marked region are effective, the marked region being all ZERO and, therefore, blank.

In the illustrative embodiment, extra processing may be added for preventing data which discriminae the desired region and the rest from each other from being omitted. For example, there may be added processing which causes even a single pixel out of eight pixels to be written in the memory 124 if it is a ONE. Further, the equation for determining the pixel E as previously stated may be modified as E = tE + (C + F) x (D + G)] x (A + B + C + D + E + F + G + H + I) to add antinoise processing. Specifically, by adding "x (A + B + C + D + E + F + G + H + I)" to the previously stated equation, it is possible to make E a ZERO even if it is a ONE, when all the surrounding pixels are a ZERO.

As described earlier, the bilevel pixel data are reduced in density from sixteen dots per millimeter to two dots per millimeter before written in the memory 124. Such a decrease in the amount of data contributes not only to a decrease in memory capacity required but also to rapid processing of the inside/outside decision circuit 132. Reading the document 34a at the density of sixteen dots per millimeter is satisfactory with regard to the quality of image reproduction and becoming popular as a standard. In this regard, even if the marking sheet 110a is read at the density of two dots per millimeter, it is needless to replace it with the usual density of sixteen dots per millimeter because the specified region is merely used to erase or etract an image which lies in that region and not reproduced as it is. Further, the density of two dots per millimeter suffices in practice considering the fact that the line 112 on the sheet 110a is written by hand by using the felt pen 114 or the like. A good experimental result was achieved by using a felt pen which was about 1. 0 to 1. 5 millimeters in line width.

While the construction and operation of the controlling section 110b has been described in relation to the document 34a and marking sheet 110a of Fig. 11, they hold true for the document 34b and marking sheet 110b also.

Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.

Claims (13)

1. A printer capable of producing a mimeograph on which images of a plurality of documents smaller in size than a thermosensitive stencil are provided side by side in a predetermined mimeograph making area of said stencil and in an intended direction of transport of said stencil, comprising: document feeding means for feeding said documents one at a time through an image reading station; reading means for reading an image printed on said document being fed; sensing means for producing an end-of-read signal by sensing a time when said image on said document has been fully read; a thermal head for perforating said stencil to form said image read; roller means rotatable to transport said stencil while pressing said stencil against said thermal head; setting means for setting a number of images to be produced side by side on said stencil while generating a set signal; and control means for controlling said document feeding means and said roller means after determining whether said mimeograph making area of said stencil is great enough to accommodate said number of images set in response to said set signal from said setting means, such that when said mimeograph making area is great enough to accommodate said number of images, said roller means is deactivated until said document fed and discharged by said document feeding means becomes ready to be again fed to said reading station while, when said mimeograph making area is not great enough to do so, said roller means is not deactivated.

2. A printer as claimed in claim 1, wherein said control means comprises a central processing unit (CPU) for controlling said entire printer by delivering a read and a make mimeograph command, a random access memory (ROM) connected to said CPU for storing said mimeograph making area which corresponds to one full mimeograph and storing a mimeograph making program, and a random access memory (RAM) connected to said CPU for deciding whether said mimeograph making area is great enough to accommodate said number of images set.

3. A printer as claimed in claim 2, further comprising an operation board operable for delivering commands for operating said entire printer and provided with a juxtapose mode key which is operable to set up a juxtapose mode in which said plurality of images are to be produced side by side on said stencil, said CPU being connected to said juxtapose mode key.

4. A printer as claimed in claim 1, further comprising drum means for supplying ink to said stencil which is fed by said roller means and perforated and wrapped around said drum means to thereby print out said images of said documents on a paper sheet, and separator means for separating said stencil after printing from said drum means to discharge said stencil.

5. A printer capable of producing a mimeograph on which images of a plurality of documents smaller in size than a thermosensitive stencil may be provided side by side in a predetermined mimeograph making area of said stencil and in an intended direction of transport of said stencil, and prior to reading said image of any of said documents reading a marking sheet which includes an indication for specifying a particular region of said image, storing data associated with said marking sheet in a memory, and processing in a preselected image processing mode said image of said document read after said marking sheet based on said particular region which is stored in said memory, said printer comprising:: document feeding means for feeding said document one at a time through an image reading station; reading means for reading said image printed on said document being fed; sensing means for producing an end-of-read signal by sensing a time when said image on said document has been fully read; a thermal head for perforating said stencil to form said image read; roller means rotatable to transport said stencil while pressing said stencil against said thermal head; setting means for setting a number of images which are to be produced side by side on said stencil while generating a set signal; image processing means for processing said image of said document in a preselected image processing mode by using said marking sheet; and control means for controlling said document feeding means and said roller means after determining whether said mimeograph making area of said stencil is great enough to accommodate said number of images set in response to said set signal from said setting means, such that when said mimeograph making area is great enough to accommodate said number of images, said roller means is deactivated until said document fed and discharged by said document feeding means becomes ready to be again fed to said reading station while, when said mimeograph making area is not great enough to do so, said roller means is not deactivated.

6. A printer as claimed in claim 5, wherein said image processing mode comprises an extract mode for extracting only image fragments which lie in said specified region, and a delete mode for deleting said image fragments.

7. A printer as claimed in claim 5, wherein said control means further controls said document feeding means such that, said document feeding means feeding first one of said documents a particular region of which has been specified by said marking sheet and to which predetermined image processing has been applied is deactivated in response to said end-of-read signal from said sensing means.

8. A printer as claimed in claim 5, wherein said control means comprises a central processing unit for controlling said entire printer by delivering a read and a make mimeograph command, a random access memory connected to said CPU for storing said mimeograph making area which corresponds to one full mimeograph and storing a mimeograph making program, and a random access memory connected to said CPU for deciding whether said mimeograph making area is great enough to accommodate said number of images set.

9. A printer as claimed in claim 8, further comprising an operation board operable for delivering commands for operating said entire printer and provided with a juxtapose mode key which is operable to set up a juxtapose mode in which said plurality of images are to be produced side by side on said stencil, said CPU being connected to said juxtapose mode key.

10. A printer as claimed in claim 9, wherein said operation board is provided with an image process mode key for selecting said image process mode.

11. A printer as claimed in claim 5, further comprising drum means for supplying ink to said stencil which is fed by said roller means and perforated and wrapped around said drum means to thereby print out said images of said documents on a paper sheet, and separator means for separating said stencil after printing from said drum means to discharge said stencil.

12. A printer as claimed in claim 5, wherein said image processing means comprises: binarizer means for reading said marking sheet and said document image to convert said sheet and document image into bilevel pixel data; density conversion means for converting density of said bilevel image data associated with an image of said marking sheet and controlling said memory such that said pixel data are written in said memory; inside/outside decision means for discriminating said pixel data stored in said memory with respect to inside/outside of said marked region and applying processing to said pixel data inside and outside of said marked region based on said predetermined editting mode; and image processor means for reading said pixel data associated with said marking sheet and stored in said memory and those associated with said document and outputted by said binarizer means while synchronizing said pixel data to each other, and applying image processing to said document in said predetermined editting mode.

13. A printer substantially as hereinbefore described, with reference to, and as illustrated by the accompanying drawings.